{ "metadata": { "name": "" }, "nbformat": 3, "nbformat_minor": 0, "worksheets": [ { "cells": [ { "cell_type": "markdown", "metadata": {}, "source": [ "

# Chapter 9: GAS POWER SYSTEMS

" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "

## Example 9.01, page: 228

" ] }, { "cell_type": "code", "collapsed": false, "input": [ "from __future__ import division\n", "import math\n", "\n", "# Initialization of Variable\n", "r = 8 #compression ratio\n", "T1 = 540 #degR\n", "V1 = 0.02 #ft3\n", "T3 = 3600 #degR\n", "P1 = 1 #atm\n", "R = 1545/28.97 #ft*lbf/lb-degR\n", "\n", "#calculations:\n", "#from Table T-9E\n", "u1 = 92.04 #Btu/lb\n", "vr1 = 144.32\n", "#from isentropic process 1-2\n", "vr2 = vr1/r\n", "#from Table T-9E\n", "T2 = 1212 #degR\n", "u2 = 211.3 #Btu/lb\n", "#Pressure\n", "P2 = P1*T2*r/T1\n", "P3 = P2*T3/T2\n", "#from Table T-9E\n", "u3 = 721.44 #Btu/lb\n", "vr3 = 0.6449\n", "#from isentropic process 3-4\n", "vr4 = vr3*r\n", "#from Table T-9E\n", "T4 = 1878 #degR\n", "u4 = 342.2 #Btu/lb\n", "#pressure\n", "P4 = P1*T4/T1\n", "#Thermal Eff\n", "n = 1 - (u4 - u1)/(u3 - u2)\n", "#net work per cycle\n", "m = P1*14.696*144*V1/(R*T1)\n", "Wcycle = m*((u3-u4)-(u2-u1))\n", "#mean effective pressure\n", "mep = Wcycle/(V1*(1 - 1/r))*778/(144*14.696)\n", "\n", "#Results\n", "print \"a)pressure and temperature at 2 are\", round(P2,2),\"atm and\", T2,\"degR\"\n", "print \" pressure and temperature at 3 are\", round(P3,2),\"atm and\", T3,\"degR\"\n", "print \" pressure and temperature at 4 are\", round(P4,2),\"atm and\", T4,\"degR\"\n", "print \"b)thermal efficiency is\", round(n*100,0),\"%\"\n", "print \"c)mean effective pressure is\",round(mep,2),\"atm\"\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "a)pressure and temperature at 2 are 17.96 atm and 1212 degR\n", " pressure and temperature at 3 are 53.33 atm and 3600 degR\n", " pressure and temperature at 4 are 3.48 atm and 1878 degR\n", "b)thermal efficiency is 51.0 %\n", "c)mean effective pressure is 8.03 atm\n" ] } ], "prompt_number": 1 }, { "cell_type": "markdown", "metadata": {}, "source": [ "

## Example 9.02, page: 232

" ] }, { "cell_type": "code", "collapsed": false, "input": [ "from __future__ import division\n", "import math\n", "\n", "# Initialization of Variable\n", "r = 18 #compression ratio\n", "T1 = 300 #K\n", "rc = 2 #cut-off ratio\n", "P1 = 0.1 #MPa\n", "R = 8314/28.97 #J/kg-K\n", "\n", "#calculations:\n", "#from Table T-9\n", "u1 = 214.07 #kJ/kg\n", "vr1 = 621.2\n", "#from isentropic process 1-2\n", "vr2 = vr1/r\n", "#from Table T-9\n", "T2 = 898.3 #K\n", "h2 = 930.98 #kJ/kg\n", "#Pressure\n", "P2 = P1*T2*r/T1\n", "P3 = P2\n", "#temp\n", "T3 = rc*T2\n", "#from Table T-9\n", "h3 = 1999.1 #kJ/kg\n", "vr3 = 0.6449\n", "#from isentropic process 3-4\n", "vr4 = vr3*r/rc\n", "#from Table T-9\n", "T4 = 887.7 #degR\n", "u4 = 664.3 #kJ/kg\n", "#pressure\n", "P4 = P1*T4/T1\n", "#Thermal Eff\n", "n = 1 - (u4 - u1)/(h3 - h2)\n", "#net work per cycle per unit mass\n", "Wmcycle = (h3-h2)-(u4-u1)\n", "#specific vol at 1\n", "v1 = R*T1/(P1*1000000)\n", "#mean effective pressure\n", "mep = Wmcycle/(v1*(1 - 1/r)*1000)\n", "\n", "#Results\n", "print \"a)pressure and temperature at 2 are\", round(P2,2),\"MPa and\", T2,\"degR\"\n", "print \" pressure and temperature at 3 are\", round(P3,2),\"MPa and\", T3,\"degR\"\n", "print \" pressure and temperature at 4 are\", round(P4,2),\"MPa and\", T4,\"degR\"\n", "print \"b)thermal efficiency is\", round(n*100,1),\"%\"\n", "print \"c)mean effective pressure is\",round(mep,2),\"MPa\"\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "a)pressure and temperature at 2 are 5.39 MPa and 898.3 degR\n", " pressure and temperature at 3 are 5.39 MPa and 1796.6 degR\n", " pressure and temperature at 4 are 0.3 MPa and 887.7 degR\n", "b)thermal efficiency is 57.8 %\n", "c)mean effective pressure is 0.76 MPa\n" ] } ], "prompt_number": 2 }, { "cell_type": "markdown", "metadata": {}, "source": [ "

## Example 9.03, page: 238

" ] }, { "cell_type": "code", "collapsed": false, "input": [ "from __future__ import division\n", "import math\n", "\n", "# Initialization of Variable\n", "r = 10 #compression ratio\n", "T1 = 300 #K\n", "AV1 = 5 #m3/s\n", "P1 = 100 #kPa\n", "R = 8314/28.97 #J/kg-K\n", "\n", "#calculations:\n", "#from Table T-9\n", "h1 = 300.19 #kJ/kg\n", "Pr1 = 1.386\n", "#reduced pressure at 2\n", "Pr2 = r*Pr1\n", "#from Table T-9\n", "h2 = 579.9 #kJ/kg\n", "T3 = 1400 #K\n", "h3 = 1515.4 #kJ/kg\n", "Pr3 = 450.5\n", "#reduced pressure at 4\n", "Pr4 = Pr3/r\n", "#from Table T-9\n", "h4 = 808.5 #kJ/kg\n", "\n", "#Thermal Eff\n", "n = 1 - (h4 - h1)/(h3 - h2)\n", "#back work ratio\n", "bwr = (h2 - h1)/(h3-h4)\n", "#net wpower developed\n", "mdot = AV1*P1*1000/(R*T1)\n", "Wmcycledot = mdot*((h3-h4)-(h2-h1))\n", "\n", "#Results\n", "print \"a)thermal efficiency is\", round(n*100,1),\"%\"\n", "print \"b)back work ratio is\", round(bwr*100,1),\"%\"\n", "print \"c)mean effective pressure is\",round(Wmcycledot,0),\"kW\"\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "a)thermal efficiency is 45.7 %\n", "b)back work ratio is 39.6 %\n", "c)mean effective pressure is 2481.0 kW\n" ] } ], "prompt_number": 3 }, { "cell_type": "markdown", "metadata": {}, "source": [ "

## Example 9.04, page: 242

" ] }, { "cell_type": "code", "collapsed": false, "input": [ "from __future__ import division\n", "import math\n", "\n", "# Initialization of Variable\n", "r = 10 #compression ratio\n", "T1 = 300 #K\n", "AV1 = 5 #m3/s\n", "P1 = 100 #kPa\n", "R = 8314/28.97 #J/kg-K\n", "nt = 0.8\n", "nc = nt\n", "\n", "#calculations:\n", "#from Table T-9\n", "h1 = 300.19 #kJ/kg\n", "Pr1 = 1.386\n", "#reduced pressure at 2\n", "Pr2 = r*Pr1\n", "#from Table T-9\n", "h2 = 579.9 #kJ/kg\n", "T3 = 1400 #K\n", "h3 = 1515.4 #kJ/kg\n", "Pr3 = 450.5\n", "#reduced pressure at 4\n", "Pr4 = Pr3/r\n", "#from Table T-9\n", "h4 = 808.5 #kJ/kg\n", "#turbine work per unit mass\n", "Wtmdot = nt*(h3-h4)\n", "#Compressor work per unit mass\n", "Wcmdot = (h2 - h1)/nc\n", "#new enthalpy at 2\n", "h2 = h1 + Wcmdot\n", "#heat transfer to the working fluid per unit of mass flow\n", "Qinmdot = h3 - h2\n", "#Thermal Eff\n", "n = (Wtmdot - Wcmdot)/Qinmdot\n", "#back work ratio\n", "bwr = Wcmdot/Wtmdot\n", "#net wpower developed\n", "mdot = AV1*P1*1000/(R*T1)\n", "Wmcycledot = mdot*(Wtmdot - Wcmdot)\n", "\n", "#Results\n", "print \"a)thermal efficiency is\", round(n*100,1),\"%\"\n", "print \"b)back work ratio is\", round(bwr*100,1),\"%\"\n", "print \"c)mean effective pressure is\",round(Wmcycledot,0),\"kW\"\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "a)thermal efficiency is 24.9 %\n", "b)back work ratio is 61.8 %\n", "c)mean effective pressure is 1254.0 kW\n" ] } ], "prompt_number": 4 }, { "cell_type": "markdown", "metadata": {}, "source": [ "

## Example 9.05, page: 245

" ] }, { "cell_type": "code", "collapsed": false, "input": [ "from __future__ import division\n", "import math\n", "\n", "# Initialization of Variable\n", "nreg = 0.8\n", "\n", "#calculations:\n", "#from Example 9.3\n", "h1 = 300.19 #kJ/kg\n", "h2 = 579.9 #kJ/kg\n", "h3 = 1515.4 #kJ/kg\n", "h4 = 808.5 #kJ/kg\n", "\n", "#specific enthalpy hx\n", "hx = nreg*(h4 - h2) + h2\n", "\n", "#Thermal Eff\n", "n = ((h3 - h4) - (h2 - h1))/(h3 - hx)\n", "\n", "#Results\n", "print \"a)thermal efficiency is\", round(n*100,1),\"%\"\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "a)thermal efficiency is 56.8 %\n" ] } ], "prompt_number": 5 }, { "cell_type": "markdown", "metadata": {}, "source": [ "

## Example 9.06, page: 247

" ] }, { "cell_type": "code", "collapsed": false, "input": [ "from __future__ import division\n", "import math\n", "\n", "# Initialization of Variable\n", "Pa = 11.8 #lbf/in2\n", "Ta = 430 #degR\n", "Va = 620 #mi/hr\n", "V1 = 0\n", "P2P1 = 8 #P2/P1\n", "T3 = 2150 #degR\n", "P5 = 11.8 #lbf/in2\n", "\n", "#Calculations:\n", "#from Table T-9E\n", "ha = 102.7 #Btu/lb\n", "h1 = ha + (Va**2)/(2*32.2*778)\n", "#\n", "Pr1 = 1.051\n", "Pra = 0.6268\n", "P1 = Pr1*Pa/Pra\n", "#\n", "P2 = P2P1*P1\n", "#\n", "Pr2 = Pr1*P2P1\n", "h2 = 216.2 #Btu/lb\n", "h3 = 546.54 #Btu/lb\n", "P3=P2\n", "h4 = h3 + h1 - h2\n", "#\n", "Pr4 = 113.8\n", "Pr3 = 233.5\n", "P4 = P3*Pr4/Pr3\n", "#\n", "P5 = Pr4*P5/P4\n", "#\n", "h5 = 265.8 #Btu/lb\n", "V5 = (2*(h4 - h5)*32.2*778)**0.5\n", "\n", "#Results\n", "print \"Pressure at 1 is\", round(P1,2),\"lbf/in2\"\n", "print \"Pressure at 2 is\", round(P2,1),\"lbf/in2\"\n", "print \"Pressure at 4 is\", round(P4,1),\"lbf/in2\"\n", "print \"velocity at nozzle exit is\", round(V5,0),\"ft/s\"\n", "#answer wrong in book\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Pressure at 1 is 19.79 lbf/in2\n", "Pressure at 2 is 158.3 lbf/in2\n", "Pressure at 4 is 77.1 lbf/in2\n", "velocity at nozzle exit is 2960.0 ft/s\n" ] } ], "prompt_number": 6 } ], "metadata": {} } ] }