Question

Two tanks are connected by a valve and line. The volumes are both 1 m³ with R-134a at 20°C, quality 15% in A and tank B is evacuated. The valve is opened and saturated vapor flows from A into B until the pressures become equal. The process occurs slowly enough that all temperatures stay at 20°C during the process. Find the total heat transfer to the R-134a during the process. 

Answer 1

C.V.: A + B State 1A: v_A1 = 0.000817 + 0.15 × 0.03524 = 0.006103 m³/kg

u_A1 = 227.03 + 0.15 × 162.16 = 251.35 kJ/kg

m_A1 = V_A/v_A1 = 163.854 kg

Process: Constant temperature and constant total volume.

m₂ = mA₁ ; V₂ = V_A + V_B = 2 m³ ; v₂ = V₂/m₂ = 0.012206 m³/kg