Problem
1. 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 0.4 lbm/s, and the expansion process can be considered a reversible polytropic process with exponent n = 1.3. Calculate the power output of the expander.
2. An expansion in a gas turbine can be approximated with a polytropic process with exponent n = 1.25. The inlet air is at 2100 R, 120 psia, and the exit pressure is 18 psia with a mass flow rate of 2 lbm/s. Find the turbine heat transfer and power output.
The response should include a reference list. Double-space, using Times New Roman 12 pnt font, one-inch margins, and APA style of writing and citations.