Splve the below problem:
Q: Helium gas enters a steady-flow expander at 120 lbf/in 2, 500 F, and exits at 18 lbf/in 2. The mass flow rate is 0.4lbm/s, and the expansion process can be considered as a reversible polytropic process with exponent, n =1.3. Calculate the power output of the expander.