Question

A 160 m³ rigid tank is filled with saturated liquid-vapor mixture of water at 50^oC. 70% of the mass is vapor and the 30% of the mass is liquid. The mixture is then heated until its pressure is 50kPa. Determine the final temperature(^oC).

Answer 1

Given,

• Mass of vapor;

m_g = 70% of m = 0.70m

Dryness fraction is given as;

Using Table A-4 (Saturated water - Temperature table);

• at T₁ = 50^oC and x₁ = 0.70

For rigid tank;

v = constant

=> v₂ = v₁ = 8.4185 m³/kg

Using Table A-5 (Saturated water - Pressure table);

• at P₂ = 50 kPa;

v_g = 3.2403 m³/kg

By comparing we can see that v₂ is greater than v_g, or;

v₂ > v_g

Hence,

State-2 = Superheated

Using Table A-6 (Superheated water);

• at P₂ = 50 kPa and v₂ = 8.4185 m³/kg, by interpolating between 600^oC and 700^oC;

...(Answer)