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diff --git a/Thermodynamics_Demystified_by_Merle_C._Potter/Chapter8_2.ipynb b/Thermodynamics_Demystified_by_Merle_C._Potter/Chapter8_2.ipynb new file mode 100755 index 00000000..2ab04749 --- /dev/null +++ b/Thermodynamics_Demystified_by_Merle_C._Potter/Chapter8_2.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 |