{ "cells": [ { "cell_type": "markdown", "metadata": {}, "source": [ "# Appendix A" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "## Example 1" ] }, { "cell_type": "code", "execution_count": 13, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "('Temperature T2 = %.1f K', 556.4270854641527)\n", "(' Compressor work = %.1f kJ/kg ', 269.2999938060093)\n", "(' Temperature T3 = %.1f K', 1373.2)\n", "(' Temperature T4 = %.1f K', 711.24546295203)\n", "(' Turbine work = %.1f kJ/kg', 664.6023551961619)\n", "(' Net work = %.1f kJ/kg', 395.30236139015256)\n", "(' Thermal Efficiency of cycle = %.1f percent', 48.205253207687875)\n" ] } ], "source": [ "# -*- coding: utf8 -*-\n", "from __future__ import division\n", "#Example: 12.1\n", "''' '''\n", "\n", "#Variable Declaration: \n", "\n", "\n", "\t\t#1-Inlet for compressor\n", "\t\t#2-Exit for compressor\n", "\t\t#T-Temperature at a state\n", "\t\t#P-Pressure at a state\n", "T1 = 288.2\t\t#K\n", "P2 = 1000\t\t#kPa\n", "P1 = 100\t\t#kPa\n", "k = 1.4\n", "T2 = T1*(P2/P1)**(1-1/k)\t\t#K\n", "Cp = 1.004\t\t#Specific heat at constant pressure in kJ/kg\n", "wc = Cp*(T2-T1)\t\t#compressor work in kJ/kg\n", "print ('Temperature T2 = %.1f K',T2)\n", "print (' Compressor work = %.1f kJ/kg ',wc)\n", "\t\t#3-Turbine Inlet\n", "\t\t#4-Turbine Exit\n", "P4 = P1\n", "P3 = P2\n", "T3 = 1373.2\t\t#K\n", "T4 = T3*(P4/P3)**(1-1/k)\t\t#K\n", "wt = Cp*(T3-T4)\n", "wnet = wt-wc\n", "print (' Temperature T3 = %.1f K',T3)\n", "print (' Temperature T4 = %.1f K',T4)\n", "print (' Turbine work = %.1f kJ/kg',wt)\n", "print (' Net work = %.1f kJ/kg',wt-wc)\n", "\t\t#2-Also high temperature heat exchanger Inlet\n", "\t\t#3-(-do-) Exit\n", "qh = Cp*(T3-T2)\t\t#Heat of source in kJ/kg\n", "\t\t#4-high temp heat exchanger inlet\n", "\t\t#1-(-do-) Exit\n", "ql = Cp*(T4-T1)\t\t#Heat of sink in kJ/kg\n", "nth = wnet/qh\n", "print (' Thermal Efficiency of cycle = %.1f percent',nth*100)" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "## Example 2" ] }, { "cell_type": "code", "execution_count": 14, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "('Temperature T2 = %.1f K', 623.4838568301909)\n", "(' Compressor work = %.1f kJ/kg ', 336.6249922575117)\n", "(' Temperature T3 = %.1f K', 1373.2)\n", "(' Temperature T4 = %.1f K', 810.5386435092256)\n", "(' Turbine work = %.1f kJ/kg', 564.9120019167375)\n", "(' Net work = %.1f kJ/kg', 228.28700965922582)\n", "(' Thermal Efficiency of cycle = %.1f percent', 30.32847854912508)\n" ] } ], "source": [ "# -*- coding: utf8 -*-\n", "from __future__ import division\n", "#Example: 12.2\n", "''' '''\n", "\n", "#Variable Declaration: \n", "\t\t#Standard brayton cycle\n", "\n", "\n", "\t\t#Calculation mistake in book\n", "\t\t#1-Inlet for compressor\n", "\t\t#2-Exit for compressor\n", "\t\t#T-Temperature at a state\n", "\t\t#P-Pressure at a state\n", "T1 = 288.2\t\t#K\n", "P2 = 1000\t\t#kPa\n", "P1 = 100\t\t#kPa\n", "k = 1.4\n", "T2s = T1*(P2/P1)**(1-1/k)\t\t#K\n", "nc = .80\t\t#Compressor Efficiency\n", "T2 = T1+(T2s-T1)/0.80\n", "Cp = 1.004\t\t#Specific heat at constant pressure in kJ/kg\n", "wc = Cp*(T2-T1)\t\t#compressor work in kJ/kg\n", "print ('Temperature T2 = %.1f K',T2)\n", "print (' Compressor work = %.1f kJ/kg ',wc)\n", "\t\t#3-Turbine Inlet\n", "\t\t#4-Turbine Exit\n", "P4 = P1\n", "P3 = P2\n", "T3 = 1373.2\t\t#K\n", "T4s = T3*(P4/P3)**(1-1/k)\t\t#K\n", "nt = 0.85\t\t#turbine Efficiency\n", "T4 = T3-(T3-T4s)*0.85\n", "wt = Cp*(T3-T4)\n", "wnet = wt-wc\n", "print (' Temperature T3 = %.1f K',T3)\n", "print (' Temperature T4 = %.1f K',T4)\n", "print (' Turbine work = %.1f kJ/kg',wt)\n", "print (' Net work = %.1f kJ/kg',wt-wc)\n", "\t\t#2-Also high temperature heat exchanger Inlet\n", "\t\t#3-(-do-) Exit\n", "qh = Cp*(T3-T2)\t\t#Heat of source in kJ/kg\n", "\t\t#4-high temp heat exchanger inlet\n", "\t\t#1-(-do-) Exit\n", "ql = Cp*(T4-T1)\t\t#Heat of sink in kJ/kg\n", "nth = wnet/qh\n", "print (' Thermal Efficiency of cycle = %.1f percent',nth*100)" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "## Example 3" ] }, { "cell_type": "code", "execution_count": 15, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "('Thermal efficiency = %.1f percent', 59.42413919202417)\n" ] } ], "source": [ "# -*- coding: utf8 -*-\n", "from __future__ import division\n", "#Example: 12.3\n", "''' '''\n", "\n", "#Variable Declaration: \n", "\n", "\n", "wnet = 395.2\t\t#kJ/kg from example no 1\n", "\t\t#Tx = T4\n", "Tx = 710.8\t\t#K from example no 1\n", "T3 = 1373.2\t\t#K from example no 1\n", "Cp = 1.004\t\t#specific heat in kJ/kg \n", "qh = Cp*(T3-Tx)\n", "nth = wnet/qh\n", "print ('Thermal efficiency = %.1f percent',nth*100) " ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "## Example 4" ] }, { "cell_type": "code", "execution_count": 18, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "('Isothermal work in compressor = %.1f kJ/kg ', -190.4546418308537)\n", "(' Isothermal work in turbine = %.1f kJ/kg', 907.4681268637344)\n" ] } ], "source": [ "# -*- coding: utf8 -*-\n", "from __future__ import division\n", "#Example: 12.4\n", "''' '''\n", "from math import log\n", "#Variable Declaration: \n", "\n", "\n", "R = 0.287\t\t#gas constant \n", "T1 = 288.2\t\t#compressor temperature K\n", "T2 = 1373.2\t\t#K turbine temperature K\n", "\t\t#Pe/Pi = c = 10, Pi/Pe = 1/c from example 12.1\n", "c = 10\n", "wc = -R*T1*log(c)\n", "print ('Isothermal work in compressor = %.1f kJ/kg ',wc)\n", "wt = -R*T2*log(1/c)\n", "print (' Isothermal work in turbine = %.1f kJ/kg',wt) " ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "## Example 5" ] }, { "cell_type": "code", "execution_count": 20, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "('Velocity of air leaving the nozel = %.0f m/s', 889.4375751001304)\n" ] } ], "source": [ "# -*- coding: utf8 -*-\n", "from __future__ import division\n", "#Example: 12.5\n", "''' '''\n", "from math import sqrt\n", "#Variable Declaration: \n", "\n", "\n", "\t\t#1-compressor inlet\n", "\t\t#2-Compressor exit\n", "\t\t#P-Pressure at given point\n", "\t\t#T-Temperature at given point\n", "P1 = 100\t\t#kPa\n", "P2 = 1000\t\t#kPa\n", "T1 = 288.2\t\t#K\n", "T2 = 556.8\t\t#K\n", "wc = 269.5\t\t#from ex 12.1 work done in compressor in kJ/kg\n", "\t\t#2-Burner inlet\n", "\t\t#3-Burner exit\n", "P3 = 1000\t\t#kPa\n", "T3 = 1373.2\t\t#K\n", "\t\t#wc = wt\n", "Cp = 1.004\t\t#specific enthalpy of heat at constant pressure in kJ/kg\n", "k = 1.4\n", "T4 = T3-wc/Cp\n", "P4 = P3*(T4/T3)**(1-1/k)\n", "\t\t#from s4 = s5 and h4 = h5+v2/2 we get\n", "T5 = 710.8\t\t#K, from second law\n", "v = sqrt(2*Cp*1000*(T4-T5))\t\t#m/s\n", "print ('Velocity of air leaving the nozel = %.0f m/s',v)" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "## Example 6" ] }, { "cell_type": "code", "execution_count": 22, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "('Coefficient of performance = %.3f ', 1.712857850240205)\n", "(' Rate at which the air enter the compressor = %.3f kg/s ', 0.013985866348928795)\n" ] } ], "source": [ "# -*- coding: utf8 -*-\n", "from __future__ import division\n", "#Example: 12.6\n", "''' '''\n", "\n", "#Variable Declaration: \n", "\n", "\n", "\t\t#1-compressor inlet\n", "\t\t#2-compressor exit\n", "P1 = 100\t\t#kPa\n", "P2 = 500\t\t#kPa\n", "k = 1.4\n", "rp = P2/P1\n", "cop = (rp**(1-1/k)-1)**-1\n", "print ('Coefficient of performance = %.3f ',cop)\n", "\t\t#3-Expander inlet\n", "\t\t#4-Expander exit\n", "P3 = P2\n", "P4 = P1\n", "T3 = 288.23\t\t#K, given and fixed\n", "T4 = T3/(P3/P4)**(1-1/k)\n", "T1 = 253.2\t\t#K, given\n", "Cp = 1.004\t\t#Specific heat at cons pressure in kJ/kg\n", "ql = Cp*(T1-T4)\t\t#heat released in kJ/kg\n", "P = 1\t\t#power required in kW \n", "ms = P/ql\t\t#kg/s\n", "print (' Rate at which the air enter the compressor = %.3f kg/s ',ms) " ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "## Example 7" ] }, { "cell_type": "code", "execution_count": 23, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "Temperature at compressor exit, T2 = %.1f K 723.925669561\n", " Pressure at compressor exit, P2 = %.3f MPa 2.51188643151\n", " Initial Temperature during heat additon process, T3 = %.0f K 3234.38592061\n", " Initial pressure during heat addition process, P3 = %.3f MPa 11.222713118\n", " Final temperature during heat addition process, T4 = %.1f K 1287.63222733\n", " Final pressure during heat addition process, P4 = %.4f MPa 0.446784256534\n", " Thermal efficiency = %.1f percent 96.0189282945\n", " Mean effective pressure = %.0f kPa 1455.36957602\n" ] } ], "source": [ "# -*- coding: utf8 -*-\n", "from __future__ import division\n", "#Example: 12.7\n", "''' '''\n", "\n", "#Variable Declaration: \n", "\n", "\n", "\t\t#1-compressor inlet\n", "\t\t#2-compressor exit\n", "P1 = 100\t\t#kPa\n", "T1 = 288.2\t\t#K\n", "R = 0.287\t\t#gas constant\n", "v1 = R*T1/P1\t\t#specific volume at inlet in m**3/kg\n", "rv = 10\t\t#compression ratio given\n", "k = 1.4\t\t#constant\n", "T2 = T1*rv**(k-1)\t\t#K\n", "print 'Temperature at compressor exit, T2 = %.1f K ',T2\n", "P2 = P1*rv**k\t\t#kPa\n", "print ' Pressure at compressor exit, P2 = %.3f MPa ',P2/1000\n", "v2 = v1/rv\t\t#specific heat at exit in m**3/kg\n", "\t\t#23-heat addition process\n", "\t\t#q23 = Cv*(T3-T2) = 1800 kJ/kg given\n", "q23 = 1800\t\t#kJ/kg heat addition, given\n", "Cv = 0.717\t\t#specific heat at constant volume in kJ/kg\n", "T3 = T2+q23/Cv\t\t#K\n", "print ' Initial Temperature during heat additon process, T3 = %.0f K ',T3\n", "P3 = P2*(T3/T2)\t\t#kPa\n", "print ' Initial pressure during heat addition process, P3 = %.3f MPa ',P3/1000\n", "r = 10\t\t#k = V4/V3 = P3/P4\n", "T4 = T3*(1/r)**(k-1)\n", "print ' Final temperature during heat addition process, T4 = %.1f K ',T4\n", "P4 = P3/r**k\t\t#kPa\n", "print ' Final pressure during heat addition process, P4 = %.4f MPa ',P4/1000\n", "nth = 1-1/r**k\t\t#thermal efficiency\n", "print ' Thermal efficiency = %.1f percent ',nth*100\n", "q41 = Cv*(T1-T4)\t\t#/heat for process 4-1 in kJ/kg\n", "wnet = q23+q41\n", "mep = wnet/(v1-v2)\t\t#effective mean pressure n kPa\n", "print ' Mean effective pressure = %.0f kPa ',mep" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "## Example 8" ] }, { "cell_type": "code", "execution_count": 24, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "Temperature at compressor exit, T2 = %.1f K 955.225647797\n", " Pressure at compressor exit, P2 = %.3f MPa 6.62890803468\n", " Initial Temperature during heat addition process, T3 = %.0f K 2748.05433306\n", " Final temperature during heat addition process, T4 = %.0f K 1265.26371322\n", " Thermal efficiency = %.1f percent 61.0802954233\n", " Mean effective pressure = %.0f kPa 1399.18182622\n" ] } ], "source": [ "# -*- coding: utf8 -*-\n", "from __future__ import division\n", "#Example: 12.8\n", "''' '''\n", "\n", "#Variable Declaration: \n", "\n", "\n", "\t\t#1-compressor inlet\n", "\t\t#2-compressor exit\n", "P1 = 100\t\t#kPa\n", "T1 = 288.2\t\t#K\n", "R = 0.287\t\t#gas constant\n", "v1 = R*T1/P1\t\t#specific volume at inlet in m**3/kg\n", "rv = 20\t\t#compression ratio given\n", "k = 1.4\t\t#constant\n", "T2 = T1*rv**(k-1)\t\t#K\n", "print 'Temperature at compressor exit, T2 = %.1f K ',T2\n", "P2 = P1*rv**k\t\t#kPa\n", "print ' Pressure at compressor exit, P2 = %.3f MPa ',P2/1000\n", "v2 = v1/rv\t\t#specific heat at exit in m**3/kg\n", "\t\t#23-heat addition process\n", "\t\t#q23 = Cv*(T3-T2) = 1800 kJ/kg given\n", "q23 = 1800\t\t#kJ/kg heat addition, given\n", "Cv = .717\n", "Cp = 1.004\t\t#specific heat at constant pressure in kJ/kg\n", "T3 = T2+q23/Cp\t\t#K\n", "print ' Initial Temperature during heat addition process, T3 = %.0f K ',T3\n", "r = T3/T2\t\t#T3/T2 = V3/V2 = r\n", "v3 = r*v2\n", "T4 = T3/(v1/v3)**(k-1)\n", "print ' Final temperature during heat addition process, T4 = %.0f K ',T4\n", "q41 = Cv*(T1-T4)\t\t#/heat for process 4-1 in kJ/kg\n", "wnet = q23+q41\n", "mep = wnet/(v1-v2)\t\t#effective mean pressure in kPa\n", "qh = 1800\t\t#heat transfer in kJ/kg\n", "nth = wnet/qh\t\t#thermal efficiency\n", "\n", "print ' Thermal efficiency = %.1f percent ',nth*100\n", "print ' Mean effective pressure = %.0f kPa ',mep" ] } ], "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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