申論題

(2) Steam is leaving a 4-liter pressure cooker whose operating pressure is 150 kPa. It is observed that the amount of liquid in the cooker has decreased by 0.6 liter in 40 minutes after the steady operating conditions are established, and the cross-sectional area of the exit openting is 8 mm². Determine

(c) the flow work per unit mass (5%). At 150 kPa, we know that the specific volume for saturated liquid water and saturated water vapor are vf= 0.001053 m³/kg and v_g= 1.1594 m³/kg, respectively. The internal energy for saturated liquid water and saturated water vapor are uf= 466.97 kJikg and u_g= 2519.2 kJfkg, respectively. The enthalpy for saturated liquid water and saturated water vapor are h_f = 467.13 kJkg and h_g = 2693.1 k.I/kg, respectively.