Question

Water at 120°C with a quality of 25% has its temperature raised 20°C in a constant volume process. What is the new quality and pressure?

Answer 1

State 1  at 120°C

v = v_f + x v_fg 

= 0.001060 + 0.25 × 0.8908 

= 0.22376 m³/kg

State 2 has same v at 140°C

x = v - v_f /v_fg  

= 0.22376 - 0.00108/0.50777 

= 0.4385

P = P_sat = 361.3 kPa