{ "metadata": { "name": "", "signature": "sha256:04fae3340038d72ec2280e59669f4edde21c4cc5f0e44781b3f3472ae74ef696" }, "nbformat": 3, "nbformat_minor": 0, "worksheets": [ { "cells": [ { "cell_type": "heading", "level": 1, "metadata": {}, "source": [ "Chapter1 - Basic Concepts of Turbo Machines" ] }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Ex-1.1 Page 18" ] }, { "cell_type": "code", "collapsed": false, "input": [ "from __future__ import division\n", "#input data\n", "P01=1#initial pressure of a fluid in bar\n", "P02=10#final pressure of a fliud in bar\n", "T01=283#initial total temperature in K\n", "ntt=0.75#total-to-total efficiency\n", "d=1000#density of water in kg/m**3\n", "r=1.4#ratio of specific heats for air\n", "Cp=1.005#specific at heat at constant pressure in kJ/kg.K\n", "\n", "#calculations\n", "h0s1=(1/d)*(P02-P01)*10**2#enthalpy in kJ/kg\n", "h01=(h0s1/ntt)#enthalpy in kJ/kg\n", "T02s=T01*(P02/P01)**((r-1)/r)#temperature in K\n", "h0s2=(Cp*(T02s-T01))#enthalpy in kJ/kg\n", "h02=(h0s2/ntt)#enthalpy in kJ/kg\n", "\n", "#output\n", "print '''The work of compression for adiabatic steady flow per kg of fliud if - \n", "(a)The fliud is liquid water is %3.1f kJ/kg\n", "(b)The fliud is air as a perfect gas is %3.2f kJ/kg'''%(h01,h02)" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "The work of compression for adiabatic steady flow per kg of fliud if - \n", "(a)The fliud is liquid water is 1.2 kJ/kg\n", "(b)The fliud is air as a perfect gas is 352.94 kJ/kg\n" ] } ], "prompt_number": 1 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Ex 1.2 Page 19" ] }, { "cell_type": "code", "collapsed": false, "input": [ "\n", "#input data\n", "P01=7#Total initial pressure of gases at entry in bar\n", "T01=1100#Total initial temperature in K\n", "P02=1.5#Total final pressure of gases at exit in bar\n", "T02=830#Total final temperature in K\n", "C2=250#Exit velocity in m/s\n", "r=1.3#Ratio of specific heats of gases\n", "M=28.7#Molecular weight of gases\n", "R1=8.314#Gas constant of air in kJ/kg.K\n", "\n", "#calculations\n", "T02s=T01*(P02/P01)**((r-1)/r)#Final temperature in K\n", "ntt=((T01-T02)/(T01-T02s))#Total-to-total efficiency\n", "R=(R1/M)#Gas constant of given gas in kJ/kg.K\n", "Cp=((r*R)/(r-1))#Specific heat of given gas at constant pressure in kJ/kg.K\n", "T2s=(T02s-((C2**2)/(2*Cp*1000)))#Temperature in isentropic process at exit in K\n", "nts=((T01-T02)/(T01-T2s))#Total-to-static efficiency\n", "\n", "#output\n", "print '''The total-to-total efficiency of gases is %0.2f %%\n", "The total-to-static efficiency of gases is %0.1f %%'''%(ntt*100,nts*100)" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "The total-to-total efficiency of gases is 82.05 %\n", "The total-to-static efficiency of gases is 76.3 %\n" ] } ], "prompt_number": 2 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Ex 1.3 Page 20" ] }, { "cell_type": "code", "collapsed": false, "input": [ "#input data\n", "h0=6#Change in total enthalpy in kJ/kg\n", "T01=303#Total inlet temperature of fluid in K\n", "P01=1#Total inlet pressure of fliud in bar\n", "Cp=1.005#specific at heat at constant pressure in kJ/kg.K\n", "ntt=0.75#Adiabatic total-to-total efficiency\n", "r=1.4#ratio of specific heats for air\n", "\n", "#calculations\n", "T02=T01+(h0/Cp)#Exit total termperature of fliud in K\n", "P1=(1+((ntt*h0)/(Cp*T01)))**(r/(r-1))#Total pressure ratio of fluid \n", "h0s=ntt*h0#Change in enthalpy of process in kJ/kg\n", "P0=((h0s*1000)/100)#Change in pressure in bar\n", "P02=P0+P01#Total outlet pressure of fliud in bar\n", "P2=(P02/P01)#Total pressure ratio of fliud\n", "\n", "#output\n", "print '''(a)The exit total temperature of fliud is %3.2f K\n", "(b)The total pressure ratio if:\n", "(1)The fliud is air is %3.3f\n", "(2)The fliud is liquid water is %3.0i'''%(T02,P1,P2)" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "(a)The exit total temperature of fliud is 308.97 K\n", "(b)The total pressure ratio if:\n", "(1)The fliud is air is 1.053\n", "(2)The fliud is liquid water is 46\n" ] } ], "prompt_number": 3 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Ex 1.4 Page 22" ] }, { "cell_type": "code", "collapsed": false, "input": [ "#input data\n", "W=100#Output power developed in kW\n", "Q=0.1#Flow through device in m**3/s\n", "d=800#Density of oil in kg/m**3\n", "ntt=0.75#Total-to-total efficiency\n", "C1=3#inlet flow velocity of oil in m/s\n", "C2=10#outlet flow velocity of oil in m/s\n", "\n", "#calculations\n", "m=d*Q#Mass flow rate of oil in kg/s\n", "h0=-(W/m)#Change in total enthalpy in kJ/kg\n", "h0s=(h0/ntt)#Isentropic change in total enthalpy in kJ/kg\n", "P0=((d*h0s)*(1/100))#Change in total pressure of oil in bar\n", "P=P0-((d/(2000*100))*(C2**2-C1**2))#Change in static pressure in bar\n", "\n", "#output\n", "print '''The change in total pressure of oil is %3.1f bar\n", "The change in static presure is %3.1f bar'''%(P0,P)" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "The change in total pressure of oil is -13.3 bar\n", "The change in static presure is -13.7 bar\n" ] } ], "prompt_number": 4 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Ex 1.5 Page 22" ] }, { "cell_type": "code", "collapsed": false, "input": [ "#input data\n", "N=4#Number of stages in turbine handling\n", "P=0.4#Stagnation presure ratio between exit and inlet of each stage\n", "ns1=0.86#Stage efficiency of first and second stages\n", "ns2=0.84#Stage efficiency of third and fourth stages\n", "r=1.4#ratio of specific heats for air\n", "\n", "#calculations\n", "u=1-(P)**((r-1)/r)#constant\n", "T03=(1-(u*ns1))**2#Temperature after the end of first two stages in (K*Cp*T01) where Cp is specific at heat at constant pressure in kJ/kg.K and T01 is initial temperature at entry of stage 1 in K\n", "W12=u*(1+(1-(u*ns1)))*ns1#Actual work output from first two stages in (kW*Cp*T01)\n", "W34=T03*u*(1+(1-(u*ns2)))*ns2#Actual work output from last two stages in (kW*Cp*T01)\n", "W=(W12+W34)#Total actual work output from turbine in (kW*Cp*T01)\n", "Ws=1-(1-u)**N#Total isentropic work due to single stage compressor in (kW*Cp*T01)\n", "n=(W/Ws)#Overall turbine efficiency\n", "\n", "#output\n", "print 'the overall efficiency of the turbine is %.1f %%'%(n*100)" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "the overall efficiency of the turbine is 89.6 %\n" ] } ], "prompt_number": 5 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Ex 1.6 Page 24" ] }, { "cell_type": "code", "collapsed": false, "input": [ "\n", "from __future__ import division\n", "from math import log10\n", "#input data\n", "P=1400#Pressure developed by compressor in mm W.G\n", "P1=1.01#Initial pressure of air in bar\n", "T1=305#Initial temperature of air in K\n", "T2=320#Final temperature of air in K\n", "P=1400*9.81*10**-5#Pressure developed by compressor in bar\n", "r=1.4#ratio of specific heats for air\n", "\n", "#calculations\n", "P2=P1+P#Final pressure of air in bar\n", "T2s=T1*(P2/P1)**((r-1)/r)#Isentropic temperature at exit in K\n", "nc=((T2s-T1)/(T2-T1))#compressor efficiency\n", "np=((r-1)/r)*((log10(P2/P1))/(log10(T2/T1)))#Infinitesimal stage efficiency\n", "\n", "#output\n", "print '''(a)The compressor efficiency is %0.2f %%\n", "(b)The infinitesimal stage efficiency is %0.2f %%'''%(nc*100,np*100)" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "(a)The compressor efficiency is 75.43 %\n", "(b)The infinitesimal stage efficiency is 75.88 %\n" ] } ], "prompt_number": 6 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Ex 1.7 Page 24" ] }, { "cell_type": "code", "collapsed": false, "input": [ "#input data\n", "P1=1.01#Input pressure to compressor in bar\n", "T1=305#Input temperature to compressor in K\n", "P2=3#Output pressure from compressor in bar\n", "r=1.4#ratio of specific heats for air\n", "nc=0.75#compressor efficiency\n", "\n", "#calculations\n", "T2s=T1*(P2/P1)**((r-1)/r)#Isentropic output temperature from compressor in K\n", "T2=T1+((T2s-T1)/nc)#Actual output temperature from compressor in K\n", "np=((r-1)/r)*((log10(P2/P1))/(log10(T2/T1)))#Infinitesimal efficiency of compressor\n", "\n", "#output\n", "print 'The infinitesimal efficiency of the compressor is %0.1f %%'%(np*100)" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "The infinitesimal efficiency of the compressor is 78.5 %\n" ] } ], "prompt_number": 7 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Ex 1.8 Page 25" ] }, { "cell_type": "code", "collapsed": false, "input": [ "#input data\n", "P=2.2#Pressure ratio across a gas turbine\n", "n=0.88#Efficiency of a gas turbine\n", "T1=1500#Inlet temperature of the gas in K\n", "r=1.4#ratio of specific heats for air\n", "\n", "#calculations\n", "T2s=T1*(1/P)**((r-1)/r)#Isentropic output temperature from gas turbine in K\n", "T2=T1-(n*(T1-T2s))#actual output temperature from gas turbine in K\n", "np=(r/(r-1))*((log10(T1/T2))/(log10(P)))#Polytropic efficiency of the turbine\n", "\n", "\n", "#output\n", "print 'The polytropic efficiency of the turbine is %0.1f %%'%(np*100)" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "The polytropic efficiency of the turbine is 86.7 %\n" ] } ], "prompt_number": 8 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Ex 1.9 Page 26" ] }, { "cell_type": "code", "collapsed": false, "input": [ "# input data\n", "P=1.3#Pressure ratio of stages\n", "N=8#Number of stages\n", "m =45#The flow rate through compressor in kg/s\n", "nc=0.8#Overall efficiency of the compressor\n", "P1=1#Initial pressure of the air at entry in bar\n", "T1=308#Initial temperature of the air at entry in K\n", "r=1.4#ratio of specific heats for air\n", "\n", "#calculations\n", "PN=(P)**8#Overall pressure ratio of all 8 stages\n", "TN=PN**((r-1)/r)#Overall temperature ratio of all 8 stages\n", "TN1s=TN*T1#Ideal exit temperature in K\n", "TN1=((TN1s-T1)/nc)+T1#Actual exit temperature in K\n", "PN1=PN*P1#Actual exit pressure in bar\n", "np=((r-1)/r)*((log10(PN1/P1))/(log10(TN1/T1)))#Polytropic efficiency of the cycle\n", "ns=((((P)**((r-1)/r))-1)/(((P)**((r-1)/(r*np)))-1))#The stage efficiency of the cycle\n", "\n", "#output\n", "print '''(a)The state of air at compressor exit are-\n", "(1)actual temperature is %3.1f K\n", "(2)actual pressure is %3.2f bar\n", "(b)The polytropic efficiency of the cycle is %0.f %%\n", "(c)The stage efficiency of the cycle is %0.2f %%'''%(TN1,PN1,np*100,ns*100)" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "(a)The state of air at compressor exit are-\n", "(1)actual temperature is 624.3 K\n", "(2)actual pressure is 8.16 bar\n", "(b)The polytropic efficiency of the cycle is 85 %\n", "(c)The stage efficiency of the cycle is 84.31 %\n" ] } ], "prompt_number": 9 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Ex - 1.10 Page 27" ] }, { "cell_type": "code", "collapsed": false, "input": [ "from math import log10\n", "#input data\n", "P=11#Overall pressure ratio in three stages of a gas turbine\n", "nt=0.88#Overall efficiency in three stages of a gas turbine\n", "T1=1500#Temperature at inlet of a gas turbine in K\n", "r=1.4#ratio of specific heats for air\n", "\n", "#calculations\n", "T0=nt*T1*(1-(1/P)**((r-1)/r))#Overall change in temperature in all stages in K\n", "TN1=T1-T0#Temperature at final stage of a gas turbine in K\n", "np=((r/(r-1))*log10(T1/TN1))/(log10(P))#Overall polytropic efficiency of the gas turbine\n", "Ts=T0/3#Individual stage change in temperature in K\n", "T2=T1-Ts#Exit temperature at the end of first stage in K\n", "P1=(T1/T2)**(r/(np*(r-1)))#Pressure ratio at first stage of gas turbine \n", "ns1=((1-(1/P1)**((np*(r-1))/r))/(1-(1/P1)**((r-1)/r)))#Stage efficiency of first stage \n", "T3=T2-Ts#Exit temperature at the end of second stage in K\n", "P2=(T2/T3)**(r/(np*(r-1)))#Pressure ratio at second stage of gas turbine\n", "ns2=((1-(1/P2)**((np*(r-1))/r))/(1-(1/P2)**((r-1)/r)))#Stage efficiency of second stage\n", "T4=T3-Ts#Exit temperature at the end of third stage in K\n", "P3=(T3/T4)**(r/(np*(r-1)))#Pressure ratio at the third stage of gas turbine\n", "ns3=((1-(1/P3)**((np*(r-1))/r))/(1-(1/P3)**((r-1)/r)))#Stage efficiency of third stage\n", "\n", "#output\n", "print '''(a)The values for first stage are -\n", "(1)Pressure ratio is %3.2f\n", "(2)stage efficiency is %0.2f %%\n", "(b)The values of second stage are -\n", "(1)Pressure ratio is %3.3f\n", "(2)Stage efficiency is %0.1f %%\n", "(c)The values of third stage are -\n", "(1)Pressure ratio is %3.2f\n", "(2)Stage efficiency is %0.2f'''%(P1,ns1*100,P2,ns2*100,P3,ns3*100)" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "(a)The values for first stage are -\n", "(1)Pressure ratio is 1.93\n", "(2)stage efficiency is 84.96 %\n", "(b)The values of second stage are -\n", "(1)Pressure ratio is 2.182\n", "(2)Stage efficiency is 85.2 %\n", "(c)The values of third stage are -\n", "(1)Pressure ratio is 2.61\n", "(2)Stage efficiency is 85.52\n" ] } ], "prompt_number": 10 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Ex 1.11 Page 29 " ] }, { "cell_type": "code", "collapsed": false, "input": [ "#input data\n", "N=4#Number of stages in compressor\n", "m=45#mass flow rate of air delivered by compressor in kg/s\n", "P1=1.2#Pressure ratio at first stage\n", "ns=0.65#Stage efficiency of first stage\n", "r=1.4#ratio of specific heats for air\n", "Cp=1.005#specific at heat at constant pressure in kJ/kg.K\n", "T1=293#Temperature of air at inlet in K\n", "\n", "#calculations\n", "P=(P1)**N#Overall pressure in all 4 stages\n", "np=((r-1)/r)*((log10(P1))/(log10((((P1**((r-1)/r))-1)/ns)+1)))#Polytropic efficiency of the cycle\n", "nc=(((P1**(N*((r-1)/r)))-1)/((P1**(N*((r-1)/(r*np))))-1))#Overall efficiency of the cycle\n", "TN1=T1*((P1**(N))**((r-1)/(r*np)))#Final temperature at the exit of the compressor at final stage in K\n", "W=m*Cp*(TN1-T1)#Power required to drive the compressor in kW\n", "\n", "#output\n", "\n", "print '''(a)The overall pressure ratio of the process is %3.1f\n", "(b)The overall efficiency of the process is %0.2f %%\n", "(c)The power required to drive the compressor is %3.2f kW'''%(P,nc*100,W)\n", "# the answer in the textbook is not correct." ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "(a)The overall pressure ratio of the process is 2.1\n", "(b)The overall efficiency of the process is 62.29 %\n", "(c)The power required to drive the compressor is 4928.55 kW\n" ] } ], "prompt_number": 11 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Ex 1.12 Page 31 " ] }, { "cell_type": "code", "collapsed": false, "input": [ "#input data\n", "P0=0.2*9.81*(10**3)*(10**-5)#Total increase in pressure in bar\n", "P01=1.04#Total inlet pressure of air in bar\n", "T01=291#Total inlet temperature of air in K\n", "ntt=0.72#Total-to-total efficiency of the process\n", "r=1.4#ratio of specific heats for air\n", "Cp=1.005#specific at heat at constant pressure in kJ/kg.K\n", "\n", "#calculations\n", "P2=P0+P01#The total exit pressure in bar\n", "T02=((((P2/P01)**((r-1)/r)-1)*T01)/ntt)+T01#Total temperature at the outlet in K\n", "h0=Cp*(T02-T01)#Actual change in total enthalpy in kJ/kg\n", "h0s=h0*ntt#Isentropic change in total enthalpy in kJ/kg\n", "\n", "#output\n", "print '''(a)The total exit pressure is %3.4f bar\n", "and the total exit temperature is %3.2f K\n", "(b)The actual change in total enthalpy is %3.3f kJ/kg\n", "and the isentropic change in total enthalpy is %3.3f kJ/kg'''%(P2,T02,h0,h0s)" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "(a)The total exit pressure is 1.0596 bar\n", "and the total exit temperature is 293.16 K\n", "(b)The actual change in total enthalpy is 2.175 kJ/kg\n", "and the isentropic change in total enthalpy is 1.566 kJ/kg\n" ] } ], "prompt_number": 12 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Ex 1.13 Page 31" ] }, { "cell_type": "code", "collapsed": false, "input": [ "#input data\n", "P=5#Pressure ratio in the process\n", "ntt=0.8#Total-to-total efficiency of the process\n", "m=5#Air flow rate through turbine in kg/s\n", "W=500#Total power output from the turbine in kW\n", "r=1.4#ratio of specific heats for air\n", "Cp=1.005*10**3#specific at heat at constant pressure in J/kg.K\n", "C2=100#Flow velocity of air in m/s\n", "\n", "#calculations\n", "T=(W*10**3)/(m*Cp)#Total change in temperature in the process in K\n", "T02s=(1/P)**((r-1)/r)#Isentropic temperature at the outlet from turvine in (K*T01)\n", "T01=(T/ntt)*(1/(1-0.631))#Inlet total temperature in K\n", "T02=T01-T#Actual exit total temperature in K\n", "T2=T02-((C2**2)/(2*Cp))#Actual exit static temperature in K\n", "T02s1=T02s*T01#Isentropic temperature at the outlet from turbine in K\n", "T2s=T02s1-((C2**2)/(2*Cp))#Actual isentropic temperature in K\n", "nts=(T/(T01-T2s))#Total-to-static efficiency\n", "\n", "#output\n", "print '''(a)The inlet total temperature is %i K\n", "(b)The actual exit total temperature is %3.1f K\n", "(c)The actual exit static temperature is %3.1f K\n", "(d)The total-to-static efficiency is %0.2f %%'''%(T01,T02,T2,nts*100)" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "(a)The inlet total temperature is 337 K\n", "(b)The actual exit total temperature is 237.6 K\n", "(c)The actual exit static temperature is 232.6 K\n", "(d)The total-to-static efficiency is 77.00 %\n" ] } ], "prompt_number": 13 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Ex 1.14 Page 33 " ] }, { "cell_type": "code", "collapsed": false, "input": [ "from math import log\n", "#input data\n", "N=3#Number of stages in turbine\n", "P=2#Pressure ratio of each stage\n", "ns=0.75#Stage efficiency of each stage\n", "T1=873#Initial temperature of air in K\n", "m=25#Flow rate of air in kg/s\n", "r=1.4#ratio of specific heats for air\n", "Cp=1.005#specific at heat at constant pressure in J/kg.K\n", "\n", "#calculations\n", "np=(r/(r-1))*((log(1-(ns*(1-(1/P)**((r-1)/r)))))/(log(1/P)))#Polytropic efficiency of the process\n", "nt=((1-(1/P)**(N*np*((r-1)/r)))/(1-(1/P)**(N*((r-1)/r))))#Overall efficiency of the turbine\n", "W=m*Cp*T1*(1-(1/P)**(N*np*((r-1)/r)))#Power developed by the turbine in kW\n", "RF=nt/ns#Reheat factor of the process\n", "\n", "#output\n", "print '''(a)The overall efficiency of the turbine is %0.2f %%\n", "(b)The power developed by the turbine is %i kW\n", "(c)The reheat factor of the process is %3.2f'''%(nt*100,W,RF)\n", "\n", "#comments\n", "# the answer in the textbook is not correct." ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "(a)The overall efficiency of the turbine is 78.63 %\n", "(b)The power developed by the turbine is 7725 kW\n", "(c)The reheat factor of the process is 1.05\n" ] } ], "prompt_number": 14 } ], "metadata": {} } ] }