From 92cca121f959c6616e3da431c1e2d23c4fa5e886 Mon Sep 17 00:00:00 2001 From: hardythe1 Date: Tue, 7 Apr 2015 15:58:05 +0530 Subject: added books --- Thermodynamics_Demystified/Chapter8.ipynb | 530 ++++++++++++++++++++++++++++++ 1 file changed, 530 insertions(+) create mode 100755 Thermodynamics_Demystified/Chapter8.ipynb (limited to 'Thermodynamics_Demystified/Chapter8.ipynb') diff --git a/Thermodynamics_Demystified/Chapter8.ipynb b/Thermodynamics_Demystified/Chapter8.ipynb new file mode 100755 index 00000000..2ab04749 --- /dev/null +++ b/Thermodynamics_Demystified/Chapter8.ipynb @@ -0,0 +1,530 @@ +{ + "metadata": { + "name": "", + "signature": "sha256:cd14818c82eb9353b8e2f9e12079fb0ba7b2a061c9a528ea53dea9dfa9a116ce" + }, + "nbformat": 3, + "nbformat_minor": 0, + "worksheets": [ + { + "cells": [ + { + "cell_type": "heading", + "level": 1, + "metadata": {}, + "source": [ + "Chapter 8:Psychrometrics" + ] + }, + { + "cell_type": "heading", + "level": 2, + "metadata": {}, + "source": [ + "Ex8.1:PG-208" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "#initialization of variables\n", + "Ra=0.287 # specific gas constant for air\n", + "P=100.0 # pressure of room in kPa\n", + "V=150.0 # volume of room in m^3\n", + "T=25+273 # temperature of air in kelvin\n", + "phi=0.6 # relative humidity\n", + "Pg=3.29 # saturation vapour pressure in kPa at 25 *C from table C.1\n", + "Mv= 18 # molecular mass of water vapor\n", + "Ma=28.97 # molecular mass of air\n", + "\n", + "Pv=Pg*phi # partial pressure of water vapour\n", + "\n", + "Pa=P-Pv # partial pressure of air\n", + "\n", + "w=0.622*(Pv/Pa) # humidity ratio in Kg of water/ Kg of dry air\n", + "Tdp=17.4 # dew point temperature from interpolation in table C.2 corresponding to partial pressure Pv=1.98 kPa\n", + "\n", + "ma=Pa*V/(Ra*T) # mass of air\n", + "mv=w*ma # mass of water vapour in kg\n", + "\n", + "# now we find volume percentage\n", + "Nv=mv/Mv # moles of vapour\n", + "Na=ma/Ma # moles of air\n", + "\n", + "Vw= Nv/(Na+Nv) # fraction of volume occupied by water vapour\n", + "\n", + "print \"The humidity ratio is\",round(w,4),\"kg water/ kg of dry air \\n\"\n", + "print \"The dew point is\",round(Tdp,1),\"degree celsius \\n \"\n", + "print \"The mass of water vapour in the air is\",round(mv,3),\"kg \\n\"\n", + "print \"The volume percentage of the room that is water vapor is\",round(Vw*100,2),\"%\"\n", + "# The answers are correct within given limits \n", + "# The variation in answers is due to approximations made by\n", + "# textbook while python is precise\n" + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "The humidity ratio is 0.0125 kg water/ kg of dry air \n", + "\n", + "The dew point is 17.4 degree celsius \n", + " \n", + "The mass of water vapour in the air is 2.153 kg \n", + "\n", + "The volume percentage of the room that is water vapor is 1.98 %\n" + ] + } + ], + "prompt_number": 12 + }, + { + "cell_type": "heading", + "level": 2, + "metadata": {}, + "source": [ + "Ex8.2:PG-209" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "#initialization of variables\n", + "Ra=0.287 # specific gas constant for air\n", + "P=100.0 # pressure of room in kPa\n", + "w1=0.0126 # old humidity ratio of example 8.1-\n", + "Pg=3.29 # saturation vapour pressure in kPa at 25 *C from table C.1\n", + "mv=2.17 # initial mass of water vapour in example 8.1\n", + "T=25+273 # temperature after reheat\n", + "V=150.0 # volume of room in m^3 \n", + "Pv=1.228 # saturation vapour pressure in kPa @ 10 degree celsius from table C.1\n", + "Pa=P-Pv # partial pressure of air\n", + "w2=0.622*(Pv/Pa) # new humidity ratio in Kg of water/ Kg of dry air\n", + "deltaw=w1-w2 # difference in humidity ratio\n", + "ma=Pa*V/(Ra*T) # mass of air\n", + "deltamv=deltaw*ma # mass of water vapour condensed\n", + "X=deltamv*100/mv # percentage of water vapour condensed\n", + "print \"The percentage that condenses is\",round(X,2),\"% \\n\"\n", + "# AFTER REHEATING\n", + "phi=1.608*w2*Pa/Pg\n", + "print \"The relative humidity is\",round(phi*100,3),\"%\"\n", + "\n", + "# The answers are correct within given limits \n", + "# The variation in answers is due to approximations made by\n", + "# textbook while python is precise\n", + "\n" + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "The percentage that condenses is 38.85 % \n", + "\n", + "The relative humidity is 37.332 %\n" + ] + } + ], + "prompt_number": 18 + }, + { + "cell_type": "heading", + "level": 2, + "metadata": {}, + "source": [ + "Ex8.3:PG-212" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "#initialization of variables\n", + "T1=40 # dry bulb temperature in degree celsius\n", + "T2=20 # wet bulb temperature in degree celsius\n", + "Cp=1.0 # specific heat\n", + "P=100 # pressure of air stream in kPa\n", + "pg1=7.383 #saturation pressure @ 40 degree celsius\n", + "hfg2=2454 # latent heat for 20 degree celsius\n", + "Pg2=2.338 # saturation pressure @ 20 degree celsius\n", + "w2=0.622*Pg2/(P-Pg2) # specific humidity for wet bulb condition\n", + "hg1=2574 # specific enthalpy of saturated vapour @ 40 degree celsius\n", + "hf2=83.9 #spedific enthalpy of saturated liquid @ 20 degree celsius\n", + "w1=((w2*hfg2)+Cp*(T2-T1))/(hg1-hf2)# specific humidity for 40 degree celsius\n", + "print \"The humidity ratio is\",round(w1,4),\"kg water/ Kg dry air \\n\"\n", + "pv1=100*w1/(0.622+w1) # partial pressure of vapour\n", + "phi=pv1/pg1 # relative humidity\n", + "print \"The relative humidity is\",round(phi*100,1),\"% \\n\"\n", + "\n", + "hv=hg1 # temperature is at DBT=40 degree celsius\n", + "h=Cp*T1+w1*hv # specific enthalpy of air\n", + "print \"The specific enthalpy is\",round(h,1),\"kJ/kg dry air\"\n", + "\n", + "\n" + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "The humidity ratio is 0.0066 kg water/ Kg dry air \n", + "\n", + "The relative humidity is 14.3 % \n", + "\n", + "The specific enthalpy is 57.1 kJ/kg dry air\n" + ] + } + ], + "prompt_number": 23 + }, + { + "cell_type": "heading", + "level": 2, + "metadata": {}, + "source": [ + "Ex8.5:PG-215" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "# initialization of variables\n", + "\n", + "T1=40 # inlet temperature in degree celsius\n", + "T2=27 # outlet temperature in degree celsius\n", + "phi1= 10 # relative humidity at inlet\n", + "# as no heat transfer takes place thus isenthalpic process\n", + "\n", + "#Thus following the enthalpy line at DBT=40 and Relative humidity=10\n", + "\n", + "phi2=45 # by interpolation of constant enthalpy line\n", + "w1=0.0046# specific humidity @ T=40 and phi1=10\n", + "w2=0.010 # specific humidity at outlet\n", + "W=w2-w1 # amount of water added\n", + "Tmin=18.5 # minimum temperature at 100% relative humidity\n", + "\n", + "print \"The relative humidity is\",round(phi2,1),\"% \\n \"\n", + "print \"The added water is\",round(W,4),\"kg water/kg dry air \\n\"\n", + "print \"The lowest possible temperature is\",round(Tmin,1),\"*C \"\n", + "\n", + "\n", + " " + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "The relative humidity is 45.0 % \n", + " \n", + "The added water is 0.0054 kg water/kg dry air \n", + "\n", + "The lowest possible temperature is 18.5 *C \n" + ] + } + ], + "prompt_number": 26 + }, + { + "cell_type": "heading", + "level": 2, + "metadata": {}, + "source": [ + "Ex8.6:PG-215" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "# initialization of variables\n", + "T1=5+273.0 # outside air temperature in kelvin\n", + "P=100.0 # pressure in kPa\n", + "Ra=0.287 # specific gas constant for air\n", + "phi=0.7 # relative humidity outside\n", + "Qf=50.0/60.0 # volume flow rate in m**3/sec\n", + "Pg1=0.872 # saturation pressure at 278 K\n", + "Pv1=phi*Pg1 # partial pressure of water vapour\n", + "Pa1=P-Pv1 # partial pressure of air\n", + "\n", + "rhoa=Pa1/(Ra*T1) # density of dry air\n", + "\n", + "mdota=Qf*rhoa # mass flow rate of dry air\n", + "\n", + "# using psychrometric chart at T1=5*C and phi1=70% \n", + "h1=14 # inlet enthalpy in kJ/kg\n", + "h2=35 # enthalpy after heating in kJ/kg\n", + "\n", + "Qdot=mdota*(h2-h1) # heat transfer rate\n", + "# from psychrometric chart for T=25 *C and 35 kJ/kg enthalpy\n", + "phi2=19 # realtive humidity\n", + "\n", + "print \"The heat transfer rate is\",round(Qdot,1),\"kJ/s \\n\"\n", + "print \"The final relative humidity is\",round(phi2,4),\"% \"\n", + "\n" + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "The heat transfer rate is 21.8 kJ/s \n", + "\n", + "The final relative humidity is 19.0 % \n" + ] + } + ], + "prompt_number": 31 + }, + { + "cell_type": "heading", + "level": 2, + "metadata": {}, + "source": [ + "Ex8.7:PG-216" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "# initialization of variables\n", + "#DATA TAKEN FROM PSYCHROMETRIC CHART\n", + "T1=5+273.0 # outside temperature in kelvin\n", + "h1=10# enthalpy in kJ/kg @ T=5 *C and 40 % relative humidity\n", + "Pg1=0.872 # saturaion pressure in kPa for 5 degree celsius DBT\n", + "phi1=0.4\n", + "h2=33 # specific enthalpy at 25 *C and 40 % relatuve humidity\n", + "h3=45.0 # specific enthalpy at state 3\n", + "P=100.0 # atmospheric pressure in kPa\n", + "Ra=0.287 # specific gas constant for air\n", + "Qf=60.0/60.0 # volume flow rate in m**3/s\n", + "Pv1=phi1*Pg1 # partial presure of water vapour \n", + "Pa1=P-Pv1 # partial pressure of air\n", + "w2=0.0021 # specific humidity @ 40 % relative humidity and 25*C temperature\n", + "w3=0.008 # final specific humidity\n", + "rhoa1=Pa1/(Ra*T1) # air density\n", + "mdota=Qf*rhoa1 # mass flow rate of dry air\n", + "\n", + "Qdot=mdota*(h2-h1) # heat transfer rate\n", + "\n", + "# as the process is isothermal thus\n", + "mdots=mdota*(w3-w2)# mass flow rate of steam by conservation of mass\n", + "print \"the rate of steam supplied is\",round(mdots,4),\"kg/s \\n\"\n", + "# also using energy balance\n", + "hs=(mdota*(h3-h2))/mdots # enthalpy of steam\n", + "hf=604.7 # enthalpy of saturated liquid @ 400 kPa\n", + "hg=2738.5 # enthalpy of saturated vapour @ 400 kPa\n", + "xs=(hs-hf)/(hg-hf)\n", + "print \"The quality of steam is\",round(xs,2)\n" + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "the rate of steam supplied is 0.0074 kg/s \n", + "\n", + "The quality of steam is 0.67\n" + ] + } + ], + "prompt_number": 34 + }, + { + "cell_type": "heading", + "level": 2, + "metadata": {}, + "source": [ + "Ex8.8:PG-217" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "# initialization of variables\n", + "# REFER TO FIG. 8.4\n", + "T1=30 # outside temperature in degree celsius\n", + "phi1=0.9 # outside relative humidity\n", + "T2=23 # room temperature in degree celsius\n", + "phi2=0.4 # relative humidity in room\n", + "\n", + "# using psychrometric chart\n", + "w1=0.0245 # specific humidity @ 30 *C and relative humidity 0.9\n", + "h1=93 # specific enthalpy @ 30 *C and relative humidity 0.9\n", + "w2=w1 # during cooling humidity remains constant \n", + "w3=0.007 # specific humidity @ 23 *C and relative humidity 0.4\n", + "h4=41 # final specific enthalpy\n", + "h3=26 # specific enthalpy @ 23 *C and relative humidity 0.4\n", + "deltaw=w3-w2 # moisture removed\n", + "print \" the amount of moisture removed is\",round(deltaw,4),\"kg \\n\"\n", + "\n", + "qout=h3-h1 # heat removed F-G-H process\n", + "\n", + "print \" the heat removed is\",round(qout,4),\"kJ/kg \\n \"\n", + "\n", + "qin=h4-h3 # heat added to bring to desired state\n", + "\n", + "print \" the heat added is\",round(qin,4),\"kJ/kg \"" + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + " the amount of moisture removed is -0.0175 kg \n", + "\n", + " the heat removed is -67.0 kJ/kg \n", + " \n", + " the heat added is 15.0 kJ/kg \n" + ] + } + ], + "prompt_number": 38 + }, + { + "cell_type": "heading", + "level": 2, + "metadata": {}, + "source": [ + "Ex8.9:PG-218" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "# initialization of variables\n", + "P=100 # atospheric pressure in kPa\n", + "R=0.287 # specific gas constant for air\n", + "T1=15+273 # outside temperature in kelvin\n", + "phi1=0.4# outside air relative humidity\n", + "Qf1=40 # outside air flow rate in m^3/min\n", + "T2=32+273 # inside temperature in kelvin\n", + "phi2=0.7 # inside air relative humidity\n", + "Qf2=20 # outside air flow rate in m^3/min\n", + "Ps1=1.7 # saturation pressure @ 15 degree celsius and 40% humidity\n", + "Ps2=4.9 # saturation pressure @ 32 degree celsius and 70% humidity\n", + "\n", + "Pv1=Ps1*phi1 # partial pressure of water vapour outside\n", + "\n", + "Pv2=Ps2*phi2 # partial pressure of water vapour inside\n", + "\n", + "Pa1=P-Pv1 #partial pressure of dry air outside\n", + "Pa2=P-Pv2 #partial pressure of dry air inside\n", + "\n", + "rhoa1=Pa1/(R*T1) # density of outside air\n", + "mdota1=Qf1*rhoa1 # mass flow rate of air outside\n", + "\n", + "rhoa2=Pa2/(R*T2) # density of inside air\n", + "mdota2=Qf2*rhoa2 # mass flow rate of inside air\n", + " # using psychrometric chart locating state 1 and 2\n", + "h1=37 # specific enthalpy @ DBT 15*C and 40 % humidity\n", + "w1=0.0073 # specific humidity @ DBT 15*C and 40 % humidity\n", + "h2=110 # specific enthalpy @ DBT 32*C and 70 % humidity\n", + "w2=0.0302 # specific humidity @ DBT 32*C and 70 % humidity\n", + "ratio=mdota1/mdota2 # ratio of distance between states \n", + "# using this ratio state 3 is located on psychrometric chart\n", + "T3=(mdota1*T1+mdota2*T2)/(mdota1+mdota2)-273 # final temparature in celsius\n", + "\n", + "phi3=65# final relative humidity at T3 from psychrometric chart\n", + "\n", + "print \" The relative humidity is\",round(phi3,4),\"% \\n\"\n", + "print \" The resultant temperature is\",round(T3),\"degree celsius\"\n" + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + " The relative humidity is 65.0 % \n", + "\n", + " The resultant temperature is 20.0 degree celsius\n" + ] + } + ], + "prompt_number": 41 + }, + { + "cell_type": "heading", + "level": 2, + "metadata": {}, + "source": [ + "Ex7.10:PG-219" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "# initialization of variables\n", + "mdotw3=10000.0 # mass flow rate of water entering in cooling tower in kg/min\n", + "Tw1=40+273.0 # temperature of water entering cooling tower in kelvin\n", + "Ta1=20+273.0 # temperature of air entering cooling tower in kelvin\n", + "phi1=0.5# relative humidity of entering air\n", + "Tw2=25+273.0 # temperature of water leaving cooling tower in kelvin\n", + "Ta2=32+273 # temperature of air leaving cooling tower in kelvin\n", + "phi2=0.98 # relative humidity of leaving air\n", + "# from psychrometric chart\n", + "h1=37.0# specific enthalpy of air @ 20*C DBT and 50% humidity\n", + "w1=0.0073 # specific humidity of air @ 20*C DBT and 50% humidity\n", + "h2=110.0 # specific enthalpy of air @ 32*C DBT and 98% humidity\n", + "w2=0.030 # specific humidity of air @ 32*C DBT and 98% humidity\n", + "\n", + "h3=167.5 # specific enthalpy of water from steam table at 40 degree celsius\n", + "h4=104.9 # specific enthalpy of water from steam table at 25 degree celsius\n", + "\n", + "mdota=(mdotw3*(h4-h3))/(h1-h2+(w2-w1)*h4) # by energy balance\n", + "\n", + "\n", + "v1=0.84 # specific volume of air entering tower from psychrometric chart\n", + "\n", + "Qf=mdota*v1 # volume flow rate in m^3/min\n", + "print \"The volume flow rate of air into the cooling tower is\",round(Qf),\" m^3/min \\n\"\n", + "\n", + "mdot4=mdotw3-(w2-w1)*mdota # by mass balance\n", + "print \"The mass flow rate of water that leaves the cooling tower \",round(mdot4),\"kg/min\"\n", + "# The answers is slightly different in textbook due to approximations in calculations while in python solution is precise\n", + "\n", + "\n" + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "The volume flow rate of air into the cooling tower is 7446.0 m^3/min \n", + "\n", + "The mass flow rate of water that leaves the cooling tower 9799.0 kg/min\n" + ] + } + ], + "prompt_number": 3 + } + ], + "metadata": {} + } + ] +} \ No newline at end of file -- cgit