From 92cca121f959c6616e3da431c1e2d23c4fa5e886 Mon Sep 17 00:00:00 2001 From: hardythe1 Date: Tue, 7 Apr 2015 15:58:05 +0530 Subject: added books --- .../Chapter8.ipynb | 764 +++++++++++++++++++++ 1 file changed, 764 insertions(+) create mode 100755 Thermodynamics_An_Engineering_Approach/Chapter8.ipynb (limited to 'Thermodynamics_An_Engineering_Approach/Chapter8.ipynb') diff --git a/Thermodynamics_An_Engineering_Approach/Chapter8.ipynb b/Thermodynamics_An_Engineering_Approach/Chapter8.ipynb new file mode 100755 index 00000000..e91e1b78 --- /dev/null +++ b/Thermodynamics_An_Engineering_Approach/Chapter8.ipynb @@ -0,0 +1,764 @@ +{ + "metadata": { + "name": "" + }, + "nbformat": 3, + "nbformat_minor": 0, + "worksheets": [ + { + "cells": [ + { + "cell_type": "heading", + "level": 1, + "metadata": {}, + "source": [ + "Chapter 8: Exergy: A Measure of Work Potential" + ] + }, + { + "cell_type": "heading", + "level": 2, + "metadata": {}, + "source": [ + "Example 8-1 ,Page No.426" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "from math import pi\n", + "\n", + "# given data\n", + "D=12.0;#diameter of rotor in m\n", + "V=10.0;#average velocity in m/s\n", + "\n", + "# density of air at 25C & 1atm\n", + "p=1.18;\n", + "\n", + "#calculations\n", + "ke=(V**2)/2/1000;#factor of 1000 for converting J into kJ\n", + "m=p*pi*(D**2)*V/4.0; \n", + "MP=m*(ke);\n", + "print'Maximum power %f kW'%round(MP,1)\n" + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "Maximum power 66.700000 kW\n" + ] + } + ], + "prompt_number": 5 + }, + { + "cell_type": "heading", + "level": 2, + "metadata": {}, + "source": [ + "Example 8-2 ,Page No.427" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "#given values\n", + "TH=2000.0;#temperature of large furnace in R\n", + "T0=77+460.0;#temperature of enviroment in R\n", + "Qin=3000.0;#heat rate in Btu/sec\n", + "\n", + "#calculation\n", + "nth=1-(T0/TH);\n", + "Wmax=nth*Qin;\n", + "Wmax=round(Wmax)\n", + "print'the rate of energy flow %i Btu/s'%round(Wmax)" + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "the rate of energy flow 2195 Btu/s\n" + ] + } + ], + "prompt_number": 8 + }, + { + "cell_type": "heading", + "level": 2, + "metadata": {}, + "source": [ + "Example 8-3 ,Page No.429" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "#given data\n", + "Tsink=300.0;#temperature of sink in K\n", + "Tsource=1200.0;#temperature of source in K\n", + "Qin=500.0;#heat rate in kJ/s\n", + "Wuout=180;#power output in W\n", + "\n", + "#calculations\n", + "Wrev=(1-Tsink/Tsource)*Qin;\n", + "print'The reversible power %i kW'%round(Wrev);\n", + "I=Wrev-Wuout;\n", + "print'the irreversiblity rate %i kW'%round(I)" + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "The reversible power 375 kW\n", + "the irreversiblity rate 195 kW\n" + ] + } + ], + "prompt_number": 11 + }, + { + "cell_type": "heading", + "level": 2, + "metadata": {}, + "source": [ + "Example 8-4 ,Page No.429" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "import math\n", + "from scipy.integrate import quad \n", + "from pylab import *\n", + "\n", + "#given data\n", + "m=500.0;#mass of iron block in kg\n", + "T1=473.0;#temperature of iron block in K\n", + "T0=300.0;#temperature of surrondings in K\n", + "\n", + "\n", + "#from Table A-3\n", + "cavg=0.45;\n", + "\n", + "#calculations\n", + "def intgrnd1(T): \n", + " return ((1-T0/T)*(-m*cavg))#intergrant\n", + "Wrev, err = quad(intgrnd1,T1,T0) ;\n", + "Qtotal=m*cavg*(T1-T0);\n", + "print'The reversible power %i kJ'%round(Wrev);\n", + "Wu=0;\n", + "I=Wrev-Wu;\n", + "print'the irreversiblity rate %i kJ'%round(I)\n" + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "The reversible power 8191 kJ\n", + "the irreversiblity rate 8191 kJ\n" + ] + } + ], + "prompt_number": 3 + }, + { + "cell_type": "heading", + "level": 2, + "metadata": {}, + "source": [ + "Example 8-5 ,Page No.431" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "#given data\n", + "Wrev=8191.0;#reversible work from Ex - 8.4\n", + "Wtotal=38925.0;#total work is equivalent to total heat lost to heat engine from Ex - 8.4\n", + "TL=278.0;#outdoor temperature in K\n", + "TH=300.0;#temperature of house in K\n", + "\n", + "#calculations\n", + "Wrm=Wtotal-Wrev;#work remaining\n", + "COPHP=1/(1-TL/TH);\n", + "Wd=COPHP*Wrev;#work delivered\n", + "PS=Wd+Wrm;\n", + "PS=round(PS/1000);#factor of 1000 for converting kJ into MJ\n", + "print'Maximum amount of heat that can be supplied %i MJ'%PS" + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "Maximum amount of heat that can be supplied 142 MJ\n" + ] + } + ], + "prompt_number": 4 + }, + { + "cell_type": "heading", + "level": 2, + "metadata": {}, + "source": [ + "Example 8-6 ,Page No.434" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "#given data\n", + "COP=1.0;# the efficiency that the dealer is referring to is the first law efficiency, meaning that for each unit of electric energy (work) consumed, the heater will supply the house with 1 unit of energy (heat). That is,the advertised heater has a COP of 1\n", + "TL=283.0;#outdoor temperature in K\n", + "TH=294.0;#indoor temperature in K\n", + "\n", + "#calculations\n", + "COPHP=1/(1-TL/TH);\n", + "nII=COP/COPHP;\n", + "print'the second law efficiency %f'%round(nII,3)\n" + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "the second law efficiency 0.037000\n" + ] + } + ], + "prompt_number": 27 + }, + { + "cell_type": "heading", + "level": 2, + "metadata": {}, + "source": [ + "Example 8-7 ,Page No.438" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "from math import log\n", + "\n", + "#given data\n", + "P1=1000.0;#pressure of compressed air in KPa\n", + "V=200.0;#volumne of rigid tank in m^3\n", + "T1=300.0;#temperature of enviroment in K\n", + "T0=T1;#state of air in tank\n", + "P0=100.0;#pressure of enviroment in KPa\n", + "\n", + "#constants used\n", + "R=0.287;#in kPa m^3/kg K\n", + "\n", + "#calculations\n", + "m1=P1*V/(R*T1);\n", + "O1=R*T0*(P0/P1-1)+R*T0*log(P1/P0);# O refers to exergy\n", + "X1=m1*O1/1000;#factor of 1000 for converting kJ into MJ\n", + "print'work obtained %i MJ'%round(X1)\n" + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "work obtained 281 MJ\n" + ] + } + ], + "prompt_number": 4 + }, + { + "cell_type": "heading", + "level": 2, + "metadata": {}, + "source": [ + "Example 8-8 ,Page No.439" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "#given data\n", + "T0=20+273;#temperature of enviroment in K\n", + "P1=0.14;#intail pressure in MPa\n", + "T1=-10;#intail temperature in K\n", + "P2=0.8;#final pressure in MPa\n", + "T2=50;#final temperature in K\n", + "\n", + "#the properties of refrigerant\n", + "#at inlet\n", + "h1=246.36;\n", + "s1=0.9724;\n", + "#at outlet\n", + "h2=286.69;\n", + "s2=0.9802;\n", + "dO=h2-h1-T0*(s2-s1);# O refers to exergy\n", + "print'the exergy change of the refrigerant %i kJ/kg'%round(dO)\n", + "wmin=dO;\n", + "print'the minimum work input that needs to be supplied is %i kJ/kg'%wmin" + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "the exergy change of the refrigerant 38 kJ/kg\n", + "the minimum work input that needs to be supplied is 38 kJ/kg\n" + ] + } + ], + "prompt_number": 5 + }, + { + "cell_type": "heading", + "level": 2, + "metadata": {}, + "source": [ + "Example 8-10 ,Page No.447" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "#given values\n", + "Q=1035.0;#rate of heat transfer in W\n", + "T0=273.0;#outdoor temperature in C\n", + "Tin=293.0;#inner wall surface temperature in K\n", + "Tout=278.0;#outer wall surface temperature in K\n", + "T1=300.0;#indoor temperature in C\n", + "\n", + "#calculations\n", + "#Xin - Xout - Xdestroyed = dX/dt\n", + "Xdestroyed=Q*(1-T0/Tin)-Q*(1-T0/Tout);\n", + "Xdestroyed=round(Xdestroyed);\n", + "print'the rate of exergy destroyed %i W'%round(Xdestroyed);\n", + "#the total rate of exergy destroyed\n", + "Xdestroyed=Q*(1-T0/T1)-Q*(1-T0/T0);\n", + "print'the total of exergy destroyed %f W'%round(Xdestroyed,1);" + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "the rate of exergy destroyed 52 W\n", + "the total of exergy destroyed 93.100000 W\n" + ] + } + ], + "prompt_number": 6 + }, + { + "cell_type": "heading", + "level": 2, + "metadata": {}, + "source": [ + "Example 8-11 ,Page No.448" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "#given data\n", + "m=0.05;#mass of steam in kg\n", + "P1=1000;#intial pressure in MPa\n", + "T1=300+273;#intial temperature in K\n", + "P2=200;#final pressure in MPa\n", + "T2=150+273;#final temperature in K\n", + "P0=100;#pressure of surroundings in KPa\n", + "T0=25+273;#temperature of surroundings in K\n", + "Qout=2;#heat losses in kJ\n", + "\n", + "#from Table A-6 & A-4\n", + "u1=2793.7;\n", + "v1=0.25799;\n", + "s1=7.1246;\n", + "u2=2577.1;\n", + "v2=0.95986;\n", + "s2=7.2810;\n", + "u0=104.83;\n", + "v0=0.00103;\n", + "s0=0.3672;\n", + "\n", + "#calculations\n", + "X1=m*(u1-u0-T0*(s1-s0)+P0*(v1-v0));\n", + "X2=m*(u2-u0-T0*(s2-s0)+P0*(v2-v0));\n", + "print'exergy of intial state %i kJ'%round(X1);\n", + "print'exergy of final state %f kJ'%round(X2,1);\n", + "dX=X2-X1;\n", + "print'exergy change in system %f kJ'%round(dX,1);\n", + "Wout=-Qout-m*(u2-u1);\n", + "Wu=Wout-P0*m*(v2-v1);\n", + "Xdestroyed=X1-X2-Wu;\n", + "print'the exergy destroyed %f kJ'%round(Xdestroyed,1);\n", + "nII=Wu/(X1-X2);\n", + "print'second law efficiency of this process is %f'%round(nII,3)" + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "exergy of intial state 35 kJ\n", + "exergy of final state 25.400000 kJ\n", + "exergy change in system -9.700000 kJ\n", + "the exergy destroyed 4.300000 kJ\n", + "second law efficiency of this process is 0.551000\n" + ] + } + ], + "prompt_number": 42 + }, + { + "cell_type": "heading", + "level": 2, + "metadata": {}, + "source": [ + "Example 8-12 ,Page No.451" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "import math\n", + "from scipy.integrate import quad \n", + "from pylab import *\n", + "\n", + "#given data\n", + "m=2.0;#mass of air in lbm\n", + "T0=70+460.0;#intial temperature in R\n", + "P1=20.0;#intial pressure in psia\n", + "T1=70+460.0;#temperature of surroundings in R\n", + "T2=130+460.0;#final temperature in R\n", + "\n", + "#constants used\n", + "Cv=0.172;#in Btu/lbm - F\n", + "\n", + "#calculations\n", + "Xdestroyed=T0*m*Cv*log(T2/T1);\n", + "print'exergy destroyed %f Btu'%round(Xdestroyed,1);\n", + "def intgrnd1(T): \n", + " return ((1-T0/T)*m*Cv)#intergrant\n", + "Wrev, err = quad(intgrnd1,T1,T2) ;\n", + "print'the reversible work %f Btu'%round(Wrev,1)" + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "exergy destroyed 19.600000 Btu\n", + "the reversible work 1.100000 Btu\n" + ] + } + ], + "prompt_number": 45 + }, + { + "cell_type": "heading", + "level": 2, + "metadata": {}, + "source": [ + "Example 8-13 ,Page No.453" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "#given data\n", + "T0=20+273.0;#temperature of surrounding in K\n", + "P0=100.0;#pressure of surrounding in kPa\n", + "Tiw=30+273.0;#temperature of water in K\n", + "mw=100.0;#mass of water in kg\n", + "Tii=350+273.0;#temperature of block in K\n", + "mi=5.0;#mass of block in kg\n", + "\n", + "#constants used(Table A-3)\n", + "cw=4.18;#specific heat of water in kJ/kg C\n", + "ci=0.45;#specific heat of iron in kJ/kg C\n", + "\n", + "#calculations\n", + "Tfk=(mi*ci*Tii+mw*cw*Tiw)/(mw*cw+mi*ci);\n", + "Tfc=Tfk-273;#in C\n", + "print'the final equilibrium temperature %f C'%round(Tfc,1);\n", + "X1i=mi*ci*(Tii-T0-T0*log(Tii/T0));\n", + "X1w=mw*cw*(Tiw-T0-T0*log(Tiw/T0));\n", + "X1t=X1i+X1w;#total exergy \n", + "print'intial exergy of combined systems %i kJ'%round(X1t);\n", + "X2i=mi*ci*(Tfk-T0-T0*log(Tfk/T0));\n", + "X2w=mw*cw*(Tfk-T0-T0*log(Tfk/T0));\n", + "X2t=X2i+X2w;#total exergy \n", + "print'intial exergy of combined systems %f kJ'%round(X2t,1);\n", + "Xdestroyed=X1t-X2t;\n", + "print'the wasted work %f kJ'%round(Xdestroyed,1)\n" + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "the final equilibrium temperature 31.700000 C\n", + "intial exergy of combined systems 315 kJ\n", + "intial exergy of combined systems 95.800000 kJ\n", + "the wasted work 219.100000 kJ\n" + ] + } + ], + "prompt_number": 46 + }, + { + "cell_type": "heading", + "level": 2, + "metadata": {}, + "source": [ + "Example 8-14 ,Page No.455" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "#given data\n", + "TR=1200.0;#temperature of furnace \n", + "T0=300;#temperature of surrounding in K\n", + "P0=100;#pressure of surrounding in kPa\n", + "Tsys=400.0;#temperature of argon in K\n", + "P1=350;#temperature of argon in K\n", + "V1=0.01;#intail volumne in m^3\n", + "V2=2*V1;#final volumne\n", + "\n", + "#calculations\n", + "W=P1*V1*log(V2/V1);\n", + "Wsurr=P0*(V2-V1);\n", + "Wu=W-Wsurr;\n", + "print'the useful work output %f kJ'%round(Wu,2);\n", + "# Qin - W = m*Cv*dT, Since dt=0\n", + "Q=W;\n", + "Sgen=Q/Tsys-Q/TR;\n", + "Xdestroyed=T0*Sgen;\n", + "print'the exergy destroyed %f kJ/K'%round(Xdestroyed,2);\n", + "Wrev=T0*Q/Tsys-Wsurr+(1-T0/TR)*Q;\n", + "print'the reversible work is done in the process %f kJ'%round(Wrev,2);\n" + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "the useful work output 1.430000 kJ\n", + "the exergy destroyed 1.210000 kJ/K\n", + "the reversible work is done in the process 2.640000 kJ\n" + ] + } + ], + "prompt_number": 48 + }, + { + "cell_type": "heading", + "level": 2, + "metadata": {}, + "source": [ + "Example 8-15 ,Page No.460" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "#calculation error in textbook in part - b which changes all the following answers\n", + "\n", + "#given data\n", + "m=8.0;#mass flow rate in kg/s\n", + "T0=298.0;#temperature of surrounding in K\n", + "P0=100.0;#pressure of surrounding in kPa\n", + "P1=3000.0;#inlet pressure in kPa\n", + "T1=450.0;#inlet temperature in K\n", + "P2=200.0;#outlet pressure in kPa\n", + "T2=150.0;#outlet temperature in K\n", + "Qout=300.0;#heat rate in kW\n", + "\n", + "#from Table A-6 and A-4\n", + "h1=3344.9;\n", + "s1=7.0856;\n", + "h2=2769.1;\n", + "s2=7.2810;\n", + "h0=104.83;\n", + "s0=0.3672;\n", + "\n", + "#calculations\n", + "# Ein = Eout\n", + "Wout=m*(h1-h2)-Qout;\n", + "Wout=round(Wout)\n", + "print'the actual power output %i kW'%Wout\n", + "# Xin = Xout\n", + "Wrev=m*(h1-h2)-(T0*(s1-s2));\n", + "Wrev=round(Wrev);\n", + "print'the maximum possible work output %i kW'%Wrev;\n", + "nII=Wout/Wrev;\n", + "print'second law efficiency is %f'%round(nII,3);\n", + "Xdestroyed=Wrev-Wout;\n", + "print'the exergy destroyed %i kW'%round(Xdestroyed);\n", + "X1=h1-h0-T0*(s1-s0);\n", + "print'the exergy of the steam at inlet conditions %i kJ/kg'%round(X1);\n" + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "the actual power output 4306 kW\n", + "the maximum possible work output 4665 kW\n", + "second law efficiency is 0.923000\n", + "the exergy destroyed 359 kW\n", + "the exergy of the steam at inlet conditions 1238 kJ/kg\n" + ] + } + ], + "prompt_number": 6 + }, + { + "cell_type": "heading", + "level": 2, + "metadata": {}, + "source": [ + "Example 8-16 ,Page No.462" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "#given data\n", + "T0=70+460;#temperature of surroundings in R\n", + "T1=50;#temperature of water in F\n", + "T2=240;#temperature of steam in F\n", + "T3=130;#outlet temperature in F\n", + "#as dicussed in example 7-20\n", + "m1=300;#mass flow rate of water in lbm/min\n", + "m2=22.7;#mass flow rate of steam in lbm/min\n", + "m3=322.7;#outlet mass flow rate in lbm/min\n", + "\n", + "#from steam tables\n", + "h1=18.07;\n", + "s1=0.03609;\n", + "h2=1162.3;\n", + "s2=1.7406;\n", + "h3=97.99;\n", + "s3=0.18174;\n", + "\n", + "#calculations\n", + "Wrev=m1*(h1-T0*s1)+m2*(h2-T0*s2)-m3*(h3-T0*s3);\n", + "Wrev=round(Wrev);\n", + "print'the reversible power %i Btu/min'%round(Wrev)\n", + "Xdestroyed=Wrev;\n", + "print'the rate of exergy destruction %i Btu/min'%Xdestroyed\n" + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "the reversible power 4588 Btu/min\n", + "the rate of exergy destruction 4588 Btu/min\n" + ] + } + ], + "prompt_number": 56 + }, + { + "cell_type": "heading", + "level": 2, + "metadata": {}, + "source": [ + "Example 8-17 ,Page No.463" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "#given data\n", + "V=200.0;#volumne of rigid tank in m^3\n", + "P1=100.0;#intial surroundings in kPa\n", + "P2=1000.0;#final pressure in kPa\n", + "P0=100.0;#pressure of surroundings in kPa\n", + "T=300.0;#temperature of surroundings in K\n", + "\n", + "#constants used\n", + "R=0.287;#in kPa m^3/kg K\n", + "\n", + "#calculations\n", + "#Xin - Xout = Xdestroyed = X2 - X1\n", + "m2=P2*V/(R*T);\n", + "X2=R*T*(log(P2/P0)+P0/P2-1);\n", + "Wrev=m2*X2/1000;\n", + "Wrev=round(Wrev);\n", + "print'Work requirement %i MJ'%Wrev\n" + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "Work requirement 281 MJ\n" + ] + } + ], + "prompt_number": 58 + } + ], + "metadata": {} + } + ] +} \ No newline at end of file -- cgit