initial commit / add all books

10 files changed, 148 insertions, 0 deletions

diff --git a/172/CH8/EX8.1/ex1.sce b/172/CH8/EX8.1/ex1.sce
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+//example 1

+//coefficient of performance of refrigerator

+clear

+clc

+Th=60 //temperature at which heat is rejected from R-134a

+Tl=0 //temperature at which heat is absorbed into the R-134a 

+s1=1.7262 //specific entropy at 0 Celsius

+s2=s1 //process of state change from 1-2 is isentropic 

+s3=1.2857 //specific entropy at 60 celsius

+s4=s3 //process of state change from 3-4 is isentropic

+disp('if Pressure is 1400 kPa,then s=1.7360 kJ/kg-K and if P=1600 kPa,then s=1.7135 kJ/kg-K.Therefore')

+P2=1400+(1600-1400)*(1.7262-1.736)/(1.7135-1.736) //pressure after compression in kPa

+B=(Th+273)/(Th-Tl) //coefficient of performance of refrigerator

+printf(" \n hence,pressure after compression is P2=%.3f kPa.\n",P2) 

+printf("\n and coefficient of performance of refrigerator is B=%.3f .\n",B)
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diff --git a/172/CH8/EX8.10/ex10.sce b/172/CH8/EX8.10/ex10.sce
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+//example 10

+//Determiining the entropy generated

+clear

+clc

+B=4 //COP of air conditioner

+W=10 //power input of air conditioner in kW

+Qh=B*W //in kW

+Ql=Qh-W //in kW

+Thigh=323 //in Kelvin

+Tlow=263 //in Kelvin

+SgenHP=(Qh*1000/Thigh)-(Ql*1000/Tlow) //in W/K

+Tl=281 // in K

+Th=294 //in K

+SgenCV1=Ql*1000/Tlow-Ql*1000/Tl //in W/K

+SgenCV2=Qh*1000/Th-Qh*1000/Thigh //in W/K

+SgenTOT=SgenCV1+SgenCV2+SgenHP //in W/K

+printf(" \n Hence,Total entropy generated is SgenTOT=%.1f W/K. \n",SgenTOT)
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diff --git a/172/CH8/EX8.2/ex2.sce b/172/CH8/EX8.2/ex2.sce
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index 000000000..36431002e
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+++ b/172/CH8/EX8.2/ex2.sce
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+//example 2 

+//heat transfer in a given process

+clear

+clc

+u1=87.94 //specific internal energy of R-12 at state 1 in kJ/kg

+u2=276.44 //specific internal energy of R-12 at state 2 in kJ/kg

+s1=0.3357 //specific entropy at state 1 in kJ/kg-K

+s2=1.2108 //specific entropy at state 2 in kJ/kg-K

+V=0.001 //volume of saturated liquid in m^3

+v1=0.000923 //specific volume in m^3/kg

+m=V/v1 //mass of saturated liquid in kg

+T=20 //temperature of liquid in celsius

+Q12=m*(T+273.15)*(s2-s1) //heat transfer in kJ to accomplish the process

+W12=m*(u1-u2)+Q12 //work required to accomplish the process

+printf(" \n hence,work required to accomplish the process is W12=%.1f kJ.\n",W12)

+printf(" \n and heat transfer is Q12=%.1f kJ.\n",Q12)
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diff --git a/172/CH8/EX8.3/ex3.sce b/172/CH8/EX8.3/ex3.sce
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index 000000000..15ab12073
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+++ b/172/CH8/EX8.3/ex3.sce
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+//example 3

+//entropy change

+clear

+clc

+C=4.184 // specific heat of water in kJ/kg-K

+T1=20 //initial temperature of water in celsius

+T2=90 //final temperature of water in celsius

+dS1=C*log((T2+273.2)/(T1+273.2)) //change in entropy in kJ/kg-K

+dS2=1.1925-0.2966 //in kJ/kg-K using steam tables

+printf("\n hence,change in entropy assuming constant specific heat is dS1=%.4f kJ/kg-K.\n",dS1)

+printf("\n using steam table is dS2=%.4f kJ/kg-K.\n",dS2) 
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diff --git a/172/CH8/EX8.4/ex4.sce b/172/CH8/EX8.4/ex4.sce
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index 000000000..9399182cc
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+//example 4

+//entropy change with different assumptions

+clear

+clc

+T1=300 //initial temperature in kelvins

+T2=1500 //final temperature in kelvins

+P1=200 //initial pressure in kPa

+P2=150 //final pressure in kPa

+R=0.2598 // in kJ/kg-K

+Cp=0.922 //specific heat in kJ/kg-K at constant pressure

+dsT2=8.0649 //in kJ/kg-K

+dsT1=6.4168 //in kJ/kg-K

+dS1=dsT2-dsT1-R*log(P2/P1) //entropy change calculated using ideal gas tables

+dS2=integrate('0.88/x-0.0001+0.54*x-0.33*x^2','x',0.3,1.5)-R*log(P2/P1) //entropy change calculated using empirical equation 

+dS3=Cp*log(T2/T1)-R*log(P2/P1) //entropy change assuming constant specific heat in kJ/kg-K

+dS4=1.0767*log(T2/T1)+0.0747 //entropy change assuming specific heat is constant at its value at 990K

+printf("\n hence,change in entropy using ideal gas tables is dS1=%.4f kJ/kg-K.\n",dS1)

+printf("\n hence,change in entropy using empirical equation is dS2=%.4f kJ/kg-K.\n",dS2)

+printf("\n hence,change in entropy using the value of specific heat at 300K is dS3=%.4f kJ/kg-K.\n",dS3)

+printf("\n hence,change in entropy assuming specific heat is constant at its value at 900K is dS4=%.4f kJ/kg-K.\n",dS4)
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diff --git a/172/CH8/EX8.5/ex5.sce b/172/CH8/EX8.5/ex5.sce
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index 000000000..f23cb3ac9
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+//example 5

+//entropy change

+clear

+clc

+Cp=1.004 //specific heat at constant pressure in kJ/kg-K

+R=0.287 //gas constant in kJ/kg-K

+P1=400 //initial pressure in kPa

+P2=300 //final pressure in kPa

+T1=300 //initial temperature in K

+T2=600 //final temperature in K

+dS1=Cp*log(T2/T1)-R*log(P2/P1) //entropy change assuming constant specific heat

+s1=6.8693 //specific entropy at T1

+s2=7.5764 //specific entropy at T2

+dS2=s2-s1-R*log(P2/P1) //entropy change assuming variable specific heat

+printf("\n hence,entropy change assuming constant specific heat is dS1=%.4f kJ/kg-K.\n",dS1)

+printf("\n and assuming variable specific heat is dS2=%.4f kJ/kg-K.\n",dS2)
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diff --git a/172/CH8/EX8.6/ex6.sce b/172/CH8/EX8.6/ex6.sce
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index 000000000..ebfbe454d
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+//example 6

+//work done by air

+clear

+clc

+T1=600 //initial temperature of air in K

+P1=400 //intial pressure of air in kPa

+P2=150 //final pressure in kPa

+u1=435.10 //specific internal energy at temperature T1 in kJ/kg

+sT1=7.5764 //specific entropy at temperature T1 in kJ/kg-K

+R=0.287 //gas constant in kJ/kg-K

+ds=0

+sT2=ds+sT1+R*log(P2/P1) //specific entropy at temperature T2 in kJ/kg-K

+disp('we know the values of s and P for state 2.So,in order to fully determine the state,we will use steam table')

+T2=457 //final temperature in K

+u2=328.14 //specific internal energy at temperature T2 in kJ/kg

+w=u1-u2 //work done by air in kJ/kg

+printf("\n hence,work done by air is w=%.2f kJ/kg.\n",w)
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diff --git a/172/CH8/EX8.7/ex7.sce b/172/CH8/EX8.7/ex7.sce
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index 000000000..18fd02c90
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+//example 7

+//work and heat transfer

+clear

+clc

+P2=500  //final pressure in cylinder in kPa

+P1=100 //initial pressure in cylinder in kPa

+T1=20+273.2 //initial temperature inside cylinder in Kelvins

+n=1.3 

+T2=(T1)*(P2/P1)^((n-1)/n) //final temperature inside cylinder in K

+R=0.2968 //gas constant in kJ/kg-K

+w12=R*(T2-T1)/(1-n) //work in kJ/kg

+Cvo=0.745 //specific heat at constant volume in kJ/kg-K

+q12=Cvo*(T2-T1)+w12 //heat transfer in kJ/kg

+printf(" \n hence,work done is w12=%.1f kJ/kg.\n",w12)

+printf("\n and heat transfer are q12=%.1f kJ/kg.\n",q12)
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diff --git a/172/CH8/EX8.8/ex8.sce b/172/CH8/EX8.8/ex8.sce
new file mode 100755
index 000000000..d5a5dbad8
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+++ b/172/CH8/EX8.8/ex8.sce
@@ -0,0 +1,13 @@
+//example 3

+//calculating increase in entropy

+clear

+clc

+m=1 //mass of saturated water vapour

+sfg=6.0480 //in kJ/K

+T=25 //temperature of surrounding air in celsius

+dScm=-m*sfg //change in entropy of control mass in kJ/K

+hfg=2257.0 //in kJ/kg

+Qtosurroundings=m*hfg //heat transferred to surroundings in kJ

+dSsurroundings=Qtosurroundings/(T+273.15) //in kJ/K

+dSnet=dScm+dSsurroundings //net increase in entropy in kJ/K

+printf(" hence,net increase in entropy of water plus surroundings is dSnet=%.4f kJ/K.\n",dSnet)  
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diff --git a/172/CH8/EX8.9/ex9.sce b/172/CH8/EX8.9/ex9.sce
new file mode 100755
index 000000000..4065db4e6
--- /dev/null
+++ b/172/CH8/EX8.9/ex9.sce
@@ -0,0 +1,8 @@
+//example 9

+//entropy generation

+clear

+clc

+Qout=1 //value of heat flux generated by 1kW of electric power

+T=600 //temperature of hot wire surface in K

+Sgen=Qout/T //entropy generation in kW/K

+printf(" \n hence,entropy generation is Sgen=%.5f kW/K.\n",Sgen)
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