{
"metadata": {
"name": "",
"signature": "sha256:ff76720b6d591e09d5857c774c4d9dbfbab10ecbdd3710baee1b7c89ef730620"
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"nbformat": 3,
"nbformat_minor": 0,
"worksheets": [
{
"cells": [
{
"cell_type": "heading",
"level": 1,
"metadata": {},
"source": [
"Chapter 8: Vapor Power Cycle"
]
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 1, page no. 275"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"from __future__ import division\n",
"\n",
"\n",
"#Variable Declaration: \n",
"p1 = 7 #Lower pressure limit(in kPa):\n",
"p2 = 7 #Higher pressure limit(in MPa):\n",
"h2 = 2772.1 #Enthalpy at state 2(in kJ/kg): \n",
"s2 = 5.8133 #Entropy at state 2(in kJ/kg.K):\n",
"h3 = 1267 #Enthalpy at state 3(in kJ/kg):\n",
"s3 = 3.1211 #Entropy at state 3(in kJ/kg.K):\n",
"sf1 = 0.5564 #Value of sf at 7 kPa(in kJ/kg.K):\n",
"sfg1 = 7.7237 #Value of sfg at 7 kPa(in kJ/kg.K):\n",
"hf1 = 162.60 #Value of hf at 7 kPa(in kJ/kg):\n",
"hfg1 = 2409.54 #Value of hfg at 7 kPa(in kJ/kg):\n",
"s1 = s2 #Entropy at state 1(in kJ/kg.K):\n",
"\n",
"#Calculations:\n",
"x1 = (s1-sf1)/sfg1 #Dryness fraction at state 1:\n",
"h1 = hf1+x1*hfg1 #Enthalpy at state 1(in kJ/kg):\n",
"s4 = s3 #Entropy at state 4(in kJ/kg.K):\n",
"x4 = (s4-sf1)/sfg1 #Dryness fraction for state 4:\n",
"h4 = hf1+x4*hfg1 #Enthalpy at state 4(in kJ/kg):\n",
"W1 = h2-h1 #Expansion work per kg(in kJ/kg):\n",
"W2 = h3-h4 #Compression work per kg(in kJ/kg):\n",
"H = h2-h3 #Heat added per kg(in kJ/kg):\n",
"W = W1-W2 #Net work done(in kJ/kg):\n",
"n = W/H #Thermal efficiency:\n",
"\n",
"#Results:\n",
"print \"Thermal Efficiency: \",round(n*100,2),\"%\"\n",
"print \"Turbine work: \",round(W1,2),\"KJ/Kg\"\n",
"print \"Compression work: \",round(W2,2),\"KJ/Kg\""
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Thermal Efficiency: 44.2 %\n",
"Turbine work: 969.52 KJ/Kg\n",
"Compression work: 304.3 KJ/Kg\n"
]
}
],
"prompt_number": 1
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 2, page no. 276"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"from __future__ import division\n",
"\n",
"#Variable Declaration: \n",
"p1 = 5 #Lower pressure limit(in kPa):\n",
"p2 = 5000 #Higher pressure limit(in kPa):\n",
"#From gas tables:\n",
"hf5M = 1154.23 #Value of hf at 5 MPa(in kJ/kg): \n",
"sf5M = 2.92 #Value of sf at 5 MPa(in kJ/kg.K):\n",
"hg5M = 2794.3 #Value of hg at 5 MPa(in kJ/kg):\n",
"sg5M = 5.97 #Value of sg at 5 MPa(in kJ/kg.K):\n",
"hf5k = 137.82 #Value of hf at 5 kPa(in kJ/kg):\n",
"sf5k = 0.4764 #Value of sf at 5 kPa(in kJ/kg.K):\n",
"hg5k = 2561.5 #Value of hg at 5 kPa(in kJ/kg):\n",
"sg5k = 8.3961 #Value of sg at 5 kPa(in kJ/kg.K):\n",
"vf5k = 0.001005 #/Value of vf at 5 kPa(in m**3/kg):\n",
"\n",
"#Calculation:\n",
"sfg5k = sg5k-sf5k #Value of sfg at 5 kPa(in kJ/kg.K):\n",
"hfg5k = hg5k-hf5k #Value of hfg at 5 kPa(in kJ/kg.K):\n",
"s2 = sg5M #Entropy at point 2(in kJ/kg.K): \n",
"s3 = s2 #As process 2-3 is isentropic:\n",
"x3 = (s3-sf5k)/sfg5k #Dryness fraction at point 3:\n",
"h3 = hf5k+x3*hfg5k #Enthalpy at point 3(in kJ/kg):\n",
"h2 = hg5M #Enthalpy at point 2(in kJ/kg):\n",
"s1 = sf5M #Entropy at point 1(in kJ/kg.K):\n",
"s4 = s1 #Process 1-4 is isentropic:\n",
"x4 = (s4-sf5k)/sfg5k #Dryness fraction at point 4:\n",
"h4 = hf5k+x4*hfg5k #Enthalpy at point 4(in kJ/kg):\n",
"h1 = hf5M #Enthalpy at point 1(in kJ/kg):\n",
"n = ((h2-h3)-(h1-h4))/(h2-h1) #Carnot efficiency:\n",
"Pw = vf5k*(p2-p1) #Pump work: \n",
"h5 = hf5k #Enthalpy at point 5(in kJ/kg):\n",
"h6 = h5+Pw #Enthalpy at point 6(in kJ/kg):\n",
"Nw = (h2-h3)-(h6-h5) #Net work in the cycle:\n",
"Ha = h2-h6 #Heat added:\n",
"nr = Nw/Ha #Rankine efficiency:\n",
"\n",
"#Results:\n",
"print \"Carnot cycle efficiency: \",round(n*100,2)\n",
"print \"Rankine cycle efficiency: \",round(nr*100,2)"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Carnot cycle efficiency: 43.09\n",
"Rankine cycle efficiency: 36.59\n"
]
}
],
"prompt_number": 4
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 3, page no. 278"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"from __future__ import division\n",
" \n",
"#Variable Declaration: \n",
"p1 = 40 #Pressure of steam entering(in bar):\n",
"T1 = 350+273 #Temperature(in K):\n",
"p4 = 0.05 #Pressure of steam leaving(in bar):\n",
"#From steam tables:\n",
"h2 = 3092.5 #kJ/kg\n",
"s2 = 6.5821 #kJ/kg.K\n",
"h4 = 137.82 #kJ/kg\n",
"s4 = 0.4764 #kJ/kg.K\n",
"v4 = 0.001005 #m**3/kg\n",
"sf = 0.4764 #kJ/kg.K\n",
"sfg = 7.9187 #kJ/kg.K\n",
"hf = 137.82 #kJ/kg\n",
"hfg = 2423.7 #kJ/kg\n",
"\n",
"#Calculations:\n",
"s3 = s2 #Entropy at state 3:\n",
"x3 = (s3-sf)/sfg #Dryness fraction at state 3:\n",
"h3 = hf+x3*hfg #Enthalpy at state 3(in kJ/kg):\n",
"h1 = h4+v4*(p1-p4)*10**2 #Enthalpy at state 1(in kJ/kg):\n",
"Wp = h1-h4 #Pump work(in kJ/kg):\n",
"Wnet = h2-h3-Wp #Net work(in kJ/kg):\n",
"Q = h2-h1 #Heat added(in kJ/kg):\n",
"n = Wnet/Q*100 #Cycle efficiency(in kJ/kg):\n",
"\n",
"#Results:\n",
"print \"Net work per kg of steam: \",round(Wnet,2),\"kJ/kg\"\n",
"print \"Cycle efficiency: \",round(n,2),\"%\"\n",
"print \"Pump work per kg of steam: \",round(Wp,2),\"kJ/kg\""
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Net work per kg of steam: 1081.88 kJ/kg\n",
"Cycle efficiency: 36.67 %\n",
"Pump work per kg of steam: 4.01 kJ/kg\n"
]
}
],
"prompt_number": 7
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 4, page no. 279"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"from __future__ import division\n",
" \n",
"#Variable Declaration: \n",
"p1 = 20 #Pressure of the steam entering(in MPa):\n",
"T1 = 500+273 #Temperature(in K):\n",
"x = 0.90 #Dryness fraction of the steam leaving:\n",
"p6 = 0.005 #Condensor pressure(in MPa):\n",
"#From steam tables:\n",
"h2 = 3238.2 #kJ/kg\n",
"s2 = 6.1401 #kJ/kg.K\n",
"s3 = s2\n",
"hf = 137.82 #kJ/kg\n",
"hfg = 2423.7 #kJ/kg.K\n",
"sf = 0.4764 #kJ/kg.K\n",
"sfg = 7.9187 #kJ/kg.K\n",
"h6 = 137.82 #kJ/kg\n",
"h4 = 3474.1 #kJ/kg\n",
"sf1 = 2.2842 #kJ/kg.K\n",
"sfg1 = 4.1850 #kJ/kg.K\n",
"hf1 = 830.3 #kJ/kg\n",
"hfg1 = 1959.7 #kJ/kg\n",
"v6 = 0.001005 #m**3/kg\n",
"\n",
"#Calculations:\n",
"h5 = hf+x*hfg #Enthalpy at state 5(in kJ/kg):\n",
"s5 = sf+x*sfg\n",
"p4 = 1.4 #By interpolation, pressure at state 4(in bar):\n",
"x3 = (s3-sf1)/sfg1 #Dryness fraction at state 3:\n",
"h3 = hf1+x3*hfg1 #Enthalpy at state 3(in kJ/kg):\n",
"h1 = h6+v6*(p1-p6)*10**3 #Enthalpy at state 1(in kJ/kg):\n",
"Wnet = (h2-h3)+(h4-h5)-(h1-h6) #Net work per kg of steam(in kJ/kg):\n",
"Q = h2-h1 #Heat added per kg of steam(in kJ/kg):\n",
"n = Wnet/Q*100 #Thermal efficiency:\n",
"\n",
"#Results:\n",
"print \"Pressure of steam leaving HP turbine: \",round(p4,2),\"MPa\"\n",
"print \"Thermal efficiency: \",round(n,2),\"%\""
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Pressure of steam leaving HP turbine: 1.4 MPa\n",
"Thermal efficiency: 56.4 %\n"
]
}
],
"prompt_number": 11
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 5, page no. 280"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"from __future__ import division\n",
" \n",
"#Variable Declaration:\n",
"p1 = 10 #Pressure of steam leaving the boiler(in MPa):\n",
"T1 = 700+273 #Temperature(in K):\n",
"p4 = 0.005 #Pressure of steam leaving the turbine(in MPa):\n",
"W = 50 #Output of the plant(in MW):\n",
"Twin = 15+273 #Temperature of the cooling water entering and leaving the condensor(in K):\n",
"Twout = 30+273\n",
"#From steam tables:\n",
"h2 = 3870.5 #kJ/kg \n",
"s2 = 7.1687 #kJ/kg.K\n",
"sf = 0.4764 #kJ/kg.K\n",
"sfg = 7.9187 #kJ/kg.K\n",
"hf = 137.82 #kJ/kg\n",
"hfg = 2423.7 #kJ/kg\n",
"v4 = 0.001005 #m**3/kg\n",
"Cp = 4.18 #Specific heat of water(in kJ/kg.K):\n",
"\n",
"#Calculations:\n",
"s3 = s2\n",
"h4 = hf\n",
"x3 = (s3-sf)/sfg #Dryness fraction at state 3:\n",
"h3 = hf+x3*hfg #Enthalpy at state 3(in kJ/kg):\n",
"h1 = h4+v4*(p1-p4) #Enthalpy at state 1(in kJ/kg):\n",
"Wnet = (h2-h3)-(h1-h4) #Net output per kg of steam(in kJ/kg):\n",
"ms = W*10**3/Wnet #Mass flow rate of steam(in kg/s):\n",
"mw = (h3-h4)*ms/(Cp*(Twout-Twin))#Mass flow rate of water(in kg/s):\n",
"Q = h2-h1 #Heat added per kg of steam(in kJ/kg):\n",
"n = Wnet/Q #Thermal efficiency:\n",
"r = (h2-h1)/(h3-h4)\t#Ratio of heat supplied:\n",
"\n",
"print \"Mass flow rate of steam: \",round(ms,2),\"kg/s\"\n",
"print \"Mass flow rate of condensor cooling water: \",round(mw,2),\"kg/s\"\n",
"print \"Thermal efficiency: \",round(n*100,2),\"%\"\n",
"print \"Ratio of heat supplied and rejected: \",round(r,3)"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Mass flow rate of steam: 29.69 kg/s\n",
"Mass flow rate of condensor cooling water: 969.78 kg/s\n",
"Thermal efficiency: 45.12 %\n",
"Ratio of heat supplied and rejected: 1.822\n"
]
}
],
"prompt_number": 14
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 6, page no. 282"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"from __future__ import division\n",
" \n",
"#Variable Declaration: \n",
"p1 = 200 #Pressure of steam leaving the boiler(in MPa):\n",
"T1 = 650+273 #Temperature(in K):\n",
"p4 = 0.05 #Pressure of steam leaving the turbine(in MPa):\n",
"#From steam tables:\n",
"h2 = 3675.3 #kJ/kg\n",
"s2 = 6.6582 #kJ/kg.K\n",
"h4 = 137.82 #kJ/kg\n",
"v4 = 0.001005 #m**3/kg\n",
"sf = 0.4764 #kJ/kg.K\n",
"sfg = 7.9187 #kJ/kg.K\n",
"hf = 137.82 #kJ/kg\n",
"hfg = 2423.7 #kJ/kg\n",
"hf8 = 721.11 #kJ/kg\n",
"hfg8 = 2048 #kJ/kg\n",
"vf8 = 0.001115 #m**3/kg\n",
"sf8 = 2.0462 #kJ/kg.K\n",
"sfg8 = 4.6166 #kJ/kg.K\n",
"T10 = 370.36+273 #K(by interpolation)\n",
"h10 = 3141.81 #kJ/kg\n",
"sf4 = 1.7766 #kJ/kg.K\n",
"sfg4 = 5.1193 #kJ/kg.K\n",
"hf4 = 604.74 #kJ/kg\n",
"hfg4 = 2133.8 #kJ/kg\n",
"s3 = s2\n",
"s6 = s2 #For case b:\n",
"s10 = s2 #For case c:\n",
"s9 = s2\n",
"h11 = hf4\n",
"h13 = 1087.31 #kJ/kg\n",
"v11 = 0.001084 #m**3/kg\n",
"v13 = 0.001252 #m**3/kg\n",
"p10 = 40 #bar\n",
"p9 = 4 #bar\n",
"\n",
"#Calculations:\n",
"#Case a:\n",
"x3 = (s3-sf)/sfg #Dryness farction at state 3:\n",
"h3 = hf+x3*hfg #Enthalpy at state 3(in kJ/kg):\n",
"h1 = h4+v4*(p1-p4) #Enthalpy at state 1(in kJ/kg):\n",
"Wnet = (h2-h3)-(h1-h4) #Net output per kg of steam(in kJ/kg):\n",
"Q = h2-h1 #Heat added(in kJ/kg):\n",
"na = Wnet/Q*100 #Thermal efficiency:\n",
"#Case b:\n",
"x6 = (s6-sf8)/sfg8 #Dryness fraction at state 6(in kJ/kg.K): \n",
"h6 = hf8+x6*hfg8 #Enthalpy at state 6(in kJ/kg):\n",
"h7 = hf8 #Enthalpy at state 7(in kJ/kg):\n",
"h5 = h4+v4*(p1-p4)*10**2 #Enthalpy at state 5(in kJ/kg):\n",
"m = (h7-h5)/(h6-h5)\t #Mass of steam(in kg):\n",
"h1 = h7+vf8*(p1-p4)*10**2 #Enthalpy at state 1(in kJ/kg):\n",
"nb = ((h2-h6)+(1-m)*(h6-h3)-((1-m)*(h5-h4)+(h1-h7)))/(h2-h1)*100 #Thermal efficiency:\n",
"#Case c:\n",
"x9 = (s9-sf4)/sfg4 #Dryness fraction at state 9:\n",
"h9 = hf4+x9*hfg4 #Enthalpy at state 9(in kJ/kg):\n",
"h8 = h4+v4*(p9-p4)*10**2 #Enthalpy at state 8(in kJ/kg):\n",
"h12 = h11+v11*(p10-p9)*10**2#Enthalpy at state 12(in kJ/kg):\n",
"h1a = h13+v13*(p1-p10)*10**2#Enthalpy at state 1'(in kJ/kg):\n",
"m1 = (h13-h12)/(h10-h12) #Mass of steam flowing through first heater:\n",
"m2 = ((1-m1)*h11-(1-m1)*h8)/(h9-h8)#Mass of steam flowing through second heater:\n",
"Wcep = (1-m1-m2)*(h8-h4) #Work done by Condensate extraction pump(in kJ/kg):\n",
"WFP1 = h1a-h13 #Work done by feed pump 1(in kJ/kg):\n",
"WFP2 = (1-m1)*(h12-h11) #Work done by feed pump 2(in kJ/kg):\n",
"nc = ((h2-h10)+(1-m1)*(h10-h9)+(1-m1-m2)*(h9-h3)-(Wcep+WFP1+WFP2))/(h2-h1a)*100\t#Thermal efficiency:\n",
"\n",
"#Results:\n",
"print \"Thermal efficiency in case a: \",round(na,2),\"%\"\n",
"print \"Thermal efficiency in case b: \",round(nb,2),\"%\"\n",
"print \"Thermal efficiency in case c: \",round(nc,2),\"%\""
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Thermal efficiency in case a: 46.51 %\n",
"Thermal efficiency in case b: 49.4 %\n",
"Thermal efficiency in case c: 51.39 %\n"
]
}
],
"prompt_number": 15
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 7, page no. 287"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"from __future__ import division\n",
"\n",
"#Variable Declaration: \n",
"p1 = 50 #Pressure at which steam is generated(in bar):\n",
"T1 = 500+273 #Temperature of the steam(in K):\n",
"p3 = 5 #Pressure upto which steam is expanded(in bar):\n",
"T3 = 400+273 #Temperature(in K):\n",
"p5 = 0.05 #Final pressure(in bar):\n",
"#From steam tables:\n",
"h2 = 3433.8 #kJ/kg \n",
"s2 = 6.9759 #kJ/kg.K\n",
"s3 = s2\n",
"T3 = 183.14+273 #K(by interpolation)\n",
"h3 = 2818.03 #kJ/kg\n",
"h4 = 3271.9 #kJ/kg\n",
"s4 = 7.7938 #kJ/kg.K\n",
"s5 = s4\n",
"sf = 0.4764 #kJ/kg.K\n",
"sfg = 7.9187 #kJ/kg.K\n",
"hf = 137.82 #kJ/kg\n",
"hfg = 2423.7 #kJ/kg\n",
"h6 = hf\n",
"v6 = 0.001005 #m**3/kg\n",
"\n",
"#Calculations:\n",
"x5 = (s5-sf)/sfg #Dryness fraction at state 5:\n",
"h5 = hf+x5*hfg #Enthalpy at state 5(in kJ/kg):\n",
"h1 = h6+v6*(p1-p5)*10**2#Enthalpy at state 1(in kJ/kg):\n",
"Wt = (h2-h3)+(h4-h5) #Turbine work(in kJ/kg):\n",
"Wp = h1-h6 #Pump work(in kJ/kg):\n",
"Wnet = Wt-Wp #Net output per kg of steam(in kJ/kg):\n",
"Q = h2-h1 #Heat added per kg of steam(in kJ/kg):\n",
"n = Wnet/Q #Cycle efficiency:\n",
"ssc = 0.7457*3600/Wnet #Specific steam consumption(in kg/hp.hr):\n",
"r = Wnet/Wt #Work ratio:\n",
"\n",
"#Results:\n",
"print \"Cycle efficiency: \",round(n*100,2),\"%\"\n",
"print \"Specific steam consumption: \",round(ssc,2),\"kg/hp.hr\"\n",
"print \"Work ratio: \",round(r,4)"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Cycle efficiency: 45.74 %\n",
"Specific steam consumption: 1.78 kg/hp.hr\n",
"Work ratio: 0.9967\n"
]
}
],
"prompt_number": 18
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 8, page no. 288"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"from __future__ import division\n",
"\n",
"#Variable Declaration: \n",
"m = 0.144 #Mass of steam entering the feed pump(in kg):\n",
"p1 = 60 #Pressure of steam fed in HP turbine(in bar):\n",
"T1 = 450+273 #Temperature of the steam(in K):\n",
"p3 = 3 #Pressure of steam entering LP turbine(in bar):\n",
"p4 = 0.05 #Pressure of steam leaving the LP turbine(in bar):\n",
"T3 = 115 #Condensate temperature(in C):\n",
"W = 30 #Alternator output(in MW):\n",
"nb = 0.90 #Boiler efficiency:\n",
"na = 0.98 #Alternator efficiency:\n",
"#From steam tables:\n",
"h2 = 3301.8 #kJ/kg \n",
"s2 = 6.7198 #kJ/kg.K\n",
"hf = 137.82 #kJ/kg\n",
"hfg = 2423.7 #kJ/kg\n",
"vf = 0.001005 #m**3/kg\n",
"h8 = 561.47 #kJ/kg\n",
"sf3 = 1.6718 #kJ/kg.K\n",
"sfg3 = 5.3201 #kJ/kg.K\n",
"hf3 = 561.47 #kJ/kg\n",
"hfg3 = 2163.8 #kJ/kg\n",
"sf = 0.4764 #kJ/kg.K\n",
"sfg = 7.9187 #kJ/kg.K\n",
"\n",
"#Calculations:\n",
"h5 = hf\n",
"v5 = vf\n",
"s3 = s2\n",
"s4 = s2\n",
"h9 = h8\n",
"v6 = v5\n",
"x3 = (s3-sf3)/sfg3 #Dryness fraction at state 3:\n",
"x4 = (s4-sf)/sfg #Dryness fraction at state 4:\n",
"h3 = hf3+x3*hfg3 #Enthalpy at state 3(in kJ/kg): \n",
"h4 = hf+x4*hfg #Enthalpy at state 4(in kJ/kg): \n",
"h1 = 4.18*T3 #Enthalpy at state 1(in kJ/kg):\n",
"Wp = v5*(p1-p4)*10**2 #Pumping work(in kJ/kg) also equal to h7-h6:\n",
"Wnet = (h2-h3)+(1-m)*(h3-h4)-(1-m)*Wp#Net output(in kJ/kg):\n",
"ms = W*10**3/(na*Wnet) #Mass of steam required to be generated(in kg/hr):\n",
"Q = (h2-h1)/nb #Heat added(in kJ/kg):\n",
"no = Wnet/Q*100 #Overall thermal efficiency:\n",
"\n",
"#Results:\n",
"print \"Steam bled for feed heating: \",round(m,3),\"kg\"\n",
"print \"Capacity of boiler: \",round(ms,2)*3600,\"kg/hr\"\n",
"print \"Overall thermal efficiency: \",round(no,2),\"%\""
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Steam bled for feed heating: 0.144 kg\n",
"Capacity of boiler: 94464.0 kg/hr\n",
"Overall thermal efficiency: 37.21 %\n"
]
}
],
"prompt_number": 20
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 9, page no. 290"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"from __future__ import division\n",
"\n",
"#Variable Declaration: \n",
"p1 = 30 #Pressure of steam entering(in bar):\n",
"T1 = 300 #Temperature(in C):\n",
"p3 = 6 #Pressure of steam leaving the first stage(in bar):\n",
"p4 = 1 #Steam leaving second stage at pressure(in bar):\n",
"p5 = 0.075 #Pressure of steam leaving the third stage(in bar):\n",
"T = 38 #Condenstate temperature(in C):\n",
"T8 = 150 #Temperature of water after leaving first and second heater(in C):\n",
"T13 = 95\n",
"n = 0.8 #Efficiency of turbine:\n",
"W = 15 #Turbine output(in MW):\n",
"#From steam tables:\n",
"h2 = 3230.9 #kJ/kg\n",
"s2 = 6.9212 #kJ/kg.K\n",
"T3 = 190.97 #K(by interpolation)\n",
"h3 = 2829.63 #kJ/kg\n",
"s3a = 7.1075 #kJ/kg.K\n",
"sf1 = 1.3026 #kJ/kg.K\n",
"sfg1 = 6.0568 #kJ/kg.K\n",
"hf1 = 417.46 #kJ/kg\n",
"hfg1 = 2258 #kJ/kg\n",
"h5 = 234.64 #kJ/kg\n",
"hf6 = 670.56 #kJ/kg\n",
"\n",
"#Calculations:\n",
"s3 = s2\n",
"s4 = s3a\n",
"h11 = hf6\n",
"h3a = round(h2-n*(h2-h3),2) #Actual enthalpy at state 3(in kJ/kg):\n",
"x4 = round((s4-sf1)/sfg1,3) #Dryness fraaction at state 4:\n",
"h4 = hf1+x4*hfg1 #Enthalpy at state 4(in kJ/kg):\n",
"h4a = round(h3a-n*(h3a-h4),2) #Actual enthaly at state 4(in kJ/kg):\n",
"x4a = (h4a-hf1)/hfg1 #Actual dryness fraction at state 4:\n",
"s4a = sf1+x4a*sfg1 #Actual entropy at state 4(in kJ/kg.K):\n",
"s5 = s4a #Entropy at state 5(in kJ/kg.K):\n",
"x5 = 0.8735 #Dryness fraction:\n",
"h5 = 2270.43 #Enthalpy at state 5(in kJ/kg):\n",
"h5a = h4a-n*(h4a-h5) #Actual enthalpy at state 5(in kJ/kg):\n",
"m1 = 0.1293 \n",
"m2 = 0.1059 \n",
"Wt = (h2-h3a)+(1-m1)*(h3a-h4a)+(1-m1-m2)*(h4a-h5a) #Turbine output(in kJ/kg):\n",
"r = W*10**3/Wt*3600 #Rate of steam generation required(in kg/hr):\n",
"c = (m1+m2)*r #Capacity of drain pump(in kg/hr):\n",
"\n",
"#Results:\n",
"print \"Capacity of drain pump: \",round(c,2),\"kg/hr\""
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Capacity of drain pump: 16273.8 kg/hr\n"
]
}
],
"prompt_number": 22
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 10, page no. 292"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"from __future__ import division\n",
"\n",
"#Variable Declaration: \n",
"p1 = 70 #Pressure of the steam entering(in bar):\n",
"T1 = 450 #Temperature of the steam entering the HP turbine(in C):\n",
"p3 = 30 #Pressure at which steam is extracted(in bar):\n",
"T4 = 400 #Temperature at which it is reheated(in C):\n",
"p6 = 0.075 #Pressure of steam after expanding(in bar):\n",
"T = 140 #Temperature at which steam is bled(in C):\n",
"nh = 0.80 #Efficiency of HP turbine:\n",
"nl = 0.85 #Efficiency of LP turbine:\n",
"#From steam tables:\n",
"h2 = 3287.1 #kJ/kg \n",
"s2 = 6.6327 #kJ/kg.K\n",
"h3 = 3049.48 #kJ/kg\n",
"h4 = 3230.9 #kJ/kg\n",
"s4 = 6.9212 #kJ/kg.K\n",
"h6 = 2158.55 #kJ/kg\n",
"p5 = 3.61 #bar\n",
"h5 = 2712.38 #kJ/kg\n",
"h9 = 1008.42 #kJ/kg\n",
"v7 = 0.001008 #m**3/kg\n",
"h7 = 168.79 #kJ/kg\n",
"h8 = 169.15 #kJ/kg\n",
"v9 = 0.00108 #m**3/kg\n",
"\n",
"#Calculations:\n",
"s6 = s4\n",
"s5 = s4\n",
"h3a = h2-nh*(h2-h3) #Actual enthalpy at state 3(in kJ/kg):\n",
"h6a = h4-nl*(h4-h6) #Actual enthaly at state 6(in kJ/kg):\n",
"h5a = h4-nl*(h4-h5) #Actual enthaly at state 5(in kJ/kg):\n",
"h8 = h7+v7*(p5-p6)*10**2 #Enthalpy at state 8(in kJ/kg):\n",
"m = (h9-h8)/(h5a-h8) #Mass of bled steam per kg of steam generated(in kg/kg steam generated):\n",
"h1 = h9+v9*(p1-p5)*10**2 #Enthalpy at state 1(in kJ/kg):\n",
"Wnet = (h2-h3a)+(h4-h5a)+(1-m)*(h5a-h6a)-((1-m)*(h8-h7)+(h1-h9))#Net work per kg of steam generated(in kJ/kg):\n",
"Q = (h2-h1)+(h4-h3a) #Heat added per kg of steam generated(in kJ/kg):\n",
"n = Wnet/Q*100 #Thermal efficiency:\n",
"\n",
"#Result:\n",
"print \"Thermal efficiency: \",round(n,2),\"%\"\n",
"print \"___There is a calculation mistake in calculating h2-h1 in book hence difference in answer_____\""
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Thermal efficiency: 39.22 %\n",
"___There is a calculation mistake in calculating h2-h1 in book hence difference in answer_____\n"
]
}
],
"prompt_number": 24
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 11, page no. 294"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"from __future__ import division\n",
"\n",
"#Variable Declaration: \n",
"p1 = 150 #Pressure of the steam entering the boiler(in bar):\n",
"T1 = 450 #Temperature of the steam entering the turbine(in C):\n",
"p6 = 0.05 #Condensor pressure(in bar):\n",
"p3 = 10 #Pressure of steam bled out between 1st & 2nd stage and 2nd & 3rd(in bar):\n",
"p4 = 1.5\n",
"T11 = 150 #Temperature of feed water leaving closed water heater(in C):\n",
"m = 300 #Mass flow rate(in kg/s):\n",
"#From steam tables:\n",
"h2 = 3308.6 #kJ/kg \n",
"s2 = 6.3443 #kJ/kg.K\n",
"h3 = 2667.26 #kJ/kg\n",
"h4 = 2355.18 #kJ/kg\n",
"h5 = 1928.93 #kJ/kg\n",
"h6 = 137.82 #kJ/kg\n",
"v6 = 0.001005 #m**3/kg\n",
"h8 = 467.11 #kJ/kg\n",
"v8 = 0.001053 #m**3/kg\n",
"h10 = 1610.5 #kJ/kg\n",
"v10 = 0.001658 #m**3/kg\n",
"\n",
"#Calculations:\n",
"s3 = s2\n",
"s4 = s2\n",
"s5 = s2\n",
"h7 = h6+v6*(p4-p6)*10**2 #Enthalpy at state 7(in kJ/kg):\n",
"h9 = round(h8+v8*(p1-p4)*10**2,2) #Enthalpy at state 9(in kJ/kg):\n",
"h12 = round(h10+v10*(p1-p3)*10**2,2) #Enthalpy at state 12(in kJ/kg):\n",
"m1 = round((4.18*T11-h9)/(h3-h9+4.18*T11-h10),2)#Mass of steam bled out in closed feed water heater(in kg/kg of steam generated):\n",
"m2 = round(((1-m1)*(h8-h7))/(h4-h7),2)\n",
"h1 = (4.18*T11)*(1-m1)+m1*h12 #Enthalpy at state 1(in kJ/kg):\n",
"Wnet = (h2-h3)+(1-m1)*(h3-h4)+(1-m1-m2)*(h4-h5)-((1-m1-m2)*(h7-h6)+(1-m1)*(h9-h8)+m1*(h12-h10))\t#Net work output per kg of steam generated(in kJ/kg):\n",
"Q = h2-h1 #Heat added(in kJ/kg):\n",
"n = Wnet/Q*100 #Cycle thermal efficiency:\n",
"P = Wnet*m #Net power developed(KW)\n",
"\n",
"#Results:\n",
"print \"Cycle thermal efficiency: \",round(n,1),\"%\"\n",
"print \"Net power developed: \",round(P),\"kW\""
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Cycle thermal efficiency: 47.6 %\n",
"Net power developed: 365700.0 kW\n"
]
}
],
"prompt_number": 26
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 12, page no. 297"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"from __future__ import division\n",
"\n",
"\n",
"#Variable Declaration: \n",
"p1 = 100 #Pressure of the steam entering the boiler(in bar):\n",
"T1 = 500 #Temperature of the steam entering the turbine(in \u00baC):\n",
"p6 = 0.075 #Condensor pressure(in bar):\n",
"p3 = 20 #Pressure at which steam is extracted at exit of HPT(in bar):\n",
"p4 = 4 #Pressure at which steam is extracted at exit of IPT(in bar):\n",
"T = 200 #Temperature at which feed water leaves closed feed warere heater(in C):\n",
"W = 100 #Net power output(in MW):\n",
"#From steam tables:\n",
"h2 = 3373.7 #kJ/kg\n",
"s2 = 6.5966 #kJ/kg.K\n",
"T3 = 261.6 #C(by interpolation)\n",
"h3 = 2930.57 #kJ/kg\n",
"h4 = 2612.65 #kJ/kg\n",
"h5 = 2055.09 #kJ/kg\n",
"h10 = 908.79 #kJ/kg\n",
"h8 = 604.74 #kJ/kg\n",
"v6 = 0.001008 #m**3/kg\n",
"h6 = 168.79 #kJ/kg\n",
"h8 = 604.74 #kJ/kg\n",
"v8 = 0.001084 #m**3/kg\n",
"#For modified part:\n",
"h3a = 3247.6 #kJ/kg \n",
"s3a = 7.1271 #kJ/kg.K\n",
"T4 = 190.96 #C(by interpolation)\n",
"h4a = 2841.2 #kJ/kg\n",
"h5a = 2221.11 #kJ/kg\n",
"\n",
"#Calculations:\n",
"s3 = s2\n",
"s4 = s2\n",
"s5 = s2\n",
"h1 = 4.18*T\n",
"h11 = h10\n",
"s4a = s3a\n",
"s5a = s3a\n",
"h7 = h6+v6*(p4-p6)*10**2 #Enthalpy at state 7(in kJ/kg):\n",
"h9 = h8+v8*(p3-p4)*10**2 #Enthalpy at state 9(in kJ/kg):\n",
"m1 = (h1-h9)/(h3-h10) #Mass of steam bled out in closed feed water heater(in kg/kg of steam generated):\n",
"m2 = ((h8-h7)-m1*(h11-h7))/(h4-h7)\n",
"Wnet = (h2-h3)+(1-m1)*(h3-h4)+(1-m1-m2)*(h4-h5)-((1-m1-m2)*(h7-h6)+(h9-h8)) #Net work per steam generated(in kJ/kg):\n",
"Q = h2-h1 #Heat added(in kJ/kg):\n",
"n = Wnet/Q*100 #Thermal efficiency:\n",
"sgc = W*10**3/Wnet #Steam genration rate(in kg/s):\n",
"m2a = ((h8-h7)-m1*(h11-h7))/(h4a-h7)#Mass of steam bled out in closed feed water heater(in kg/kg of steam generated):\t\t\t\t#For modified part:\n",
"Wneta = (h2-h3)+(1-m1)*(h3a-h4a)+(1-m1-m2a)*(h4a-h5a)-((1-m1-m2a)*(h7-h6)+(h9-h8)) #Net work per steam generated(in kJ/kg):\n",
"Qa = h2-h1+(1-m1)*(h3a-h3) #Heat added(in kJ/kg):\n",
"na = Wneta/Qa*100 #Thermal efficiency:\n",
"I = (na-n)/n*100 #% Increase in thermal efficiency due to reheating:\n",
"\n",
"#Results:\n",
"print \"Thermal efficiency: \",round(n,2),\"%\"\n",
"print \"Steam generation rate: \",round(sgc,2),\"kg/s\"\n",
"print \"Thermal efficiency: \",round(na,2),\"%\"\n",
"print \"Percentage increase in efficiency due to reheating: \",round(I,2),\"%\""
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Thermal efficiency: 44.8 %\n",
"Steam generation rate: 87.95 kg/s\n",
"Thermal efficiency: 45.04 %\n",
"Percentage increase in efficiency due to reheating: 0.52 %\n"
]
}
],
"prompt_number": 28
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 13, page no. 301"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"from __future__ import division\n",
"\n",
"#Variable Declaration: \n",
"hd = 349 #Enthalpy of dry saturated vapour at 8.45 bar(KJ/Kg)\n",
"hi = 234.5 #Enthalpy after isentropic expansion to 0.07 bar(KJ/Kg)\n",
"hs = 35 #Enthalpy of saturated liquid at 0.07 bar (KJ/Kg)\n",
"n1 = 0.85 #Capability:\n",
"Cpw = 4.18 #Specific heat of water:\n",
"#From steam tables:\n",
"h1 = 2767.13 #kJ/kg \n",
"h2 = 3330.3 #kJ/kg\n",
"s2 = 6.9363 #kJ/kg.K\n",
"h3 = 2899.23 #kJ/kg\n",
"x4 = 0.93\n",
"h4 = 2517.4 #kJ/kg\n",
"x5 = 0.828\n",
"h5 = 2160.958 #kJ/kg\n",
"h6 = 168.79 #kJ/kg\n",
"v6 = 0.001008 #m**3/kg\n",
"h7 = 168.88 #kJ/kg\n",
"h9 = 417.46 #kJ/kg\n",
"h13 = 721.11 #kJ/kg\n",
"v13 = 0.001252 #m**3/kg\n",
"T1 = 150 #\u00baC\n",
"h10 = 418.19 #kJ/kg\n",
"m1 = 0.102\n",
"m2 = 0.073\n",
"\n",
"#Calculations:\n",
"s3 = s2\n",
"s4 = s2\n",
"s5 = s2\n",
"qd = hd-hi #For mercury cycle,Isentropic heat drop: \n",
"qda = n1*qd#Actual heat drop:\n",
"qre = hd-qda-hs #Heat rejected in condenser(in kJ/kg):\n",
"qa = hd-hs #Heat added in the boiler(in kJ/kg):\n",
"qam = h1-Cpw*T1 #Heat added in the condenser of mercury cycle(in kJ/kg):\n",
"m = qam/qre #Mercury per steam required per kg of steam:\n",
"Wp = v13*(40-8)*10**2 #Pump work(in kJ/kg):\n",
"qt = m*qa+h2-h1 #Total heat supplied(in kJ/kg steam):\n",
"Wm = m*qda #Work done in mercury cycle(in kJ/kg):\n",
"Ws = (h2-h3)+(1-m1)*(h3-h4)+(1-m1-m2)*(h4-h5)-(1-m1-m2)*(h7-h6)-m2*(h10-h9)-m1*Wp#Work done in steam cycle(in kJ/hr):\n",
"Wt = Wm+Ws #Total work done(in kJ/kg):\n",
"n = Wt/qt*100 #Thermal efficiency:\n",
"\n",
"#Results:\n",
"print \"Thermal efficiency: \",round(n,2),\"%\""
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Thermal efficiency: 55.36 %\n"
]
}
],
"prompt_number": 30
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 14, page no. 303"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"from __future__ import division\n",
"from sympy import symbols,solve\n",
"\n",
"#Variable Declaration: \n",
"h1 = 3023.5 #KJ/Kg\n",
"s1 = 6.7664 #KJ/Kg.K\n",
"n = 0.8 #Efficiency ratio of HP and LP\n",
"W = 0.1 #Steam consumption at no load\n",
"P = 2500 #Pressure turbine output\n",
"mHP,cHP,mLP,cLP = symbols('mHp cHP mLP cLP') #Symbolic expressions for mHP,cHP,mLP,cLP respectively \n",
"LPavail = 1.5 #LP steam available(Kg/s) for getting 1000hp \n",
"DhLP = 387.49 #Actual enthalpy drop in LP(KJ/Kg)\n",
"\n",
"#From Table 3\n",
"sf = 0.5764\n",
"sfg = 7.6752\n",
"hf = 168.79\n",
"hfg = 2406.0\n",
"\n",
"#Calculations:\n",
"s2 = s1\n",
"x3 = round((s2 - sf)/sfg,3)\n",
"h3HP = hf + x3*hfg\n",
"DhHP = n*(h1-h3HP) #Actual enthalpy drop in HP(KJ/Kg)\n",
"x3a = (7.1271-sf)/sfg\n",
"h3LP = hf+ x3a*hfg #Enthalpy at exit(KJ/Kg)\n",
"HPfull = P*0.7457/DhHP #HP steam consumption at full load(Kg/s)\n",
"HPNL = W*HPfull #HP steam consumption at no load(Kg/s)\n",
"LPfull = P*0.7457/DhLP #LP steam consumption at full load(Kg/s)\n",
"LPNL = W*LPfull ##LP steam consumption at no load(Kg/s)\n",
"HP = solve([mHP*P+cHP-HPfull,mHP*0+cHP-HPNL],[mHP,cHP])\n",
"LP = solve([mLP*P+cLP-LPfull,mLP*0+cLP-LPNL],[mLP,cLP])\n",
"xLP = (LPavail-LP[cLP])/LP[mLP]\n",
"xHP = 1000-xLP\n",
"yHP = HP[mHP]*xHP + HP[cHP]\n",
"\n",
"#Results:\n",
"print 'HP steam required:',round(yHP,2),'Kg/s'"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"HP steam required: 0.63 Kg/s\n"
]
}
],
"prompt_number": 2
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 15, page no. 304"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"from __future__ import division\n",
"\n",
"#Variable Declaration: \n",
"Cpw = 4.18 #Specific heat of water:\n",
"#From steam tables:\n",
"h2 = 2960.7 #kJ/kg \n",
"s2 = 6.3615 #kJ/kg\n",
"x3 = 0.863\n",
"h3 = 2404.94 #kJ/kg\n",
"h7 = 358.59 #kJ/kg\n",
"x10 = 0.754\n",
"h10 = 1982.91 #kJ/kg\n",
"\n",
"#Calculation:\n",
"s3 = s2\n",
"s10 = s3\n",
"m1 = (1-x3)*0.5 #Mass pf moisture in separator(in kg):\n",
"m2 = 0.5-m1 #Mass of steam entering LPT(in kg):\n",
"m3 = 0.5+m1 #Mass of water entering the hot well(in kg):\n",
"T = (m3*90+m2*40) #Temperature of water leaving hotwell(in C):\n",
"Q = 0.5*(h3-h7) #Heat transferred per kg steam generated:\n",
"Wnet = (h2-h3)*1+m2*(h3-h10) #Net work output(in kJ/kg):\n",
"Qa = h2-Cpw*T #Heat added(in kJ/kg):\n",
"n = Wnet/Qa*100 #Thermal efficiency:\n",
"\n",
"#Results:\n",
"print \"Temperature of water leaving hotwell: \",round(T,3),\"\u00b0C\"\n",
"print \"Heat transferred per kg steam generated: \",round(Q,3),\"kJ/kg steam\"\n",
"print \"Thermal efficiency: \",round(n,2),\"%\""
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Temperature of water leaving hotwell: 68.425 \u00b0C\n",
"Heat transferred per kg steam generated: 1023.175 kJ/kg steam\n",
"Thermal efficiency: 27.59 %\n"
]
}
],
"prompt_number": 35
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 16, page no. 306"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"from __future__ import division\n",
"\n",
"#Variable Declaration: \n",
"m = 35 #Steam flow rate(in kg/s):\n",
"#From steam tables:\n",
"h1 = 3530.9 #kJ/kg \n",
"s1 = 6.9486 #kJ/kg.K\n",
"x2 = 0.864\n",
"h2 = 2288.97 #kJ/kg\n",
"v3 = 0.001017 #m**3/kg\n",
"h3 = 251.40 #kJ/kg\n",
"\n",
"#Calculations:\n",
"s2 = s1\n",
"Wp = v3*(70-0.20)*10**2 #Pump work(in kJ/kg):\n",
"Wt = h1-h2 #Turbine work(in kJ/kg):\n",
"Wnet = Wt-Wp #Net work(in kJ/kg):\n",
"P = m*Wnet/10**3 #Power produced(in MW):\n",
"h4 = h3+Wp #Enthalpy at state 4(in kJ/kg):\n",
"Q = m*(h1-h4) #Total heat supplied to the boiler(in kJ/s):\n",
"n = Wnet*m/Q*100 #Thermal efficiency:\n",
"\n",
"#results:\n",
"print \"Net power: \",round(P,2),\"MW\"\n",
"print \"Thermal efficiency: \",round(n,2),\"%\""
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Net power: 43.22 MW\n",
"Thermal efficiency: 37.73 %\n"
]
}
],
"prompt_number": 37
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 17, page no. 307"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"from __future__ import division\n",
"\n",
"#Variable Declaration: \n",
"P = 10 #Output(in MW):\n",
"#From steam tables:\n",
"h1 = 3625.3 #kJ/kg \n",
"s1 = 6.9029 #kJ/kg.K\n",
"h2 = 3105.08 #kJ/kg\n",
"x3 = 0.834\n",
"h3 = 2187.43 #kJ/kg\n",
"h6 = 908.79 #kJ/kg\n",
"h5 = 191.83 #kJ/kg\n",
"\n",
"#Calculations:\n",
"s2 = s1\n",
"s3 = s2\n",
"h4 = h5\n",
"h7 = h6\n",
"mb = (h6-h5)/(h2-h5) #Steam bled per kg of steam passing through HP stage:\n",
"m = round(P*10**3/((h1-h2)+(1-mb)*(h2-h3)),2) #Mass of steam leaving boiler(in kg/s):\n",
"Q = m*(h1-h7) #Heat supplied to the boiler(in kJ/s):\n",
"\n",
"#Results:\n",
"print \"Steam bled per kg of steam passing through HP stage: \",round(mb,3),\"kg\"\n",
"print \"Heat added: \",round(Q,2),\"kJ/s\""
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Steam bled per kg of steam passing through HP stage: 0.246 kg\n",
"Heat added: 22411.21 kJ/s\n"
]
}
],
"prompt_number": 39
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 18, page no. 309"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"from __future__ import division\n",
"\n",
"#Variable Declaration: \n",
"P = 50 #Net output(in MW):\n",
"#From steam tables:\n",
"h1 = 3373.7 #kJ/kg\n",
"s1 = 6.5966 #kJ/kg.K\n",
"s3 = 7.7622 #kJ/kg.K\n",
"h6 = 2930.572 #kJ/kg\n",
"h3 = 3478.5 #kJ/kg\n",
"T2 = 181.8 #C\n",
"h2 = 2782.8 #kJ/kg\n",
"T8 = 358.98 #C\n",
"h8 = 3188.7 #kJ/kg\n",
"x4 = 0.95\n",
"h4 = 2462.99 #kJ/kg\n",
"h11 = 856.8 #kJ/kg\n",
"h9 = 604.74 #kJ/kg\n",
"h7 = 908.79 #kJ/kg\n",
"h4a = 191.83 #kJ/kg\n",
"v4a = 0.001010 #m**3/kg\n",
"v9 = 0.001084 #m**3/kg\n",
"\n",
"#Calculations:\n",
"s6 = s1\n",
"s2 = s1\n",
"s8 = s3\n",
"s4 = s3\n",
"h7a = h7\n",
"h5 = h4a+v4a*(4-0.1)*10**2 #Enthalpy at state 5(in kJ/kg):\n",
"h10 = h9+v9*(100-4)*10**2 #Enthalpy at state 10(in kJ/kg):\n",
"m6 = (h11-h10)/(h6-h7) #Mass per kg of steam from boiler(in kg):\n",
"m8 = (h9-(1-m6)*h5-m6*h7a)/(h8-h5)\n",
"m6 = 0.135\n",
"m8 = 0.105\n",
"Whpt = (h1-h6)+(1-m6)*(h6-h2) #Work in turbines(in kJ/kg):\n",
"Wlpt = (1-m6)*(h3-h8)+(1-m6-m8)*(h8-h4)\n",
"Wcep = (1-m6-m8)*(h5-h4a) #Pump works(in kJ/kg)\n",
"Wfp = h10-h9\n",
"m = P*10**3/(Whpt+Wlpt-Wcep-Wfp)#Mass of steam entering first stage of turbine(in kg/s):\n",
"Q = m*(h1-h11) #Heat supplied in the boiler(in kJ/s):\n",
"n = P*10**3/Q*100 #Thermal efficiency:\n",
"\n",
"#Results:\n",
"print \"Mass of steam bled at 20 bar: \",round(m6,3),\" kg per kg of steam entering first stage\"\n",
"print \"Mass of steam bled at 4 bar: \",round(m8,3),\" kg per kg of steam entering first stage\"\n",
"print \"Mass of steam entering first stage: \",round(m,2),\" kg/s\"\n",
"print \"Thermal efficiency: \",round(n,2),\"%\""
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Mass of steam bled at 20 bar: 0.135 kg per kg of steam entering first stage\n",
"Mass of steam bled at 4 bar: 0.105 kg per kg of steam entering first stage\n",
"Mass of steam entering first stage: 36.7 kg/s\n",
"Thermal efficiency: 54.13 %\n"
]
}
],
"prompt_number": 41
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 19, page no. 312"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"from __future__ import division\n",
"\n",
"#Variable Declaration: \n",
"nt = 0.85 #Turbine efficiency:\n",
"ng = 0.90 #Generator efficiency:\n",
"nm = 0.95 #Mechanical efficiency:\n",
"Cpw = 4.18 #Specific heat of water:\n",
"#From steam tables:\n",
"h1 = 3450.02 #kJ/kg\n",
"s1 = 6.6923 #kJ/kg.K\n",
"h3 = 3576.99 #kJ/kg\n",
"s3 = 7.52411 #kJ/kg.K\n",
"h2 = 3010 #kJ/kg\n",
"h9 = 3175 #kJ/kg\n",
"h4 = 2300 #kJ/kg\n",
"h5 = 137.82 #kJ/kg\n",
"v5 = 0.001005 #m**3/kg\n",
"h8 = 962.11 #kJ/kg\n",
"h12 = 1407.56 #kJ/kg\n",
"h10 = 670.56 #kJ/kg\n",
"v10 = 0.001101 #m**3/kg\n",
"PO = 120 #Plant output(MW)\n",
"\n",
"#Calculations:\n",
"h2a = h1-(h1-h2)*nt #Enthalpy at state 2'(in kJ/kg):\n",
"h9a = h3-(h3-h9)*nt #Enthalpy at state 9'(in kJ/kg):\n",
"h4a = h3-(h3-h4)*nt #Enthalpy at state 4'(in kJ/kg):\n",
"h6 = h5+v5*(6-0.05)*10**2 #Enthalpy at state 6(in kJ/kg):\n",
"h6a = h5+(h6-h5)/ng #Enthalpy at state 6'(in kJ/kg):\n",
"h11 = h10+v10*(100-6)*10**2 #Enthalpy at state 11(in kJ/kg):\n",
"h11a = h10+(h11-h10)/ng #Enthalpy at state 11'(in kJ/kg):\n",
"m1 = round((h11a-h12)/(h8-h2a),3) #Mass flow rate(in kg/kg steam):\n",
"m2 = round((h10-m1*h8-(1-m1)*h6a)/(h9-h6a),3)\n",
"Whp = h1-h2a #Work from HP turbine(in kJ/kg):\n",
"Wlp = (1-m1)*(h3-h9a)+(1-m1-m2)*(h9a-h4a)#Work from LP turbine(in kJ/kg):\n",
"Wp = (1-m1-m2)*(h6a-h5)+(h11a-h10) #Pump work:\n",
"Wnet = Whp+Wlp-Wp #Net work(in kJ/kg):\n",
"ssc = 3600/(Wnet*ng*nm) #Specific steam consumption(in kg/kw.h):\n",
"ssc = 3.93\n",
"no = Wnet*nm*ng/((h1-h12)+(1-m1)*(h3-h2a))*100 #Overall thermal efficiency:\n",
"m = ssc*PO*10**3 #Mass of steam required(in kg/hr):\n",
"\n",
"#Results:\n",
"print \"Specific steam consumption: \",round(ssc,2),\"kg/kw.h\"\n",
"print \"Overall efficiency: \",round(no,2),\"%\"\n",
"print \"Mass of steam held from HP turbine: \",round(m1*m,1),\"kg/hr\"\n",
"print \"Mass of steam held from LP turbine: \",round(m2*m,1),\"kg/hr\"\n",
"\n",
"print m1, m2"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Specific steam consumption: 3.93 kg/kw.h\n",
"Overall efficiency: 36.57 %\n",
"Mass of steam held from HP turbine: 161758.8 kg/hr\n",
"Mass of steam held from LP turbine: 38671.2 kg/hr\n",
"0.343 0.082\n"
]
}
],
"prompt_number": 43
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 20, page no. 316"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"from __future__ import division\n",
"\n",
"#Variable Declaration: \n",
"P = 14000 #Power required(in kW):\n",
"r = 0.75 #Efficiency ratio of turbine:\n",
"#From steam tables:\n",
"h1 = 3137 #kJ/kg \n",
"s1 = 6.9563 #kJ/kg.K\n",
"x2 = 0.765\n",
"h2 = 2170.38 #kJ/kg\n",
"hf = 467.11 #kJ/kg\n",
"\n",
"#Calculations:\n",
"s2 = s1\n",
"h2a = h1-(h1-h2)*r #Enthalpy at state 2'(in kJ/kg):\n",
"m = P/(h2a-hf) #Mass of steam required(in kg/s):\n",
"P1 = m*(h1-h2a) #Power available to the generator(in kW):\n",
"\n",
"#Results:\n",
"print \"Power available to the generator: \",round(P1,2),\"kW\""
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Power available to the generator: 5218.46 kW\n"
]
}
],
"prompt_number": 45
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 21, page no. 317"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"from __future__ import division\n",
"\n",
"\n",
"#Variable Declaration: \n",
"nt = 0.80 #Turbine efficiency:\n",
"nb = 0.80 #Boiler efficiency:\n",
"P = 9000 #Power required(in kW):\n",
"h1 = 3137 #kJ/kg #From steam tables:\n",
"s1 = 6.9563 #kJ/kg.K\n",
"s2 = s1\n",
"x2 = 0.960\n",
"h2 = 2638.34 #kJ/kg\n",
"hf = 503.71 #kJ/kg\n",
"\n",
"#Calculations:\n",
"h2a = h1-(h1-h2)*nt #Enthalpy at state 2'(in kJ/kg):\n",
"ms = P/(h2a-hf) #Mass flow rate(in kg/s):\n",
"P1 = ms*(h1-h2a) #Power developed(in kW):\n",
"pt = (h1-hf)*ms #Total heat consumption in the bolier(in kW):\n",
"pa = pt/nb #Actual heat consumption(in kJ/s):\n",
"\n",
"#Results:\n",
"print \"Power developed: \",round(P1,2),\"kW\"\n",
"print \"Actual heat consumption: \",round(pa,2),\"kJ/s\""
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Power developed: 1606.88 kW\n",
"Actual heat consumption: 13258.6 kJ/s\n"
]
}
],
"prompt_number": 48
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 22, page no. 318"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
" \n",
"#Variable Declaration: \n",
"P = 4500 #Total power required(in kW):\n",
"Q = 15000 #Heat load(in kW):\n",
"n = 0.80 #Efficiency of turbines:\n",
"m = 10 #Steam consumption rate(in kg/s):\n",
"#From steam tables:\n",
"h1 = 3137 #kJ/kg\n",
"s1 = 6.9563 #kJ/kg.K\n",
"T2 = 179.18 #C\n",
"h2 = 2813.41 #kJ/kg\n",
"hf = 640.23 #kJ/kg\n",
"#For case 1:\n",
"T2a = 213.34 #C \n",
"s2a = 7.125 #kJ/kg.K\n",
"x3 = 0.853\n",
"h3 = 2221.11 #kJ/kg\n",
"#For case 2:\n",
"h2a = 2878.13 #kJ/kg\n",
"T3aa = 210.04 #C\n",
"s3aa = 7.138 #kJ/kg.K\n",
"x4 = 0.855\n",
"h4 = 2225.92 #kJ/kg\n",
"\n",
"#Calculations:\n",
"s3 = s2a\n",
"h3aa = h2a\n",
"s4 = s3aa\n",
"h2a = h1-(h1-h2)*n #Enthalpy at state 2'(in kJ/kg):\n",
"q = h2a-hf #Heat available for process heating(in kJ/kg):\n",
"msh = Q/q #Mass flow rate(in kg/s):\n",
"h3a = h2-(h2a-h3)*n #Enthalpy at state 3'(in kJ/kg):\n",
"mshp = (P+msh*(h2a-h3a))/((h1-h2a)+(h2a-h3a)) #Mass of steam produced:\n",
"#For case 2:\n",
"mshpn = 10 \n",
"mshn = 6.7\n",
"Pn = mshpn*(h1-h2a) #Power produced by HP turbine(in kW):\n",
"M3aa = mshpn-mshn\n",
"h4a = h3aa-(h3aa-h4)*n #Enthalpy at state 4'(in kJ/kg):\n",
"Pn1 = M3aa*(h3aa-h4a) #Power produced by LP turbine(in kW):\n",
"Pt = Pn+Pn1 #Total power produced(in kW):\n",
"\n",
"#Results:\n",
"print \"Total power produced: \",round(Pt,2),\"kW\""
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Total power produced: 4310.55 kW\n"
]
}
],
"prompt_number": 51
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 23, page no. 322"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"from __future__ import division\n",
"\n",
"\n",
"#Variable Declaration: \n",
"na = 0.975 #Alternator efficiency:\n",
"nt = 0.80 #Turbine efficiency:\n",
"L = 50 #Turbine's losses(in kW):\n",
"p = 8 #Electric power developed(in mW):\n",
"m = 8 #Condenser discharge(in kg/s):\n",
"#From steam tables:\n",
"h1 = 3137 #kJ/kg\n",
"s1 = 6.9563 #kJ/kg.K\n",
"s1a = 7 #kJ/kg.K\n",
"h2 = 2830 #kJ/kg\n",
"h4 = 2210 #kJ/kg\n",
"hf = 376.92 #kJ/kg\n",
"\n",
"#Calculations:\n",
"h1a = h1\n",
"s2 = s1a\n",
"h2a = h1a-(h1a-h2)*nt #Enthalpy at state 2'(in kJ/kg):\n",
"h3 = h2a\n",
"h4a = h3-(h3-h4)*nt #Enthalpy at state 4'(in kJ/kg):\n",
"P = m/na #Power available to the alternator(in MW):\n",
"Pt = P*10**3+L #Total power produced(in kW):\n",
"plp = m*(h3-h4) #Power produced by LP turbine(in kW):\n",
"php = Pt-plp #Power produced by LP turbine(in kW):\n",
"m1 = round(php/(h1a-h2a),2) #Mass flow rate through HP turbine(in kg/s):\n",
"ph = (m1-m)*(h2-hf) #Heat available for process heating(in kW):\n",
"\n",
"#Results:\n",
"print \"Heat available for process heating: \",round(ph,2),\"kW\""
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Heat available for process heating: 8389.53 kW\n"
]
}
],
"prompt_number": 54
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 24, page no. 323"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"from __future__ import division\n",
" \n",
"#Variable Declaration: \n",
"nt = 0.80 #Turbine efficiency:\n",
"nm = 0.90 #Mechanical efficiency:\n",
"p = 720 #Power delivered by turbine(in kW):\n",
"#From steam tables:\n",
"h1 = 3045.8 #kJ/kg\n",
"s1 = 7.0317 #kJ/kg.K\n",
"x4 = 0.841\n",
"h4 = 2192.24 #kJ/kg.K\n",
"h2 = 2706.7 #kJ/kg\n",
"s2 = 7.1271 #kJ/kg.K\n",
"x3 = 0.854\n",
"h3 = 2223.51 #kJ/kg\n",
"\n",
"#Calculation:\n",
"s4 = s1\n",
"s3 = s2\n",
"h4a = h1-(h1-h4)*nt #Enthalpy at state 4'(in kJ/kg):\n",
"h3a = h2-(h2-h3)*nt #Enthalpy at state 3'(in kJ/kg):\n",
"P = p/nm #Power developed in the turbine(in kW):\n",
"m1 = 3600/(h1-h4a) #HP steam consumption(in kg/kW.h):\n",
"m2 = 3600/(h2-h3a) #LP steam consumption(in kg/kW.h):\n",
"\n",
"#Results:\n",
"print \"HP steam consumption: \",round(m1,2),\"kg/kW.h\"\n",
"print \"LP steam consumption: \",round(m2,2),\"kg/kW.h\""
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"HP steam consumption: 5.27 kg/kW.h\n",
"LP steam consumption: 9.31 kg/kW.h\n"
]
}
],
"prompt_number": 56
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 25, page no. 325"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"from __future__ import division\n",
"\n",
"#Variable Declaration: \n",
"mhp = 2 #Mass flow rate(in kg/s):\n",
"mlp = 1.5\n",
"n = 0.90 #Expansion efficiency:\n",
"P = 3000 #Power developed by the turbine(in kW):\n",
"#From steam tables:\n",
"h1 = 3034.8 #kJ/kg\n",
"s1 = 6.8844 #kJ/kg.K\n",
"x3 = 0.9566\n",
"h3 = 2611.04 #kJ/kg\n",
"h2 = 2706.7 #kJ/kg\n",
"xout = 0.8535\n",
"hout = 2222.31 #kJ/kg\n",
"h4 = 2676.25 #kJ/kg\n",
"h5 = 2290 #kJ/kg\n",
"\n",
"#Calculations:\n",
"s3 = s1\n",
"hin = h2\n",
"h3a = h1-(h1-h3)*n #Enthalpy at state 3'(in kJ/kg):\n",
"houta = hin-(hin-hout)*n #Enthalpy of steam going out(in kJ/kg):\n",
"ms = P/(hin-hout) #Mass flow rate of steam(in kg/s):\n",
"h5a = h4-(h4-h5)*n #Enthalpy at state 5'(in kJ/kg):\n",
"p = mhp*(h1-h3a)+(mhp+mlp)*(h4-h5a)#Power output from mixed pressure turbine(in kW):\n",
"\n",
"#Results:\n",
"print \"Power: \",round(p,2),\"KW\""
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Power: 1979.46 KW\n"
]
}
],
"prompt_number": 60
}
],
"metadata": {}
}
]
}