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{
"metadata": {
"name": "",
"signature": "sha256:13df1b90ea06630bb54a561fa81d4ebbaaa2d68a225d0631603576a208acfb40"
},
"nbformat": 3,
"nbformat_minor": 0,
"worksheets": [
{
"cells": [
{
"cell_type": "heading",
"level": 1,
"metadata": {},
"source": [
"CHAPTER13:Gas Mixtures"
]
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Ex13.3:Pg-533"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"#ques3\n",
"#calculating humidity ratio, dew point,mass of air, mass of vapor\n",
"\n",
"r=0.70;#relative humidity\n",
"Pg=5.628;#saturation pressure in kPa\n",
"Pv=r*Pg;#vapour pressure in kPa\n",
"P=100;#net pressure kPa \n",
"Pa=P-Pv;#Partial pressure of air\n",
"w=0.622*Pv/Pa;#humidity ratio formula\n",
"V=100;#volume in m^3\n",
"Ra=0.287;#gas constant for water vapour\n",
"T=308.2;#Temperature in K\n",
"ma=Pa*V/(Ra*T);#mass in kg\n",
"mv=w*ma;#mass of vapour\n",
"print\" Mass of vapour is\",round(mv,3),\"Kg \""
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
" Mass of vapour is 2.77 Kg \n"
]
}
],
"prompt_number": 2
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Ex13.3E:Pg-533"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"#ques3\n",
"#calculating humidity ratio, dew point,mass of air, mass of vapor\n",
"\n",
"r=0.70;#relative humidity\n",
"Pg=0.6988 ;#saturation pressure in lbf/in^2\n",
"Pv=r*Pg;#vapour pressure in lbf/in^2\n",
"P=14.7;#net pressure in lbf/in^2\n",
"Pa=P-Pv;#Partial pressure of air\n",
"w=0.622*Pv/Pa;#humidity ratio formula\n",
"V=2000;#volume in ft^3\n",
"Ra=53.34;#gas constant for water vapour\n",
"T=70;#Temperature in F\n",
"ma=Pa*V*144/(Ra*(T+480));#mass in lbm\n",
"mv=w*ma;#mass of vapour\n",
"print\" Mass of vapour is\",round(mv,2),\"lbm\""
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
" Mass of vapour is 2.99 lbm\n"
]
}
],
"prompt_number": 11
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Ex13.4:Pg-534"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"#ques4 \n",
"#calculating amount of water vapour condensed on cooling\n",
"\n",
"#from example 3\n",
"w1=0.0255;#w1=w, humidity ratio at initial temperature\n",
"ma=108.6;#mass of air in kg\n",
"P=100;#kPa net pressure\n",
"#at 5 C mixture is saturated so Pv2=Pg2\n",
"Pg2=0.8721;\n",
"Pv2=Pg2;\n",
"w2=0.622*Pv2/(P-Pg2);\n",
"mc=ma*(w1-w2);\n",
"print\"Mass of vapour condense is \",round(mc,3),\"kg \""
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Mass of vapour condense is 2.175 kg \n"
]
}
],
"prompt_number": 6
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Ex13.4E:Pg-535"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"#ques4 \n",
"#calculating amount of water vapour condensed on cooling\n",
"\n",
"#from example 3 \n",
"w1=0.02135;#w1=w, humidity ratio at initial temperature\n",
"ma=139.6;#mass of air in lbm\n",
"P=14.7;#net pressure in lbf/in^2\n",
"#at 40 degree F mixture is saturated so Pv2=Pg2\n",
"Pg2=0.1217 # lbf/in^2\n",
"Pv2=Pg2;\n",
"w2=0.622*Pv2/(P-Pg2);# humidity ratio at final temperature\n",
"mc=ma*(w1-w2); #Mass of vapour condense in lbm\n",
"print\"Mass of vapour condense is \",round(mc,3),\"lbm \""
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Mass of vapour condense is 2.256 lbm \n"
]
}
],
"prompt_number": 13
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Ex13.5:Pg-536"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"#ques5\n",
"#calculating heat transfer per kilogram of dry air\n",
"\n",
"#1-inlet state\n",
"#2-Exit state\n",
"r1=0.80;#realtive humidity at state 1\n",
"Pg1=4.246;#saturation pressure of vapour in kPa\n",
"P1=105.0;#net pressure at state 1 in kPa\n",
"P2=100.0;#net pressure at state 2 in kPa\n",
"Pv1=r1*Pg1;#partial pressure of vapour in kPa\n",
"w1=0.622*Pv1/(P1-Pv1);#humidity ratio at state 1\n",
"r2=0.95;#relative humidity at state 2\n",
"Pg2=1.7051;#saturation pressure of vapour in kPa\n",
"Pv2=r2*Pg2;#partial pressure of vapour in kPa\n",
"w2=0.622*Pv2/(P2-Pv2);#humidity ratio at state 2\n",
"T1=30.0;#C\n",
"T2=15.0;#C\n",
"Cp=1.004;#specific heat of water vapour in kJ/kg\n",
"hv2=2528.9;#enthalpy of vapourisation of vapour in kJ/kg\n",
"hv1=2556.3;#enthalpy of vapourisation of vapour in kJ/kg\n",
"hl2=62.99;#enthalpy of \n",
"q=Cp*(T2-T1)+w2*hv2-w1*hv1+hl2*(w1-w2);#kJ/kg\n",
"print\" Heat transferred per unit mass =\",round(q,1),\"kJ/kg of dry air\""
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
" Heat transferred per unit mass = -41.7 kJ/kg of dry air\n"
]
}
],
"prompt_number": 11
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Ex13.6:Pg-537"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"#ques6\n",
"#calculating heat transferred in gas vapour mixture\n",
"\n",
"#n-Nitrogen\n",
"#v-water vapour\n",
"Pn2=1995;#Pressure of nitrogen in kPa\n",
"V=0.5;#Volume in m^3\n",
"Rn2=0.2968;#Gas constant for nitrogen in kJ/kg.K\n",
"Rv=0.4615;#gas constant for vapour\n",
"T1=323.2;#Temperature in K\n",
"T2=283.2;#Temperature in K\n",
"Pv1=5;#Pressure of water vapour in kPa at state 1\n",
"Pv2=1.2276;#Pressure of water vapour in kPa at state 2\n",
"mn2=Pn2*V/(Rn2*T1);#mass of nitrogen\n",
"mv1=Pv1*V/(Rv*T1);#mass of vapour in kg\n",
"mv2=Pv2*V/(Rv*T2);#mass of vapour in kg\n",
"ml2=mv1-mv2;#mass of liquid condensed n kg\n",
"uv1=2443.1;#specific internal energy of vapour in kJ/kg at state 1\n",
"uv2=2389.2;#specific internal energy of vapour in kJ/kg at state 2\n",
"ul2=42.0;#specific internal energy of liquid water in kJ/kg\n",
"Cv=0.745;#specific heat at constant volume in kJ/kg.K\n",
"Q=mn2*Cv*(T2-T1)+mv2*uv2+ml2*ul2-mv1*uv1;\n",
"print\"Heat transferred =\",round(Q,2),\"kJ \"\n",
"\n",
"#the answer is different in book due to intermediate approximization "
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Heat transferred = -339.1 kJ \n"
]
}
],
"prompt_number": 13
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Ex13.7:Pg-539"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"#ques7\n",
"#calculating humidity ratio and relative humidity \n",
"\n",
"#1-Inlet state\n",
"#2-Exit state\n",
"P=100;#net pressure in kPa \n",
"#it is steady state adiabatic process\n",
"#water vapour leaving is saturated so Pv2=Pg2\n",
"Pg2=2.339;#saturation pressure of vapour in kPa\n",
"Pv2=Pg2;#partial pressure of vapour\n",
"w2=0.622*Pv2/(P-Pg2);\n",
"Cpa=1.004;#specific heat n kJ/kg/K\n",
"T2=20;# final temp in C\n",
"T1=30;# initial temp in C\n",
"Hfg2=2454.1;#specific heat difference at state 2 in kJ/kg\n",
"hv1=2556.3;#enthalpy of water vapour at state 1 in kJ/kg\n",
"hl2=83.96;#enthalpy of liquid water in kJ/kg\n",
"w1=(Cpa*(T2-T1)+w2*Hfg2)/(hv1-hl2);\n",
"print \" Relative humidity =\",round(w1,4)\n",
"#also w1=0.622*Pv1/(100-Pv2)\n",
"Pv1=100*w1/(0.622+w1);\n",
"Pg1=4.246;#saturation pressure at state 1 in kPa\n",
"r=Pv1/Pg1;#humidity ratio\n",
"print\" Humidity ratio =\",round(r,4)"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
" Relative humidity = 0.0107\n",
" Humidity ratio = 0.3993\n"
]
}
],
"prompt_number": 16
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Ex13.7E:Pg-540"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"#ques7\n",
"#calculating humidity ratio and relative humidity \n",
"\n",
"#1-Inlet state\n",
"#2-Exit state\n",
"P=14.7;#net pressure in lbf/in^2\n",
"#it is steady state adiabatic process\n",
"#water vapour leaving is saturated so Pv2=Pg2\n",
"Pg2=0.3632;#saturation pressure of vapour in lbf/in^2\n",
"Pv2=Pg2;#partial pressure of vapour\n",
"w2=0.622*Pv2/(P-Pg2);\n",
"Cpa=0.24;#specific heat n Btu/lbm/F\n",
"T2=70;# final temp in F\n",
"T1=84;# initial temp in F\n",
"Hfg2=1054.0;#specific heat difference at state 2 in Btu/lbm\n",
"hv1=1098.1;#enthalpy of water vapour at state 1 in Btu/lbm\n",
"hl2=38.1;#enthalpy of liquid water in Btu/lbm\n",
"w1=(Cpa*(T2-T1)+w2*Hfg2)/(hv1-hl2);\n",
"print \" Relative humidity =\",round(w1,4)\n",
"#also w1=0.622*Pv1/(100-Pv2)\n",
"Pv1=14.7*w1/(0.622+w1);\n",
"Pg1=0.584;#saturation pressure at state 1 in lbf/in^2\n",
"r=Pv1/Pg1;#humidity ratio\n",
"print\" Humidity ratio =\",round(r,4)"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
" Relative humidity = 0.0125\n",
" Humidity ratio = 0.4958\n"
]
}
],
"prompt_number": 18
}
],
"metadata": {}
}
]
}
|
