1. 2. 3. AERO215 - Thermofluids Homework 2 Due : Thursday 22nd September 2022 Please provide short answers (no more than 50 words per question) to the short answer questions. What is the function of the second law? What does exergy tell us? Steam at 7 MPa and 450C is throttled in a valve to a pressure of 3 MPa during a steady-flow process. Determine the entropy change. 4. Air in a large building is kept warm by heating it with steam in a heat exchanger as shown in the figure. Saturated water vapor enters this unit at 35C at a rate of 10,000 kg/h and leaves as saturated liquid at 32C. Air at 1-atm pressure enters the unit at 20C and leaves at 30C at about the same pressure. Determine the entropy changes of the two streams and find the total entropy change. 32C Steam 35C- 10,000 kg/h Air 20C (3 (4) 30C 5. Refrigerant-134a is expanded isentropically from 600 kPa and 70C at the inlet of a steady-flow turbine to 100 kPa at the outlet. The outlet area is 1 m, and the inlet area is 0.5 m. Calculate the inlet and outlet velocities when the mass flow rate is 0.75 kg/s.