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"worksheets": [
{
"cells": [
{
"cell_type": "heading",
"level": 1,
"metadata": {},
"source": [
"Chapter 16: Shell and Tube Heat Exchangers"
]
},
{
"cell_type": "heading",
"level": 3,
"metadata": {},
"source": [
"ILLUSTRATIVE EXAMPLE 16.5, Page number: 334"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"from math import log\n",
"\n",
"#Variable declaration:\n",
"#From figure 16.13, for ideal countercurrent heat exchanger:\n",
"T1 = 150.0 #Inlet temperature of hot fluid (\u00b0F)\n",
"T2 = 100.0 #Outet temperature of hot fluid (\u00b0F)\n",
"t1 = 50.0 #Inlet temperature of cold fluid (\u00b0F)\n",
"t2 = 80.0 #Outet temperature of hot fluid (\u00b0F)\n",
"#From figure 16.14, for shell and tube exchanger:\n",
"T_1 = 50.0 #Inlet temperature of cold fluid (\u00b0F)\n",
"T_2 = 80.0 #Outet temperature of hot fluid (\u00b0F)\n",
"t_1 = 150.0 #Inlet temperature of hot fluid (\u00b0F)\n",
"t_2 = 100.0 #Outet temperature of hot fluid (\u00b0F)\n",
"\n",
"#Calculation:\n",
"DT1 = T1 - t2 #Temperature driving force 1 (\u00b0F)\n",
"DT2 = T2 - t1 #Temperature driving force 1 (\u00b0F)\n",
"DTlm1 = ((DT1-DT2)/log(DT1/DT2)) #Log mean temperature driving force for ideal countercurrent heat exchanger (\u00b0F)\n",
"P = (t2-t1)/(T1 - t1) #Dimensionless ratio P\n",
"R = (T1-T2)/(t2-t1) #Dimensionless ratio R\n",
"#From figure 16.7:\n",
"F = 0.925 #Correction Factor\n",
"DTlm2 = F*DTlm1 #Log mean temperature driving force for shell and tube exchanger (\u00b0F)\n",
"\n",
"#Result:\n",
"print \"The log mean temperature difference for ideal system is :\",round(DTlm1,1),\" \u00b0F .\"\n",
"print \"The log mean temperature difference for real system is :\",round(DTlm2,2),\" \u00b0F .\""
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"The log mean temperature difference for ideal system is : 59.4 \u00b0F .\n",
"The log mean temperature difference for real system is : 54.98 \u00b0F .\n"
]
}
],
"prompt_number": 5
},
{
"cell_type": "heading",
"level": 3,
"metadata": {},
"source": [
"ILLUSTRATIVE EXAMPLE 16.6, Page number: 335"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"from math import log\n",
"5\n",
"#Variable declaration:\n",
"T1 = 400.0 #Temperature of fluid entering the shell (\u00b0F)\n",
"T2 = 250.0 #Temperature of fluid leaving the shell (\u00b0F)\n",
"t1 = 100.0 #Temperature of fluid entering the tube (\u00b0F)\n",
"t2 = 175.0 #Temperature of fluid leaving the tube (\u00b0F)\n",
"\n",
"#Calculation:\n",
"DT1 = T1 - T2 #Temperature driving force 1 (\u00b0F)\n",
"DT2 = t2 - t1 #Temperature driving force 1 (\u00b0F)\n",
"DTlm1 = ((DT1-DT2)/log(DT1/DT2)) #Log mean temperature driving force for ideal countercurrent heat exchanger (\u00b0F)\n",
"P = (t2-t1)/(T1 - t1) #Dimensionless ratio P\n",
"R = (T1-T2)/(t2-t1) #Dimensionless ratio R\n",
"#From figure 16.8:\n",
"F = 0.985 #Correction factor\n",
"DTlm2 = F*DTlm1 #Log mean temperature driving force for shell and tube exchanger (\u00b0F)\n",
"\n",
"#Result:\n",
"print \"The log mean temperature difference between the hot fluid and the cold fluid is :\",round(DTlm2,1),\" \u00b0F .\""
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"The log mean temperature difference between the hot fluid and the cold fluid is : 106.6 \u00b0F .\n"
]
}
],
"prompt_number": 6
},
{
"cell_type": "heading",
"level": 3,
"metadata": {},
"source": [
"ILLUSTRATIVE EXAMPLE 16.7, Page number: 336"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"#Variable declaration:\n",
"#From example 16.5:\n",
"P1 = 0.30 #Dimensionless ratio P\n",
"R1 = 1.67 #Dimensionless ratio R\n",
"#From example 16.6:\n",
"P2 = 0.30 #Dimensionless ratio P\n",
"R2 = 1.67 #Dimensionless ratio R\n",
"\n",
"#Calculation:\n",
"#Applying Equation 16.27:\n",
"F1 = 0.92 #Correction Factor\n",
"#Applying Equation 16.33:\n",
"F2 = 0.985 #Correction Factor\n",
"#From example 16.6:\n",
"LMTD1 = 59.4 #Log mean temperature driving force 1 for ideal countercurrent heat exchanger (\u00b0F)\n",
"LMTD2 = 108.0 #Log mean temperature driving force 2 for ideal countercurrent heat exchanger (\u00b0F)\n",
"DTlm1 = F1*LMTD1 #Log mean temperature driving force 1 for shell and tube exchanger (\u00b0F)\n",
"DTlm2 = F2*LMTD2 #Log mean temperature driving force 2 for shell and tube exchanger (\u00b0F)\n",
"\n",
"#Result:\n",
"print \"The log mean temperature difference for real system (in example 16.5) is :\",round(DTlm1,2),\" \u00b0F .\"\n",
"print \"The log mean temperature difference for real system (in example 16.6) is :\",round(DTlm2,1),\" \u00b0F .\""
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"The log mean temperature difference for real system (in example 16.5) is : 54.65 \u00b0F .\n",
"The log mean temperature difference for real system (in example 16.6) is : 106.4 \u00b0F .\n"
]
}
],
"prompt_number": 7
},
{
"cell_type": "heading",
"level": 3,
"metadata": {},
"source": [
"ILLUSTRATIVE EXAMPLE 16.8, Page number: 337"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"\n",
"from math import log\n",
"\n",
"#Variable declaration:\n",
"t2 = 75.0 #Temperature of water leaving the shell (\u00b0C)\n",
"t1 = 35.0 #Temperature of water enteringing the shell (\u00b0C)\n",
"T2 = 75.0 #Temperature of oil leaving the tube (\u00b0C)\n",
"T1 = 110.0 #Temperature of oil entering the tube (\u00b0C)\n",
"m = 1.133 #Mass flowrate of water (kg/s)\n",
"cp = 4180.0 #Heat capacity of water (J/kg.K)\n",
"F = 0.965 #Correction factor\n",
"U = 350.0 #Overall heat transfer coefficient (W/m^2.K)\n",
"\n",
"#Calculation:\n",
"Q = m*cp*(t2-t1) #Heat load (W)\n",
"DT1 = T1-t2 #Temperature driving force 1 (\u00b0C)\n",
"DT2 = T2-t1 #Temperature driving force 2 (\u00b0C)\n",
"DTlm1 = (DT1-DT2)/log(DT1/DT2)+273.0 #Countercurrent log-mean temperature difference (K)\n",
"DTlm2 = F*DTlm1 #Corrected log-mean temperature difference (K)\n",
"A = Q/(U*DTlm2) #Required heat transfer area (m^2)\n",
"\n",
"#Result:\n",
"print \"The required heat-transfer area is :\",round(A,3),\" m^2 .\""
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"The required heat-transfer area is : 1.807 m^2 .\n"
]
}
],
"prompt_number": 8
},
{
"cell_type": "heading",
"level": 3,
"metadata": {},
"source": [
"ILLUSTRATIVE EXAMPLE 16.10, Page number: 338"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"\n",
"from math import log\n",
"\n",
"#Variable declaration:\n",
"t2 = 84.0 #Temperature of water leaving the tube (\u00b0C)\n",
"t1 = 16.0 #Temperature of water entering the tube (\u00b0C)\n",
"m1 = 10000.0/3600.0 #Mass flowrate of water (kg/s)\n",
"T2 = 94.0 #Temperature of oil leaving the shell (\u00b0C)\n",
"T1 = 160.0 #Temperature of oil entering the shell (\u00b0C)\n",
"\n",
"#Calculation:\n",
"Tw = (t1+t2)/2.0 #Average bulk temperature of water (\u00b0C)\n",
"To = (T1+T2)/2.0 #Average bulk temperature of oil (\u00b0C)\n",
"#From table 16.1:\n",
"p1 = 987.0 #Density of water (kg/m^3)\n",
"cp1 = 4176.0 #Heat capacity of water (J/kg.\u00b0C)\n",
"p2 = 822.0 #Density of oil (kg/m^3)\n",
"Q = m1*cp1*(t2-t1) #Heat load (W)\n",
"cp2 = 4820.0 #Heat capacity of oil (J/kg.\u00b0C)\n",
"m2 = Q/(cp2*(T1-T2)) #Mass flowrate of oil (kg/s)\n",
"DT1 = T2-t1 #Temperature driving force 1 (\u00b0C)\n",
"DT2 = T1-t2 #Temperature driving force 2 (\u00b0C)\n",
"DTlm1 = ((DT1-DT2)/log(DT1/DT2)) #Log mean temperature driving force for ideal countercurrent heat exchanger (\u00b0C)\n",
"P = (t2-t1)/(T1 - t1) #Dimensionless ratio P\n",
"R = (T1-T2)/(t2-t1) #Dimensionless ratio R\n",
"#From figure 16.7:\n",
"F = 0.965 #Correction factor\n",
"DTlm2 = F*DTlm1 #Log mean temperature driving force for 1-4 shell and tube exchanger (\u00b0C)\n",
"\n",
"#Result:\n",
"print \"1. The heat load is :\",round(Q/10**6,3),\" MW .\"\n",
"print \"2. The countercurrent flow log mean temperature difference is :\",round(DTlm1),\" \u00b0C .\"\n",
"print \"3. The F correction factor and the corrected log mean temperature difference is :\",round(DTlm2,1),\" \u00b0C .\""
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"1. The heat load is : 0.789 MW .\n",
"2. The countercurrent flow log mean temperature difference is : 77.0 \u00b0C .\n",
"3. The F correction factor and the corrected log mean temperature difference is : 74.3 \u00b0C .\n"
]
}
],
"prompt_number": 10
},
{
"cell_type": "heading",
"level": 3,
"metadata": {},
"source": [
"ILLUSTRATIVE EXAMPLE 16.11, Page number: 340"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"\n",
"from math import pi\n",
"\n",
"#Variable declaration:\n",
"#From example 16.10:\n",
"U = 350.0 #Over all heat transfer coefficient (W/m^2.\u00b0C)\n",
"DTlm = 74.3 #Log mean temperature driving force for 1-4 shell and tube exchanger (\u00b0C)\n",
"Q = 788800.0 #Heat load (W)\n",
"Nt = 11.0 #Number of tubes per pass\n",
"Np = 4.0 #Number of passes\n",
"Di = 0.0229 #Inside diameter of tube (m)\n",
"\n",
"#Calculation:\n",
"A = Q/(U*DTlm) #Heat transfer area required for heat exchanger (m^2)\n",
"N = Nt*Np #Total number of tubes\n",
"L = A/(pi*Di*N) #Tube length (m)\n",
"\n",
"#Result:\n",
"print \"The heat transfer area required for the heat exchanger is :\",round(A,2),\" m^2 .\"\n",
"print \"The length of the tubes required for the heat exchanger is :\",round(L*3.28,1),\" ft .\""
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"The heat transfer area required for the heat exchanger is : 30.33 m^2 .\n",
"The length of the tubes required for the heat exchanger is : 31.4 ft .\n"
]
}
],
"prompt_number": 11
},
{
"cell_type": "heading",
"level": 3,
"metadata": {},
"source": [
"ILLUSTRATIVE EXAMPLE 16.18, Page number: 349"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"\n",
"\n",
"#Variable declaration:\n",
"#From example 16.10:\n",
"m1 = 2.778 #Mass flowrate of water (kg/s)\n",
"cp1 = 4176.0 #Heat capacity of water (J/kg.\u00b0C)\n",
"cp2 = 4820.0 #Heat capacity of oil (J/kg.\u00b0C)\n",
"m2 = 2.48 #Mass flowrate of oil (kg/s)\n",
"t2 = 84.0 #Temperature of water leaving the tube (\u00b0C)\n",
"t1 = 16.0 #Temperature of water entering the tube (\u00b0C)\n",
"T2 = 94.0 #Temperature of oil leaving the shell (\u00b0C)\n",
"T1 = 160.0 #Temperature of oil entering the shell (\u00b0C)\n",
"U = 350.0 #Over all heat transfer coefficient (W/m^2.\u00b0C)\n",
"A = 30.33 #Heat transfer area required for heat exchanger (m^2)\n",
"\n",
"#Calculation:\n",
"C1 = m1*cp1 #Capacitance rate of water (W/\u00b0C)\n",
"C2 = m2*cp2 #Capacitance rate of oil (W/\u00b0C)\n",
"Q = C1*(t2-t1) #Heat load of water (W)\n",
"Qmax = C1*(T1-t1) #Maximum heat load of water (W)\n",
"E = Q/Qmax #Effectiveness\n",
"if (C1