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clear;
clc;
disp('Example 7.8');
// aim : To determine
// the change of entropy
// Given values
m = .3;// [kg]
P1 = 350;// [kN/m^2]
T1 = 273+35;// [K]
P2 = 700;// [kN/m^2]
V3 = .2289;// [m^3]
cp = 1.006;// [kJ/kg K]
cv = .717;// [kJ/kg K]
// solution
// for constant volume process
R = cp-cv;// [kJ/kg K]
// using PV=mRT
V1 = m*R*T1/P1;// [m^3]
// for constant volume process P/T=constant,so
T2 = T1*P2/P1;// [K]
s21 = m*cv*log(P2/P1);// formula for entropy change for constant volume process
mprintf('\n The change of entropy in constant volume process is = %f kJ/kg K\n',s21);
// 'For the above part result given in the book is wrong
V2 = V1;
// for constant pressure process
T3 = T2*V3/V2;// [K]
s32 = m*cp*log(V3/V2);// [kJ/kg K]
mprintf('\n The change of entropy in constant pressure process is = %f kJ/kg K\n',s32);
// there is misprint in the book's result
// End
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