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clc
clear
//DATA GIVEN
m=1; //mass of steam in kg
p=20; //pressure of steam in bar
Tsup=400+273; //temp. of steam in K
x=0.9; //dryness fraction
Cps=2.3; //specific heat of steam in kJ/kgK
//At 20 bar, from steam tables
Ts=212.4+273; //in K
hf=908.6; //kJ/kg
hfg=1888.6; //kJ/kg
vg=0.0995; //m^3/kg
hsup=hf+hfg+Cps*(Tsup-Ts); //kJ/kg
//Assume superheated steam to behave as a perfect gas from the commencement of superheating and thus obey Charle's Law
//By vg/Ts=vsup/Tsup
vsup=vg*Tsup/Ts;
usup=hsup-p*10^5*vsup*10^-3; //internal energy of 1 kg of superheated steam in kJ/kg
h=hf+x*hfg;
u=h-p*10^5*x*vg*10^-3; //internal energy of 1 kg of wet steam in kJ/kg
printf('(i) The Internal energy of 1 kg of superheated steam at 400 deg celsius is: %4.2f kJ/kg. \n',usup);
printf('(ii) The Internal energy of 1 kg of wet steam with dryness fraction 0.9 is: %4.2f kJ/kg. \n',u);
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