Steam is produced at 70 bar and some unknown temperature. A small amount of steam is bled off just before entering a turbine and goes through an adiabatic throttling valve to atmospheric pressure. The temperature of the steam exiting the throttling valve is 400C. The unthrottled steam is fed into the turbine, where it is adiabatically expanded to atmospheric pressure.
A) What is the temperature of the steam entering the turbine?
B) What is the maximum work per kilogram of steam that can be obtained using the turbine in its present mode of operation?
C) Tests on the turbine exhaust indicate that the steam leaving is a saturated vapor. What is the efficiency of the turbine and the entropy generated per kilogram of steam?
D) If the ambient pressure is 25 C and the ambient pressure is 1 bar, what is the maximum possible work that could be obtained per kilogram of steam in any continuous process?