PKIԁBaBaThermal Engineering/ch1.ipynb{
"cells": [
{
"cell_type": "markdown",
"metadata": {},
"source": [
"# Chapter 1 : Fuels and Combustion"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Example 1.1 Page no : 15"
]
},
{
"cell_type": "code",
"execution_count": 1,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"Minimum mass of air per kg of coal is 11.45 kg\n"
]
}
],
"source": [
"\n",
"# Variables\n",
"C = 0.91;\t\t\t#Percentage composition of Carbon\n",
"H = 0.03;\t\t\t#Percentage composition of Hydrogen\n",
"O = 0.02;\t\t\t#Percentage composition of Oxygen\n",
"N = 0.008;\t\t\t#Percentage composition of Nitrogen\n",
"S = 0.008;\t\t\t#Percentage composition of Sulphur\n",
"\n",
"# Calculations\n",
"m = (11.5*C)+(34.5*(H-(O/8)))+(4.3*S);\t\t\t#Mass of air per kg of coal in kg\n",
"\n",
"# Results\n",
"print 'Minimum mass of air per kg of coal is %3.2f kg'%(m)\n"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Example 1.2 Page no : 16"
]
},
{
"cell_type": "code",
"execution_count": 2,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"Theoretical volume of air at N.T.P per kg fuel is 10.85 m**3)/kg of fuel\n"
]
}
],
"source": [
"\n",
"# Variables\n",
"C = 0.86;\t\t\t#Percentage composition of Carbon\n",
"H = 0.12;\t\t\t#Percentage composition of Hydrogen\n",
"O = 0.01;\t\t\t#Percentage composition of Oxygen\n",
"S = 0.01;\t\t\t#Percentage composition of Sulphur\n",
"v = 0.773;\t\t\t#Specific volume of air at N.T.P in (m**3)/kg\n",
"\n",
"# Calculations\n",
"m = (11.5*C)+(34.5*(H-(O/8)))+(4.3*S);\t\t\t#Theoretical mass of air per kg of coal in kg\n",
"vth = m*v;\t\t\t#Theoretical volume of air at N.T.P per kg fuel in (m**3)/kg of fuel\n",
"\n",
"# Results\n",
"print 'Theoretical volume of air at N.T.P per kg fuel is %3.2f m**3)/kg of fuel'%(vth)\n"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Example 1.3 Page no : 16"
]
},
{
"cell_type": "code",
"execution_count": 3,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"Minimum quantity of air required for complete combustion is 10.83 kg \n",
"Total mass of products of combustion is 11.792 kg\n"
]
}
],
"source": [
"\n",
"\n",
"# Variables\n",
"C = 0.78;\t\t\t#Percentage composition of Carbon\n",
"H = 0.06;\t\t\t#Percentage composition of Hydrogen\n",
"O = 0.078;\t\t\t#Percentage composition of Oxygen\n",
"N = 0.012;\t\t\t#Percentage composition of Nitrogen\n",
"S = 0.03;\t\t\t#Percentage composition of Sulphur\n",
"\n",
"# Calculations\n",
"m = (11.5*C)+(34.5*(H-(O/8)))+(4.3*S);\t\t\t#Minimum quantity of air required in kg\n",
"mt = ((11*C)/3)+(9*H)+(2*S)+(8.32+N);\t\t\t#Total mass of products of combustion in kg\n",
"\n",
"# Results\n",
"print 'Minimum quantity of air required for complete combustion is %3.2f kg \\\n",
"\\nTotal mass of products of combustion is %3.3f kg'%(m,mt)\n"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Example 1.4 Page no : 17"
]
},
{
"cell_type": "code",
"execution_count": 2,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"Mass of dry flue gases per kg of coal burnt is 19 kg\n"
]
}
],
"source": [
"\n",
"# Variables\n",
"C = 0.84;\t\t\t#Percentage composition of Carbon\n",
"H = 0.09;\t\t\t#Percentage composition of Hydrogen\n",
"CO2 = 0.0875;\t\t\t#Volumetric composition of CO2\n",
"CO = 0.0225;\t\t\t#Volumetric composition of CO\n",
"O2 = 0.08;\t\t\t#Volumetric composition of Oxygen\n",
"N2 = 0.81;\t\t\t#Volumetric composition of Nitrogen\n",
"M1 = 44.;\t\t\t#Molecular mass of CO2\n",
"M2 = 28.;\t\t\t#Molecular mass of CO\n",
"M3 = 32.;\t\t\t#Molecular mass of O2\n",
"M4 = 28.;\t\t\t#Molecular mass of N2\n",
"\n",
"# Calculations\n",
"c1 = CO2*M1;\t\t\t#Proportional mass of CO2\n",
"c2 = CO*M2;\t \t\t#Proportional mass of CO\n",
"c3 = O2*M3;\t\t \t#Proportional mass of O2\n",
"c4 = N2*M4;\t\t\t #Proportional mass of N2\n",
"c = c1+c2+c3+c4;\t\t\t#Total proportional mass of constituents\n",
"m1 = c1/c;\t\t \t#Mass of CO2 per kg of flue gas in kg\n",
"m2 = c2/c;\t\t \t#Mass of CO per kg of flue gas in kg\n",
"m3 = c3/c;\t\t \t#Mass of O2 per kg of flue gas in kg\n",
"m4 = c4/c;\t\t \t#Mass of N2 per kg of flue gas in kg\n",
"d1 = m1*100;\t\t\t#Mass analysis of CO2\n",
"d2 = m2*100;\t\t\t#Mass analysis of CO\n",
"d3 = m3*100;\t\t\t#Mass analysis of O2\n",
"d4 = m4*100;\t\t\t#Mass analysis of N2\n",
"m = ((3*m1)/11)+((3*m2)/7.);\t\t\t#Mass of carbon in kg\n",
"md = C/m;\t\t\t #Mass of dry flue gas in kg\n",
"\n",
"# Results\n",
"print 'Mass of dry flue gases per kg of coal burnt is %.f kg'%(md)\n",
"\n",
"# note : rounding off error"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Example 1.5 Page no : 17"
]
},
{
"cell_type": "code",
"execution_count": 5,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"Minimum air required to burn 1 kg of coal is 8.43 kg \n",
"Mass of air actually supplied per kg of coal is 11.521 kg \n",
"Amount of excess air supplied per kg of coal burnt is 3.090 kg\n"
]
}
],
"source": [
"\n",
"\n",
"# Variables\n",
"C = 0.624;\t\t\t#Percentage composition of Carbon\n",
"H = 0.042;\t\t\t#Percentage composition of Hydrogen\n",
"O = 0.045;\t\t\t#Percentage composition of Oxygen\n",
"CO2 = 0.13;\t\t\t#Volumetric composition of CO2\n",
"CO = 0.003;\t\t\t#Volumetric composition of CO\n",
"O2 = 0.06;\t\t\t#Volumetric composition of Oxygen\n",
"N2 = 0.807;\t\t\t#Volumetric composition of Nitrogen\n",
"M1 = 44;\t\t\t#Molecular mass of CO2\n",
"M2 = 28;\t\t\t#Molecular mass of CO\n",
"M3 = 32;\t\t\t#Molecular mass of O2\n",
"M4 = 28;\t\t\t#Molecular mass of N2\n",
"mw = 0.378;\t\t\t#Mass of H2O in kg\n",
"\n",
"# Calculations\n",
"m = (11.5*C)+(34.5*(H-(O/8)));\t\t\t#Minimum air required in kg\n",
"c1 = CO2*M1;\t\t\t#Proportional mass of CO2\n",
"c2 = CO*M2;\t\t\t#Proportional mass of CO\n",
"c3 = O2*M3;\t\t\t#Proportional mass of O2\n",
"c4 = N2*M4;\t\t\t#Proportional mass of N2\n",
"c = c1+c2+c3+c4;\t\t\t#Total proportional mass of constituents\n",
"m1 = c1/c;\t\t\t#Mass of CO2 per kg of flue gas in kg\n",
"m2 = c2/c;\t\t\t#Mass of CO per kg of flue gas in kg\n",
"m3 = c3/c;\t\t\t#Mass of O2 per kg of flue gas in kg\n",
"m4 = c4/c;\t\t\t#Mass of N2 per kg of flue gas in kg\n",
"d1 = m1*100;\t\t\t#Mass analysis of CO2\n",
"d2 = m2*100;\t\t\t#Mass analysis of CO\n",
"d3 = m3*100;\t\t\t#Mass analysis of O2\n",
"d4 = m4*100;\t\t\t#Mass analysis of N2\n",
"mC = ((3*m1)/11)+((3*m2)/7);\t\t\t#Mass of carbon in kg\n",
"md = C/mC;\t\t\t#Mass of dry flue gas in kg\n",
"mact = (md+mw)-(C+H+O);\t\t\t#Actual air supplied per kg of fuel in kg\n",
"me = mact-m;\t\t\t#Mass of excess air per kg of fuel in kg\n",
"\n",
"# Results\n",
"print 'Minimum air required to burn 1 kg of coal is %3.2f kg \\\n",
"\\nMass of air actually supplied per kg of coal is %3.3f kg \\\n",
"\\nAmount of excess air supplied per kg of coal burnt is %3.3f kg'%(m,mact,me)\n",
"#rounding-off errors"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Example 1.6 Page no : 19"
]
},
{
"cell_type": "code",
"execution_count": 6,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"Mass of air to be supplied is 9.92 kg \n",
"Mass of CO2 produced per kg of coal is 2.86 kg \n",
"Mass of H2O produced per kg of coal is 0.27 kg\n",
"Mass of SO2 produced per kg of coal is 0.02 kg \n",
"Mass of excess O2 produced per kg of coal is 0.69 kg \n",
"Mass of N2 produced per kg of coal is 9.90 kg \n"
]
}
],
"source": [
"\n",
"\n",
"# Variables\n",
"C = 0.78;\t\t\t#Percentage composition of Carbon\n",
"H = 0.03;\t\t\t#Percentage composition of Hydrogen\n",
"O = 0.03;\t\t\t#Percentage composition of Oxygen\n",
"S = 0.01;\t\t\t#Percentage composition of Sulphur\n",
"me = 0.3;\t\t\t#Mass of excess air supplied\n",
"\n",
"# Calculations\n",
"m = (11.5*C)+(34.5*(H-(O/8)))+(4.3*S);\t\t\t#Mass of air per kg of coal in kg\n",
"mec = me*m;\t\t\t#Excess air supplied per kg of coal in kg\n",
"mact = m+mec;\t\t\t#Actual mass of air supplied per kg of coal in kg\n",
"mCO2 = (11*C)/3;\t\t\t#Mass of CO2 produced per kg of coal in kg\n",
"mHw = 9*H;\t\t\t#Mass of H2O produced per kg of coal in kg\n",
"mSO2 = 2*S;\t\t\t#Mass of SO2 produced per kg of coal in kg\n",
"mO2 = 0.232*mec;\t\t\t#Mass of excess O2 produced per kg of coal in kg\n",
"mN2 = 0.768*mact;\t\t\t#Mass of N2 produced per kg of coal in kg\n",
"\n",
"# Results\n",
"print 'Mass of air to be supplied is %3.2f kg \\\n",
"\\nMass of CO2 produced per kg of coal is %3.2f kg \\\n",
"\\nMass of H2O produced per kg of coal is %3.2f kg\\\n",
"\\nMass of SO2 produced per kg of coal is %3.2f kg \\\n",
"\\nMass of excess O2 produced per kg of coal is %3.2f kg \\\n",
"\\nMass of N2 produced per kg of coal is %3.2f kg '%(m,mCO2,mHw,mSO2,mO2,mN2)\n"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Example 1.7 Page no : 20"
]
},
{
"cell_type": "code",
"execution_count": 3,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"Minimum mass of air required is 11.4 kg \n",
"Total mass of dry flue gases per kg of fuel is 17.93 kg \n",
"Percentage composition of CO2 by volume is 12.69 percent \n",
"Percentage composition of SO2 by volume is 0.048 percent \n",
"Percentage composition of O2 by volume is 7.2 percent \n",
"Percentage composition of N2 by volume is 80.08 percent\n"
]
}
],
"source": [
"\n",
"\n",
"# Variables\n",
"C = 0.9;\t\t\t#Percentage composition of Carbon\n",
"H = 0.033;\t\t\t#Percentage composition of Hydrogen\n",
"O = 0.03;\t\t\t#Percentage composition of Oxygen\n",
"N = 0.008;\t\t\t#Percentage composition of Nitrogen\n",
"S = 0.009;\t\t\t#Percentage composition of Sulphur\n",
"M1 = 44;\t\t\t#Molecular mass of CO2\n",
"M2 = 64;\t\t\t#Molecular mass of SO2\n",
"M3 = 32;\t\t\t#Molecular mass of O2\n",
"M4 = 28;\t\t\t#Molecular mass of N2\n",
"\n",
"# Calculations\n",
"m = (11.5*C)+(34.5*(H-(O/8)))+(4.3*S);\t\t\t#Minimum mass of air per kg of coal in kg\n",
"mCO2 = (11*C)/3;\t\t\t#Mass of CO2 produced per kg of coal in kg\n",
"mHw = 9*H;\t\t\t#Mass of H2O produced per kg of coal in kg\n",
"mSO2 = 2*S;\t\t\t#Mass of SO2 produced per kg of coal in kg\n",
"mt = 11.5*1.5;\t\t\t#Total mass of air supplied per kg of coal in kg\n",
"me = mt-m;\t\t\t#Excess air supplied in kg\n",
"mO2 = 0.232*me;\t\t\t#Mass of excess O2 produced per kg of coal in kg\n",
"mN2 = 0.768*mt;\t\t\t#Mass of N2 produced per kg of coal in kg\n",
"mtN2 = mN2+N;\t\t\t#Total mass of Nitrogen in exhaust in kg\n",
"md = mCO2+mSO2+mO2+mtN2;\t\t\t#Total mass of dry flue gases per kg of fuel in kg\n",
"CO2 = (mCO2/md)*100;\t\t\t#Percentage composition of CO2 by mass in percent\n",
"SO2 = (mSO2/md)*100;\t\t\t#Percentage composition of SO2 by mass in percent\n",
"O2 = (mO2/md)*100;\t\t\t#Percentage composition of O2 by mass in percent\n",
"N2 = (mN2/md)*100;\t\t\t#Percentage composition of N2 by mass in percent\n",
"c1 = CO2/M1;\t\t\t#Proportional volume of CO2\n",
"c2 = SO2/M2;\t\t\t#Proportional volume of SO2\n",
"c3 = O2/M3;\t\t\t#Proportional volume of O2\n",
"c4 = N2/M4;\t\t\t#Proportional volume of N2\n",
"c = c1+c2+c3+c4;\t\t\t#Total proportional volume of constituents\n",
"m1 = c1/c;\t\t\t#Volume of CO2 in 1 (m**3) of flue gas\n",
"m2 = c2/c;\t\t\t#Volume of SO2 in 1 (m**3) of flue gas\n",
"m3 = c3/c;\t\t\t#Volume of O2 in 1 (m**3) of flue gas\n",
"m4 = c4/c;\t\t\t#Volume of N2 in 1 (m**3) of flue gas\n",
"d1 = m1*100;\t\t\t#Volume analysis of CO2\n",
"d2 = m2*100;\t\t\t#Volume analysis of SO2\n",
"d3 = m3*100;\t\t\t#Volume analysis of O2\n",
"d4 = m4*100;\t\t\t#Volume analysis of N2\n",
"\n",
"# Results\n",
"print 'Minimum mass of air required is %3.1f kg \\\n",
"\\nTotal mass of dry flue gases per kg of fuel is %3.2f kg \\\n",
"\\nPercentage composition of CO2 by volume is %3.2f percent \\\n",
"\\nPercentage composition of SO2 by volume is %3.3f percent \\\n",
"\\nPercentage composition of O2 by volume is %3.1f percent \\\n",
"\\nPercentage composition of N2 by volume is %3.2f percent'%(m,md,d1,d2,d3,d4)\n",
"\n",
"# note : rounding off error"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Example 1.8 Page no : 21"
]
},
{
"cell_type": "code",
"execution_count": 5,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"Mass of air actually supplied per kg of coal is 18.20 kg \n",
"Percentage of excess air is 60 percent\n"
]
}
],
"source": [
"\n",
"\n",
"# Variables\n",
"C = 0.88;\t\t\t#Percentage composition of Carbon\n",
"H = 0.036;\t\t\t#Percentage composition of Hydrogen\n",
"O = 0.048;\t\t\t#Percentage composition of oxygen\n",
"CO2 = 0.109;\t\t\t#Volumetric composition of CO2\n",
"CO = 0.01;\t\t\t#Volumetric composition of CO\n",
"O2 = 0.071;\t\t\t#Volumetric composition of Oxygen\n",
"N2 = 0.81;\t\t\t#Volumetric composition of Nitrogen\n",
"M1 = 44.;\t\t\t#Molecular mass of CO2\n",
"M2 = 28.;\t\t\t#Molecular mass of CO\n",
"M3 = 32.;\t\t\t#Molecular mass of O2\n",
"M4 = 28.;\t\t\t#Molecular mass of N2\n",
"\n",
"# Calculations\n",
"m = (11.5*C)+(34.5*(H-(O/8)));\t\t\t#Theoretical air required in kg\n",
"c1 = CO2*M1;\t\t\t#Proportional mass of CO2\n",
"c2 = CO*M2;\t\t\t#Proportional mass of CO\n",
"c3 = O2*M3;\t\t\t#Proportional mass of O2\n",
"c4 = N2*M4;\t\t\t#Proportional mass of N2\n",
"c = c1+c2+c3+c4;\t\t\t#Total proportional mass of constituents\n",
"m1 = c1/c;\t\t\t#Mass of CO2 per kg of flue gas in kg\n",
"m2 = c2/c;\t\t\t#Mass of CO per kg of flue gas in kg\n",
"m3 = c3/c;\t\t\t#Mass of O2 per kg of flue gas in kg\n",
"m4 = c4/c;\t\t\t#Mass of N2 per kg of flue gas in kg\n",
"mC = ((3*m1)/11)+((3*m2)/7);\t\t\t#Mass of carbon in kg\n",
"md = C/mC;\t\t\t#Mass of dry flue gas in kg\n",
"hc = H*9;\t\t\t#Hydrogen combustion in kg of H2O\n",
"mair = (md+hc)-(C+H+O);\t\t\t#Mass of air supplied per kg of coal in kg\n",
"me = mair-m;\t\t\t#Excess air per kg of coal in kg\n",
"mN2 = m4*md;\t\t\t#Mass of nitrogen per kg of coal in kg\n",
"mact = mN2/0.768;\t\t\t#Actual mass of air per kg of coal in kg\n",
"pe = (me/m)*100;\t\t\t#Perccentage excess air in percent\n",
"\n",
"# Results\n",
"print 'Mass of air actually supplied per kg of coal is %3.2f kg \\\n",
"\\nPercentage of excess air is %.f percent'%(mact,pe)\n",
"\n",
"# note : rounding off error"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Example 1.9 Page no : 22"
]
},
{
"cell_type": "code",
"execution_count": 1,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"Mass of excess air supplied per kg of fuel burnt is 6.0 kg/kg of fuel \n",
"Air-fuel ratio is 20.7:1\n"
]
}
],
"source": [
"\n",
"\n",
"# Variables\n",
"C = 0.84;\t\t\t#Percentage composition of Carbon\n",
"H = 0.14;\t\t\t#Percentage composition of Hydrogen\n",
"O = 0.02;\t\t\t#Percentage composition of oxygen\n",
"CO2 = 8.85;\t\t\t#Volumetric composition of CO2\n",
"CO = 1.2;\t\t\t#Volumetric composition of CO\n",
"O2 = 6.8;\t\t\t#Volumetric composition of Oxygen\n",
"N2 = 83.15;\t\t\t#Volumetric composition of Nitrogen\n",
"M1 = 44.;\t\t\t#Molecular mass of CO2\n",
"M2 = 28.;\t\t\t#Molecular mass of CO\n",
"M3 = 32.;\t\t\t#Molecular mass of O2\n",
"M4 = 28.;\t\t\t#Molecular mass of N2\n",
"a = 8/3.;\t\t\t#O2 required per kg C\n",
"b = 8.; \t\t\t#O2 required per kg H2\n",
"mair = 0.23;\t\t\t#Mass of air\n",
"\n",
"# Calculations\n",
"c = C*a;\t\t\t#O2 required per kg of fuel for C\n",
"d = H*b;\t\t\t#O2 required per kg of fuel for H2\n",
"tO2 = c+d+O;\t\t\t#Theoreticcal O2 required in kg/kg of fuel\n",
"tm = tO2/mair;\t\t\t#Theoretical mass of air in kg/kg of fuel\n",
"c1 = CO2*M1;\t\t\t#Proportional mass of CO2 by Volume\n",
"c2 = CO*M2;\t\t\t#Proportional mass of CO by Volume\n",
"c3 = O2*M3;\t\t\t#Proportional mass of O2 by Volume\n",
"c4 = N2*M4;\t\t\t#Proportional mass of N2 by Volume\n",
"c = c1+c2+c3+c4;\t\t\t#Total proportional mass of constituents\n",
"m1 = c1/c;\t\t\t#Mass of CO2 per kg of flue gas in kg\n",
"m2 = c2/c;\t\t\t#Mass of CO per kg of flue gas in kg\n",
"m3 = c3/c;\t\t\t#Mass of O2 per kg of flue gas in kg\n",
"m4 = c4/c;\t\t\t#Mass of N2 per kg of flue gas in kg\n",
"mC = ((m1*12)/M1)+((m2*12)/M2);\t\t\t#Mass of carbon per kg of dry flue gas in kg\n",
"md = C/mC;\t\t\t#Mass of dry flue per kg of fuel in kg\n",
"p = (4*m2)/7;\t\t\t#Oxygen required to burn CO in kg\n",
"meO2 = md*(m3-p);\t\t\t#Mass of excess O2 per kg of fuel in kg\n",
"me = meO2/mair;\t\t\t#Mass of excess air in kg/kg fuel\n",
"mt = tm+me;\t\t\t#Total air required per kg fuel\n",
"\n",
"# Results\n",
"print 'Mass of excess air supplied per kg of fuel burnt is %3.1f kg/kg of fuel \\\n",
"\\nAir-fuel ratio is %3.1f:1'%(me,mt)\n",
"\n",
"# rounding off error"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Example 1.10 Page no : 23"
]
},
{
"cell_type": "code",
"execution_count": 10,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"Volume of air required for complete combustion is 1.178 m**3)\n"
]
}
],
"source": [
"\n",
"# Variables\n",
"H2 = 0.27;\t\t\t#Percentage composition of H2 by volume\n",
"CO2 = 0.18;\t\t\t#Percentage composition of CO2 by volume\n",
"CO = 0.125;\t\t\t#Percentage composition of CO by volume\n",
"CH4 = 0.025;\t\t\t#Percentage composition of CH4 by volume\n",
"N2 = 0.4;\t\t\t#Percentage composition of N2 by volume\n",
"\n",
"# Calculations\n",
"v = (2.38*(H2+CO))+(9.52*CH4);\t\t\t#Volume of air required for complete combustion in (m**3)\n",
"\n",
"# Results\n",
"print 'Volume of air required for complete combustion is %3.3f m**3)'%(v)\n"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Example 1.11 Page no : 24"
]
},
{
"cell_type": "code",
"execution_count": 3,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"Air-fuel ratio by volume is 5.055\n"
]
}
],
"source": [
"\n",
"# Variables\n",
"H2 = 0.5;\t\t\t#Percentage composition of H2 by volume\n",
"CO2 = 0.1;\t\t\t#Percentage composition of CO2 by volume\n",
"CO = 0.05;\t\t\t#Percentage composition of CO by volume\n",
"CH4 = 0.25;\t\t\t#Percentage composition of CH4 by volume\n",
"N2 = 0.1;\t\t\t#Percentage composition of N2 by volume\n",
"pCO2 = 8;\t\t\t#Percentage volumetric analysis of CO2\n",
"pO2 = 6;\t\t\t#Percentage volumetric analysis of O2\n",
"pN2 = 86;\t\t\t#Percentage volumetric analysis of N2\n",
"\n",
"\n",
"# Calculations\n",
"v = (2.38*(H2+CO))+(9.52*CH4);\t\t\t#Volume of air required for complete combustion in (m**3)\n",
"vN2 = v*0.79;\t\t\t#Volume of nitrogen in the air in m**3\n",
"a = CO+CH4+CO2;\t\t\t#CO2 formed per m**3 of fuel gas burnt\n",
"b = vN2+N2;\t\t\t#N2 formed per m**3 of fuel gas burnt\n",
"vt = a+b;\t\t\t#Total volume of dry flue gas formed in m**3\n",
"ve = (pO2*vt)/(21-pO2);\t\t\t#Excess air supplied in m**3\n",
"V = v+ve;\t\t\t#Total quantity of air supplied in m**3\n",
"afr = V/1\n",
"\n",
"# Results\n",
"print 'Air-fuel ratio by volume is %3.3f'%(afr)\n"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Example 1.12 Page no : 24"
]
},
{
"cell_type": "code",
"execution_count": 12,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"Volume of air required for complete combustion is 0.952 m**3) \n",
"Volume of CO2 per m**3 of gas fuel is 0.29 m**3/m**3 of gas fuel \n",
"Volume of N2 per m**3 of gas fuel is 1.603 m**3/m**3 of gas fuel \n",
"Volume of excess O2 per m**3 of gas fuel is 0.08 m**3/m**3 of gas fuel \n",
"Total volume of dry combustion products is 1.973 m**3/m**3 of gas fuel \n",
"Percentage volume of CO2 is 14.7 percent \n",
"Percentage volume of N2 is 81.25 percent \n",
"Percentage volume of O2 is 4.05 percent\n"
]
}
],
"source": [
"\n",
"# Variables\n",
"H2 = 0.14;\t\t\t#Percentage composition of H2 by volume\n",
"CO2 = 0.05;\t\t\t#Percentage composition of CO2 by volume\n",
"CO = 0.22;\t\t\t#Percentage composition of CO by volume\n",
"CH4 = 0.02;\t\t\t#Percentage composition of CH4 by volume\n",
"O2 = 0.02;\t\t\t#Percentage composition of O2 by volume\n",
"N2 = 0.55;\t\t\t#Percentage composition of N2 by volume\n",
"e = 0.4;\t\t\t#Excess air supplied\n",
"# Calculations\n",
"v = (2.38*(H2+CO))+(9.52*CH4)-(4.76*O2);\t\t\t#Volume of air required for complete combustion in (m**3)\n",
"ve = v*e;\t\t\t#Volume of excess air supplied in m**3\n",
"vtN2 = v-(v*0.21);\t\t\t#Volume of N2 in theoretical air in m**3\n",
"veN2 = ve-(ve*0.21);\t\t\t#Volume of N2 in excess air in m**3\n",
"vt = vtN2+veN2;\t\t\t#Total volume of N2 in air supplied in m**3\n",
"vCO2 = CO+CH4+CO2;\t\t\t#CO2 formed per m**3 of fuel gas\n",
"vN2 = vt+N2;\t\t\t#N2 formed per m**3 of fuel gas\n",
"veO2 = ve*0.21;\t\t\t#Volume of excess O2 per m**3 of fuel gas\n",
"vT = vCO2+vN2+veO2;\t\t\t#Total volume of dry combustion products\n",
"pCO2 = (vCO2*100)/vT;\t\t\t#Percentage volume of CO2\n",
"pN2 = (vN2*100)/vT;\t\t\t#Percentage volume of N2\n",
"pO2 = (veO2*100)/vT;\t\t\t#Percentage volume of O2\n",
"\n",
"# Results\n",
"print 'Volume of air required for complete combustion is %3.3f m**3) \\\n",
"\\nVolume of CO2 per m**3 of gas fuel is %3.2f m**3/m**3 of gas fuel \\\n",
"\\nVolume of N2 per m**3 of gas fuel is %3.3f m**3/m**3 of gas fuel \\\n",
"\\nVolume of excess O2 per m**3 of gas fuel is %3.2f m**3/m**3 of gas fuel \\\n",
"\\nTotal volume of dry combustion products is %3.3f m**3/m**3 of gas fuel \\\n",
"\\nPercentage volume of CO2 is %3.1f percent \\\n",
"\\nPercentage volume of N2 is %3.2f percent \\\n",
"\\nPercentage volume of O2 is %3.2f percent'%(v,vCO2,vN2,veO2,vT,pCO2,pN2,pO2)\n"
]
}
],
"metadata": {
"kernelspec": {
"display_name": "Python 2",
"language": "python",
"name": "python2"
},
"language_info": {
"codemirror_mode": {
"name": "ipython",
"version": 2
},
"file_extension": ".py",
"mimetype": "text/x-python",
"name": "python",
"nbconvert_exporter": "python",
"pygments_lexer": "ipython2",
"version": "2.7.6"
}
},
"nbformat": 4,
"nbformat_minor": 0
}
PKIaĽ̌Thermal Engineering/ch2.ipynb{
"cells": [
{
"cell_type": "markdown",
"metadata": {},
"source": [
"# Chapter 2 : Gas Power Cycles"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Example 2.1 Page no : 55"
]
},
{
"cell_type": "code",
"execution_count": 1,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"Maximum pressure of the cycle is 9.434 MPa \n",
"Maximum temperature of the cycle is 3632 K \n",
"Cycle efficiency is 56.4 percent \n",
"Mean effective pressure is 1.533 MPa\n"
]
}
],
"source": [
"\n",
"# Variables\n",
"P1 = 0.1;\t\t\t#Pressure of air supplied in MPa\n",
"T1 = 308;\t\t\t#Temperature of air supplied in K\n",
"rv = 8;\t\t\t#Compression ratio\n",
"q1 = 2100;\t\t\t#Heat supplied in kJ/kg\n",
"Cp = 1.005;\t\t\t#Specific heat at constant pressure in kJ/kg-K\n",
"Cv = 0.718;\t\t\t#Specific heat at constant volume in kJ/kg-K\n",
"R = 0.287;\t\t\t#Universal gas constant in kJ/kg-K\n",
"\n",
"# Calculations\n",
"y = Cp/Cv;\t\t\t#Ratio of specific heats\n",
"n = (1-(1/(rv**(y-1))))*100;\t\t\t#Cycle efficiency\n",
"v1 = (R*T1)/(P1*1000);\t\t\t#Specific volume at point 1 in (m**3)/kg\n",
"v2 = v1/rv;\t\t\t#Specific volume at point 2 in (m**3)/kg\n",
"T2 = T1*(rv**(y-1));\t\t\t#Temperature at point 2 in K\n",
"T3 = (q1/Cv)+T2;\t\t\t#Temperature at point 3 in K\n",
"P2 = P1*(rv**y);\t\t\t#Pressure at point 2 in MPa\n",
"P3 = P2*(T3/T2);\t\t\t#Pressure at point 3 in MPa\n",
"wnet = (q1*n)/100;\t\t\t#Net workdone in J/kg\n",
"MEP = (wnet/(v1-v2))/1000;\t\t\t#Mean effective pressure in MPa\n",
"\n",
"# Results\n",
"print 'Maximum pressure of the cycle is %3.3f MPa \\\n",
"\\nMaximum temperature of the cycle is %3.0f K \\\n",
"\\nCycle efficiency is %3.1f percent \\\n",
"\\nMean effective pressure is %3.3f MPa'%(P3,T3,n,MEP)\n"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Example 2.2 Page no : 57"
]
},
{
"cell_type": "code",
"execution_count": 2,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"Relative efficiency of the engine is 38.8 percent\n"
]
}
],
"source": [
"\n",
"# Variables\n",
"d = 80;\t\t\t#Bore in mm\n",
"L = 85;\t\t\t#Stroke in mm\n",
"Vc = 0.06;\t\t\t#Clearance volume in litre\n",
"n = 0.22;\t\t\t#Actual thermal efficiency\n",
"y = 1.4;\t\t\t#Ratio of specific heats\n",
"\n",
"# Calculations\n",
"Vs = (3.147/4)*(d**2)*L;\t\t\t#Stroke volume in mm**3\n",
"Vt = Vs+(Vc*(10**6));\t\t\t#Total volume in mm**3\n",
"rv = Vt/(Vc*(10**6));\t\t\t#Compression ratio\n",
"ni = (1-(1/(rv**(y-1))));\t\t\t#Ideal thermal efficiency\n",
"nr = (n/ni)*100;\t\t\t#Relative efficiency\n",
"\n",
"# Results\n",
"print 'Relative efficiency of the engine is %3.1f percent'%(nr)\n"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Example 2.3 Page no : 57"
]
},
{
"cell_type": "code",
"execution_count": 3,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"Clearance volume is 14.6 percent of swept volume \n",
"Otto cycle efficiency is 56.15 percent\n"
]
}
],
"source": [
"\n",
"\n",
"# Variables\n",
"d = 0.137;\t\t\t#Bore in m\n",
"L = 0.13;\t\t\t#Stroke in m\n",
"Vc = 280*(10**-6);\t\t\t#Clearance volume in m**3\n",
"y = 1.4;\t\t\t#Ratio of specific heats\n",
"\n",
"# Calculations\n",
"Vs = (3.147/4)*(d**2)*L;\t\t\t#Stroke volume in m**3\n",
"rv = (Vc/Vs)*100;\t\t\t#Compression ratio\n",
"rvf = (Vs+Vc)/Vc;\t\t\t#final compression ratio\n",
"n = (1-(1/rvf**(y-1)))*100;\t\t\t#Cycle efficiency\n",
"\n",
"# Results\n",
"print 'Clearance volume is %3.1f percent of swept volume \\\n",
"\\nOtto cycle efficiency is %3.2f percent'%(rv,n)\n"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Example 2.4 Page no : 58"
]
},
{
"cell_type": "code",
"execution_count": 1,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"Maximum pressure of the cycle is 6449.19 kPa \n",
"Maximum temperature of the cycle is 1968.7 K \n",
"Amount of heat transferred is 0.65 kJ \n",
"Thermal efficiency is 59.4 percent \n",
"Mean effective pressure is 718.3 kPa\n"
]
}
],
"source": [
"\n",
"# Variables\n",
"rv = 9.5;\t\t\t#Compression ratio\n",
"P1 = 100.;\t\t\t#Air pressure in kPa\n",
"T1 = 290.;\t\t\t#Air temperature in K\n",
"V1 = 600.*(10**-6);\t\t\t#Volume of air in m**3\n",
"T4 = 800.;\t\t\t#Final temperature in K\n",
"R = 287.;\t\t\t#Universal gas constant in J/kg.K\n",
"Cv = 0.718;\t\t\t#Specific heat at constant volume in kJ/kg.K\n",
"y = 1.4;\t\t\t#Ratio of specific heats\n",
"\n",
"# Calculations\n",
"T3 = T4*(rv**(y-1));\t\t\t#Temperature at the end of constant volume heat addition in K\n",
"P2 = P1*(rv**y);\t\t\t#Pressure at point 2 in kPa\n",
"T2 = T1*(rv**(y-1));\t\t\t#Temperature at point 2 in K\n",
"P3 = P2*(T3/T2);\t\t\t#Pressure at point 3 in kPa\n",
"m = (P1*1000*V1)/(R*T1);\t\t\t#Specific mass in kg/s\n",
"Q = m*Cv*(T3-T2);\t\t\t#Heat transferred in kJ\n",
"n = (1-(1/rv**(y-1)))*100;\t\t\t#Thermal efficiency\n",
"Wnet = (n*Q)/100;\t\t\t#Net workdone in kJ\n",
"MEP = Wnet/(V1*(1-(1/rv)));\t\t\t#Mean effective pressure in kPa\n",
"\n",
"# Results\n",
"print 'Maximum pressure of the cycle is %3.2f kPa \\\n",
"\\nMaximum temperature of the cycle is %3.1f K \\\n",
"\\nAmount of heat transferred is %3.2f kJ \\\n",
"\\nThermal efficiency is %3.1f percent \\\n",
"\\nMean effective pressure is %3.1f kPa'%(P3,T3,Q,n,MEP)\n",
"\n",
"# rounding off error"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Example 2.5 Page no : 60"
]
},
{
"cell_type": "code",
"execution_count": 5,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"Pressure at the end of heat addition process is 4392.3 kPa\n",
"Temperature at the end of heat addition process is 1733.8 K\n",
"Net work output is 423.54 kJ/kg\n",
"Thermal efficiency is 56.47 percent\n",
"Mean effective pressure is 534 kPa\n"
]
}
],
"source": [
"\n",
"\n",
"# Variables\n",
"rv = 8.;\t\t\t#Compression ratio\n",
"P1 = 95.;\t\t\t#Pressure at point 1 in kPa\n",
"T1 = 300.;\t\t\t#Temperature at point 1 in K\n",
"q23 = 750.;\t\t\t#Heat transferred during consmath.tant volume heat addition process in kJ/kg\n",
"y = 1.4;\t\t\t#Ratio of specific heats\n",
"Cv = 0.718;\t\t\t#Specific heat at constant volume in kJ/kg-K\n",
"R = 287.;\t\t\t#Universal gas constant in J/kg-K\n",
"\n",
"# Calculations\n",
"T2 = T1*(rv**(y-1));\t\t\t#Temperature at point 2 in K\n",
"P2 = P1*(rv**y);\t\t\t#Pressure at point 2 in kPa\n",
"T3 = (q23/Cv)+T2;\t\t\t#Temperature at point 3 in K\n",
"P3 = P2*(T3/T2);\t\t\t#Pressure at point 3 in kPa\n",
"nth = (1-(1/(rv**(y-1))))*100;\t\t\t#Thermal efficiency\n",
"Wnet = (nth*q23)/100;\t\t\t#Net work output in kJ/kg\n",
"v1 = (R*T1)/(P1*1000);\t\t\t#Speific volume at point 1 in (m**3)/kg\n",
"MEP = Wnet/(v1*(1-(1/rv)));\t\t\t#Mean effective pressure in kPa\n",
"\n",
"# Results\n",
"print 'Pressure at the end of heat addition process is %3.1f kPa'%P3\n",
"print 'Temperature at the end of heat addition process is %3.1f K'%T3\n",
"print 'Net work output is %3.2f kJ/kg'%Wnet\n",
"print 'Thermal efficiency is %3.2f percent'%nth\n",
"print 'Mean effective pressure is %3.0f kPa'%MEP\n"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Example 2.6 Page no : 61"
]
},
{
"cell_type": "code",
"execution_count": 6,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"Air standard efficiency is 60.4 percent\n"
]
}
],
"source": [
"\n",
"# Variables\n",
"rv = 14.;\t\t\t#Compression ratio\n",
"c = 0.06;\t\t\t#Cut-off percentage\n",
"y = 1.4;\t\t\t#Ratio of specific heats\n",
"\n",
"# Calculations\n",
"rc = 1.78;\t\t\t#Cut-off ratio\n",
"nth = (1-(((rc**y)-1)/((rv**(y-1))*y*(rc-1))))*100;\t\t\t#Thermal efficiency\n",
"\n",
"# Results\n",
"print 'Air standard efficiency is %3.1f percent'%(nth)\n"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Example 2.7 Page no : 62"
]
},
{
"cell_type": "code",
"execution_count": 8,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"Cut-off ratio is 2.01 \n",
"Heat supplied is 884.4 kJ/kg\n",
"Cycle efficiency is 61.3 percent \n",
"Mean effective pressure is 699.35 kPa\n"
]
}
],
"source": [
"\n",
"\n",
"# Variables\n",
"rv = 16.;\t\t\t#Compression ratio\n",
"P1 = 0.1;\t\t\t#Pressure at point 1 in MPa\n",
"T1 = 288.;\t\t\t#Temperature at point 1 in K\n",
"T3 = 1753.;\t\t\t#Temperature at point 3 in K\n",
"y = 1.4;\t\t\t#Ratio of specific heats\n",
"Cp = 1.005;\t\t\t#Specific heat at constant pressure in kJ/kg-K\n",
"R = 0.287;\t\t\t#Universal gas constant in kJ/kg-K\n",
"\n",
"# Calculations\n",
"T2 = int(T1*(rv**(y-1)));\t\t\t#Temperature at point 2 in K\n",
"rc = round(T3/T2,2);\t\t\t#Cut-off ratio\n",
"q1 = Cp*(T3-T2);\t\t\t#Heat supplied in kJ/kg\n",
"nth = (1-(((rc**y)-1)/((rv**(y-1))*y*(rc-1))))*100;\t\t\t#Cycle efficiency\n",
"wnet = int((q1*nth)/100);\t\t\t#Net work done in kJ/kg\n",
"v1 = round((R*T1)/(P1*1000),3);\t\t\t#Speific volume at point 1 in (m**3)/kg\n",
"v2 = round(v1/rv,3);\t\t\t#Speific volume at point 2 in (m**3)/kg\n",
"MEP = wnet/(v1-v2);\t\t\t#Mean effective pressure in kPa\n",
"\n",
"# Results\n",
"print 'Cut-off ratio is %3.2f \\\n",
"\\nHeat supplied is %3.1f kJ/kg\\\n",
"\\nCycle efficiency is %3.1f percent \\\n",
"\\nMean effective pressure is %3.2f kPa'%(rc,q1,nth,MEP)\n",
"\n",
"# rounding off error"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Example 2.8 Page no : 64"
]
},
{
"cell_type": "code",
"execution_count": 8,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"Air standard efficiency at 5 percent cut-off is 59.36 percent\n",
"Air standard efficiency at 8 percent cut-off is 57.40 percent\n",
"Percentage loss in efficiency is 1.95 percent\n"
]
}
],
"source": [
"\n",
"\n",
"# Variables\n",
"d = 0.15;\t\t\t#Bore in m\n",
"L = 0.25;\t\t\t#Stroke in m\n",
"Vc = 400*(10**-6);\t\t\t#Clearance volume in m**3\n",
"V2 = Vc;\t\t\t#Clearance volume in m**3\n",
"c1 = 0.05;\t\t\t#Cut-off percentage 1\n",
"c2 = 0.08;\t\t\t#Cut-off percentage 2\n",
"y = 1.4;\t\t\t#Ratio of specific heats\n",
"\n",
"# Calculations\n",
"Vs = (3.147/4)*(d**2)*L;\t\t\t#Stroke volume in m**3\n",
"V31 = V2+(c1*Vs);\t\t\t#Volume at the point of cut-off in m**3\n",
"rc1 = V31/V2;\t\t\t#Cut-off ratio 1\n",
"rv = (Vc+Vs)/Vc;\t\t\t#Compression ratio\n",
"nth1 = (1-(((rc1**y)-1)/((rv**(y-1))*y*(rc1-1))))*100;\t\t\t#Air standard efficiency 1\n",
"V32 = V2+(c2*Vs);\t\t\t#Volume at the point of cut-off in m**3\n",
"rc2 = V32/V2;\t\t\t#Cut-off ratio 2\n",
"nth2 = (1-(((rc2**y)-1)/((rv**(y-1))*y*(rc2-1))))*100;\t\t\t#Air standard efficiency 2\n",
"pl = nth1-nth2;\t\t\t#Percentage loss in efficiency\n",
"\n",
"# Results\n",
"print 'Air standard efficiency at 5 percent cut-off is %3.2f percent\\\n",
"\\nAir standard efficiency at 8 percent cut-off is %3.2f percent\\\n",
"\\nPercentage loss in efficiency is %3.2f percent'%(nth1,nth2,pl)\n"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Example 2.9 Page no : 65"
]
},
{
"cell_type": "code",
"execution_count": 9,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"Maximum temperature attained during the cycle is 1595.4 oC \n",
"Thermal efficiency of the cycle is 60.3 percent\n"
]
}
],
"source": [
"\n",
"\n",
"# Variables\n",
"e = 7.5;\t\t\t#Expansion ratio\n",
"c = 15.;\t\t\t#Compression ratio\n",
"P1 = 98.;\t\t\t#Pressure at point 1 in kN/(m**2)\n",
"P4 = 258.;\t\t\t#Pressure at point 4 in kN/(m**2)\n",
"T1 = 317.;\t\t\t#Temperature at point 1 in K\n",
"y = 1.4;\t\t\t#Ratio of specific heats\n",
"\n",
"# Calculations\n",
"T4 = T1*(P4/P1);\t\t\t#Temperature at point 4 in K\n",
"T3 = T4*(e**(y-1));\t\t\t#Temperature at point 3 in K\n",
"t3 = T3-273;\t\t\t#Temperature at point 3 in oC\n",
"T2 = T1*(c**(y-1));\t\t\t#Temperature at point 2 in K\n",
"n = (1-((T4-T1)/(y*(T3-T2))))*100;\t\t\t#Thermal efficiency\n",
"\n",
"# Results\n",
"print 'Maximum temperature attained during the cycle is %3.1f oC \\\n",
"\\nThermal efficiency of the cycle is %3.1f percent'%(t3,n)\n",
"\n",
"# rounding off error"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Example 2.10 Page no : 66"
]
},
{
"cell_type": "code",
"execution_count": 11,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"Thermal efficiency is 63.5 percent \n",
"Mean effective pressure is 933 kPa\n"
]
}
],
"source": [
"\n",
"# Variables\n",
"rv = 20.;\t\t\t#Compression ratio\n",
"P1 = 95.;\t\t\t#Pressure at point 1 in kPa\n",
"T1 = 293.;\t\t\t#Temperature at point 1 in K\n",
"T3 = 2200.;\t\t\t#Temperature at point 3 in K\n",
"y = 1.4;\t\t\t#Ratio of specific heats\n",
"R = 287.;\t\t\t#Universal gas constant in J/kg-K\n",
"Cp = 1.005;\t\t\t#Specific heat at constant pressure in kJ/kg-K\n",
"\n",
"# Calculations\n",
"P2 = P1*(rv**y);\t\t\t#Pressure at point 2 in kPa\n",
"T2 = T1*(rv**(y-1));\t\t\t#Temperature at point 2 in K\n",
"v2 = (R*T2)/(P2*1000);\t\t\t#Specific volume at point 2 in (m**3)/kg\n",
"v3 = v2*(T3/T2);\t\t\t#Specific volume at point 3 in (m**3)/kg\n",
"rc = v3/v2;\t\t\t#Cut-off ratio\n",
"nth = (1-(((rc**y)-1)/((rv**(y-1))*y*(rc-1))))*100;\t\t\t#Thermal efficiency\n",
"q23 = Cp*(T3-T2);\t\t\t#Heat flow between points 2 and 3 in kJ/kg\n",
"wnet = (nth*q23)/100;\t\t\t#Net workdone in kJ/kg\n",
"MEP = wnet/(v2*(rv-1));\t\t\t#Mean effective pressure in kPa\n",
"\n",
"# Results\n",
"print 'Thermal efficiency is %3.1f percent \\\n",
"\\nMean effective pressure is %.f kPa'%(nth,MEP)\n",
"\n",
"# rounding off error"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Example 2.11 Page no : 68"
]
},
{
"cell_type": "code",
"execution_count": 11,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"Cut-off ratio is 2 \n",
"Air standard efficiency is 65.36 percent\n"
]
}
],
"source": [
"\n",
"# Variables\n",
"rv = 21.;\t\t\t#Compression ratio\n",
"re = 10.5;\t\t\t#Expansion ratio\n",
"y = 1.4;\t\t\t#Ratio of specific heats\n",
"\n",
"# Calculations\n",
"rc = rv/re;\t\t\t#Cut-off ratio\n",
"nth = (1-(((rc**y)-1)/((rv**(y-1))*y*(rc-1))))*100;\t\t\t#Air standard efficiency\n",
"\n",
"# Results\n",
"print 'Cut-off ratio is %3.0f \\\n",
"\\nAir standard efficiency is %3.2f percent'%(rc,nth)\n"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Example 2.12 Page no : 69"
]
},
{
"cell_type": "code",
"execution_count": 12,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"Ideal efficiency of engine is 61.5 percent\n"
]
}
],
"source": [
"\n",
"# Variables\n",
"rv = 16.;\t\t\t#Compression ratio\n",
"rp = 1.5;\t\t\t#Pressure ratio\n",
"y = 1.4;\t\t\t#Ratio of specific heats\n",
"cp = 8;\t\t\t#Cut-off percentage\n",
"\n",
"# Calculations\n",
"rc = 2.2;\t\t\t#Cut-off ratio\n",
"ntd = (1-((rp*(rc**y)-1)/((rv**(y-1)*((rp-1)+(y*rp*(rc-1)))))))*100;\t\t\t#Dual cycle efficiency\n",
"\n",
"# Results\n",
"print 'Ideal efficiency of engine is %3.1f percent'%(ntd)\n"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Example 2.13 Page no : 69"
]
},
{
"cell_type": "code",
"execution_count": 13,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"Ideal efficiency of the engine is 62.2 percent\n"
]
}
],
"source": [
"\n",
"# Variables\n",
"d = 0.2;\t\t\t#Bore in m\n",
"L = 0.5;\t\t\t#Stroke in m\n",
"c = 0.06;\t\t\t#Cut-off percentage\n",
"y = 1.4;\t\t\t#Ratio of specific heats\n",
"rv = 15.;\t\t\t#Compression ratio\n",
"rp = 1.4;\t\t\t#Pressure ratio\n",
"\n",
"# Calculations\n",
"Vs = (3.147/4)*(d**2)*L;\t\t\t#Stroke volume in m**3\n",
"DV = c*Vs;\t\t\t#Difference in volumes at points 4 and 3\n",
"V3 = Vs/(rv-1);\t\t\t#Specific volume at point 3 in m**3\n",
"V4 = V3+DV;\t\t\t#Specific volume at point 4 in m**3\n",
"rc = V4/V3;\t\t\t#Cut-off ratio\n",
"ntd = (1-((rp*(rc**y)-1)/((rv**(y-1)*((rp-1)+(y*rp*(rc-1)))))))*100;\t\t\t#Ideal efficiency\n",
"\n",
"# Results\n",
"print 'Ideal efficiency of the engine is %3.1f percent'%(ntd)\n"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Example 2.14 Page no : 70"
]
},
{
"cell_type": "code",
"execution_count": 12,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"Amount of heat added is 1742.1 kJ/kg \n",
"Amount of heat rejected is 772.91 kJ/kg \n",
"Workdone per cycle is 12.23 kJ/cycle \n",
"Thermal efficiency is 55.63 percent\n"
]
}
],
"source": [
"\n",
"\n",
"# Variables\n",
"d = 0.2;\t\t\t#Bore in m\n",
"L = 0.3;\t\t\t#Stroke in m\n",
"c = 0.04;\t\t\t#Cut-off percentage\n",
"y = 1.4;\t\t\t#Ratio of specific heats\n",
"rv = 8.;\t\t\t#Compression ratio\n",
"P1 = 1.;\t\t\t#Pressure at point 1 in bar\n",
"P3 = 60.;\t\t\t#Pressure at point 3 in bar\n",
"T1 = 298.;\t\t\t#Temperature at point 1 in K\n",
"R = 287.;\t\t\t#Universal gas constant in J/kg\n",
"Cv = 0.718;\t\t\t#Speific heat at constant volume in kJ/kg-K\n",
"Cp = 1.005;\t\t\t#Speific heat at constant pressure in kJ/kg-K\n",
"\n",
"# Calculations\n",
"Vs = (3.147/4)*(d**2)*L;\t\t\t#Stroke volume in m**3\n",
"V2 = Vs/(rv-1);\t\t\t#Specific volume at point 2 in m**3\n",
"V3 = V2;\t\t\t#Specific volume at point 3 in m**3\n",
"V1 = V2+Vs;\t\t\t#Specific volume at pont 1 in m**3\n",
"V5 = V1;\t\t\t#Specific volume at pont 5 in m**3\n",
"P2 = P1*(rv**y);\t\t\t#Pressure at point 2 in bar\n",
"T2 = T1*(rv**(y-1));\t\t\t#Temperature at point 2 in K\n",
"T3 = T2*(P3/P2);\t\t\t#Temperature at point 3 in K\n",
"V4 = V3+(c*(V1-V2));\t\t\t#Specific volume at point 4 in m**3\n",
"T4 = T3*(V4/V3);\t\t\t#Temperature at point 4 in K\n",
"T5 = T4*((V4/V5)**(y-1));\t\t\t#Temperature at point 5 in K\n",
"q1 = (Cv*(T3-T2))+(Cp*(T4-T3));\t\t\t#Heat added in kJ/kg\n",
"q2 = Cv*(T5-T1);\t\t\t#Heat rejected in kJ/kg\n",
"nth = (1-(q2/q1))*100;\t\t\t#Thermal efficiency\n",
"m = (P1*V1*(10**5))/(R*T1);\t\t\t#Mass of air supplied in kg\n",
"W = m*(q1-q2);\t\t\t#Workdone in kJ/cycle\n",
"\n",
"# Results\n",
"print 'Amount of heat added is %3.1f kJ/kg \\\n",
"\\nAmount of heat rejected is %3.2f kJ/kg \\\n",
"\\nWorkdone per cycle is %3.2f kJ/cycle \\\n",
"\\nThermal efficiency is %3.2f percent'%(q1,q2,W,nth)\n",
"\n",
"# rounding off error"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Example 2.15 Page no : 72"
]
},
{
"cell_type": "code",
"execution_count": 15,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"Mean effective pressure is 19.78 bar\n",
"Thermal efficiency is 56.48 percent\n"
]
}
],
"source": [
"\n",
"\n",
"# Variables\n",
"P1 = 1.;\t\t\t#Pressure at point 1 in bar\n",
"P3 = 70.;\t\t\t#Pressure at point 3 in bar\n",
"T1 = 310.;\t\t\t#Temperature at point 1 in K\n",
"rv = 10.;\t\t\t#Compression ratio\n",
"y = 1.4;\t\t\t#Ratio of specific heats\n",
"qin = 2805.;\t\t\t#Heat added in kJ/kg\n",
"m = 1.;\t\t\t#Mass of air in kg\n",
"R = 287.;\t\t\t#Universal gas constant in J/kg\n",
"Cv = 0.718;\t\t\t#Speific heat at constant volume in kJ/kg-K\n",
"Cp = 1.005;\t\t\t#Speific heat at constant pressure in kJ/kg-K\n",
"\n",
"# Calculations\n",
"V1 = (m*R*T1)/(P1*(10**5));\t\t\t#Volume at point 1 in m**3\n",
"T2 = T1*(rv**(y-1));\t\t\t#Temperature at point 2 in K\n",
"P2 = P1*(rv**y);\t\t\t#Pressure at point 2 in K\n",
"T3 = T2*(P3/P2);\t\t\t#Temperature at point 3 in K\n",
"q23 = Cv*(T3-T2);\t\t\t#Heat supplied at constant volume in kJ/kg\n",
"q34 = qin-q23;\t\t\t#Heat supplied at constant pressure in kJ/kg\n",
"T4 = (q34/Cp)+T3;\t\t\t#Temperature at point 4 in K\n",
"V2 = V1/rv;\t\t\t#Volume at point 2 in m**3\n",
"V4 = V2*(T4/T3);\t\t\t#Volume at point 4 in m**3\n",
"V5 = V1;\t\t\t#Volume at point 5 in m**3\n",
"T5 = T4*((V4/V5)**(y-1));\t\t\t#Temperature at point 5 in K\n",
"qout = Cv*(T5-T1);\t\t\t#Heat rejected in kJ/kg\n",
"nth = (1-(qout/qin))*100;\t\t\t#Thermal efficiency\n",
"W = qin-qout;\t\t\t#Workdone in kJ/kg\n",
"Vs = V1*(1-(1/rv));\t\t\t#Swept volume in (m**3)/kg\n",
"MEP = (W/Vs)/100;\t\t\t#Mean effective pressure in bar\n",
"\n",
"# Results\n",
"print 'Mean effective pressure is %3.2f bar\\\n",
"\\nThermal efficiency is %3.2f percent'%(MEP,nth)"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Example 2.16 Page no : 74"
]
},
{
"cell_type": "code",
"execution_count": 17,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"Cycle efficiency is 26.94 percent \n",
"Heat supplied to air is 517.7 kJ/kg \n",
"Work available at the shaft is 139.47 kJ/kg\n",
"Heat rejected in the cooler is 378.23 kJ/kg \n",
"Turbine exit temperature is 674.34 K\n"
]
}
],
"source": [
"\n",
"\n",
"# Variables\n",
"P1 = 1.;\t\t\t#Pressure at point 1 in bar\n",
"T1 = 298.;\t\t\t#Temperature at point 1 in K\n",
"P2 = 3.;\t\t\t#Pressure at point 2 in bar\n",
"T3 = 923.;\t\t\t#Temperature at point 3 in K\n",
"y = 1.4;\t\t\t#Ratio of specific heats\n",
"Cp = 1.005;\t\t\t#Speific heat at constant pressure in kJ/kg-K\n",
"\n",
"# Calculations\n",
"x = (y-1)/y;\t\t\t#Ratio\n",
"rp = P2/P1;\t\t\t#Pressure ratio\n",
"nth = (1-(1/(rp**x)))*100;\t\t\t#Cycle efficiency\n",
"T2 = T1*(rp**x);\t\t\t#Temperature at point 2 in K\n",
"q1 = Cp*(T3-T2);\t\t\t#Heat supplied in kJ/kg\n",
"Wout = (nth*q1)/100;\t\t\t#Work output in kJ/kg\n",
"q2 = q1-Wout;\t\t\t#Heat rejected in kJ/kg\n",
"T4 = T3*((1/rp)**x);\t\t\t#Temperature at point 4 in K\n",
"\n",
"# Results\n",
"print 'Cycle efficiency is %3.2f percent \\\n",
"\\nHeat supplied to air is %3.1f kJ/kg \\\n",
"\\nWork available at the shaft is %3.2f kJ/kg\\\n",
"\\nHeat rejected in the cooler is %3.2f kJ/kg \\\n",
"\\nTurbine exit temperature is %3.2f K'%(nth,q1,Wout,q2,T4)\n"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Example 2.17 Page no : 75"
]
},
{
"cell_type": "code",
"execution_count": 14,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"Optimum pressure ratio is 14.74 \n",
"Maximum net specific work output 401 kJ/kg \n",
"Thermal efficiency 54 percent \n",
"Work ratio is 0.54 \n",
"Carnot efficiency is 79 percent\n"
]
}
],
"source": [
"\n",
"import math\n",
"\n",
"# Variables\n",
"T1 = 283.;\t\t\t#Temperature at point 1 in K\n",
"T3 = 1353.;\t\t\t#Temperature at point 3 in K\n",
"y = 1.41;\t\t\t#Ratio of specific heats\n",
"Cp = 1.007;\t\t\t#Specific heat constant pressure in kJ/kg-K\n",
"\n",
"# Calculations\n",
"x = (y-1)/y;\t \t\t#Ratio\n",
"rpmax = ((T3/T1)**(1/x));\t\t\t#Maximum pressure ratio\n",
"rpopt = math.sqrt(rpmax);\t\t\t#Optimum pressure ratio\n",
"T2 = T1*(rpopt**x);\t \t\t#Temperature at point 2 in K\n",
"T4 = T2;\t\t\t #Maximum temperature at point 4 in K\n",
"Wmax = Cp*((T3-T4)-(T2-T1));\t\t\t#Maximum net specific work output in kJ/kg\n",
"nth = (Wmax/(Cp*(T3-T2)))*100;\t\t\t#Thermal efficiency\n",
"WR = nth/100; \t\t\t#Work ratio\n",
"nc = ((T3-T1)/T3)*100;\t \t\t#Carnot efficiency\n",
"\n",
"# Results\n",
"print 'Optimum pressure ratio is %3.2f \\\n",
"\\nMaximum net specific work output %3.0f kJ/kg \\\n",
"\\nThermal efficiency %3.0f percent \\\n",
"\\nWork ratio is %3.2f \\\n",
"\\nCarnot efficiency is %3.0f percent'%(rpopt,Wmax,nth,WR,nc)\n",
"\n",
"# rounding off error. please check."
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Example 2.18 Page no : 76"
]
},
{
"cell_type": "code",
"execution_count": 20,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"Maximum work per kg of air is 239.47 kJ/kg \n",
"Cycle efficiency is 47 percent\n",
"Ratio of brayton cycle efficiency to carnot efficieny is 0.654\n"
]
}
],
"source": [
"\n",
"\n",
"# Variables\n",
"Tmin = 300.;\t\t\t#Minimum temperature in K\n",
"Tmax = 1073.;\t\t\t#Maximum temperature in K\n",
"Cp = 1.005;\t\t\t#Specific heat at constant pressure in kJ/kg-K\n",
"\n",
"# Calculations\n",
"Wmax = Cp*((math.sqrt(Tmax)-math.sqrt(Tmin))**2);\t\t\t#Maximum work output in kJ/kg\n",
"nB = (1-math.sqrt(Tmin/Tmax))*100;\t\t\t#Brayton cycle efficiency\n",
"nC = (1-(Tmin/Tmax))*100;\t\t \t#Carnot efficiency\n",
"r = nB/nC;\t \t\t #Ratio of brayton cycle efficiency to carnot efficieny\n",
"\n",
"# Results\n",
"print 'Maximum work per kg of air is %3.2f kJ/kg \\\n",
"\\nCycle efficiency is %3.0f percent\\\n",
"\\nRatio of brayton cycle efficiency to carnot efficieny is %3.3f'%(Wmax,nB,r)\n"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Example 2.19 Page no : 77"
]
},
{
"cell_type": "code",
"execution_count": 21,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"Net power output of the turbine is 1014 kW \n",
"Thermal efficiency of the plant is 32 percent\n",
"Work ratio is 0.446\n"
]
}
],
"source": [
"\n",
"\n",
"# Variables\n",
"T1 = 291.;\t\t\t#Temperature at point 1 in K\n",
"P1 = 100.;\t\t\t#Pressure at point 1 in kN/(m**2)\n",
"nC = 0.85;\t\t\t#Isentropic efficiency of compressor\n",
"nT = 0.88;\t\t\t#Isentropic effficiency of turbine\n",
"rp = 8.;\t\t\t#Pressure ratio\n",
"T3 = 1273.;\t\t\t#Temperature at point 3 in K\n",
"m = 4.5;\t\t\t#Mass flow rate of air in kg/s\n",
"y = 1.4;\t\t\t#Ratio of speciifc heats\n",
"Cp = 1.006;\t\t\t#Specific heat at constant pressure in kJ/kg-K\n",
"\n",
"# Calculations\n",
"x = (y-1)/y;\t\t\t#Ratio\n",
"T2s = T1*(rp**x);\t\t\t#Temperature at point 2s in K\n",
"T2 = T1+((T2s-T1)/nC);\t\t\t#Temperature at point 2 in K\n",
"t2 = T2-273;\t\t\t#Temperature at point 2 in oC\n",
"T4s = T3*((1/rp)**x);\t\t\t#Temperature at point 4s in K\n",
"T4 = T3-((T3-T4s)*nT);\t\t\t#Temperature at point 4 in K\n",
"t4 = T4-273;\t\t\t#Temperature at point 4 in oC\n",
"W = m*Cp*((T3-T4)-(T2-T1));\t\t\t#Net power output in kW\n",
"nth = (((T3-T4)-(T2-T1))/(T3-T2))*100;\t\t\t#Thermal efficiency\n",
"WR = W/(m*Cp*(T3-T4));\t\t\t#Work ratio\n",
"\n",
"# Results\n",
"print 'Net power output of the turbine is %3.0f kW \\\n",
"\\nThermal efficiency of the plant is %3.0f percent\\\n",
"\\nWork ratio is %3.3f'%(W,nth,WR)\n",
"\n"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Example 2.20 Page no : 79"
]
},
{
"cell_type": "code",
"execution_count": 1,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"Percentage increase in the cycle efficiency due to regeneration is 41.41 percent\n"
]
}
],
"source": [
"\n",
"# Variables\n",
"P1 = 0.1;\t\t\t#Pressure at point 1 in MPa\n",
"T1 = 303.;\t\t\t#Temperature at point 1 in K\n",
"T3 = 1173.;\t\t\t#Temperature at point 3 in K\n",
"rp = 6.; \t\t\t#Pressure ratio\n",
"nC = 0.8;\t\t\t#Compressor efficiency\n",
"nT = nC;\t\t\t#Turbine efficiency\n",
"e = 0.75;\t\t\t#Regenerator effectiveness\n",
"y = 1.4;\t\t\t#Ratio of specific heats\n",
"Cp = 1.005;\t\t\t#Specific heat at constant pressure in kJ/kg-K\n",
"\n",
"# Calculations\n",
"x = (y-1)/y; \t\t\t#Ratio\n",
"T2s = T1*(rp**x);\t\t\t#Temperature at point 2s in K\n",
"T4s = T3/(rp**x);\t\t\t#Temperature at point 4s in K\n",
"DTa = (T2s-T1)/nC;\t\t\t#Difference in temperatures at point 2 and 1 in K\n",
"DTb = (T3-T4s)*nT;\t\t\t#Difference in temperatures at point 3 and 4 in K\n",
"wT = Cp*DTb;\t \t\t#Turbine work in kJ/kg\n",
"wC = Cp*DTa;\t\t \t#Compressor work in kJ/kg\n",
"T2 = DTa+T1;\t\t\t #Temperature at point 2 in K\n",
"q1 = Cp*(T3-T2);\t\t\t#Heat supplied in kJ/kg\n",
"nth1 = ((wT-wC)/q1)*100;\t\t\t#Cycle efficiency without regenerator\n",
"T4 = T3-DTb;\t\t \t#Temperature at point 4 in K\n",
"T5 = T2+(e*(T4-T2));\t\t\t#Temperature at point 5 in K\n",
"q2 = Cp*(T3-T5);\t\t\t#Heat supplied with regenerator in kJ/kg\n",
"nth2 = ((wT-wC)/q2)*100;\t\t\t#Cycle efficiency with regenerator\n",
"p = ((nth2-nth1)/nth1)*100;\t\t\t#Percentage increase due to regeneration\n",
"\n",
"# Results\n",
"print 'Percentage increase in the cycle efficiency due to regeneration is %3.2f percent'%(p)\n",
"\n",
"# rounding off error. please check."
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Example 2.21 Page no : 80"
]
},
{
"cell_type": "code",
"execution_count": 23,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"Velocity of air leaving the nozzle is 712.5 m/s\n"
]
}
],
"source": [
"\n",
"# Variables\n",
"P1 = 1.;\t\t\t#Pressure at point 1 in atm\n",
"P3 = 5.;\t\t\t#Pressure at point 3 in atm\n",
"T1 = 288.;\t\t\t#Temperature at point 1 in K\n",
"T4 = 1143.;\t\t\t#Temperature at point 4 in K\n",
"y = 1.4;\t\t\t#Ratio of specific heats\n",
"Cp = 1.005;\t\t\t#Specific heat at constant pressure in kJ/kg-K\n",
"\n",
"# Calculations\n",
"rp = P3/P1;\t\t\t#Pressure ratio\n",
"x = round((y-1)/y,3);\t\t\t#Ratio\n",
"rpx = round(rp**x,2)\n",
"T3 = round(T1*(rpx));\t\t\t#Temperature at point 3 in K\n",
"T5 = T4-(T3-T1);\t\t\t#Temperature at point 5 in K\n",
"T6 = T4/(rpx);\t\t\t#Temperature at point 6 in K\n",
"C6 = math.sqrt(2000*Cp*(T5-T6));\t\t\t#Velocity of air leaving the nozzle in m/s\n",
"\n",
"\n",
"# Results\n",
"print 'Velocity of air leaving the nozzle is %3.1f m/s'%(C6)\n",
"\n",
"# rounding error. Please check. there is rounding off error in book"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Example 2.22 Page no : 81"
]
},
{
"cell_type": "code",
"execution_count": 24,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"Pressure at the turbine exit is 374.2 kPa \n",
"Velocity of exhaust gases are 933.5 m/s \n",
"Propulsive efficiency is 26.9 percent\n"
]
}
],
"source": [
"\n",
"\n",
"# Variables\n",
"C1 = 280.;\t\t\t#Velocity of aircraft in m/s\n",
"P1 = 48.;\t\t\t#Pressure at point 1 kPa\n",
"T1 = 260.;\t\t\t#Temperature at point 1 in K\n",
"rp = 13.;\t\t\t#Pressure ratio\n",
"T4 = 1300.;\t\t\t#Temperature at point 4 in K\n",
"Cp = 1005.;\t\t\t#Specific heat at constant pressure in J/kg\n",
"y = 1.4;\t\t\t#Ratio of specific heats\n",
"\n",
"# Calculations\n",
"x = (y-1)/y;\t\t\t#Ratio\n",
"T2 = T1+((C1**2)/(2*Cp));\t\t\t#Temperature at point 2 in K\n",
"P2 = P1*((T2/T1)**(1/x));\t\t\t#Pressure at point 2 in kPa\n",
"P3 = rp*P2;\t\t\t#Pressure at point 3 in kPa\n",
"P4 = P3;\t\t\t#Pressure at point 4 in kPa\n",
"T3 = T2*(rp**x);\t\t\t#Temperature at point 3 in K\n",
"T5 = T4-T3+T2;\t\t\t#Temperature at point 5 in K\n",
"P5 = P4*((T5/T4)**(1/x));\t\t\t#Pressure at point 5 in kPa\n",
"P6 = P1;\t\t\t#Pressure at point 6 in kPa\n",
"T6 = T5*((P6/P5)**x);\t\t\t#Temperature at point 6 in K\n",
"C6 = math.sqrt(2*Cp*(T5-T6));\t\t\t#Velocity of air at nozzle exit in m/s\n",
"W = (C6-C1)*C1;\t\t\t#Propulsive power in J/kg\n",
"Q = Cp*(T4-T3);\t\t\t#Total heat transfer rate in J/kg\n",
"nP = (W/Q)*100;\t\t\t#Propulsive efficiency\n",
"\n",
"# Results\n",
"print 'Pressure at the turbine exit is %3.1f kPa \\\n",
"\\nVelocity of exhaust gases are %3.1f m/s \\\n",
"\\nPropulsive efficiency is %3.1f percent'%(P5,C6,nP)\n",
"\n"
]
}
],
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PKIt="<"<Thermal Engineering/ch3.ipynb{
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{
"cells": [
{
"cell_type": "heading",
"level": 1,
"metadata": {},
"source": [
"Chapter 3 :\n",
"Internal Combustion Engines"
]
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 3.1 Page no : 139"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"# Variables\n",
"d = 200.;\t\t\t#diameter of cylinder in mm\n",
"L = 300.;\t\t\t#stroke of cylinder in mm\n",
"Vc = 1.73;\t\t\t#Clearance volume in litres\n",
"imep = 650.;\t\t\t#indicated mean effective pressure in kN/(m**2)\n",
"g = 6.2;\t\t\t#gas consumption in (m**3)/h\n",
"CV = 38.5;\t\t\t#Calorific value in MJ/(m**3)\n",
"y = 1.4;\t\t\t#Ratio of specific heats\n",
"N = 150.;\t\t\t#No. of firing cycles per minute\n",
"\n",
"# Calculations\n",
"Vs = ((3.1415/4)*(d**2)*L)*(10**-6);\t\t\t#Stroke volume in litres\n",
"Vt = Vs+Vc;\t\t\t#Total volume in litres\n",
"rv = (Vt/Vc);\t\t\t#Compression ratio\n",
"n = (1-(1/rv**(y-1)))*100;\t\t\t#Air standard efficiency\n",
"IP = imep*(Vs*10**-3)*(N/60);\t\t\t#Indicated power in kW\n",
"F = (g*CV*1000)/3600;\t\t\t#Fuel energy input in kW\n",
"nT = (IP/F)*100;\t\t\t#Indicated thermal efficiency\n",
"\n",
"# Results\n",
"# 1st answer is wrong in book\n",
"print 'Air Standard Efficiency is %3.1f percent \\\n",
"\\nIndicated Power is %3.1f kW \\\n",
"\\nIndicated thermal efficiency is %3.0f percent'%(n,IP,nT)\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Air Standard Efficiency is 52.5 percent \n",
"Indicated Power is 15.3 kW \n",
"Indicated thermal efficiency is 23 percent\n"
]
}
],
"prompt_number": 1
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 3.2 Page no : 140"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"# Variables\n",
"Vs = 0.0008;\t\t\t#Swept volume in m**3\n",
"Vc = 0.00015;\t\t\t#Clearance volume in m**3\n",
"CV = 38.;\t\t\t#Calorific value in MJ/(m**3)\n",
"v = 0.45;\t\t\t#volume in m**3\n",
"IP = 81.5;\t\t\t#Indicated power in kW\n",
"y = 1.4;\t\t\t#Ratio of specific heats\n",
"\n",
"# Calculations\n",
"rv = (Vs+Vc)/Vc;\t\t\t#Compression ratio\n",
"n = (1-(1/rv**(y-1)));\t\t\t#Air standard efficiency\n",
"Ps = (v*CV*1000.)/60;\t\t\t#Power supplied in kW\n",
"nact = IP/Ps;\t\t\t#Actual efficiency\n",
"nr = (nact/n)*100;\t\t\t#Relative efficiency\n",
"\n",
"\n",
"# Results\n",
"print 'Relative Efficiency is %3.2f percent'%(nr)\n",
"\n",
"# rounding error in book answer. please check."
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Relative Efficiency is 54.77 percent\n"
]
}
],
"prompt_number": 2
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 3.3 Page no : 141"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"# Variables\n",
"n = 6.;\t\t\t #No. of cylinders\n",
"d = 0.61;\t\t\t#Diameter in m\n",
"L = 1.25;\t\t\t#Stroke in m\n",
"N = 2.;\t\t \t#No.of revolutions per second\n",
"m = 340.;\t\t\t#mass of fuel oil in kg\n",
"CV = 44200.;\t\t#Calorific value in kJ/kg\n",
"T = 108.;\t\t\t#Torque in kN-m\n",
"imep = 775.;\t\t#Indicated mean efective pressure in kN/(m**2)\n",
"\n",
"# Calculations\n",
"IP = (imep*L*3.1415*(d**2)*N)/(8);\t\t\t#Indicated power in kW\n",
"TotalIP = (n*IP);\t\t\t #Total indicated power in kW\n",
"BP = (2*3.1415*N*T);\t\t\t#Brake power in kW\n",
"PI = (m*CV)/3600.;\t\t\t #Power input in kW\n",
"nB = (BP/PI)*100.;\t\t \t#Brake thermal efficiency\n",
"bmep = (BP*8)/(n*L*3.1415*(d**2)*2);\t\t\t#Brake mean effective pressure in kN/(m**2)\n",
"nM = (BP/TotalIP)*100;\t\t\t#Mechanical efficiency\n",
"bsfc = m/BP;\t \t\t#Brake specific fuel consumption in kg/kWh\n",
"\n",
"# Results\n",
"print 'Total Indicated Power is %3.1f kW \\\n",
"\\nBrake Power is %3.1f kW \\\n",
"\\nBrake thermal efficiency is %3.1f percent \\\n",
"\\nBrake mean effective pressure is %3.1f kN/m**2 \\\n",
"\\nMechanical efficiency is %3.1f percent \\\n",
"\\nBrake specific fuel consumption is %3.3f kg/kW.hr'%(TotalIP,BP,nB,bmep,nM,bsfc)\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Total Indicated Power is 1698.6 kW \n",
"Brake Power is 1357.1 kW \n",
"Brake thermal efficiency is 32.5 percent \n",
"Brake mean effective pressure is 619.2 kN/m**2 \n",
"Mechanical efficiency is 79.9 percent \n",
"Brake specific fuel consumption is 0.251 kg/kW.hr\n"
]
}
],
"prompt_number": 2
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 3.4 Page no : 142"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"# Variables\n",
"Hm = 21.;\t\t\t#Mean height of indicator diagram in mm\n",
"isn = 27.;\t\t\t#indicator spring number in kN/(m**2)/mm\n",
"Vs = 14.;\t\t\t#Swept volume in litres\n",
"N = 6.6;\t\t\t#Speed of engine in rev/s\n",
"Pe = 77.;\t\t\t#Effective brake load in kg\n",
"Re = 0.7;\t\t\t#Effective vrake radius in m\n",
"mf = 0.002;\t\t\t#fuel consumed in kg/s\n",
"CV = 44000.;\t\t\t#Calorific value of fuel in kJ/kg\n",
"mc = 0.15;\t\t\t#cooling water circulation in kg/s\n",
"Ti = 311.;\t\t\t#cooling water inlet temperature in K\n",
"To = 344.;\t\t\t#cooling water outlet temperature in K\n",
"C = 4.18;\t\t\t#specific heat capacity of water in kJ/kg-K\n",
"Ee = 33.6;\t\t\t#Energy to exhaust gases in kJ/s\n",
"g = 9.81;\t\t\t#Acceleration due to geravity in m/(s**2)\n",
"\n",
"# Calculations\n",
"imep = isn*Hm;\t\t\t#Indicated mean efective pressure in kN/(m**2)\n",
"IP = (imep*Vs*N)/(2000);\t\t\t#Indicated Power in kW\n",
"BP = (2*3.1415*N*g*Pe*Re)/1000;\t\t\t#Brake Power in kW\n",
"nM = (BP/IP)*100;\t\t\t#Mechanical efficiency\n",
"Ef = mf*CV;\t\t\t#Eneergy from fuel in kJ/s\n",
"Ec = mc*C*(To-Ti);\t\t\t#Energy to cooling water in kJ/s\n",
"Es = Ef-(BP+Ec+Ee);\t\t\t#Energy to surroundings in kJ/s\n",
"p = (BP*100)/Ef;\t\t\t#Energy to BP in %\n",
"q = (Ec*100)/Ef;\t\t\t#Energy to coolant in %\n",
"r = (Ee*100)/Ef;\t\t\t#Energy to exhaust in %\n",
"w = (Es*100)/Ef;\t\t\t#Energy to surroundings in %\n",
"\n",
"# Results\n",
"print 'Indicated Power is %3.1f kW \\\n",
"\\nBrake Power is %3.0f kW \\\n",
"\\nMechanical Efficiency is %3.0f percent \\\n",
"\\nENERGY BALANCE kJ/s Percentage \\\n",
"\\nEnergy from fuel %3.0f 100 \\\n",
"\\nEnergy to BP %3.0f %3.0f \\\n",
"\\nEnergy to coolant %3.01f %3.1f \\\n",
"\\nEnergy to exhaust %3.1f %3.1f \\\n",
"\\nEnergy to surroundings, etc %3.1f %3.1f'%(IP,BP,nM,Ef,BP,p,Ec,q,Ee,r,Es,w)\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Indicated Power is 26.2 kW \n",
"Brake Power is 22 kW \n",
"Mechanical Efficiency is 84 percent \n",
"ENERGY BALANCE kJ/s Percentage \n",
"Energy from fuel 88 100 \n",
"Energy to BP 22 25 \n",
"Energy to coolant 20.7 23.5 \n",
"Energy to exhaust 33.6 38.2 \n",
"Energy to surroundings, etc 11.8 13.4\n"
]
}
],
"prompt_number": 2
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 3.5 Page no : 143"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"# Variables\n",
"t = 30.;\t\t\t#duration of trial in minutes\n",
"N = 1750.;\t\t\t#speed in rpm\n",
"T = 330.;\t\t\t#brake torque in Nm\n",
"m = 9.35;\t\t\t#mass of fuel in kg\n",
"CV = 42300.;\t\t\t#Calorific value in kJ/kg\n",
"mj = 483.;\t\t\t#jacket cooling water circulation in kg\n",
"Ti = 290.;\t\t\t#inlet temperature in K\n",
"T0 = 350.;\t\t\t#outlet temperature in K\n",
"ma = 182.;\t\t\t#air consumption in kg\n",
"Te = 759.;\t\t\t#exhaust temperature in K\n",
"Ta = 256.;\t\t\t#atmospheric temperature in K\n",
"nM = 0.83;\t\t\t#Mechanical efficiency\n",
"ms = 1.25;\t\t\t#mean specific heat capacity of exhaust gas in kJ/kg-K\n",
"Cw = 4.18;\t\t\t#specific heat capacity of water in kJ/kg-K\n",
"\n",
"# Calculations\n",
"BP = (2*3.1415*T*N)/(60*1000);\t\t\t#Brake power in kW\n",
"sfc = (m*2)/BP;\t\t\t#specific fuel consumption in kg/kWh\n",
"IP = BP/nM;\t\t\t#Indicated power in kW\n",
"nIT = IP/(m*2/3600*CV)*100 \t\t\t#Indicated thermal efficiency\n",
"Ef = (m/t*CV) \t\t\t#Eneergy from fuel in kJ/min\n",
"EBP = BP*60;\t\t\t#Energy to BP in kJ/min\n",
"Ec = (mj*Cw*(T0-Ti))/t;\t\t\t#Energy to cooling water in kJ/min\n",
"Ee = ((ma+m)*ms*(Te-Ti))/30;\t\t\t#Energy to exhaust in kJ/min\n",
"Es = Ef-(EBP+Ec+Ee);\t\t\t#Energy to surroundings in kJ/min\n",
"\n",
"# Results\n",
"print 'Break power is %3.1f kW \\\n",
"\\nSpecific fuel consumption is %3.3f kg/kWh \\\n",
"\\nIndicated thermal efficiency is %3.1f percent \\\n",
"\\nEnergy from fuel is %3.0f kJ/min \\\n",
"\\nEnergy to BP is %3.0f kJ/min \\\n",
"\\nEnergy to cooling water is %3.0f kJ/min \\\n",
"\\nEnergy to exhaust is %3.0f kJ/min \\\n",
"\\nEnergy to surroundings is %d kJ/min'%(BP,sfc,nIT,round(Ef,-2),EBP,Ec,Ee,Es)\n",
"\n",
"# rounding off error"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Break power is 60.5 kW \n",
"Specific fuel consumption is 0.309 kg/kWh \n",
"Indicated thermal efficiency is 33.2 percent \n",
"Energy from fuel is 13200 kJ/min \n",
"Energy to BP is 3628 kJ/min \n",
"Energy to cooling water is 4038 kJ/min \n",
"Energy to exhaust is 3739 kJ/min \n",
"Energy to surroundings is 1777 kJ/min\n"
]
}
],
"prompt_number": 6
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 3.6 Page no : 144"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"# Variables\n",
"BP0 = 12.;\t\t\t#Brake Power output in kW\n",
"BP1 = 40.5;\t\t\t#Brake Power in trial 1 in kW\n",
"BP2 = 40.2;\t\t\t#Brake Power in trial 2 in kW\n",
"BP3 = 40.1;\t\t\t#Brake Power in trial 3 in kW\n",
"BP4 = 40.6;\t\t\t#Brake Power in trial 4 in kW\n",
"BP5 = 40.7;\t\t\t#Brake Power in trial 5 in kW\n",
"BP6 = 40.0;\t\t\t#Brake Power in trial 6 in kW\n",
"\n",
"# Calculations\n",
"BPALL = BP0+BP6;\t\t\t#Total Brake Power in kW\n",
"IP1 = BPALL-BP1;\t\t\t#Indicated Power in trial 1 in kW\n",
"IP2 = BPALL-BP2;\t\t\t#Indicated Power in trial 2 in kW\n",
"IP3 = BPALL-BP3;\t\t\t#Indicated Power in trial 3 in kW\n",
"IP4 = BPALL-BP4;\t\t\t#Indicated Power in trial 4 in kW\n",
"IP5 = BPALL-BP5;\t\t\t#Indicated Power in trial 5 in kW\n",
"IP6 = BPALL-BP6;\t\t\t#Indicated Power in trial 6 in kW\n",
"IPALL = IP1+IP2+IP3+IP4+IP5+IP6;\t\t\t#Total Indicated Power in kW\n",
"nM = (BPALL/IPALL)*100;\t\t\t#Mechanical efficiency\n",
"\n",
"# Results\n",
"print 'Indicated Power of the engine is %3.1f kW \\\n",
"\\nMechanical efficiency of the engine is %3.1f percent'%(IPALL,nM)\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Indicated Power of the engine is 69.9 kW \n",
"Mechanical efficiency of the engine is 74.4 percent\n"
]
}
],
"prompt_number": 6
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 3.7 Page no : 145"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"import math\n",
"\n",
"# Variables\n",
"n = 2.;\t\t\t#No. of cylinders\n",
"N = 4000.;\t\t\t#speed of engine in rpm\n",
"nV = 0.77;\t\t\t#Volumetric efficiency\n",
"nM = 0.75;\t\t\t#Mechanical efficiency\n",
"m = 10.;\t\t\t#fuel consumed in lit/h\n",
"g = 0.73;\t\t\t#spcific gravity of fuel\n",
"Raf = 18.;\t\t\t#air-fuel ratio\n",
"Np = 600.;\t\t\t#piston speed in m/min\n",
"imep = 5.;\t\t\t#Indicated mean efective pressure in bar\n",
"R = 281.;\t\t\t#Universal gas constant in J/kg-K\n",
"T = 288.;\t\t\t#Standard temperature in K\n",
"P = 1.013;\t\t\t#Standard pressure in bar\n",
"\n",
"\n",
"# Calculations\n",
"L = Np/(2*N);\t\t\t#Piston stroke in m\n",
"mf = m*g;\t\t\t#mass of fuel in kg/h\n",
"ma = mf*Raf;\t\t\t#mass of air required in kg/h\n",
"Va = (ma*R*T)/(P*60*(10**5));\t\t\t#volume of air required in (m**3)/min\n",
"D = math.sqrt((2*Va)/(nV*L*N*3.1415));\t\t\t#Diameter in m\n",
"IP = (2*imep*100*L*3.1415*(D**2)*N)/(4.*60);\t\t\t#Indicated Power in kW\n",
"BP = nV*IP;\t\t\t#Brake Power in kW\n",
"\n",
"# Results\n",
"print 'Piston Stroke is %3.3f m \\\n",
"\\nBore diameter is %3.4f m \\\n",
"\\nBrake power is %3.1f kW'%(L,D,BP)\n",
"\n",
"# rounding off error"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Piston Stroke is 0.075 m \n",
"Bore diameter is 0.0694 m \n",
"Brake power is 14.6 kW\n"
]
}
],
"prompt_number": 5
}
],
"metadata": {}
}
]
}PKIThermal Engineering/ch4.ipynb{
"cells": [
{
"cell_type": "markdown",
"metadata": {},
"source": [
"# Chapter 4 : Steam nozzles and Steam turbines"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Example 4.1 Page no : 161"
]
},
{
"cell_type": "code",
"execution_count": 1,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"Throat area is 255 mm**2 \n",
"Exit area is 344 mm**2 \n",
"Mach number at exit is 1.49\n"
]
}
],
"source": [
"\n",
"# Variables\n",
"P1 = 3.5;\t\t\t#Pressure at entry in MN/(m**2)\n",
"T1 = 773.;\t\t\t#Temperature at entry in K\n",
"P2 = 0.7;\t\t\t#Pressure at exit in MN/(m**2)\n",
"ma = 1.3;\t\t\t#mass flow rate of air in kg/s\n",
"y = 1.4;\t\t\t#Ratio of specific heats\n",
"R = 0.287;\t\t\t#Universal gas constant in KJ/Kg-K\n",
"\n",
"# Calculations\n",
"c = y/(y-1); \t\t\t#Ratio\n",
"Pt = ((2/(y+1))**c)*P1;\t\t\t#Throat pressure in MN/(m**2)\n",
"v1 = (R*T1)/(P1*1000);\t\t\t#Specific volume at entry in (m**3)/kg\n",
"Ct = ((2*c*P1*v1*(1-((Pt/P1)**(1/c))))**0.5)*1000;\t\t\t#Velocity at throat in m/s\n",
"vt = v1*((P1/Pt)**(1/y));\t\t\t#Specific volume at throat in (m**3)/kg\n",
"At = ((ma*vt)/Ct)*(10**6);\t\t\t#Area of throat in (mm**2)\n",
"C2 = ((2*c*P1*v1*(1-((P2/P1)**(1/c))))**0.5)*1000;\t\t\t#Velocity at exit in m/s\n",
"v2 = v1*((P1/P2)**(1/y));\t\t\t#Specific volume at exit in (m**3)/kg\n",
"A2 = ((ma*v2)/C2)*(10**6);\t\t\t#Area of exit in (mm**2)\n",
"M = C2/Ct;\t\t\t #Mach number at exit\n",
"\n",
"# Results\n",
"print 'Throat area is %3.0f mm**2 \\\n",
"\\nExit area is %3.0f mm**2 \\\n",
"\\nMach number at exit is %3.2f'%(At,A2,M)\n",
"\n",
"# rounding off error"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Example 4.2 Page no : 163"
]
},
{
"cell_type": "code",
"execution_count": 2,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"Increase in temperature is 356 K \n",
"Increase in pressure is 2.46 MN/m**2 \n",
"Increase in internal energy is 255 kJ/kg\n"
]
}
],
"source": [
"\n",
"# Variables\n",
"T1 = 273.;\t\t\t#Temperature at section 1 in K\n",
"P1 = 140.;\t\t\t#Pressure at section 1 in KN/(m**2)\n",
"v1 = 900.;\t\t\t#Velocity at section 1 in m/s\n",
"v2 = 300.;\t\t\t#Velocity at section 2 in m/s\n",
"Cp = 1.006;\t\t\t#Specific heat at constant pressure in kJ/kg-K\n",
"Cv = 0.717;\t\t\t#Specific heat at constant volume in kJ/kg-K\n",
"y = 1.4;\t\t\t#Ratio of specific heats\n",
"\n",
"# Calculations\n",
"c = y/(y-1);\t\t\t#Ratio\n",
"R = Cp-Cv;\t\t\t#Universal gas constant in KJ/Kg-K\n",
"T2 = T1-(((v2)**2-(v1)**2)/(2000*c*R));\t\t\t#Temperature at section 2 in K\n",
"DT = T2-T1;\t\t\t#Increase in temperature in K\n",
"P2 = P1*((T2/T1)**c);\t\t\t#Pressure at section 2 in KN/(m**2)\n",
"DP = (P2-P1)/1000;\t\t\t#Increase in pressure in MN/(m**2)\n",
"IE = Cv*(T2-T1);\t\t\t#Increase in internal energy in kJ/kg\n",
"\n",
"# Results\n",
"print 'Increase in temperature is %3.0f K \\\n",
"\\nIncrease in pressure is %3.2f MN/m**2 \\\n",
"\\nIncrease in internal energy is %3.0f kJ/kg'%(DT,DP,IE)\n"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Example 4.3 Page no : 163"
]
},
{
"cell_type": "code",
"execution_count": 2,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"Throat area is 2888 mm**2 \n",
"Exit area is 4280 mm**2 \n",
"Degree of undercooling at exit is 10.3 K\n"
]
}
],
"source": [
"\n",
"\n",
"# Variables\n",
"P1 = 2;\t\t\t#Pressure at entry in MN/(m**2)\n",
"T1 = 598;\t\t\t#Temperature at entry in K\n",
"P2 = 0.36;\t\t\t#Pressure at exit in MN/(m**2)\n",
"m = 7.5;\t\t\t#mass flow rate of steam in kg/s\n",
"n = 1.3;\t\t\t#Adiabatic gas constant\n",
"v1 = 0.132;\t\t\t#Volume at entry in (m**3)/kg from steam table\n",
"Ts = 412.9;\t\t\t#Saturation temperature in K\n",
"\n",
"# Calculations\n",
"c = n/(n-1);\t\t\t#Ratio\n",
"Pt = ((2/(n+1))**c)*P1;\t\t\t#Throat pressure in MN/(m**2)\n",
"Ct = ((2*c*P1*v1*(1-((Pt/P1)**(1/c))))**0.5)*1000;\t\t\t#Velocity at throat in m/s\n",
"vt = v1*((P1/Pt)**(1/n));\t\t\t#Specific volume at throat in (m**3)/kg\n",
"At = ((m*vt)/Ct)*(10**6);\t\t\t#Area of throat in (mm**2)\n",
"C2 = ((2*c*P1*v1*(1-((P2/P1)**(1/c))))**0.5)*1000;\t\t\t#Velocity at exit in m/s\n",
"v2 = v1*((P1/P2)**(1/n));\t\t\t#Specific volume at exit in (m**3)/kg\n",
"A2 = ((m*v2)/C2)*(10**6);\t\t\t#Area of exit in (mm**2)\n",
"T2 = T1*((P2/P1)**(1/c));\t\t\t#Temperature at exit in K\n",
"D = Ts-T2;\t\t\t#Degree of undercooling at exit in K\n",
"\n",
"# Results\n",
"print 'Throat area is %3.0f mm**2 \\\n",
"\\nExit area is %3.0f mm**2 \\\n",
"\\nDegree of undercooling at exit is %3.1f K'%(At,round(A2,-1),D)\n"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Example 4.4 Page no : 165"
]
},
{
"cell_type": "code",
"execution_count": 3,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"Throat velocity is 548 m/s \n",
"Exit velocity is 800 m/s \n",
"Throat area is 3210 mm**2 \n",
"Exit area is 6050 mm**2 \n"
]
}
],
"source": [
"\n",
"\n",
"# Variables\n",
"P1 = 2.2;\t\t\t#Pressure at entry in MN/(m**2)\n",
"T1 = 533.;\t\t\t#Temperature at entry in K\n",
"P2 = 0.4;\t\t\t#Pressure at exit in MN/(m**2)\n",
"m = 11.;\t\t\t#mass flow rate of steam in kg/s\n",
"n = 0.85;\t\t\t#Efficiency of expansion\n",
"h1 = 2940.;\t\t\t#Enthalpy at entrance in kJ/kg from Moiller chart\n",
"ht = 2790.;\t\t\t#Enthalpy at throat in kJ/kg from Moiller chart\n",
"h2s = 2590.;\t\t\t#Enthalpy below exit level in kJ/kg from Moiller chart\n",
"vt = 0.16;\t\t\t#Throat volume in (m**3)/kg\n",
"v2 = 0.44;\t\t\t#Volume at exit in (m**3)/kg\n",
"\n",
"# Calculations\n",
"Ct = (2000*(h1-ht))**0.5;\t\t\t#Throat velocity in m/s\n",
"h2 = ht-(0.85*(ht-h2s));\t\t\t#Enthalpy at exit in kJ/kg\n",
"C2 = (2000*(h1-h2))**0.5;\t\t\t#Exit velocity in m/s\n",
"At = ((m*vt)/Ct)*(10**6);\t\t\t#Area of throat in (mm**2)\n",
"A2 = ((m*v2)/C2)*(10**6);\t\t\t#Area of exit in (mm**2)\n",
"\n",
"# Results\n",
"print 'Throat velocity is %3.0f m/s \\\n",
"\\nExit velocity is %3.0f m/s \\\n",
"\\nThroat area is %3.0f mm**2 \\\n",
"\\nExit area is %3.0f mm**2 '%(Ct,C2,round(At,-1),A2)\n"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Example 4.5 Page no : 166"
]
},
{
"cell_type": "code",
"execution_count": 5,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"Cross section of nozzle is 26.7 mm * 8.9 mm \n",
"Degree of undercooling is 35.8 K and Degree of supersaturation is 2.58 \n",
"Loss in available heat drop due to irreversibility is 6.16 kJ/kg \n",
"Increase in entropy is 0.01390 kJ/kg-K \n",
"Ratio of mass flow rate with metastable expansion to the thermal expansion is 1.065\n"
]
}
],
"source": [
"\n",
"\n",
"# Variables\n",
"P1 = 35.;\t\t\t#Pressure at entry in bar\n",
"T1 = 573.;\t\t\t#Temperature at entry in K\n",
"P2 = 8.;\t\t\t#Pressure at exit in bar\n",
"Ts = 443.4;\t\t\t#Saturation temperature in K\n",
"Ps = 3.1;\t\t\t#Saturation pressure in bar\n",
"m = 5.2;\t\t\t#mass flow rate of steam in kg/s\n",
"n = 1.3;\t\t\t#Adiabatic gas consmath.tant\n",
"v1 = 0.06842;\t\t\t#Specific volume at entry in (m**3)/kg from steam table\n",
"v3 = 0.2292;\t\t\t#Specific volume at exit in (m**3)/kg from steam table\n",
"h1 = 2979.;\t\t\t#Enthalpy in kJ/kg from Moiller chart\n",
"h3 = 2673.3;\t\t\t#Enthalpy in kJ/kg from Moiller chart\n",
"\n",
"# Calculations\n",
"c = n/(n-1);\t\t\t#Ratio\n",
"C2 = ((2*c*P1*(10**5)*v1*(1-((P2/P1)**(1/c))))**0.5);\t\t\t#Velocity at exit in m/s\n",
"v2 = v1*((P1/P2)**(1/n));\t\t\t#Specific volume at exit in (m**3)/kg\n",
"A2 = ((m*v2)/C2)*(10**4);\t\t\t#Area of exit in (cm**2)\n",
"a = ((A2/18)**0.5)*10;\t\t\t#Length in mm\n",
"b = 3*a;\t\t\t#Breadth in mm\n",
"T2 = T1*((P2/P1)**(1/c));\t\t\t#Temperature at exit in K\n",
"D = Ts-T2;\t\t\t#Degree of undercooling in K\n",
"Ds = P2/Ps;\t\t\t#Degree of supersaturation\n",
"hI = h1-h3;\t\t\t#Isentropic enthalpy drop in kJ/kg\n",
"ha = (C2**2)/2000;\t\t\t#Actual enthalpy drop in kJ/kg\n",
"QL = hI-ha;\t\t\t#Loss in available heat in kJ/kg\n",
"DS = QL/Ts;\t\t\t#Increase in entropy in kJ/kg-K\n",
"C3 = (2000*(h1-h3))**0.5;\t\t\t#Exit velocity from nozzle\n",
"mf = ((A2*C3*(10**-4))/v3);\t\t\t#Mass flow rate in kg/s\n",
"Rm = m/mf;\t\t\t#Ratio of mass rate\n",
"\n",
"# Results\n",
"print 'Cross section of nozzle is %3.1f mm * %3.1f mm \\\n",
"\\nDegree of undercooling is %3.1f K and Degree of supersaturation is %3.2f \\\n",
"\\nLoss in available heat drop due to irreversibility is %3.2f kJ/kg \\\n",
"\\nIncrease in entropy is %3.5f kJ/kg-K \\\n",
"\\nRatio of mass flow rate with metastable expansion to the thermal expansion is %3.3f'%(b,a,D,Ds,QL,DS,Rm)\n"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Example 4.6 Page no : 169"
]
},
{
"cell_type": "code",
"execution_count": 1,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"Nozzle efficiency is 88.9 percent \n",
"Exit area is 7000 mm**2 \n",
"Throat velocity is 529 m/s\n"
]
}
],
"source": [
"\n",
"import math\n",
"\n",
"# Variables\n",
"m = 14.;\t\t\t#Mass flow rate of steam in kg/s\n",
"P1 = 3.;\t\t\t#Pressure of Steam in MN/(m**2)\n",
"T1 = 300.;\t\t\t#Steam temperature in oC\n",
"h1 = 2990.;\t\t\t#Enthalpy at point 1 in kJ/kg\n",
"h2s = 2630.;\t\t\t#Enthalpy at point 2s in kJ/kg\n",
"ht = 2850.;\t\t\t#Enthalpy at point t in kJ/kg\n",
"n = 1.3;\t\t\t#Adiabatic gas consmath.tant\n",
"C2 = 800.;\t\t\t#Exit velocity in m/s\n",
"v2 = 0.4;\t\t\t#Specific volume at exit in (m**3)/kg\n",
"\n",
"# Calculations\n",
"x = n/(n-1);\t\t\t#Ratio\n",
"Pt = ((2/(n+1))**x)*P1;\t\t\t#Temperature at point t in MN/(m**2)\n",
"h2 = h1-((C2**2)/2000);\t\t\t#Exit enthalpy in kJ/kg\n",
"nN = ((h1-h2)/(h1-h2s))*100;\t\t\t#Nozzle efficiency\n",
"A2 = ((m*v2)/C2)*(10**6);\t\t\t#Exit area in (mm**2)\n",
"Ct = math.sqrt(2*(h1-ht)*10**3);\t\t\t#Throat velocity in m/s\n",
"\n",
"# Results\n",
"print 'Nozzle efficiency is %3.1f percent \\\n",
"\\nExit area is %3.0f mm**2 \\\n",
"\\nThroat velocity is %3.0f m/s'%(nN,A2,Ct)\n"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Example 4.7 Page no : 170"
]
},
{
"cell_type": "code",
"execution_count": 6,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"Throat area is 388 mm**2 \n",
"Exit area is 1275 mm**2 \n",
"Steam quality at exit is 95 percent\n"
]
}
],
"source": [
"import math\n",
"\n",
"# Variables\n",
"P1 = 10.;\t\t\t#Pressure at point 1 in bar\n",
"P2 = 0.5;\t\t\t#Pressure at point 2 in bar\n",
"h1 = 3050.;\t\t\t#Enthalpy at point 1 in kJ/kg\n",
"h2s = 2480.;\t\t\t#Enthalpy at point 2s in kJ/kg\n",
"ht = 2910.;\t\t\t#Enthalpy at throat in kJ/kg\n",
"n = 1.3;\t\t\t#Adiabatic gas constant\n",
"r = 0.1;\t\t\t#Total available heat drop\n",
"v1 = 0.258;\t\t\t#Specific volume at point 1 in (m**3)/kg\n",
"h2f = 340.6;\t\t\t#Enthalpy for exit pressure from steam tables in kJ/kg\n",
"hfg = 2305.4;\t\t\t#Enthalpy for exit pressure from steam tables in kJ/kg\n",
"m = 0.5;\t\t\t#Mass flow rate in kg/s\n",
"\n",
"# Calculations\n",
"x = n/(n-1);\t\t\t#Ratio\n",
"Pt = ((2/(n+1))**x)*P1;\t\t\t#Temperature at throat in bar\n",
"h2 = h2s+(r*(h1-h2s));\t\t\t#Enthalpy at point 2 in kJ/kg\n",
"vt = ((P1/Pt)**(1/n))*v1;\t\t\t#Specific volume at throat in (m**3)/kg\n",
"v2 = ((P1/P2)**(1/n))*v1;\t\t\t#Specific volume at point 2 in (m**3)/kg\n",
"Ct = math.sqrt(2000*(h1-ht));\t\t\t#Throat velocity in m/s\n",
"At = ((m*vt)/Ct)*(10**6);\t\t\t#Throat area in (mm**2)\n",
"C2 = math.sqrt(2000*(h1-h2));\t\t\t#Exit velocity in m/s\n",
"A2 = ((m*v2)/C2)*(10**6);\t\t\t#Exit area in (mm**2)\n",
"x2 = ((h2-h2f)/hfg)*100;\t\t\t#Steam quality at exit\n",
"\n",
"# Results\n",
"print 'Throat area is %d mm**2 \\\n",
"\\nExit area is %d mm**2 \\\n",
"\\nSteam quality at exit is %3.0f percent'%(At,A2,x2)\n",
"\n",
"# rounding off error"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Example 4.8 Page no : 171"
]
},
{
"cell_type": "code",
"execution_count": 7,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"Maximum discharge is 13.294 kg/min \n",
"Exit area is 493.8 mm**2\n"
]
}
],
"source": [
"import math\n",
"\n",
"# Variables\n",
"P1 = 3.5;\t\t\t#Dry saturated steam in bar\n",
"P2 = 1.1;\t\t\t#Exit pressure in bar\n",
"At = 4.4;\t\t\t#Throat area in cm**2\n",
"h1 = 2731.6;\t\t\t#Enthalpy at P1 in kJ/kg\n",
"v1 = 0.52397;\t\t\t#Specific volume at P1 in m**3/kg\n",
"n = 1.135;\t\t\t#Adiabatic gas constant\n",
"ht = 2640.;\t\t\t#Enthalpy at Pt in kJ/kg\n",
"vt = 0.85;\t\t\t#Specific volume at throat in m**3/kg\n",
"h2 = 2520.;\t\t\t#Enthalpy at P2 in kJ/kg\n",
"v2 = 1.45;\t\t\t#Specific volume at P2 in m**3/kg\n",
"\n",
"# Calculations\n",
"x = n/(n-1);\t\t\t#Ratio\n",
"Pt = ((2/(n+1))**x)*P1;\t\t\t#Throat pressure in bar\n",
"Ct = math.sqrt(2000*(h1-ht));\t\t\t#Throat velocity in m/s\n",
"mmax = ((At*Ct*(10**-4))/vt)*60;\t\t\t#Maximum discharge in kg/min\n",
"C2 = math.sqrt(2000*(h1-h2));\t\t\t#Exit velocity in m/s\n",
"A2 = ((mmax*v2)/(C2*60))*(10**6);\t\t\t#Exit area in mm**2\n",
"\n",
"# Results\n",
"print 'Maximum discharge is %3.3f kg/min \\\n",
"\\nExit area is %3.1f mm**2'%(mmax,A2)\n"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Example 4.9 Page no : 172"
]
},
{
"cell_type": "code",
"execution_count": 5,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"Since throat pressure is greater than exit pressure,nozzle used is convergent-divergent nozzle \n",
"Minimum area of nozzle required is 2.14e-03 m**2\n"
]
}
],
"source": [
"import math\n",
"\n",
"# Variables\n",
"P1 = 10.;\t\t\t#Pressure at point 1 in bar\n",
"T1 = 200.;\t\t\t#Temperature at point 1 in oC\n",
"P2 = 5.;\t\t\t#Pressure at point 2 in bar\n",
"n = 1.3;\t\t\t#Adiabatic gas consmath.tant\n",
"h1 = 2830.;\t\t\t#Enthalpy at P1 in kJ/kg\n",
"ht = 2710.;\t\t\t#Enthalpy at point Pt in kJ/kg\n",
"vt = 0.35;\t\t\t#Specific volume at Pt in m**3/kg\n",
"m = 3. \t\t\t#Nozzle flow in kg/s\n",
"\n",
"# Calculations\n",
"x = n/(n-1);\t\t\t#Ratio\n",
"Pt = ((2/(n+1))**x)*P1;\t\t\t#Throat pressure in bar\n",
"Ct = math.sqrt(2000*(h1-ht));\t\t\t#Throat velocity in m/s\n",
"At = (m*vt)/Ct;\t\t\t#Throat area in m**2\n",
"\n",
"# Results\n",
"print 'Since throat pressure is greater than exit pressure,nozzle used is\\\n",
" convergent-divergent nozzle \\\n",
" \\nMinimum area of nozzle required is %.2e m**2'%(At)\n"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Example 4.10 Page no : 173"
]
},
{
"cell_type": "code",
"execution_count": 1,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"Throat velocity is 443.27 m/s \n",
"Mass flow rate of steam is 1549.90 kg/m**2\n"
]
}
],
"source": [
"import math \n",
"\n",
"# Variables\n",
"P1 = 10.5;\t\t\t#Pressure at point 1 in bar\n",
"x1 = 0.95;\t\t\t#Dryness fraction\n",
"n = 1.135;\t\t\t#Adiabatic gas constant\n",
"P2 = 0.85;\t\t\t#Pressure at point 2 in bar\n",
"vg = 0.185;\t\t\t#Specific volume in m**3/kg\n",
"\n",
"\n",
"# Calculations\n",
"c = n/(n-1);\t\t\t#Ratio\n",
"Pt = round(((2/(n+1))**c)*P1,2);\t\t\t#Throat pressure in MN/(m**2)\n",
"v1 = round(x1*vg,3);\t\t\t#Specific volume at point 1 in m**3/kg\n",
"Ct = round(math.sqrt((2*n*P1*v1*(10**5)/(n+1))),2);\t\t\t#Velocity at throat in m/s\n",
"vt = round(((P1/Pt)*(v1**n))**(1/1.135),3);\t\t\t#Specific volume at throat in m**3/kg\n",
"m = Ct/vt;\t\t\t#Mass flow rate per unit throat area in kg/(m**2)\n",
"\n",
"# Results\n",
"print 'Throat velocity is %3.2f m/s \\\n",
"\\nMass flow rate of steam is %3.2f kg/m**2'%(Ct,m)\n"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Example 4.11 Page no : 174"
]
},
{
"cell_type": "code",
"execution_count": 2,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"Degree of supersaturation is 4.98 \n",
"Degree of undercooling 50 C\n"
]
}
],
"source": [
"\n",
"# Variables\n",
"P1 = 10.;\t\t\t#Pressure at point 1 in bar\n",
"T1 = 452.9;\t\t\t#Temperature at point 1 in K\n",
"P2 = 4.;\t\t\t#Pressure at point 2 in bar\n",
"n = 1.3;\t\t\t#Adiabatic gas constant\n",
"Ps = 0.803;\t\t\t#Saturation pressure at T2 in bar\n",
"Ts = 143.6;\t\t\t#Saturation temperature at P2 in oC\n",
"# Calculations\n",
"x = (n-1)/n;\t\t\t#Ratio\n",
"T2 = ((P2/P1)**x)*T1;\t\t\t#Temperature at point 2 in K\n",
"Ds = P2/Ps;\t\t\t#Degree of supersaturation\n",
"Du = Ts-(T2-273);\t\t\t#Degree of undercooling\n",
"\n",
"# Results\n",
"print 'Degree of supersaturation is %3.2f \\\n",
"\\nDegree of undercooling %3.0f C'%(Ds,Du)\n"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Example 4.12 Page no : 174"
]
},
{
"cell_type": "code",
"execution_count": 14,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"Quantity of steam used per second is 0.012 kg/s \n",
"Exit velocity of steam is 816.09 m/s\n"
]
}
],
"source": [
"\n",
"import math \n",
"\n",
"# Variables\n",
"P1 = 9.;\t\t\t#Pressure at point 1 in bar\n",
"P2 = 1.;\t\t\t#Pressure at point 2 in bar\n",
"Dt = 0.0025;\t\t\t#Throat diameter in m\n",
"nN = 0.9;\t\t\t#Nozzle efficiency\n",
"n = 1.135;\t\t\t#Adiabatic gas constant\n",
"h1 = 2770.;\t\t\t#Enthalpy at point 1 in kJ/kg\n",
"ht = 2670.;\t\t\t#Throat enthlapy in kJ/kg\n",
"h3 = 2400.;\t\t\t#Enthlapy at point 2 in kJ/kg\n",
"x2 = 0.96;\t\t\t#Dryness fraction 2\n",
"vg2 = 0.361;\t\t\t#Specific volume in m**3/kg\n",
"\n",
"# Calculations\n",
"x = n/(n-1);\t\t\t#Ratio\n",
"Pt = ((2/(n+1))**x)*P1;\t\t\t#Throat pressure in bar\n",
"Ct = math.sqrt(2000*(h1-ht)*nN);\t\t\t#Throat velocity in m/s\n",
"At = (3.147*2*(Dt**2))/4;\t\t\t#Throat area in m**2\n",
"vt = x2*vg2;\t\t\t#Specific volume at throat in m**3/kg\n",
"m = (At*Ct)/vt;\t\t\t#Mass flow rate of steam in kg/s\n",
"hact = nN*(h1-h3);\t\t\t#Actual enthalpy drop in kJ/kg\n",
"C2 = math.sqrt(2000*hact);\t\t\t#Exit velocity of steam in m/s\n",
"\n",
"# Results\n",
"print 'Quantity of steam used per second is %3.3f kg/s \\\n",
"\\nExit velocity of steam is %3.2f m/s'%(m,C2)\n"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Example 4.13 Page no : 202"
]
},
{
"cell_type": "code",
"execution_count": 15,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"Blade angles are 33 degrees, 33 degrees \n",
"Tangential force on blades is 840 N \n",
"Axial thrust is 0 \n",
"Diagram power is 336 kW \n",
"Diagram efficiency 89.6 percent\n"
]
}
],
"source": [
"\n",
"# Variables\n",
"C1 = 1000.;\t\t\t#Steam velocity in m/s\n",
"a1 = 20.;\t\t\t#Nozzle angle in degrees\n",
"U = 400.;\t\t\t#Mean blade speed in m/s\n",
"m = 0.75;\t\t\t#Mass flow rate of steam in kg/s\n",
"b1 = 33.;\t\t\t#Blade angle at inlet from the velocity triangle in degrees\n",
"b2 = b1;\t\t\t#Blade angle at exit from the velocity triangle in degrees\n",
"Cx = 1120.;\t\t\t#Change in whirl velocity from the velocity triangle in m/s\n",
"Ca = 0;\t\t \t#Change in axial velocity from the velocity triangle in m/s\n",
"\n",
"# Calculations\n",
"Fx = m*Cx;\t\t \t #Tangential force on blades in N\n",
"Fy = m*Ca;\t\t\t #Axial thrust in N\n",
"W = (m*Cx*U)/1000;\t\t\t#Diagram power in kW\n",
"ndia = ((2*U*Cx)/(C1**2))*100;\t\t\t#Diagram efficiency\n",
"\n",
"# Results\n",
"print 'Blade angles are %3.0f degrees, %3.0f degrees \\\n",
"\\nTangential force on blades is %3.0f N \\\n",
"\\nAxial thrust is %3.0f \\\n",
"\\nDiagram power is %3.0f kW \\\n",
"\\nDiagram efficiency %3.1f percent'%(b1,b2,Fx,Fy,W,ndia)\n"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Example 4.14 Page no : 203"
]
},
{
"cell_type": "code",
"execution_count": 14,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"Power developed is 3800 kW \n",
"Blade efficiency is 78.7 percent \n",
"Steam consumed is 9.46 kg/kWh\n"
]
}
],
"source": [
"# Variables\n",
"D = 2.5;\t\t\t#Mean diameter of blade ring in m\n",
"N = 3000.;\t\t\t#Speed in rpm\n",
"a1 = 20.;\t\t\t#Nozzle angle in degrees\n",
"r = 0.4;\t\t\t#Ratio blade velocity to steam velocity\n",
"Wr = 0.8;\t\t\t#Blade friction factor\n",
"m = 10.;\t\t\t#Steam flow in kg/s\n",
"x = 3.;\t \t\t#Sum in blade angles in degrees\n",
"b1 = 32.5;\t\t\t#Blade angle at inlet from the velocity triangle in degrees\n",
"W1 = 626.7;\t\t\t#Relative velocity at inlet from the velocity triangle in m/s\n",
"Cx = 967.;\t\t\t#Change in whirl velocity from the velocity triangle in m/s\n",
"\n",
"# Calculations\n",
"U = (3.147*D*N)/60;\t\t\t#Blade velocity in m/s\n",
"C1 = U/r;\t\t\t#Steam velocity in m/s\n",
"b2 = b1-x;\t\t\t#Blade angle at exit in degrees\n",
"W2 = Wr*W1;\t\t\t#Relative velocity at outlet from the velocity triangle in m/s\n",
"W = (m*Cx*U)/1000;\t\t\t#Power developed in kW\n",
"ndia = ((2*U*Cx)/(C1**2))*100;\t\t\t#Blade efficiency\n",
"sc = (m*3600)/W;\t\t\t#Steam consumption in kg/kWh\n",
"\n",
"# Results\n",
"print 'Power developed is %3.0f kW \\\n",
"\\nBlade efficiency is %3.1f percent \\\n",
"\\nSteam consumed is %3.2f kg/kWh'%(round(W,-1),ndia,sc)\n"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Example 4.15 Page no : 204"
]
},
{
"cell_type": "code",
"execution_count": 17,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"Blading efficiency is 68.3 percent \n",
"Blade velocity co-efficient is 0.49\n"
]
}
],
"source": [
"\n",
"# Variables\n",
"m = 3.;\t \t\t#Mass flow rate of steam in kg/s\n",
"C1 = 425.;\t\t\t#Steam velocity in m/s\n",
"r = 0.4;\t\t\t#Ratio of blade speed to jet speed\n",
"W = 170.;\t\t\t#Stage output in kW\n",
"IL = 15.;\t\t\t#Internal losses in kW\n",
"a1 = 16.;\t\t\t#Nozzle angle in degrees\n",
"b2 = 17.;\t\t\t#Blade angle at exit in degrees\n",
"W1 = 265.;\t\t\t#Relative velocity at inlet from the velocity triangle in m/s\n",
"W2 = 130.;\t\t\t#Relative velocity at outlet from the velocity triangle in m/s\n",
"\n",
"# Calculations\n",
"U = C1*r;\t\t\t#Blade speed in m/s\n",
"P = (W+IL)*1000;\t\t\t#Total power developed in W\n",
"Cx = P/(m*W);\t\t\t#Change in whirl velocity in m/s\n",
"ndia = ((2*U*Cx)/(C1**2))*100;\t\t\t#Blading efficiency\n",
"Wr = W2/W1;\t\t\t#Blade velocity co-efficient\n",
"\n",
"# Results\n",
"print 'Blading efficiency is %3.1f percent \\\n",
"\\nBlade velocity co-efficient is %3.2f'%(ndia,Wr)\n"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Example 4.16 Page no : 205"
]
},
{
"cell_type": "code",
"execution_count": 18,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"Blade angles assumed are 34 degrees, 41 degrees \n",
"Power developed by turbine is 52.8 kW\n"
]
}
],
"source": [
"\n",
"# Variables\n",
"C1 = 375.;\t\t\t#Steam velocity in m/s\n",
"a1 = 20.;\t\t\t#Nozzle angle\n",
"U = 165.;\t\t\t#Blade speed in m/s\n",
"m = 1.;\t\t\t#Mass flow rate of steam in kg/s\n",
"Wr = 0.85;\t\t\t#Blade friction factor\n",
"Ca1 = 130.;\t\t\t#Axial velocity at inlet from the velocity triangle in m/s\n",
"Ca2 = Ca1;\t\t\t#Axial velocity at outlet in m/s\n",
"W1 = 230.;\t\t\t#Relative velocity at inlet from the velocity triangle in m/s\n",
"Cx = 320.;\t\t\t#Change in whirl velocity from the velocity triangle in m/s\n",
"\n",
"# Calculations\n",
"b2 = 41;\t\t\t#Blade angle at exit from the velocity triangle in degrees\n",
"b1 = 34;\t\t\t#Blade angle at exit from the velocity triangle in degrees\n",
"W = (m*Cx*U)/1000;\t\t\t#Power developed by turbine in kW\n",
"\n",
"# Results\n",
"print 'Blade angles assumed are %3.0f degrees, %3.0f degrees \\\n",
"\\nPower developed by turbine is %3.1f kW'%(b1,b2,W)\n"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Example 4.17 Page no : 206"
]
},
{
"cell_type": "code",
"execution_count": 19,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"Nozzle angle is 19 degrees \n",
"Blade angles are 33 degrees, 36 degrees\n"
]
}
],
"source": [
"\n",
"# Variables\n",
"m = 2.;\t\t\t#Mass flow rate of steam in kg/s\n",
"W = 130.;\t\t\t#Turbine power in kW\n",
"U = 175.;\t\t\t#Blade velocity in m/s\n",
"C1 = 400.;\t\t\t#Steam velocity in m/s\n",
"Wr = 0.9;\t\t\t#Blade friction factor\n",
"W1 = 240.;\t\t\t#Realtive velocity at inlet from the velocity triangle in m/s\n",
"\n",
"# Calculations\n",
"Cx1 = (W*1000)/(m*U);\t\t\t#Whirl velocity at inlet in m/s\n",
"W2 = Wr*W1;\t\t\t#Realtive velocity at outlet from the velocity triangle in m/s\n",
"a1 = 19;\t\t\t#Nozzle angle from the velocity triangle in degrees\n",
"b1 = 33;\t\t\t#Blade angle at inlet from the velocity triangle in degrees\n",
"b2 = 36;\t\t\t#Blade angle at outlet from the velocity triangle in degrees\n",
"\n",
"# Results\n",
"print 'Nozzle angle is %3.0f degrees \\\n",
"\\nBlade angles are %3.0f degrees, %3.0f degrees'%(a1,b1,b2)\n"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Example 4.18 Page no : 207"
]
},
{
"cell_type": "code",
"execution_count": 20,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"Diagram efficiency is 76.2 percent\n"
]
}
],
"source": [
"# find Diagram efficiency\n",
"\n",
"# Variables\n",
"U = 150.;\t\t\t#Blade speed in m/s\n",
"m = 3.;\t\t\t#Mass flow rate of steam in kg/s\n",
"P = 10.5;\t\t\t#Pressure in bar\n",
"r = 0.21;\t\t\t#Ratio blade velocity to steam velocity\n",
"a1 = 16.;\t\t\t#Nozzle angle in first stage in degrees\n",
"b2 = 20.;\t\t\t#Blade angle at exit in first stage in degrees\n",
"a3 = 24.;\t\t\t#Nozzle angle in second stage in degrees\n",
"b4 = 32.;\t\t\t#Blade angle at exit in second stage in degrees\n",
"Wr = 0.79;\t\t\t#Blade friction factor for first stage\n",
"Wr2 = 0.88;\t\t\t#Blade friction factor for second stage\n",
"Cr = 0.83;\t\t\t#Blade velocity coefficient\n",
"W1 = 570.;\t\t\t#Relative velocity at inlet from the velocity triangle for first stage in m/s\n",
"C2 = 375.;\t\t\t#Velocity in m/s\n",
"W3 = 185.;\t\t\t#Relative velocity at inlet from the velocity triangle for second stage in m/s\n",
"\n",
"# Calculations\n",
"C1 = U/r;\t\t\t#Steam speed at exit in m/s\n",
"W2 = Wr*W1;\t\t\t#Relative velocity at outlet for first stage in m/s\n",
"C3 = Cr*C2;\t\t\t#Steam velocity at inlet for second stage in m/s\n",
"W4 = Wr2*W3;\t\t\t#Relative velocity at exit for second stage in m/s\n",
"DW1 = W1+W2;\t\t\t#Change in relative velocity for first stage in m/s\n",
"DW2 = 275;\t\t\t#Change in relative velocity from the velocity triangle for second stage in m/s\n",
"ndia = ((2*U*(DW1+DW2))/(C1**2))*100;\t\t\t#Diagram efficiency\n",
"\n",
"# Results\n",
"print 'Diagram efficiency is %3.1f percent'%(ndia)\n"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Example 4.19 Page no : 208"
]
},
{
"cell_type": "code",
"execution_count": 21,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"Blade speed is 124.7 m/s \n",
"Blade tip angles of the fixed blade are 17 degrees and 43 degrees \n",
"Diagram efficiency is 79.5 percent\n"
]
}
],
"source": [
"import math\n",
"# Variables\n",
"b1 = 30.;\t\t\t#Blade angle at inlet in first stage in degrees\n",
"b2 = 30.;\t\t\t#Blade angle at exit in first stage in degrees\n",
"b3 = 30.;\t\t\t#Blade angle at inlet in second stage in degrees\n",
"b4 = 30.;\t\t\t#Blade angle at exit in second stage in degrees\n",
"t1 = 240.;\t\t\t#Temperature at entry in oC\n",
"P1 = 11.5;\t\t\t#Pressure at entry in bar\n",
"P2 = 5.;\t\t\t#Pressure in wheel chamber in bar\n",
"vl = 10.;\t\t\t#Loss in velocity in percent\n",
"h = 155.;\t\t\t#Enthalpy at P2 in kJ/kg\n",
"W4 = 17.3;\t\t\t#Relative velocity at exit from the velocity triangle for second stage in m/s\n",
"a4 = 90.;\t\t\t#Nozzle angle in second stage in degrees\n",
"C3 = 33.;\t\t\t#Steam velocity at inlet from the velocity triangle for second stage in m/s\n",
"W2 = 49.;\t\t\t#Relative velocity at outlet from the velocity triangle for first stage in m/s\n",
"x = 15.;\t\t\t#Length of AB assumed for drawing velocity triangle in mm\n",
"y = 67.;\t\t\t#Length of BC from the velocity triangle in mm\n",
"\n",
"# Calculations\n",
"C1 = math.sqrt(2000*h);\t\t\t#Velocity of steam in m/s\n",
"W3 = W4/0.9;\t\t\t#Relative velocity at inlet for second stage in m/s\n",
"C2 = C3/0.9;\t\t\t#Velocity in m/s\n",
"W1 = W2/0.9;\t\t\t#Relative velocity at inlet for first stage in m/s\n",
"C1n = C1/y;\t\t\t#Velocity of steam in m/s\n",
"U = x*C1n;\t\t\t#Blade speed in m/s\n",
"a3 = 17.;\t\t\t#Nozzle angle in second stage from the velocity triangle in degrees\n",
"a2 = 43.;\t\t\t#Nozzle angle from the velocity triangle in degrees\n",
"DW1 = 731.5;\t\t\t#Change in relative velocity from the velocity triangle for first stage in m/s\n",
"DW2 = 257.5;\t\t\t#Change in relative velocity from the velocity triangle for second stage in m/s\n",
"ndia = ((2*U*(DW1+DW2))/(C1**2))*100;\t\t\t#Diagram efficiency\n",
"\n",
"# Results\n",
"print 'Blade speed is %3.1f m/s \\\n",
"\\nBlade tip angles of the fixed blade are %3.0f degrees and %3.0f degrees \\\n",
"\\nDiagram efficiency is %3.1f percent'%(U,a3,a2,ndia)\n"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Example 4.20 Page no : 210"
]
},
{
"cell_type": "code",
"execution_count": 17,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"Blade speed is 160.5 m/s \n",
"Power developed by the turbine is 530.66 kW\n"
]
}
],
"source": [
"\n",
"# Variables\n",
"C1 = 600.;\t\t\t#Steam velocity in m/s\n",
"b1 = 30.;\t\t\t#Blade angle at inlet in first stage in degrees\n",
"b2 = 30.;\t\t\t#Blade angle at exit in first stage in degrees\n",
"b3 = 30.;\t\t\t#Blade angle at inlet in second stage in degrees\n",
"b4 = 30.;\t\t\t#Blade angle at exit in second stage in degrees\n",
"a4 = 90.;\t\t\t#Nozzle angle in second stage in degrees\n",
"m = 3.;\t\t\t#Mass of steam in kg/s\n",
"x = 15.;\t\t\t#Length for drawing velocity triangle in mm\n",
"y = 56.;\t\t\t#Length of BC from the velocity triangle in mm\n",
"\n",
"# Calculations\n",
"C1n = round(C1/y,1);\t\t\t#Velocity of steam in m/s\n",
"U = round(x*C1n,1);\t\t\t#Blade speed in m/s\n",
"l = 103.;\t\t\t#Length from velocity triangle in mm\n",
"P = (m*l*C1n*U)/1000;\t\t\t#Power developed in kW\n",
"\n",
"# Results\n",
"print 'Blade speed is %3.1f m/s \\\n",
"\\nPower developed by the turbine is %3.2f kW'%(U,P)\n"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Example 4.21 Page no : 211"
]
},
{
"cell_type": "code",
"execution_count": 18,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"Mean diameter of drum is 963 mm \n",
"Volume of steam flowing per second is 8.18 m**3/s\n"
]
}
],
"source": [
"import math\n",
"# Variables\n",
"N = 400.;\t\t\t#Speed in rpm\n",
"m = 8.33;\t\t\t#Mass of steam in kg/s\n",
"P = 1.6;\t\t\t#Pressure of steam in bar\n",
"x = 0.9;\t\t\t#Dryness fraction\n",
"W = 10.;\t\t\t#Stage power in kW\n",
"r = 0.75;\t\t\t#Ratio of axial flow velocity to blade velocity\n",
"a1 = 20.;\t\t\t#Nozzle angle at inlet in degrees\n",
"a2 = 35.;\t\t\t#Nozzle angle at exit in degrees\n",
"b1 = a2;\t\t\t#Blade tip angle at exit in degrees\n",
"b2 = a1;\t\t\t#Blade tip angle at inlet in degrees\n",
"a = 25.;\t\t\t#Length of AB from velocity triangle in mm\n",
"vg = 1.091;\t\t\t#Specific volume of steam from steam tables in (m**3)/kg\n",
"\n",
"# Calculations\n",
"Cx = 73.5;\t\t\t#Change in whirl velocity from the velocity triangle by measurement in mm\n",
"y = Cx/a;\t\t\t#Ratio of change in whirl velocity to blade speed\n",
"U = math.sqrt((W*1000)/(m*y));\t\t\t#Blade speed in m/s\n",
"D = ((U*60)/(3.147*N))*1000;\t\t\t#Mean diameter of drum in mm\n",
"v = m*x*vg;\t\t\t#Volume flow rate of steam in (m**3)/s\n",
"\n",
"# Results\n",
"print 'Mean diameter of drum is %3.0f mm \\\n",
"\\nVolume of steam flowing per second is %3.2f m**3/s'%(D,v)\n",
"\n",
"# rounding off error"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Example 4.22 Page no : 212"
]
},
{
"cell_type": "code",
"execution_count": 24,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"Drum diameter is 1.030 m \n",
"Blade height is 78 mm\n"
]
}
],
"source": [
"\n",
"import math\n",
"\n",
"# Variables\n",
"N = 300.;\t\t\t#Speed in rpm\n",
"m = 4.28;\t\t\t#Mass of steam in kg/s\n",
"P = 1.9;\t\t\t#Pressure of steam in bar\n",
"x = 0.93;\t\t\t#Dryness fraction\n",
"W = 3.5;\t\t\t#Stage power in kW\n",
"r = 0.72;\t\t\t#Ratio of axial flow velocity to blade velocity\n",
"a1 = 20.;\t\t\t#Nozzle angle at inlet in degrees\n",
"b2 = a1;\t\t\t#Blade tip angle at inlet in degrees\n",
"l = 0.08;\t\t\t#Tip leakage steam\n",
"vg = 0.929;\t\t\t#Specific volume of steam from steam tables in (m**3)/kg\n",
"\n",
"# Calculations\n",
"mact = m-(m*l);\t\t\t#Actual mass of steam in kg/s\n",
"a = (3.147*N)/60;\t\t\t#Ratio of blade velocity to mean dia\n",
"b = r*a;\t\t\t#Ratio of axial velocity to mean dia\n",
"c = 46;\t\t\t#Ratio of change in whirl velocity to mean dia\n",
"D = math.sqrt((W*1000)/(mact*c*a));\t\t\t#Mean dia in m\n",
"Ca = b*D;\t\t\t#Axial velocity in m/s\n",
"h = ((mact*x*vg)/(3.147*D*Ca))*1000;\t\t\t#Blade height in mm\n",
"D1 = D-(h/1000);\t\t\t#Drum dia in m\n",
"\n",
"# Results\n",
"print 'Drum diameter is %3.3f m \\\n",
"\\nBlade height is %3.0f mm'%(D1,h)\n"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Example 4.23 Page no : 214"
]
},
{
"cell_type": "code",
"execution_count": 27,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"Rotor blade angles are 58.56 degrees and 58.56 degrees \n",
"Flow coefficient is 0.611 \n",
"Blade loading coefficient is 2 \n",
"Power developed is 13.8 MW\n"
]
}
],
"source": [
"import math\n",
"# Variables\n",
"P0 = 800.;\t\t\t#Steam pressure in kPa\n",
"P2 = 100.;\t\t\t#Pressure at point 2 in kPa\n",
"T0 = 973.;\t\t\t#Steam temperature in K\n",
"a1 = 73.;\t\t\t#Nozzle angle in degrees\n",
"ns = 0.9;\t\t\t#Steam efficiency\n",
"m = 35.;\t\t\t#Mass flow rate in kg/s\n",
"Cp = 1.005;\t\t\t#Specific heat at constant pressure in kJ/kg-K\n",
"y = 1.4;\t\t\t#Ratio of specific heats\n",
"\n",
"# Calculations\n",
"tanb1 = math.tan(math.radians(a1))/2;\t\t\t#Blade angle at inlet in degrees\n",
"b1 = math.degrees(math.atan(tanb1))\n",
"b2 = b1;\t\t\t#Blade angle at exit in degrees\n",
"p = 2/math.tan(math.radians(a1));\t\t\t#Flow coefficient\n",
"s = p*(math.tan(math.radians(b1))+math.tan(math.radians(b2)));\t\t\t#Blade loading coefficient\n",
"Dh = ns*Cp*T0*(1-((P2/P0)**((y-1)/y)));\t\t\t#Difference in enthalpies in kJ/kg\n",
"W = (m*Dh)/1000;\t\t\t#Power developed in MW\n",
"\n",
"# Results\n",
"print 'Rotor blade angles are %3.2f degrees and %3.2f degrees \\\n",
"\\nFlow coefficient is %3.3f \\\n",
"\\nBlade loading coefficient is %3.0f \\\n",
"\\nPower developed is %3.1f MW'%(b1,b2,p,s,W)\n",
"\n",
"# answer in book is wrong for W. please check."
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Example 4.24 Page no : 215"
]
},
{
"cell_type": "code",
"execution_count": 10,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"Rotor blade angles for first stage are 53.95 degrees and 53.95 degrees \n",
"Rotor blade angles for second stage are 53.95 degrees and 53.95 degrees \n",
"Power developed is 9.90 MW \n",
"Final state of steam at first stage is 3306.52 kJ/kg \n",
"Final state of steam at second stage is 3257.00 kJ/kg \n",
"Blade height at first stage is 0.0114 m \n",
"Blade height at second stage is 0.0139 m\n"
]
}
],
"source": [
"import math\n",
"\n",
"# Variables\n",
"P0 = 100.;\t\t\t#Steam pressure in bar\n",
"T0 = 773.;\t\t\t#Steam temperature in K\n",
"a1 = 70.;\t\t\t#Nozzle angle in degrees\n",
"ns = 0.78;\t\t\t#Steam efficiency\n",
"m = 100.;\t\t\t#Mass flow rate of steam in kg/s\n",
"D = 1.;\t\t\t#Turbine diameter in m\n",
"N = 3000.;\t\t\t#Turbine speed in rpm\n",
"h0 = 3370.;\t\t\t#Steam enthalpy from Moiller chart in kJ/kg\n",
"v2 = 0.041;\t\t\t#Specific volume at P2 from steam tables in (m**3)/kg\n",
"v4 = 0.05;\t\t\t#Specific volume at P4 from steam tables in (m**3)/kg\n",
"\n",
"# Calculations\n",
"U = (3.147*D*N)/60;\t\t\t#Blade speed in m/s\n",
"C1 = (2*U)/math.sin(math.radians(a1));\t\t\t#Steam speed in m/s\n",
"b1 = math.tan(math.radians(a1))/2;\t\t\t#Blade angle at inlet for first stage in degrees\n",
"b1 = math.degrees(math.atan(b1))\n",
"b2 = b1;\t\t\t#Blade angle at exit for first stage in degrees\n",
"b3 = b1;\t\t\t#Blade angle at inlet for second stage in degrees\n",
"b4 = b2;\t\t\t#Blade angle at exit for second stage in degrees\n",
"Wt = (4*m*(U**2))/(10**6);\t\t\t#Total workdone in MW\n",
"Dh = (2*(U**2))/1000;\t\t\t#Difference in enthalpies in kJ/kg\n",
"Dhs = Dh/ns;\t\t\t#Difference in enthalpies in kJ/kg\n",
"h2 = h0-Dh;\t\t\t#Enthalpy at point 2 in kJ/kg\n",
"h2s = h0-Dhs;\t\t\t#Enthalpy at point 2s in kJ/kg\n",
"Dh2 = (2*(U**2))/1000;\t\t\t#Difference in enthalpies in kJ/kg\n",
"Dh2s = Dh2/ns;\t\t\t#Difference in enthalpies in kJ/kg\n",
"h4 = h2-Dh2;\t\t\t#Enthalpy at point 4 in kJ/kg\n",
"h4s = h2-Dh2s;\t\t\t#Enthalpy at point 4s in kJ/kg\n",
"Ca = C1*math.cos(math.radians(a1));\t\t\t#Axial velocity in m/s\n",
"hI = (m*v2)/(math.pi*D*Ca);\t\t\t#Blade height at first stage in m/s\n",
"hII = (m*v4)/(math.pi*D*Ca);\t\t\t#Blade height at second stage in m/s\n",
"\n",
"# Results\n",
"print 'Rotor blade angles for first stage are %3.2f degrees and %3.2f degrees \\\n",
"\\nRotor blade angles for second stage are %3.2f degrees and %3.2f degrees \\\n",
"\\nPower developed is %3.2f MW \\\n",
"\\nFinal state of steam at first stage is %3.2f kJ/kg \\\n",
"\\nFinal state of steam at second stage is %3.2f kJ/kg \\\n",
"\\nBlade height at first stage is %3.4f m \\\n",
"\\nBlade height at second stage is %3.4f m'%(b1,b2,b3,b4,Wt,h2s,h4s,hI,hII)\n",
"\n",
"# rounding off error"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Example 4.25 Page no : 218"
]
},
{
"cell_type": "code",
"execution_count": 4,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"Rotor blade angles for first stage are 64.11 degrees and 64.11 degrees \n",
"Rotor blade angles for second stage are 34.48 degrees and 34.48 degrees \n",
"Power developed is 19.81 MW \n",
"Final state of steam at first stage is 3171.9 kJ/kg \n",
"Final state of steam at second stage is 3065.27 kJ/kg \n",
"Rotor blade height is 0.0146 m\n"
]
}
],
"source": [
"import math\n",
"\n",
"# Variables\n",
"P0 = 100.;\t\t\t#Steam pressure in bar\n",
"T0 = 773.;\t\t\t#Steam temperature in K\n",
"a1 = 70.;\t\t\t#Nozzle angle in degrees\n",
"ns = 0.78;\t\t\t#Steam efficiency\n",
"m = 100.;\t\t\t#Mass flow rate of steam in kg/s\n",
"D = 1.;\t\t\t#Turbine diameter in m\n",
"N = 3000.;\t\t\t#Turbine speed in rpm\n",
"h0 = 3370.;\t\t\t#Steam enthalpy from Moiller chart in kJ/kg\n",
"P4 = 27.;\t\t\t#Pressure at point 4 in bar\n",
"T4 = 638.;\t\t\t#Temperature at point 4 in K\n",
"v4 = 0.105;\t\t\t#Specific volume at P4 from mollier chart in (m**3)/kg\n",
"ns = 0.65;\t\t\t#Stages efficiency\n",
"\n",
"# Calculations\n",
"U = (3.147*D*N)/60;\t\t\t#Blade speed in m/s\n",
"C1 = (4*U)/math.sin(math.radians(a1));\t\t\t#Steam speed in m/s\n",
"Ca = C1*math.cos(math.radians(a1));\t\t\t#Axial velocity in m/s\n",
"tanb1 = (3*U)/Ca;\t\t\t#Blade angle at inlet for first stage in degrees\n",
"b1 = math.degrees(math.atan(tanb1))\n",
"b2 = b1;\t\t\t#Blade angle at exit for first stage in degrees\n",
"b4 = math.degrees(math.atan(U/Ca));\t\t\t#Blade angle at exit for second stage in degrees\n",
"b3 = b4;\t\t\t#Blade angle at inlet for second stage in degrees\n",
"WI = m*6*(U**2);\t\t\t#Power developed in first stage in MW\n",
"WII = m*2*(U**2);\t\t\t#Power developed in second stage in MW\n",
"W = (WI+WII)/(10**6);\t\t\t#Total power developed in MW\n",
"Dh = (W*1000)/100;\t\t\t#Difference in enthalpies in kJ/kg\n",
"Dhs = (W*1000)/(ns*100);\t\t\t#Difference in enthalpies in kJ/kg\n",
"h4 = h0-Dh;\t\t\t#Enthalpy at point 4 in kJ/kg\n",
"h4s = h0-Dhs;\t\t\t#Enthalpy at point 4s in kJ/kg\n",
"h = (m*v4)/(3.147*D*Ca);\t\t\t#Rotor blade height in m\n",
"\n",
"\n",
"# Results\n",
"print 'Rotor blade angles for first stage are %3.2f degrees and %3.2f degrees \\\n",
"\\nRotor blade angles for second stage are %3.2f degrees and %3.2f degrees \\\n",
"\\nPower developed is %3.2f MW \\\n",
"\\nFinal state of steam at first stage is %3.1f kJ/kg \\\n",
"\\nFinal state of steam at second stage is %3.2f kJ/kg \\\n",
"\\nRotor blade height is %3.4f m'%(b1,b2,b3,b4,W,h4,h4s,h)\n",
"\n",
"# rounding off error"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Example 4.26 Page no : 221"
]
},
{
"cell_type": "code",
"execution_count": 40,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"Blade angle at inlet is 10 degrees \n",
"Blade angle at exit is 60 degrees\n"
]
}
],
"source": [
"\n",
"import math \n",
"\n",
"# Variables\n",
"a1 = 30.;\t\t\t#Nozzle angle in degrees\n",
"Ca = 180.;\t\t\t#Axial velocity in m/s\n",
"U = 280.;\t\t\t#Rotor blade speed in m/s\n",
"R = 0.5;\t\t\t#Degree of reaction\n",
"\n",
"# Calculations\n",
"a1n = 90-a1;\t\t\t#Nozzle angle measured from axial direction in degrees\n",
"Cx1 = Ca*math.tan(math.radians(a1n));\t\t\t#Whirl velocity in m/s\n",
"b1 = math.degrees(math.atan((Cx1-U)/Ca));\t\t\t#Blade angle at inlet in degrees\n",
"b2 = a1n;\t\t\t#Blade angle at exit in degrees\n",
"\n",
"# Results\n",
"print 'Blade angle at inlet is %3.0f degrees \\\n",
"\\nBlade angle at exit is %3.0f degrees'%(b1,b2)\n"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Example 4.27 Page no : 222"
]
},
{
"cell_type": "code",
"execution_count": 30,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"Rotor blade angles are 0 degrees and 70 degrees \n",
"Power developed is 1.92 MW \n",
"Isentropic enthalpy drop is 30.12 kJ/kg\n"
]
}
],
"source": [
"\n",
"import math \n",
"\n",
"# Variables\n",
"P0 = 800.;\t\t\t#Steam pressure in kPa\n",
"T0 = 900.;\t\t\t#Steam temperature in K\n",
"a1 = 70.;\t\t\t#Nozzle angle in degrees\n",
"ns = 0.85;\t\t\t#Steam efficiency\n",
"m = 75.;\t\t\t#Mass flow rate of steam in kg/s\n",
"R = 0.5;\t\t\t#Degree of reaction\n",
"U = 160.;\t\t\t#Blade speed in m/s\n",
"\n",
"# Calculations\n",
"C1 = U/math.sin(a1);\t\t\t#Steam speed in m/s\n",
"Ca = C1*math.cos(a1);\t\t\t#Axial velocity in m/s\n",
"b1 = 0;\t\t\t #Blade angle at inlet from velocity triangle in degrees\n",
"b2 = a1; \t\t\t#Blade angle at exit in degrees\n",
"a2 = b1;\t\t\t #Nozzle angle in degrees\n",
"W = (m*(U**2))/(10**6);\t\t\t#Power developed in MW\n",
"Dhs = (W*1000)/(ns*m);\t\t\t#Isentropic enthalpy drop in kJ/kg\n",
"\n",
"# Results\n",
"print 'Rotor blade angles are %3.0f degrees and %3.0f degrees \\\n",
"\\nPower developed is %3.2f MW \\\n",
"\\nIsentropic enthalpy drop is %3.2f kJ/kg'%(b1,b2,W,Dhs)\n"
]
}
],
"metadata": {
"kernelspec": {
"display_name": "Python 2",
"language": "python",
"name": "python2"
},
"language_info": {
"codemirror_mode": {
"name": "ipython",
"version": 2
},
"file_extension": ".py",
"mimetype": "text/x-python",
"name": "python",
"nbconvert_exporter": "python",
"pygments_lexer": "ipython2",
"version": "2.7.6"
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PKIThermal Engineering/ch5.ipynb{
"metadata": {
"name": "",
"signature": "sha256:2b6bc93922bd7b11c4334e4b77fa7e0b05d2efd84a162a89a3c4553815d1a094"
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"worksheets": [
{
"cells": [
{
"cell_type": "heading",
"level": 1,
"metadata": {},
"source": [
"Chapter 5 :\n",
"Air Compressors"
]
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 5.1 Page no : 250"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"# Variables\n",
"D = 0.2;\t\t\t#Cylinder diameter in m\n",
"L = 0.3;\t\t\t#Cylinder Stroke in m\n",
"P1 = 1.;\t\t\t#Pressure at entry in bar\n",
"T1 = 300.;\t\t\t#Temperature at entry in K\n",
"P2 = 8.;\t\t\t#Pressure at exit in bar\n",
"n = 1.25;\t\t\t#Adiabatic gas constant\n",
"N = 100.;\t\t\t#Speed in rpm\n",
"R = 287.;\t\t\t#Universal gas constant in J/kg-K\n",
"\n",
"# Calculations\n",
"x = (n-1)/n;\t\t\t#Ratio\n",
"V1 = (3.147*L*(D**2))/4;\t\t\t#Volume of cylinder in m**3/cycle\n",
"W = (P1*(10**5)*V1*(((P2/P1)**x)-1))/x;\t\t\t#Work done in J/cycle\n",
"Pc = (W*100)/(60*1000);\t\t\t#Indicated power of compressor in kW\n",
"m = (P1*(10**5)*V1)/(R*T1);\t\t\t#Mass of air delivered in kg/cycle\n",
"md = m*N;\t\t\t#Mass delivered per minute in kg\n",
"T2 = T1*((P2/P1)**x);\t\t\t#Temperature of air delivered in K\n",
"\n",
"# Results\n",
"print 'Indicated power of compressor is %3.2f kW \\\n",
"\\nMass of air delivered by compressor per minute is %3.2f kg \\\n",
"\\nTemperature of air delivered is %3.1fK'%(Pc,md,T2)\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Indicated power of compressor is 4.06 kW \n",
"Mass of air delivered by compressor per minute is 1.10 kg \n",
"Temperature of air delivered is 454.7K\n"
]
}
],
"prompt_number": 1
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 5.2 Page no : 251"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"import math \n",
"\n",
"# Variables\n",
"IP = 37.;\t\t\t#Indicated power in kW\n",
"P1 = 0.98;\t\t\t#Pressure at entry in bar\n",
"T1 = 288.;\t\t\t#Temperature at entry in K\n",
"P2 = 5.8;\t\t\t#Pressure at exit in bar\n",
"n = 1.2;\t\t\t#Adiabatic gas constant\n",
"N = 100.;\t\t\t#Speed in rpm\n",
"Ps = 151.5;\t\t\t#Piston speed in m/min\n",
"a = 2.;\t\t\t#For double acting compressor\n",
"\n",
"# Calculations\n",
"L = Ps/(2*N);\t\t\t#Stroke length in m\n",
"x = (n-1)/n;\t\t\t#Ratio\n",
"r = (3.147*L)/4;\t\t\t#Ratio of volume to bore\n",
"D = math.sqrt((IP*1000*60*x)/(N*a*r*P1*(10**5)*(((P2/P1)**x)-1)));\t\t\t#Cylinder diameter in m\n",
"\n",
"# Results\n",
"print 'Stroke length of cylinder is %3.4f m \\\n",
"\\nCylinder diameter is %3.4f m'%(L,D)\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Stroke length of cylinder is 0.7575 m \n",
"Cylinder diameter is 0.3030 m\n"
]
}
],
"prompt_number": 2
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 5.3 Page no : 251"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"import math \n",
"\n",
"# Variables\n",
"IP = 11.;\t\t\t#Indicated power in kW\n",
"P1 = 1.;\t\t\t#Pressure at entry in bar\n",
"P2 = 7.;\t\t\t#Pressure at exit in bar\n",
"n = 1.2;\t\t\t#Adiabatic gas consmath.tant\n",
"Ps = 150.;\t\t\t#Piston speed in m/s\n",
"a = 2.; \t\t\t#For double acting compressor\n",
"r = 1.5;\t\t\t#Storke to bore ratio\n",
"\n",
"# Calculations\n",
"x = (n-1)/n;\t\t\t#Ratio\n",
"y = 3.147/(4*(r**2));\t\t\t#Ratio of volume to the cube of stroke\n",
"z = (P1*(10**2)*y*(((P2/P1)**x)-1))/x;\t\t\t#Ratio of workdone to the cube of stroke\n",
"L = (math.sqrt(IP/(z*Ps)))*1000;\t\t\t#Stroke in mm\n",
"D = (L/r);\t\t\t#Bore in mm\n",
"\n",
"# Results\n",
"print 'Stroke length of cylinder is %3.0f mm \\\n",
"\\nBore diameter of cylinder is %3.0f mm'%(L,D)\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Stroke length of cylinder is 30 mm \n",
"Bore diameter of cylinder is 20 mm\n"
]
}
],
"prompt_number": 3
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 5.4 Page no : 252"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"# Variables\n",
"x = 0.05 # ratio\n",
"P1 = 1.;\t\t\t#Pressure at point 1 in bar\n",
"T1 = 310.;\t\t\t#Temperature at point 1 in K\n",
"n = 1.2;\t\t\t#Adiabatic gas constant\n",
"P2 = 7.;\t\t\t#Pressure at point 2 in bar\n",
"Pa = 1.01325;\t\t\t#Atmospheric pressure in bar\n",
"Ta = 288.;\t\t\t#Atmospheric temperature in K\n",
"\n",
"# Calculations\n",
"V1 = 1+x;\t\t\t#Ratio of volume of air sucked to stroke volume\n",
"V4 = ((P2/P1)**(1/n))/20;\t\t\t#Ratio of volume delivered to stroke volume\n",
"DV = V1-V4;\t\t\t#Difference in volumes\n",
"nv1 = DV*100;\t\t\t#Volumetric efficiency\n",
"V = (P1*DV*Ta)/(T1*Pa);\t\t\t#Ratio of volumes referred to atmospheric conditions\n",
"nv2 = V*100;\t\t\t#Volumetric efficiency referred to atmospheric conditions\n",
"W = (n*0.287*T1*((P2/P1)**((n-1)/n)-1))/(n-1);\t\t\t#Work required in kJ/kg\n",
"\n",
"# Results\n",
"print 'Volumetric efficiency is %3.1f percent \\\n",
"\\nVolumetric efficiency referred to atmospheric conditions is %3.1f percent \\\n",
"\\nWork required is %3.1f kJ/kg'%(nv1,nv2,W)\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Volumetric efficiency is 79.7 percent \n",
"Volumetric efficiency referred to atmospheric conditions is 73.1 percent \n",
"Work required is 204.5 kJ/kg\n"
]
}
],
"prompt_number": 2
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 5.5 Page no : 253"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"# Variables\n",
"D = 0.2;\t\t\t#Bore in m\n",
"L = 0.3;\t\t\t#Stroke in m\n",
"P1 = 1.;\t\t\t#Pressure at point 1 in bar\n",
"P2 = 7.;\t\t\t#Pressure at point 2 in bar\n",
"n = 1.25;\t\t\t#Adiabatic gas constant\n",
"lc = 0.015\n",
"\n",
"# Calculations\n",
"V3 = (3.147*(D**2)*lc)/4.;\t\t\t#Clearance volume in m**3\n",
"Vs = (3.147*(D**2)*L)/4.;\t\t\t#Stoke volume in m**3\n",
"C = V3/Vs;\t\t\t#Clearance ratio\n",
"nv = (1+C-(C*((P2/P1)**(1/n))))*100;\t\t\t#Volumetric efficiency\n",
"DV = (nv*Vs)/100.;\t\t\t#Volume of air taken in (m**3)/stroke\n",
"\n",
"# Results\n",
"print 'Theoretical volume of air taken in per stroke is %.2e m**3/stroke'%(DV)\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Theoretical volume of air taken in per stroke is 7.67e-03 m**3/stroke\n"
]
}
],
"prompt_number": 4
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 5.6 Page no : 254"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"import math \n",
"\n",
"# Variables\n",
"D = 0.2;\t\t\t#Bore in m\n",
"L = 0.3;\t\t\t#Stroke in m\n",
"P1 = 1.;\t\t\t#Pressure at point 1 in bar\n",
"r = 0.05 # ratio\n",
"T1 = 293.;\t\t\t#Temperature at point 1 in K\n",
"P2 = 5.5;\t\t\t#Pressure at point 2 in bar\n",
"n = 1.3;\t\t\t#Adiabatic gas constant\n",
"N = 500.;\t\t\t#Speed of compressor in rpm\n",
"\n",
"# Calculations\n",
"x = (n-1)/n;\t\t\t#Ratio\n",
"Vs = (3.147*L*(D**2))/4;\t\t\t#Stroke volume in m**3\n",
"Vc = r*Vs;\t\t\t#Clearance volume in m**3\n",
"V1 = Vc+Vs;\t\t\t#Volume at point 1 in m**3\n",
"V4 = Vc*((P2/P1)**(1/n));\t\t\t#Volume at point 4 in m**3\n",
"EVs = V1-V4;\t\t\t#Effective swept volume in m**3\n",
"W = (P1*(10**5)*EVs*(((P2/P1)**x)-1))/x;\t\t\t#Work done in J/cycle\n",
"MEP = (W/Vs)/(10**5);\t\t\t#Mean effective pressure in bar\n",
"P = (W*N)/(60*1000);\t\t\t#Power required in kW\n",
"\n",
"# Results\n",
"print 'Mean effective pressure is %3.2f bar \\\n",
"\\nPower required is %3.2f kW'%(MEP,P)\n",
"\n",
"# rounding off error"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Mean effective pressure is 1.81 bar \n",
"Power required is 14.21 kW\n"
]
}
],
"prompt_number": 5
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 5.7 Page no : 255"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"import math \n",
"\n",
"# Variables\n",
"D = 0.2;\t\t\t#Bore in m\n",
"L = 0.3;\t\t\t#Stroke in m\n",
"P1 = 97.;\t\t\t#Pressure at entry in kN/(m**2)\n",
"P4 = P1;\t\t\t#Pressure at point 4 in kN/(m**2)\n",
"T1 = 293.;\t\t\t#Temperature at point 1 in K\n",
"P2 = 550.;\t\t\t#Compression Pressure in kN/(m**2)\n",
"P3 = P2;\t\t\t#Pressure at point 3 in kN/(m**2)\n",
"n = 1.3;\t\t\t#Adiabatic gas constant\n",
"N = 500.;\t\t\t#Speed of compressor in rpm\n",
"Pa = 101.325;\t\t\t#Air pressure in kN/(m**2)\n",
"Ta = 288.;\t\t\t#Air temperature in K\n",
"\n",
"# Calculations\n",
"x = (n-1)/n;\t\t\t#Ratio\n",
"DV = (3.147*L*(D**2))/4;\t\t\t#Difference in volumes in m**3\n",
"V3 = r*DV;\t\t\t#Clearance volume in m**3\n",
"V1 = V3+DV;\t\t\t#Volume at point 1 in m**3\n",
"V4 = V3*((P3/P4)**(1/n));\t\t\t#Volume at point 4 in m**3\n",
"Vs = V1-V4;\t\t\t#Effective swept volume in m**3\n",
"EVs = Vs*N;\t\t\t#Effective swept volume per min\n",
"Va = (P1*EVs*Ta)/(Pa*T1);\t\t\t#Free air delivered in (m**3)/min\n",
"nV = ((V1-V4)/(V1-V3))*100;\t\t\t#Volumetric effciency\n",
"T2 = T1*((P2/P1)**x);\t\t\t#Air delivery temperature in K\n",
"t2 = T2-273;\t\t\t#Air delivery temperature in oC\n",
"W = (n*P1*(V1-V4)*(((P2/P1)**x)-1))*N/((n-1)*60);\t\t\t#Cycle power in kW\n",
"Wiso = P1*V1*(math.log(P2/P1));\t\t\t#Isothermal workdone\n",
"niso = (Wiso/(4.33*0.493))*100;\t\t\t#Isothermal efficiency\n",
"\n",
"# Results\n",
"print 'Free air delivered is %3.3f m**3/min \\\n",
"\\nVolumetric efficiency is %3.0f percent \\\n",
"\\nAir delivery temperature is %3.1f oC \\\n",
"\\nCycle power is %3.0f kW \\\n",
"\\nIsothermal efficiency is %3.1f percent'%(Va,nV,t2,W,round(niso,-1))\n",
"\n",
"# rounding off error"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Free air delivered is 3.820 m**3/min \n",
"Volumetric efficiency is 86 percent \n",
"Air delivery temperature is 164.3 oC \n",
"Cycle power is 14 kW \n",
"Isothermal efficiency is 80.0 percent\n"
]
}
],
"prompt_number": 12
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 5.8 Page no : 257"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"import math \n",
"\n",
"# Variables\n",
"Ve = 30.;\t\t\t#Volume of air entering compressor per hour in m**3\n",
"P1 = 1.;\t\t\t#Presure of air entering compressor in bar\n",
"N = 450.;\t\t\t#Speed in rpm\n",
"P2 = 6.5;\t\t\t#Pressure at point 2 in bar\n",
"nm = 0.8;\t\t\t#Mechanical efficiency\n",
"nv = 0.75;\t\t\t#Volumetric efficiency\n",
"niso = 0.76;\t\t\t#Isothermal efficiency\n",
"\n",
"# Calculations\n",
"Vs = Ve/(nv*3600);\t\t\t#Swept volume per sec in (m**3)/s\n",
"V = (Vs*60)/N;\t\t\t#Swept volume per cycle in m**3\n",
"V1 = (Ve*60)/(3600*N);\t\t\t#Volume at point 1 in m**3\n",
"Wiso = P1*100*V1*math.log(P2/P1);\t\t\t#Isothermal workdone per cycle\n",
"Wact = Wiso/niso;\t\t\t#Actual workdone per cycle on air\n",
"MEP = (Wact/V)/100;\t\t\t#Mean effective pressure in bar\n",
"IP = (Wact*N)/60;\t\t\t#Indicated power in kW\n",
"BP = IP/nm;\t\t\t#Brake power in kW\n",
"\n",
"# Results\n",
"print 'Mean effective pressure is %3.3f bar \\\n",
"\\nBrake power is %3.2f kW'%(MEP,BP)\n",
"\n",
"# rounding off error"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Mean effective pressure is 1.847 bar \n",
"Brake power is 2.57 kW\n"
]
}
],
"prompt_number": 13
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 5.9 Page no : 258"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"import math \n",
"\n",
"# Variables\n",
"Va = 15.;\t\t\t#Volume of air in (m**3)/min\n",
"Pa = 1.01325;\t\t\t#Pressure of air in bar\n",
"Ta = 302.;\t\t\t#Air temperature in K\n",
"P1 = 0.985;\t\t\t#Pressure at point 1 in bar\n",
"r = 0.04 # ratio\n",
"T1 = 313.;\t\t\t#Temperature at point 1 in K\n",
"y = 1.3;\t\t\t#Ratio of stroke to bore diameter\n",
"N = 300.;\t\t\t#Speed in rpm\n",
"n = 1.3;\t\t\t#Adiabatic gas constant\n",
"P2 = 7.5;\t\t\t#Pressure at point 2 in bar\n",
"\n",
"# Calculations\n",
"x=((P2/P1)**(1./n))-1;\n",
"a = x*r;\t\t\t#Ratio of volume at point 4 to swept volume\n",
"nv = 1-a;\t\t\t#Volumetric efficiency\n",
"V1 = (Pa*Va*T1)/(Ta*P1);\t\t\t#Volume at point 1 in (m**3)/min\n",
"Vs = V1/(nv*N*2);\t\t\t#Swept volume in m**3\n",
"D = ((Vs*4)/(math.pi*y))**(1./3);\t\t\t#Bore in m\n",
"L = y*D;\t\t\t#Stroke in m\n",
"\n",
"# Results\n",
"print 'Cylinder bore in %3.3f m \\\n",
"\\nCylinder stroke %3.3f m'%(D,L)\n",
"\n",
"# rounding off error"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Cylinder bore in 0.313 m \n",
"Cylinder stroke 0.407 m\n"
]
}
],
"prompt_number": 22
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 5.10 Page no : 259"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"import math \n",
"\n",
"# Variables\n",
"P1 = 0.98;\t\t\t#Pressure at point 1 in bar\n",
"P4 = P1;\t\t\t#Pressure at point 4 in bar\n",
"P2 = 7.;\t\t\t#Pressure at point 2 in bar\n",
"P3 = P2;\t\t\t#Pressure at point 3 in bar\n",
"n = 1.3;\t\t\t#Adiabatic gas consmath.tant\n",
"Ta = 300.;\t\t\t#Air temperature in K\n",
"Pa = 1.013;\t\t\t#Air pressure in bar\n",
"T1 = 313.;\t\t\t#Temperature at point 1 in K\n",
"Va = 15.;\t\t\t#Volume of air delivered in m**3\n",
"R = 0.287;\t\t\t#Universal gas constant in kJ/kg-K\n",
"c = 0.04\n",
"\n",
"# Calculations\n",
"x = (n-1)/n;\t\t\t#Ratio\n",
"r = (P2/P1)**(1/n);\t\t\t#Ratio of volumes\n",
"a = r*c;\t\t\t#Ratio of volume at point 4 to swept volume\n",
"DV = 1+c-a;\t\t\t#Difference in volumes\n",
"V = (P1*DV*Ta)/(T1*Pa);\t\t\t#Volume of air delivered per cycle\n",
"nv = V*100;\t\t\t#Volumetric efficiency\n",
"DV1 = (Pa*Va*T1)/(Ta*P1);\t\t\t#Difference in volumes\n",
"T2 = T1*((P2/P1)**x);\t\t\t#Temperature at point 2 in K\n",
"ma = (Pa*100*Va)/(R*Ta);\t\t\t#Mass of air delivered in kg/min\n",
"IP = (ma*R*(T2-T1))/(x*60);\t\t\t#Indicated power in kW\n",
"Piso = (ma*R*T1*math.log(P2/P1))/60;\t\t\t#Isothermal indicated power in kW\n",
"niso = (Piso/IP)*100;\t\t\t#Isothermal efficiency\n",
"\n",
"# Results\n",
"print 'Volumetric efficiency is %3.1f percent \\\n",
"\\nIndicated power is %3.2f kW \\\n",
"\\nIsothermal efficiency is %3.0f percent'%(nv,IP,niso)\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Volumetric efficiency is 79.6 percent \n",
"Indicated power is 65.74 kW \n",
"Isothermal efficiency is 79 percent\n"
]
}
],
"prompt_number": 23
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 5.11 Page no : 261"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"# Variables\n",
"V1 = 7.*(10**-3);\t\t\t#Volume of air in (m**3)/s\n",
"P1 = 1.013;\t\t\t#Pressure of air in bar\n",
"T1 = 288.;\t\t\t#Air temperature in K\n",
"P2 = 14.;\t\t\t#Pressure at point 2 in bar\n",
"n = 1.3;\t\t\t#Adiabatic gas constant\n",
"nm = 0.82;\t\t\t#Mechanical efficiency\n",
"\n",
"# Calculations\n",
"x = (n-1)/n;\t\t\t#Ratio\n",
"W = (P1*100*V1*(((P2/P1)**x)-1))/x;\t\t\t#Work done by compressor in kW\n",
"P = W/nm;\t\t\t#Power requred to drive compressor in kW\n",
"\n",
"# Results\n",
"print 'Power requred to drive compressor is %3.2f kW'%(P)\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Power requred to drive compressor is 3.12 kW\n"
]
}
],
"prompt_number": 24
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 5.12 Page no : 261"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"# Variables\n",
"L = 0.15;\t\t\t#Stroke in mm\n",
"D = 0.15;\t\t\t#Bore in mm\n",
"N = 8.;\t\t\t#Speed in rps\n",
"P1 = 100.;\t\t\t#Pressure at point 1 in kN/(m**2)\n",
"P2 = 550.;\t\t\t#Pressure at point 2 in kN/(m**2)\n",
"n = 1.32;\t\t\t#Adiabatic gas constant\n",
"C = 0.06 # RATIO\n",
"\n",
"# Calculations\n",
"x = (n-1)/n;\t\t\t#Ratio\n",
"nv = (1+C-(C*((P2/P1)**(1/n))))*100;\t\t\t#Volumetric efficiency\n",
"DV = (3.147*(D**2)*L)/4;\t\t\t#Difference in volumes at points 1 and 3\n",
"DV1 = (nv*DV)/100;\t\t\t#Difference in volumes at points 1 and 4\n",
"V2 = DV1*((P1/P2)**(1/n))*N;\t\t\t#Volume of air delivered per second\n",
"W = (P1*DV1*(((P2/P1)**x)-1))*N/x;\t\t\t#Power of compressor in kW\n",
"\n",
"# Results\n",
"print 'Theoretical volume efficiency is %3.1f percent \\\n",
"\\nVolume of air delivered is %3.5f m**3/s \\\n",
"\\nPower of compressor is %3.3f kW'%(nv,V2,W)\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Theoretical volume efficiency is 84.2 percent \n",
"Volume of air delivered is 0.00491 m**3/s \n",
"Power of compressor is 3.774 kW\n"
]
}
],
"prompt_number": 26
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 5.13 Page no : 262"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"import math \n",
"\n",
"# Variables\n",
"V = 16.;\t\t\t#Volume of air compresssed in m**3\n",
"P1 = 1.;\t\t\t#Pressure at point 1 in bar\n",
"P3 = 10.5;\t\t\t#Pressure at point 3 in bar\n",
"T1 = 294.;\t\t\t#Temperature at point 1 in K\n",
"Tc = 25.;\t\t\t#Temperature of cooling water in oC\n",
"n = 1.35;\t\t\t#Adiabatics gas constant\n",
"R = 0.287;\t\t\t#Universal gas constant in kJ/kg-K\n",
"Cp = 1.005;\t\t\t#Specific heat at constant pressure in kJ/kg-K\n",
"Cw = 4.187;\t\t\t#Specific heat of water in kJ/kg-K\n",
"\n",
"# Calculations\n",
"x = (n-1)/n;\t\t\t#Ratio\n",
"P2 = math.sqrt(P1*P3);\t\t\t#Pressure at point 2 in bar\n",
"W1 = (2*P1*100*V*(((P2/P1)**x)-1))/(x*60);\t\t\t#Indicated power of compressor from P1 to P2 in kW\n",
"W2 = (P1*100*V*(((P3/P1)**x)-1))/(x*60);\t\t\t#Indicated power of compressor from P1 to P3 in kW\n",
"T4 = T1*((P2/P1)**x);\t\t\t#Maximum temperature for two stage compression in K\n",
"T2 = T1*((P3/P1)**x);\t\t\t#Maximum temperature for single stage compression in K\n",
"m = (P1*100*V)/(R*T1);\t\t\t#Mass of air compressed in kg/min\n",
"Q = m*Cp*(T4-T1);\t\t\t#Heat rejected by air in kJ/min\n",
"mc = Q/(Cw*Tc);\t\t\t#Mass of cooling water in kg/min\n",
"\n",
"# Results\n",
"print 'Minimum indicated power required for 2 stage compression is %3.1f kW \\\n",
"\\nPower required for single stage compression is 18 percent more than that for \\\n",
"two stage compression with perfect intercooling \\\n",
"\\nMaximum temperature for two stage compression is %3.1f K \\\n",
"\\nMaximum temperature for single stage compression is %3.1f K \\\n",
"\\nHeat rejected by air is %3.1f kJ/min \\\n",
"\\nMass of cooling water required is %3.1f kg/min'%(W1,T4,T2,Q,mc)\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Minimum indicated power required for 2 stage compression is 73.3 kW \n",
"Power required for single stage compression is 18 percent more than that for two stage compression with perfect intercooling \n",
"Maximum temperature for two stage compression is 398.8 K \n",
"Maximum temperature for single stage compression is 540.9 K \n",
"Heat rejected by air is 1996.6 kJ/min \n",
"Mass of cooling water required is 19.1 kg/min\n"
]
}
],
"prompt_number": 1
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 5.14 Page no : 264"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"import math \n",
"\n",
"# Variables\n",
"V = 0.2;\t\t\t#Air flow rate in (m**3)/s\n",
"P1 = 0.1;\t\t\t#Intake pressure in MN/(m**2)\n",
"P3 = 0.7;\t\t\t#Final pressure in MN/(m**2)\n",
"T1 = 289.;\t\t\t#Intake temperature in K\n",
"n = 1.25;\t\t\t#Adiabatic gas constant\n",
"N = 10.;\t\t\t#Compressor speed in rps\n",
"\n",
"# Calculations\n",
"x = (n-1)/n;\t\t\t#Ratio\n",
"P2 = math.sqrt(P1*P3);\t\t\t#Intermediate pressure in MN/(m**2)\n",
"V1 = (V/N)*1000;\t\t\t#Total volume of LP cylinder in litres\n",
"V2 = ((P1*V1)/P2);\t\t\t#Total volume of HP cylinder in litres\n",
"W = ((2*P1*V*(((P2/P1)**x)-1))/x)*1000;\t\t\t#Cycle power in kW\n",
"\n",
"# Results\n",
"print 'Intermediate pressure is %3.3f MN/m**2 \\\n",
"\\nTotal volume of LP cylinder is %3.0f litres \\\n",
"\\nTotal volume of HP cylinder is %3.1f litres \\\n",
"\\nCycle power is %3.0f kW'%(P2,V1,V2,W)\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Intermediate pressure is 0.265 MN/m**2 \n",
"Total volume of LP cylinder is 20 litres \n",
"Total volume of HP cylinder is 7.6 litres \n",
"Cycle power is 43 kW\n"
]
}
],
"prompt_number": 28
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 5.15 Page no : 265"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"# Variables\n",
"P1 = 1.;\t\t\t#Pressure at point 1 in bar\n",
"T1 = 290.;\t\t\t#Temperature at point 1 in K\n",
"P3 = 60.;\t\t\t#Pressure at point 3 in bar\n",
"P2 = 8.;\t\t\t#Pressure at point 2 in bar\n",
"T2 = 310.;\t\t\t#Temperature at point 2 in K\n",
"L = 0.2;\t\t\t#Stroke in m\n",
"D = 0.15;\t\t\t#Bore in m\n",
"n = 1.35;\t\t\t#Adiabatic gas constant\n",
"N = 200.;\t\t\t#Speed in rpm\n",
"\n",
"# Calculations\n",
"x = (n-1)/n;\t \t\t#Ratio\n",
"V1 = (3.147*(D**2)*L)/4;\t\t\t#Volume at point 1 in m**3\n",
"V2 = (P1*V1*T2)/(T1*P2);\t\t\t#Volume of air entering LP cylinder in m**3\n",
"W = ((P1*(10**5)*V1*(((P2/P1)**x)-1))/x)+((P2*(10**5)*V2*(((P3/P2)**x)-1))/x);\t\t\t#Workdone by compressor per cycle in J\n",
"P = (W*N)/(60*1000);\t\t \t#Power of compressor in kW\n",
"\n",
"# Results\n",
"print 'Power of compressor is %3.2f kW'%(P)\n",
"\n",
"# rounding off error"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Power of compressor is 6.59 kW\n"
]
}
],
"prompt_number": 2
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 5.16 Page no : 265"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"import math \n",
"\n",
"# Variables\n",
"N = 220.;\t\t\t#Speed of compressor in rpm\n",
"P1 = 1.;\t\t\t#Pressure entering LP cylinder in bar\n",
"T1 = 300.;\t\t\t#Temperature at point 1 in K\n",
"Dlp = 0.36;\t\t\t#Bore of LP cylinder in m\n",
"Llp = 0.4;\t\t\t#Stroke of LP cylinder in m\n",
"Lhp = 0.4;\t\t\t#Stoke of HP cylinder in m\n",
"P2 = 4.;\t\t\t#Pressure leaving LP cylinder in bar\n",
"P5 = 3.8;\t\t\t#Pressure entering HP cylinder in bar\n",
"T3 = 300.;\t\t\t#Temperature entering HP cylinder in K\n",
"P6 = 15.2;\t\t\t#Dicharge pressure in bar\n",
"n = 1.3;\t\t\t#Adiabatic gas constant\n",
"Cp = 1.0035;\t\t\t#Specific heat at constant pressure in kJ/kg-K\n",
"R = 0.287;\t\t\t#Universal gas constant in kJ/kg-K\n",
"T5 = T1;\t\t\t#Temperature at point 5 in K\n",
"C = 0.04\n",
"# Calculations\n",
"x = (n-1)/n;\t\t\t#Ratio\n",
"Vslp = round((math.pi*(Dlp**2)*Llp*N*2)/4,2);\t\t\t#Swept volume of LP cylinder in m**3/min\n",
"nv = round(1+C-(C*((P2/P1)**(1/n))),4);\t\t\t#Volumetric efficiency\n",
"V1 = nv*Vslp;\t\t\t#Volume of air drawn at point 1 in (m**3)/min\n",
"m = round((P1*100*V1)/(R*T1),2);\t\t\t#Mass of air in kg/min\n",
"T2 = round(T1*((P2/P1)**x));\t\t\t#Temperature at point 2 in K\n",
"QR = m*Cp*(T2-T5);\t\t\t#Heat rejected in kJ/min\n",
"V5 = (m*R*T5)/(P5*100);\t\t\t#Volume of air drawn in HP cylinder M**3/min\n",
"Plp = P2/P1;\t\t\t#Pressure ratio of LP cylinder\n",
"Php = P6/P5;\t\t\t#Pressure ratio of HP cylinder\n",
"Vshp = V5/nv;\t\t\t#Swept volume of HP cylinder in m**3/min\n",
"Dhp = math.sqrt((Vshp*4)/(3.147*Lhp*N*2));\t\t\t#Bore of HP cylinder in m\n",
"P = (m*R*(T2-T1))/(x*60);\t\t\t#Power required for HP cylinder in kW\n",
"\n",
"print V5,Plp,Php,Vshp,Dhp,P\n",
"# Results\n",
"print 'Heat rejected in intercooler is %3.1f kJ/min \\\n",
"\\nDiameter of HP cylinder is %3.4f m \\\n",
"\\nPower required for HP cylinder is %3.0f kW'%(QR,Dhp,P)\n",
"\n",
"# rounding off error. please check\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"4.35484736842 4.0 4.0 4.71405863652 0.184511219993 45.0178314444\n",
"Heat rejected in intercooler is 2179.5 kJ/min \n",
"Diameter of HP cylinder is 0.1845 m \n",
"Power required for HP cylinder is 45 kW\n"
]
}
],
"prompt_number": 8
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 5.17 Page no : 267"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"import math \n",
"\n",
"# Variables\n",
"P1 = 1.;\t\t\t#Pressure at point 1 in bar\n",
"P3 = 30.;\t\t\t#Pressure at point 3 in bar\n",
"T1 = 300.;\t\t\t#Temperature at point 1 in K\n",
"n = 1.3;\t\t\t#Adiabatics gas constant\n",
"\n",
"# Calculations\n",
"P2 = math.sqrt(P1*P3);\t\t\t#Intermediate pressure in bar\n",
"rD = math.sqrt(P2/P1);\t\t\t#Ratio of cylinder diameters\n",
"\n",
"# Results\n",
"print 'Ratio of cylinder diameters is %3.2f'%(rD)\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Ratio of cylinder diameters is 2.34\n"
]
}
],
"prompt_number": 41
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 5.18 Page no : 268"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"# Variables\n",
"P1 = 1.013;\t\t\t#Pressure at point 1 in bar\n",
"T1 = 288.;\t\t\t#Temperaturea at point 1 in K\n",
"v1 = 8.4;\t\t\t#free air delivered by compressor in m**3\n",
"P4 = 70.;\t\t\t#Pressure at point 4 in bar\n",
"n = 1.2;\t\t\t#Adiabatic gas constant\n",
"Cp = 1.0035;\t\t\t#Specific heat at constant pressure in kJ/kg-K\n",
"\n",
"# Calculations\n",
"x = (n-1)/n;\t\t\t#Ratio\n",
"P2 = P1*((P4/P1)**(1./3));\t\t\t#LP cylinder delivery pressure in bar\n",
"P3 = P2*((P4/P1)**(1./3));\t\t\t#IP cylinder delivery pressure in bar\n",
"r = P2/P1;\t\t\t#Ratio of cylinder volumes\n",
"r1 = P3/P2;\t\t\t#Ratio of cylinder volumes\n",
"r2 = r*r1;\t\t\t#Ratio of cylinder volumes\n",
"V3 = 1;\t\t\t#Volume at point 3 in m**3\n",
"T4 = T1*((P2/P1)**x);\t\t\t#Three stage outlet temperature in K\n",
"QR = Cp*(T4-T1);\t\t\t#Heat rejected in intercooler in kJ/kg of air\n",
"W = ((3*P1*100*v1*(((P4/P1)**(x/3))-1))/(x*60));\t\t\t#Total indiacted power in kW\n",
"\n",
"# Results\n",
"print 'LP cylinder delivery pressure is %3.3f bar \\\n",
"\\nIP cylinder delivery pressure is %3.2f bar \\\n",
"\\nRatio of cylinder volumes is %3.2f:%3.1f:%3.0f \\\n",
"\\nTemperature at end of each stage is %3.2f K \\\n",
"\\nHeat rejected in each intercooler is %3.1f kJ/kg of air \\\n",
"\\nTotal indicated power is %3.2f kW'%(P2,P3,r2,r1,V3,T4,QR,W)\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"LP cylinder delivery pressure is 4.157 bar \n",
"IP cylinder delivery pressure is 17.06 bar \n",
"Ratio of cylinder volumes is 16.84:4.1: 1 \n",
"Temperature at end of each stage is 364.41 K \n",
"Heat rejected in each intercooler is 76.7 kJ/kg of air \n",
"Total indicated power is 67.72 kW\n"
]
}
],
"prompt_number": 42
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 5.19 Page no : 269"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"# Variables\n",
"D = 0.45;\t\t\t#Bore in m\n",
"L = 0.3;\t\t\t#Stroke in m\n",
"P1 = 1.;\t\t\t#Pressure at point 1 inn bar\n",
"T1 = 291.;\t\t\t#Temperature at point 1 in K\n",
"P4 = 15.;\t\t\t#Pressure at point 4 in bar\n",
"n = 1.3;\t\t\t#Adiabatic gas constant\n",
"R = 0.29;\t\t\t#Universal gas constant in kJ/kg-K\n",
"\n",
"# Calculations\n",
"x = (n-1)/n;\t\t\t#Ratio\n",
"k = (P4/P1)**(1./3);\t\t\t#Pressure ratio\n",
"P2 = k*P1;\t\t\t#Pressure at point 2 in bar\n",
"P3 = k*P2;\t\t\t#Pressure at point 1 in bar\n",
"Vslp = (3.147*(D**2)*L)/4;\t\t\t#Swept volume of LP cylinder\n",
"V7 = C*Vslp;\t\t\t#Volume at point 7 in m**3\n",
"V1 = Vslp+V7;\t\t\t#Volume at point 1 in m**3\n",
"V8 = V7*(k**(1/n));\t\t\t#Volume at point 8 in m**3\n",
"EVs = (V1-V8)*1000;\t\t\t#Effective swept volume in litres\n",
"T4 = T1*(k**x);\t\t\t#Temperature at point 4 in K\n",
"t4 = T4-273;\t\t\t#Delivery temperature in oC\n",
"DV = ((P1*T4*(V1-V8))/(P4*T1))*1000;\t\t\t#Delivery volume per stroke in litres\n",
"W = (3*R*T1*((k**x)-1))/x;\t\t\t#Workdone per kg of air in kJ\n",
"\n",
"# Results\n",
"print 'Intermediate pressures are %3.3f bar and %3.3f bar \\\n",
"\\nEffective swept volume of LP cylinder is %3.2f litres \\\n",
"\\nTemperature of air delivered per stroke is %3.1f oC \\\n",
"\\nVolume of air delivered per stroke is %3.2f litres \\\n",
"\\nWork done per kg of air is %3.1f kJ'%(P2,P3,EVs,t4,DV,W)\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Intermediate pressures are 2.466 bar and 6.082 bar \n",
"Effective swept volume of LP cylinder is 44.92 litres \n",
"Temperature of air delivered per stroke is 85.4 oC \n",
"Volume of air delivered per stroke is 3.69 litres \n",
"Work done per kg of air is 254.1 kJ\n"
]
}
],
"prompt_number": 43
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 5.20 Page no : 271"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"import math \n",
"\n",
"# Variables\n",
"P1 = 1.;\t\t\t#Pressure at point 1 in bar\n",
"Pns = 100.;\t\t\t#Maximum pressure in bar\n",
"p = 4.; \t\t\t#Pressure ratio\n",
"\n",
"# Calculations\n",
"Ns = math.log(Pns)/math.log(p);\t\t\t#Number of stages\n",
"y = math.ceil(Ns);\t \t\t#Rounding off to next higher integer\n",
"ps = (Pns/P1)**(1/y);\t\t\t #Exact stage pressure ratio\n",
"P2 = ps*P1;\t\t\t#Pressure at point 2 in bar\n",
"P3 = ps*P2;\t\t\t#Pressure at point 3 in bar\n",
"P4 = ps*P3;\t\t\t#Pressure at point 4 in bar\n",
"\n",
"# Results\n",
"print 'Number of stages are %3.2f \\\n",
"\\nExact stage pressure ratio is %3.3f \\\n",
"\\nIntermediate pressures are %3.3f bar, %3.2f bar, %3.2f bar'%(y,ps,P2,P3,P4)\n",
"\n",
"# rounding off error"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Number of stages are 4.00 \n",
"Exact stage pressure ratio is 3.162 \n",
"Intermediate pressures are 3.162 bar, 10.00 bar, 31.62 bar\n"
]
}
],
"prompt_number": 51
}
],
"metadata": {}
}
]
}PKIGwGwThermal Engineering/ch6.ipynb{
"metadata": {
"name": "",
"signature": "sha256:4962285b4f62f2bf376e81ac1782d3fcaba245abd75f93d7b849812ce5c45ab3"
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"nbformat": 3,
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"worksheets": [
{
"cells": [
{
"cell_type": "heading",
"level": 1,
"metadata": {},
"source": [
"Chapter 6 :\n",
"Refrigeration Cycles"
]
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 6.1 Page no : 308"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"# Variables\n",
"COP = 8.5;\t\t\t#Co-efficient of performance\n",
"T1 = 300.;\t\t\t#Room temperature in K\n",
"T2 = 267.;\t\t\t#Refrigeration temperature in K\n",
"\n",
"# Calculations\n",
"COPmax = T2/(T1-T2);\t\t\t#Maximum COP possible\n",
"\n",
"# Results\n",
"print 'Maximum COP possible is %3.2f \\\n",
"\\nSince the COP claimed by the inventor is more than the maximum possible COP\\\n",
" his claim is not correct'%(COPmax)\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Maximum COP possible is 8.09 \n",
"Since the COP claimed by the inventor is more than the maximum possible COP his claim is not correct\n"
]
}
],
"prompt_number": 1
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 6.2 Page no : 309"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"# Variables\n",
"TL = 268.;\t\t\t#Low temperature in K\n",
"TH = 293.;\t\t\t#High temperature in K\n",
"t = 24.;\t\t\t#time in hrs\n",
"C = 2100.;\t\t\t#Capacity of refrigerator in kJ/s\n",
"Tw = 10.;\t\t\t#Water temperature in oC\n",
"L = 335.;\t\t\t#Latent heat of ice in kJ/kg\n",
"\n",
"# Calculations\n",
"COP = TL/(TH-TL);\t\t\t#Co-efficient of performance\n",
"Pmin = C/COP;\t\t\t#Minimum power required in kW\n",
"Qr = (4.187*(Tw-0))+L;\t\t\t#Heat removed from water in kJ/kg\n",
"m = C/Qr;\t\t\t#mass of ice formed in kg/s\n",
"W = (m*t*3600)/1000;\t\t\t#Weight of ice formed in tons\n",
"\n",
"# Results\n",
"print 'Minimum power required is %3.2f kW \\\n",
"\\nWeight of ice formed in 24 hours is %3.2f tons'%(Pmin,W)\n",
"\n",
"# rounding off error"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Minimum power required is 195.90 kW \n",
"Weight of ice formed in 24 hours is 481.44 tons\n"
]
}
],
"prompt_number": 3
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 6.3 Page no : 309"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"# Variables\n",
"TL = -10.;\t\t\t#Temperature of brine in oC\n",
"TH = 20.;\t\t\t#Temperature of water in oC\n",
"L = 335.;\t\t\t#Latent heat of ice in kJ/kg\n",
"\n",
"# Calculations\n",
"Qr = (4.187*(TH-0))+L;\t\t\t#Heat removed from water in kJ/kg\n",
"COP = (TL+273)/(TH-TL);\t\t\t#Co-efficient of performance\n",
"mi = (COP*3600)/Qr;\t\t\t#mass of ice formed per kWh in kg\n",
"\n",
"# Results\n",
"print 'Mass of ice formed per kWh is %3.1f kg'%(mi)\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Mass of ice formed per kWh is 75.4 kg\n"
]
}
],
"prompt_number": 3
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 6.4 Page no : 310"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"# Variables\n",
"P1 = 1.2;\t\t\t#Pressure at point 1 in bar\n",
"P2 = 7.;\t\t\t#Pressure at point 2 in bar\n",
"m = 0.05;\t\t\t#mass flow rate of refrigerant in kg/s\n",
"h1 = 340.1;\t\t\t#Enthalpy at point 1 from refrigerant-12 tables in kJ/kg\n",
"s1 = 1.57135;\t\t\t#Entropy at point 1 from refrigerant-12 tables in kJ/kg-K\n",
"s2 = 1.57135;\t\t\t#Entropy at point 2 from refrigerant-12 tables in kJ/kg-K\n",
"h2 = 372.;\t\t\t#Enthalpy at point 2 from refrigerant-12 tables in kJ/kg\n",
"h3 = 226.575;\t\t\t#Enthalpy at point 3 from refrigerant-12 tables in kJ/kg\n",
"h4 = 226.575;\t\t\t#Enthalpy at point 4 from refrigerant-12 tables in kJ/kg\n",
"\n",
"# Calculations\n",
"Q2 = m*(h1-h4);\t\t\t#Rate of heat removed from the refrigerated space in kW\n",
"W = m*(h2-h1);\t\t\t#Power input to the compressor in kW\n",
"Q1 = m*(h2-h3);\t\t\t#Rate of heat rejection to the environment in kW\n",
"COP = Q2/W;\t\t\t#Co-efficient of performance\n",
"\n",
"# Results\n",
"print 'Rate of heat removed from the refrigerated space is %3.2f kW \\\n",
"\\nPower input to the compressor is %3.3f kW \\\n",
"\\nRate of heat rejection to the environment is %3.2f kW \\\n",
"\\nCo-efficient of performance is %3.2f'%(Q2,W,Q1,COP)\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Rate of heat removed from the refrigerated space is 5.68 kW \n",
"Power input to the compressor is 1.595 kW \n",
"Rate of heat rejection to the environment is 7.27 kW \n",
"Co-efficient of performance is 3.56\n"
]
}
],
"prompt_number": 4
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 6.5 Page no : 311"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"# Variables\n",
"T2 = 40.;\t\t\t#Temperature at point 2 in oC\n",
"T1 = -10.;\t\t\t#Temperature at point 1 in oC\n",
"h2 = 367.155;\t\t\t#Enthalpy at point 2 from refrigerant-12 tables in kJ/kg\n",
"s2 = 1.54057;\t\t\t#Entropy at point 2 from refrigerant-12 tables in kJ/kg-K\n",
"s1 = 1.54057;\t\t\t#Entropy at point 1 from refrigerant-12 tables in kJ/kg-K\n",
"sg = 1.56004;\t\t\t#Entropy from refrigerant-12 tables in kJ/kg-K\n",
"sf = 0.96601;\t\t\t#Entropy from refrigerant-12 tables in kJ/kg-K\n",
"hf = 190.822;\t\t\t#Enthalpy from refrigerant-12 tables in kJ/kg-K\n",
"hfg = 156.319;\t\t\t#Enthalpy from refrigerant-12 tables in kJ/kg-K\n",
"h3 = 238.533;\t\t\t#Enthalpy at point 3 from refrigerant-12 tables in kJ/kg-K\n",
"h4 = h3;\t\t\t#Enthalpy at point 4 from refrigerant-12 tables in kJ/kg-K\n",
"\n",
"# Calculations\n",
"x1 = (s1-sf)/(sg-sf);\t\t\t#Quality factor\n",
"h1 = hf+(x1*hfg);\t\t\t#Enthalpy at point 1 from refrigerant-12 tables in kJ/kg\n",
"COP = (h1-h4)/(h2-h1);\t\t\t#Co-efficient of performance\n",
"\n",
"# Results\n",
"print 'COP of the system is %3.2f'%(COP)\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"COP of the system is 4.12\n"
]
}
],
"prompt_number": 5
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 6.6 Page no : 311"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"# Variables\n",
"Tc = 35.;\t\t\t#Temperature of condenser in oC\n",
"Te = -15.;\t\t\t#Temperature of evaporator in oC\n",
"m = 10.;\t\t\t#Mass of ice per day in tons\n",
"Tw = 30.;\t\t\t#Temperature of water in oC\n",
"Ti = -5.;\t\t\t#Temperature of ice in oC\n",
"nv = 0.65;\t\t\t#Volumetric efficiency\n",
"N = 1200.;\t\t\t#Speed in rpm\n",
"x = 1.2;\t\t\t#Stroke to bore ratio\n",
"na = 0.85;\t\t\t#Adiabatic efficiency\n",
"nm = 0.95;\t\t\t#Mechanical efficiency\n",
"S = 4.187;\t\t\t#Specific heat of water in kJ/kg\n",
"L = 335.;\t\t\t#Latent heat of ice in kJ/kg\n",
"h1 = 1667.24;\t\t\t#Enthalpy at Te from Ammonia chart in kJ/kg\n",
"h2 = 1925.;\t\t\t#Enthalpy at Te from Ammonia chart in kJ/kg\n",
"h4 = 586.41;\t\t\t#Enthalpy at Tc from Ammonia chart in kJ/kg\n",
"v1 = 0.508;\t\t\t#Specific humidity at Te from Ammonia chart in (m**3)/kg\n",
"\n",
"# Calculations\n",
"Qr = (((m*1000)/24)*((S*(Tw-0))+L+(1.94*(0-Ti))))/3600;\t\t\t#Refrigerating capacity in kW\n",
"mr = Qr/(h1-h4);\t\t\t#Refrigerant mass flow rate in kg/s\n",
"T2 = 112;\t\t\t#Discharge temperature in oC\n",
"D = ((mr*v1*4*60)/(nv*3.14*x*N))**(1./3);\t\t\t#Cylinder diameter in m\n",
"L = x*D;\t\t\t#Stroke length in m\n",
"W = (mr*(h2-h1))/(na*nm);\t\t\t#Compressor motor power in kW\n",
"COPth = (h1-h4)/(h2-h1);\t\t\t#Theoretical COP\n",
"COPact = Qr/W;\t\t\t#Actual COP\n",
"\n",
"# Results\n",
"print 'Refrigerating capacity of plant is %3.2f kW \\\n",
"\\nRefrigerant mass flow rate is %3.4f kg/s \\\n",
"\\nDischarge temperature is %3.0f oC \\\n",
"\\nCylinder diameter is %3.3f m \\\n",
"\\nStroke length is %3.3f m \\\n",
"\\nCompressor motor power is %3.2f kW \\\n",
"\\nTheoretical COP is %3.2f \\\n",
"\\nActual COP is %3.2f'%(Qr,mr,T2,D,L,W,COPth,COPact)\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Refrigerating capacity of plant is 54.43 kW \n",
"Refrigerant mass flow rate is 0.0504 kg/s \n",
"Discharge temperature is 112 oC \n",
"Cylinder diameter is 0.128 m \n",
"Stroke length is 0.153 m \n",
"Compressor motor power is 16.08 kW \n",
"Theoretical COP is 4.19 \n",
"Actual COP is 3.39\n"
]
}
],
"prompt_number": 6
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 6.7 Page no : 313"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"# Variables\n",
"T1 = -5.;\t\t\t#Temperature at point 1 in oC\n",
"T2 = 30.;\t\t\t#Temperature at point 2 in oC\n",
"m = 13500.;\t\t\t#mass of ice per day in kg\n",
"Tw = 20.;\t\t\t#Temperature of water in oC\n",
"COP = 0.6;\t\t\t#Co-efficient of performance\n",
"h2 = 1709.33;\t\t\t#Enthalpy at point 2 in kJ/kg\n",
"s2 = 6.16259;\t\t\t#Entropy at point 2 in kJ/kg-K\n",
"s1 = 6.16259;\t\t\t#Entropy at point 1 in kJ/kg-K\n",
"sf = 1.8182;\t\t\t#Entropy in kJ/kg-K\n",
"sg = 6.58542;\t\t\t#Entropy in kJ/kg-K\n",
"hf = 400.98;\t\t\t#Enthalpy in kJ/kg\n",
"hfg = 1278.35;\t\t\t#Enthalpy in kJ/kg\n",
"h4 = 562.75;\t\t\t#Enthalpy at point 4 in kJ/kg\n",
"S = 4.187;\t\t\t#Specific heat of water in kJ/kg\n",
"L = 336.;\t\t\t#Latent heat of ice in kJ/kg\n",
"\n",
"# Calculations\n",
"x1 = (s1-sf)/(sg-sf);\t\t\t#Quality factor\n",
"h1 = hf+(x1*hfg);\t\t\t#Enthalpy at point 1 from refrigerant-12 tables in kJ/kg\n",
"COPi = (h1-h4)/(h2-h1);\t\t\t#Ideal COP\n",
"COPact = COP*COPi;\t\t\t#Actual COP\n",
"Qr = ((m*S*(Tw-0))+(m*L))/(24*3600);\t\t\t#Total amount of heat removed in kJ/s\n",
"mr = Qr/(h1-h4);\t\t\t#Circulation rate of ammonia in kg/s\n",
"W = mr*(h2-h1);\t\t\t#Power required in kW\n",
"\n",
"# Results\n",
"print 'Circulation rate of ammonia is %3.3f kg/s \\\n",
"\\nPower required is %3.3f kW \\\n",
"\\nCOP is %3.3f'%(mr,W,COPact)\n",
"\n",
"# rounding off error"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Circulation rate of ammonia is 0.065 kg/s \n",
"Power required is 9.374 kW \n",
"COP is 4.198\n"
]
}
],
"prompt_number": 4
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 6.8 Page no : 314"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"\n",
"# Variables\n",
"Tc = 20.;\t\t\t#Temperature of condenser in oC\n",
"Te = -25.;\t\t\t#Temperature of evaporator in oC\n",
"m = 15.;\t\t\t#Mass of ice per day in tons\n",
"Ts = 5.;\t\t\t#Subcooled temperature in oC\n",
"Tsh = 10.;\t\t\t#Superheated temperature in oC\n",
"n = 6.;\t\t\t#No. of cylinders\n",
"N = 950.;\t\t\t#Speed of compressor in rpm\n",
"x = 1.;\t\t\t#Stroke to bore ratio\n",
"h1 = 402.;\t\t\t#Enthalpy at point 1 from R-22 tables in kJ/kg\n",
"h2 = 442.;\t\t\t#Enthalpy at point 2 from R-22 tables in kJ/kg\n",
"h3 = 216.;\t\t\t#Enthalpy at point 3 from R-22 tables in kJ/kg\n",
"h4 = 216.;\t\t\t#Enthalpy at point 4 from R-22 tables in kJ/kg\n",
"v1 = 2.258;\t\t\t#Specific volume at point 1 in (m**3)/min\n",
"\n",
"# Calculations\n",
"Re = h1-h4; \t\t\t#Refrigerating effect in kJ/kg\n",
"mr = (m*14000)/(Re*60);\t\t\t#Mass flow of refrigerant in kg/min\n",
"Pth = (mr*(h2-h1))/60;\t\t\t#Theoretical power in kW\n",
"COP = (h1-h4)/(h2-h1);\t\t\t#Co-efficient of performance\n",
"Dth = v1/n;\t\t\t #Theoretical print lacement per cylinder\n",
"D = (((Dth*4)/(3.147*N))**(1./3))*1000;\t\t\t#Theoretical bore of compressor in mm\n",
"L = D; \t\t\t#Theoretical stroke of compressor in mm\n",
"\n",
"# Results\n",
"print 'Refrigerating effect is %3.0f kJ/kg \\\n",
"\\nMass flow of refrigerant per minute is %3.2f kg/min \\\n",
"\\nTheoretical input power is %3.2f kW COP is %3.2f \\\n",
"\\nTheoretical bore of compressor is %3.2f mm \\\n",
"\\nTheoretical stroke of compressor is %3.2f mm'%(Re,mr,Pth,COP,D,L)\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Refrigerating effect is 186 kJ/kg \n",
"Mass flow of refrigerant per minute is 18.82 kg/min \n",
"Theoretical input power is 12.54 kW COP is 4.65 \n",
"Theoretical bore of compressor is 79.56 mm \n",
"Theoretical stroke of compressor is 79.56 mm\n"
]
}
],
"prompt_number": 8
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 6.9 Page no : 316"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"# Variables\n",
"T2 = 40.;\t\t\t#Temperature at point 2 in oC\n",
"T1 = -5.;\t\t\t#Temperature at point 1 in oC\n",
"h2 = 367.155;\t\t\t#Enthalpy at point 2 from F-12 tables in kJ/kg\n",
"sg = 1.55717;\t\t\t#Entropy from F-12 tables in kJ/kg-K\n",
"s1 = 1.54057;\t\t\t#Entropy at point 1 from F-12 tables in kJ/kg-K\n",
"sf = 0.98311;\t\t\t#Entropy from F-12 tables in kJ/kg-K\n",
"hf = 195.394;\t\t\t#Enthalpy from F-12 tables in kJ/kg\n",
"hfg = 153.934;\t\t\t#Enthalpy from F-12 tables in kJ/kg\n",
"h4 = 238.533;\t\t\t#Enthalpy at point 4 from F-12 tables in kJ/kg\n",
"h4s = 218;\t\t\t#Enthalpy at point 4 with subcooling from F-12 tables in kJ/kg\n",
"\n",
"# Calculations\n",
"x1 = (s1-sf)/(sg-sf);\t\t\t#Quality factor\n",
"h1 = hf+(x1*hfg);\t\t\t#Enthalpy at point 1 from refrigerant-12 tables in kJ/kg\n",
"COPns = (h1-h4)/(h2-h1);\t\t\t#Co-efficient of performance with no subcooling\n",
"COPs = (h1-h4s)/(h2-h1);\t\t\t#Co-efficient of performance with subcooling\n",
"\n",
"# Results\n",
"print 'COP with no subcooling is %3.3f \\\n",
"\\nCOP with subcooling is %3.3f'%(COPns,COPs)\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"COP with no subcooling is 4.773 \n",
"COP with subcooling is 5.695\n"
]
}
],
"prompt_number": 9
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 6.10 Page no : 309"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"# Variables\n",
"Tg = 470.;\t\t\t#Heating temperature in K\n",
"T0 = 290.;\t\t\t#Cooling temperature in K\n",
"TL = 270.;\t\t\t#Refrigeration temperature in K\n",
"\n",
"# Calculations\n",
"COP = ((Tg-T0)/Tg)*(TL/(T0-TL));\t\t\t#Ideal COP of absorption refrigeration system\n",
"\n",
"# Results\n",
"print 'Ideal COP of absorption refrigeration system is %3.2f'%(COP)\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Ideal COP of absorption refrigeration system is 5.17\n"
]
}
],
"prompt_number": 10
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 6.11 Page no : 317"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"# Variables\n",
"T1 = -18.;\t\t\t#Temperature at point 1 in oC\n",
"T3 = 27.;\t\t\t#Temperature at point 3 in oC\n",
"rp = 4.;\t\t\t#Pressure ratio\n",
"m = 0.045;\t\t\t#mass flow rate in kg/s\n",
"y = 1.4;\t\t\t#Ratio of specific heats\n",
"Cp = 1.005;\t\t\t#Specific heat at constant pressure in kJ/kg-K\n",
"\n",
"# Calculations\n",
"x = (y-1)/y;\t\t\t#Ratio\n",
"T2 = (rp**x)*(273+T1);\t\t\t#Temperature at point 2 in K\n",
"Tmax = T2-273;\t\t\t#Maximum temperature in oC\n",
"T4 = ((1/rp)**x)*(273+T3);\t\t\t#Temperature at point 4 in K\n",
"Tmin = T4-273;\t\t\t#Minimum temperature in oC\n",
"qL = Cp*(T1-Tmin);\t\t\t#Heat rejected\n",
"Wcin = Cp*(Tmax-T1);\t\t\t#Compressor work\n",
"Wtout = Cp*(T3-Tmin);\t\t\t#Turbine work\n",
"Wnet = Wcin-Wtout;\t\t\t#Net work done\n",
"COP = qL/Wnet;\t\t\t#Co-efficient of performance\n",
"Qref = m*qL;\t\t\t#Rate of refrigeration in kW\n",
"\n",
"# Results\n",
"print 'Maximum temperature in the cycle is %3.0f oC \\\n",
"\\nMinimum temperature in the cycle is %3.0f oC \\\n",
"\\nCOP is %3.2f \\\n",
"\\nRate of refrigeration is %3.2f kW'%(Tmax,Tmin,COP,Qref)\n",
"\n",
"# rounding off error"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Maximum temperature in the cycle is 106 oC \n",
"Minimum temperature in the cycle is -71 oC \n",
"COP is 2.06 \n",
"Rate of refrigeration is 2.40 kW\n"
]
}
],
"prompt_number": 8
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 6.12 Page no : 318"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"# Variables\n",
"P1 = 1.;\t\t\t#Pressure at point 1 in bar\n",
"T1 = 268.;\t\t\t#Temperature at point 1 in K\n",
"P2 = 5.;\t\t\t#Pressure at point 2 in bar\n",
"T3 = 288.;\t\t\t#Temperature at point 3 in K\n",
"n = 1.3;\t\t\t#Adiabatic gas constant\n",
"Cp = 1.005;\t\t\t#Specific heat at constant pressure in kJ/kg-K\n",
"\n",
"# Calculations\n",
"x = (n-1)/n;\t\t\t#Ratio\n",
"T2 = ((P2/P1)**x)*T1;\t\t\t#Temperature at point 2 in K\n",
"T4 = ((P1/P2)**x)*T3;\t\t\t#Temperature at point 4 in K\n",
"W = Cp*(T3-T4);\t\t\t#Work developed per kg of air in kJ/kg\n",
"Re = Cp*(T1-T4);\t\t\t#Refrigerating effect per kg of air in kJ/kg\n",
"Wnet = Cp*((T2-T1)-(T3-T4));\t\t\t#Net work output in kJ/kg\n",
"COP = Re/Wnet;\t\t\t#Co-efficient of performance\n",
"\n",
"# Results\n",
"print 'Work developed per kg of air is %3.3f kJ/kg \\\n",
"\\nRefrigerating effect per kg of air is %3.3f kJ/kg \\\n",
"\\nCOP of the cycle is %3.2f'%(W,Re,COP)\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Work developed per kg of air is 89.795 kJ/kg \n",
"Refrigerating effect per kg of air is 69.695 kJ/kg \n",
"COP of the cycle is 2.22\n"
]
}
],
"prompt_number": 12
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 6.13 Page no : 319"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"# Variables\n",
"T1 = 277.;\t\t\t#Temperature at point 1 in K\n",
"T3 = 328.;\t\t\t#Temperature at point 3 in K\n",
"P1 = 0.1;\t\t\t#Pressure at point 1 in MPa\n",
"P2 = 0.3;\t\t\t#Pressure at point 2 in MPa\n",
"nc = 0.72;\t\t\t#Isentropic efficiency of compressor\n",
"nt = 0.78;\t\t\t#Isentropic efficiency of turbine\n",
"y = 1.4;\t\t\t#Adiabatic gas constant\n",
"Cp = 1.005;\t\t\t#Specific heat at constant pressure in kJ/kg-K\n",
"m = 3.;\t\t\t#Cooling load in tonnes\n",
"\n",
"# Calculations\n",
"x = (y-1)/y;\t\t\t#Ratio\n",
"T2s = T1*((P2/P1)**x);\t\t\t#Temperature at point 2s in K\n",
"T2 = ((T2s-T1)/nc)+T1;\t\t\t#Temerature at point 2 in K\n",
"T4s = T3*((P1/P2)**x);\t\t\t#Temperature at point 4s in K\n",
"T4 = T3-((T3-T4s)*nt);\t\t\t#Temperature at point 4 in K\n",
"Re = Cp*(T1-T4);\t\t\t#Refrigerating effect in kJ/kg\n",
"Wnet = Cp*((T2-T1)-(T3-T4));\t\t\t#Net work output in kJ/kg\n",
"COP = Re/Wnet;\t\t\t#Co-efficient of performance\n",
"P = (m*3.52)/COP;\t\t\t#Driving power required in kW\n",
"ma = (m*3.52)/Re;\t\t\t#Mass flow rate of air in kg/s\n",
"\n",
"# Results\n",
"print 'COP of refrigerator is %3.2f \\\n",
"\\nDriving power required is %3.0f kW \\\n",
"\\nMass flow rate of air is %3.2f kg/s'%(COP,P,ma)\n",
"\n",
"# rounding off error"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"COP of refrigerator is 0.25 \n",
"Driving power required is 43 kW \n",
"Mass flow rate of air is 0.59 kg/s\n"
]
}
],
"prompt_number": 11
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 6.14 Page no : 321"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"# Variables\n",
"P1 = 2.5;\t\t\t#Pressure at point 1 in bar\n",
"P3 = 9.;\t\t\t#Pressure at point 3 in bar\n",
"COPr = 0.65;\t\t\t#Ratio of actual COP to the theoretical COP\n",
"m = 5.;\t\t\t#Refrigerant flow in kg/min\n",
"T1 = 309;\t\t\t#Temperature at point 1 in K\n",
"T2s = 300;\t\t\t#Temperature at point 2s in K\n",
"h1 = 570.3;\t\t\t#Enthalpy at P1 from the given tables in kJ/kg\n",
"h4 = 456.4;\t\t\t#Enthalpy at P3 from the given tables in kJ/kg\n",
"h2g = 585.3;\t\t\t#Enthalpy at P3 from the given tables in kJ/kg\n",
"s2 = 4.76;\t\t\t#Entropy at P1 from the given tables in kJ/kg-K\n",
"s2g = 4.74;\t\t\t#Entropy at P3 from the given tables in kJ/kg-K\n",
"Cp = 0.67;\t\t\t#Specific heat at P3 in kJ/kg-K\n",
"\n",
"# Calculations\n",
"T2 = (2.718**((s2-s2g)/Cp))*T2s;\t\t\t#Temperature at point 2 in K\n",
"h2 = h2g+(Cp*(T2-T2s));\t\t\t#Enthalpy at point 2 in kJ/kg\n",
"COPR = (h1-h4)/(h2-h1);\t\t\t#Refrigerant COP\n",
"COPact = COPr*COPR;\t\t\t#Actual COP\n",
"qL = COPact*(h2-h1);\t\t\t#Heat rejected in kJ/kg\n",
"QL = ((m*qL*60)/3600)/3.516;\t\t\t#Cooling produced per kg of refrigerant in tonnes of refrigeration\n",
"\n",
"# Results\n",
"print 'Theoretical COP is %3.2f \\\n",
"\\nNet cooling produced per hour is %3.2f TR'%(COPR,QL)\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Theoretical COP is 5.40 \n",
"Net cooling produced per hour is 1.75 TR\n"
]
}
],
"prompt_number": 3
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 6.15 Page no : 322"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"# Variables\n",
"T2 = 298.;\t\t\t#Temperature at point 2 in K\n",
"T1 = 268.;\t\t\t#Temperature at point 1 in K\n",
"hf1 = -7.54;\t\t\t#Liquid Enthalpy at T1 in kJ/kg\n",
"x1 = 0.6;\t\t\t#Quality factor 1\n",
"hfg1 = 245.3;\t\t\t#Latent heat at T1 in kJ/kg\n",
"sf1 = 0.251;\t\t\t#Liquid Entropy at T1 in kJ/kg-K\n",
"s1 = 0.507;\t\t\t#Entropy at point 1 in kJ/kg-K\n",
"hfg2 = 121.4;\t\t\t#Latent heat at T2 in kJ/kg\n",
"hf2 = 81.3;\t\t\t#Liquid Enthalpy at T2 in kJ/kg\n",
"h4 = hf2;\t\t\t#Enthalpy at point 4 in kJ/kg\n",
"\n",
"# Calculations\n",
"h1 = hf1+(x1*hfg1);\t\t\t#Enthalpy at point 1 in kJ/kg\n",
"x2 = ((s1-sf1)*T2)/hfg2;\t\t\t#Quality factor 2\n",
"h2 = hf2+(x2*hfg2);\t\t\t#Enthalpy at point 2 in kJ/kg\n",
"COP = (h1-h4)/(h2-h1);\t\t\t#COP of the machine\n",
"\n",
"# Results\n",
"print 'COP of the machine is %3.2f'%(COP)\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"COP of the machine is 3.25\n"
]
}
],
"prompt_number": 15
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 6.16 Page no : 323"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"\n",
"# Variables\n",
"P1 = 25.;\t\t\t#Pressure at point 1 in bar\n",
"P2 = 60.;\t\t\t#Pressure at point 2 in bar\n",
"h2 = 208.1;\t\t\t#Vapour enthalpy at P2 in kJ/kg\n",
"h3 = 61.9;\t\t\t#Liquid enthalpy at P2 in kJ/kg\n",
"h4 = h3;\t\t\t#Liquid enthalpy at P2 in kJ/kg\n",
"s2 = 0.703;\t\t\t#Vapour entropy at P2 in kJ/kg-K\n",
"sf1 = -0.075;\t\t\t#Liquid entropy at P1 in kJ/kg-K\n",
"sfg1 = 0.971;\t\t\t#Entropy in kJ/kg-K\n",
"hf1 = -18.4;\t\t\t#Liquid Enthalpy at P1 in kJ/kg\n",
"hfg1 = 252.9;\t\t\t#Latent heat at P1 in kJ/kg\n",
"m = 5.;\t\t\t#Refrigerant flow in kg/min\n",
"\n",
"# Calculations\n",
"x1 = (s2-sf1)/sfg1;\t\t\t#Quality factor 1\n",
"h1 = hf1+(x1*hfg1);\t\t\t#Enthalpy at point 1 in kJ/kg\n",
"COP = (h1-h4)/(h2-h1);\t\t\t#Co-efficient of performance\n",
"QL = (m*(h1-h4))/60;\t\t\t#Capacity of the refrigerator in kW\n",
"\n",
"# Results\n",
"print 'COP of refrigerator is %3.2f \\\n",
"\\nCapacity of refrigerator is %3.2f kW'%(COP,QL)\n",
"\n",
"# rounding off error"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"COP of refrigerator is 5.13 \n",
"Capacity of refrigerator is 10.19 kW\n"
]
}
],
"prompt_number": 12
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 6.17 Page no : 324"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"\n",
"import math \n",
"\n",
"# Variables\n",
"T1 = 271.;\t\t\t#Temperature at point 1 in K\n",
"T = 265.;\t\t\t#Temperature at point 1' in K\n",
"Ta = 303.;\t\t\t#Temperature at point 2' in K\n",
"Cpv = 0.733;\t\t\t#Specific heat of vapour in kJ/kg\n",
"Cpl = 1.235;\t\t\t#Specific heat of liquid in kJ/kg\n",
"h = 184.07;\t\t\t#Liquid enthalpy at T in kJ/kg\n",
"s = 0.7;\t\t\t#Entropy at point 1' in kJ/kg-K\n",
"sa = 0.685;\t\t\t#Vapour entropy at Ta in kJ/kg-K\n",
"ha = 199.62;\t\t\t#Enthalpy at point 2' in kJ/kg\n",
"hfb = 64.59;\t\t\t#Liquid enthalpy at Ta in kJ/kg\n",
"DT3 = 5.;\t\t\t#Temperature difference in oC\n",
"Q = 2532.;\t\t\t#Refrigeration capacity in kJ/min\n",
"\n",
"# Calculations\n",
"s2 = s+(Cpv*((math.log(T1/T))/(math.log(2.718))));\t\t\t#Entropy at point 1 in kJ/kg-K\n",
"h1 = h+(Cpv*(T1-T));\t\t\t#Enthalpy at point 1 in kJ/kg-K\n",
"T2 = (2.718**((s2-sa)/Cpv))*Ta;\t\t\t#Temperature at point 2 in K\n",
"h2 = ha+(Cpv*(T2-Ta));\t\t\t#Enthalpy at point 2 in kJ/kg\n",
"h4 = hfb-(Cpl*DT3);\t\t\t#Enthalpy at point 4 in kJ/kg\n",
"COP = (h1-h4)/(h2-h1);\t\t\t#Co-efficient of performance\n",
"m = Q/(h1-h4);\t\t\t#Mass flow rate of refrigerant in kJ/min\n",
"P = (m*(h2-h1))/(60*12);\t\t\t#Power required in kW/TR\n",
"\n",
"# Results\n",
"print 'COP is %3.2f \\\n",
"\\nTheoretical power required per tonne of refrigeration is %3.3f kW/TR'%(COP,P)\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"COP is 6.23 \n",
"Theoretical power required per tonne of refrigeration is 0.564 kW/TR\n"
]
}
],
"prompt_number": 17
}
],
"metadata": {}
}
]
}PKI{<7hhThermal Engineering/ch7.ipynb{
"cells": [
{
"cell_type": "markdown",
"metadata": {},
"source": [
"# Chapter 7 : Air Conditioning"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Example 7.1 Page no : 345"
]
},
{
"cell_type": "code",
"execution_count": 1,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"Heating capacity of coil is 5.40 kW \n",
"Surface temperature of coil is 35 C \n",
"Capacity of humidifier is 3.33 kg/hr\n"
]
}
],
"source": [
"\n",
"# Variables\n",
"DBTo = 10.;\t\t\t#Out door Dry bulb temperature in oC\n",
"WBTo = 8.;\t\t\t#Out door Wet bulb temperature in oC\n",
"DBTi = 20.;\t\t\t#In door Dry bulb temperature in oC\n",
"RH = 0.6;\t\t\t#Re-Heat factor\n",
"a = 0.3;\t\t\t#amount of air circulated in (m**3)/min/person\n",
"S = 50.;\t\t\t#Seating capacity of office\n",
"BPF = 0.32;\t\t\t#ByPass factor\n",
"ha = 25.;\t\t\t#Enthalpy at point a from Psychrometric chart shown in Page 346 in kJ/kg\n",
"hb = 42.5;\t\t\t#Enthalpy at point b from Psychrometric chart shown in Page 346 in kJ/kg\n",
"hc = 42.5;\t\t\t#Enthalpy at point c from Psychrometric chart shown in Page 346 in kJ/kg\n",
"Wa = 0.006;\t\t\t#Specific humidity at point a from Psychrometric chart shown in Page 346 in kg/kg dry air\n",
"Wc = 0.009;\t\t\t#Specific humidity at point c from Psychrometric chart shown in Page 346 in kg/kg dry air\n",
"Tb = 27.;\t\t\t#Temperature at point b in oC\n",
"na = 0.81;\t\t\t#Specific Volume from Psychrometric chart shown in page 346 in (m**3)/kg\n",
"\n",
"# Calculations\n",
"ma = (a*S)/(na*60);\t\t\t#mass of air circulated per second in kg/s\n",
"Hc = ma*(hb-ha);\t\t\t#Heating capacity of coil in kW\n",
"Ts = (Tb-(BPF*DBTo))/(1-BPF);\t\t\t#Heating coil surface temperature in oC\n",
"C = (ma*3600)*(Wc-Wa);\t\t\t#Capacity of humidifier in kg/hr\n",
"\n",
"# Results\n",
"print 'Heating capacity of coil is %3.2f kW \\\n",
"\\nSurface temperature of coil is %3.0f C \\\n",
"\\nCapacity of humidifier is %3.2f kg/hr'%(Hc,Ts,C)\n",
"\n",
"# rounding off error"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Example 7.2 Page no : 346"
]
},
{
"cell_type": "code",
"execution_count": 2,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"Capacity of cooling coil is 6.16 tonnes \n",
"Capacity of heating coil is 3.6 kW \n",
"Amount of water vapour removed per hour is 17.80 kg/hr \n",
"Bypass factor is 0.385\n"
]
}
],
"source": [
"# Variables\n",
"S = 60.;\t\t\t#No. of staff\n",
"DBTo = 30.;\t\t\t#Out door Dry bulb temperature in oC\n",
"RHo = 0.7;\t\t\t#Re-Heat factor at out-door\n",
"a = 0.4;\t\t\t#amount of air circulated in (m**3)/min/person\n",
"DBTi = 20.;\t\t\t#In door Dry bulb temperature in oC\n",
"RHi = 0.6;\t\t\t#Re-Heat factor at indoor\n",
"Td = 25.;\t\t\t#Heating coil surface temperature in oC\n",
"ha = 82.5;\t\t\t#Enthalpy at point a from Psychrometric chart shown in Page 347 in kJ/kg\n",
"hb = 34.5;\t\t\t#Enthalpy at point b from Psychrometric chart shown in Page 347 in kJ/kg\n",
"hc = 42.5;\t\t\t#Enthalpy at point c from Psychrometric chart shown in Page 347 in kJ/kg\n",
"Wa = 0.020;\t\t\t#Specific humidity at point a from Psychrometric chart shown in Page 347 in kg/kg dry air\n",
"Wb = 0.009;\t\t\t#Specific humidity at point b from Psychrometric chart shown in Page 347 in kg/kg dry air\n",
"Tb = 12.;\t\t\t#Temperature at point b in oC\n",
"na = 0.89;\t\t\t#Specific Volume from Psychrometric chart shown in page 346 in (m**3)/kg\n",
"\n",
"# Calculations\n",
"ma = (a*S)/(na*60);\t\t\t#mass of air circulated per second in kg/s\n",
"Hc = (ma*(ha-hb))/3.5;\t\t\t#Heating capacity of cooling coil in tonnes\n",
"Hh = ma*(hc-hb);\t\t\t#Heating capacity of heating coil in kW\n",
"W = (ma*3600)*(Wa-Wb);\t\t\t#Amount of water vapour removed per hour in kg/hr\n",
"BPF = (Td-DBTi)/(Td-Tb);\t\t\t#By-Pass factor\n",
"\n",
"# Results\n",
"print 'Capacity of cooling coil is %3.2f tonnes \\\n",
"\\nCapacity of heating coil is %3.1f kW \\\n",
"\\nAmount of water vapour removed per hour is %3.2f kg/hr \\\n",
"\\nBypass factor is %3.3f'%(Hc,Hh,W,BPF)\n"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"## Example 7.3 Page no : 347"
]
},
{
"cell_type": "code",
"execution_count": 2,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"Supply air condition to the room is 2.74 kg/s \n",
"Refrigeration load due to reheat is 4.93 ton \n",
"Total refrigerating capacity is 16.28 ton \n",
"Quantity of fresh air supplied is 0.365 m**3/s\n"
]
}
],
"source": [
"\n",
"\n",
"# Variables\n",
"RSH = 10.;\t\t\t#Room sensible heat in kW\n",
"RLH = 10.;\t\t\t#Room latent heat in kW\n",
"td1 = 25.;\t\t\t#Inside temperature in oC\n",
"RH1 = 0.5;\t\t\t#Inside Re-Heat factor\n",
"h1 = 50.4;\t\t\t#Enthalpy at point 1 in kJ/kg\n",
"td2 = 35.;\t\t\t#Out door Dry bulb temperature in oC\n",
"tw2 = 28.;\t\t\t#Out door Wet bulb temperature in oC\n",
"CR = 4.;\t\t\t#Cooling coil ratio\n",
"BPF = 0.1;\t\t\t#Cooling coil bypass factor\n",
"tADP = 10;\t\t\t#Apparatus dew point temperature in oC\n",
"RH3 = 0.55;\t\t\t#Re-Heat factor at point 3\n",
"h3 = 58.2;\t\t\t#Enthalpy at point 3 in kJ/kg\n",
"RH4 = 0.95;\t\t\t#Re-Heat factor at point 4\n",
"h4 = 32.2;\t\t\t#Enthalpy at point 4 in kJ/kg\n",
"RH5 = 0.81;\t\t\t#Re-Heat factor at point 5\n",
"h5 = 36.8;\t\t\t#Enthalpy at point 5 in kJ/kg\n",
"RH6 = 0.54;\t\t\t#Re-Heat factor at point 6\n",
"h6 = 43.1;\t\t\t#Enthalpy at point 5 in kJ/kg\n",
"td6 = 22.;\t\t\t#Temperature at point 6 in oC\n",
"\n",
"# Calculations\n",
"td3 = ((td2-td1)/5)+td1;\t\t\t#Temperature at point 3 from Psychrometric chart shown in Page 348 in oC\n",
"td4 = (BPF*(td3-tADP))+tADP;\t\t\t#Temperature at point 4 from Psychrometric chart shown in Page 348 in oC\n",
"td5 = td4+((td1-td4)/5);\t\t\t#Temperature at point 5 from Psychrometric chart shown in Page 348 in oC\n",
"RSHF = RSH/(RSH+RLH);\t\t\t#Room Sensible Heat Factor\n",
"QR = h1-h6;\t\t\t#Total heat removed in kJ/kg\n",
"S = (RSH+RLH)/QR;\t\t\t#Supply air quantity in kg/s\n",
"R = (S*(h6-h5))/3.5;\t\t\t#Refrigeration load due to reheat in ton\n",
"D = (S*4)/5;\t\t\t#Dehumidified air quantity in kg/s\n",
"T = (D*(h3-h4))/3.5;\t\t\t#Total refrigerating capacity in ton\n",
"Q = (D/5)/1.2;\t\t\t#Quantity of fresh air supplied in (m**3)/s\n",
"\n",
"# Results\n",
"print 'Supply air condition to the room is %3.2f kg/s \\\n",
"\\nRefrigeration load due to reheat is %3.2f ton \\\n",
"\\nTotal refrigerating capacity is %3.2f ton \\\n",
"\\nQuantity of fresh air supplied is %3.3f m**3/s'%(S,R,T,Q)\n"
]
}
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