Question

One kg of air at 100 kPa is mixed with one kg air at 200 kPa, both at 300 K, in a rigid insulated tank. Find the final state (P, T) and the entropy generation in the process. 

Answer 1

C.V. All the air. Energy

Eq.: U₂ – U₁ = 0 – 0

Entropy Eq.: S₂ – S₁ = 0 + ₁S_{2 gen}

Process Eqs.: V = C; W = 0, Q = 0

States A1, B1: u_A1 = u_B1