Question

Two flows of air both at 200 kPa; one has 1 kg/s at 400 K and the other has 2 kg/s at 290 K. The two flows are mixed together in an insulated box to produce a single exit flow at 200 kPa. Find the exit temperature and the total rate of entropy generation. 

Answer 1

Continuity Eq.

The pressure correction part of the entropy terms cancel out as all three states have the same pressure.