Question

0.05 kg of steam at 10 bar, dryness fraction 0.84, is heated reversibly in a rigid vessel until the pressure is 20 bar. Calculate the change of entropy and the heat supplied.

Answer 1

Change in entropy

Cps log_e(T_sup/T_s)

C_ps =2.303 KJ/Kg

T_sup=400⁰ C, T_s=212.4⁰C

Change in entropy

=(2.303KJ/Kg)log(400^oC/212.4^oC)

0.634 KJ/Kg