Example 34.2 Evaluating a performance claim a single stream of air An inventor claims: T1=21C P1=5 bars a device requiring no energy transfer by work or 2 Inlet heat transfer.Separate air T2=79C into hot and cold streams. P2=I bar Hot outlet Evaluate the inventor's claim, Cold outlet T3=-18C P3=I bar 60%mass Assumption: 1.Steady state 2.CV:Qcv=0,Wcv=0 3. ideal gas model for air,cp=1.0 kJ/kg-K 4.ignoring APE and AKE of the streams from inlet to exit. 上游充通大 April 23,2019 10 SHANGHAI JLAO TONG UNIVERSITYApril 23, 2019 10 Example 34.2 : Evaluating a performance claim An inventor claims: a device requiring no energy transfer by work or heat transfer. Separate air into hot and cold streams. Evaluate the inventor’s claim, a single stream of air 60% mass Assumption: 1. Steady state 2. CV: Qcv=0, Wcv=0 3. ideal gas model for air, cp=1.0 kJ/kg-K 4. ignoring ∆PE and ∆KE of the streams from inlet to exit