Question

Problem 4 – Entropy transfer in a control volume (18 pts) An adiabatic reversible steam turbine steadily processes 2 kg/s of steam at 5 MPa and 450°C, which is exhausted at 100 kPa and 100°C. The turbine exhibits an isentropic efficiency of 0.85. a) Draw a schematic representation of the system with all the energy interactions involved. (2pts) b) Determine the h (kJ/kg) and s (kJ/kg-K) at the inlet. (2 pts) c) Determine the actual h (kJ/kg) and s (kJ/kg-K) at the exit. (2 pts) d) Determine the h (kJ/kg) and s (kJ/kg-K) at the exit for the isentropic process. (3 pts) e) For the control volume, write an entropy balance in a rate form including the entropy generated and entropy transfer. (3 pts) f) Determine the entropy generated through the process, in kW/K. (3 pts) g) Plot the process on a T-s diagram for both the ideal and actual turbines. (3 pts)

Problem 4 Entropy transfer in a control volume (18 pts) An adiabatic reversible steam turbine steadily processes 2 kg/s of steam at 5 MPa and 450°C, which is exhausted at 100 kPa and 100°C. The turbine exhibits an isentropic efficiency of 0.85 a) Draw a schematic representation of the system with all the energy interactions involved. (2pts) b) Determine the h (kJ/kg) and s (kJ/kg-K) at the inlet. (2 pts) c) Determine the actual h (kJ/kg) and s (kJ/kg-K) at the exit. (2 pts) d) Determine the h (kJ/kg) and s (kJ/kg-K) at the exit for the isentropic process. (3 pts) e) For the control volume, write an entropy balance in a rate form including the entropy generated and entropy transfer. (3 pts) f) Determine the entropy generated through the process, in kW/K. (3 pts) g) Plot the process on a T-s diagram for both the ideal and actual turbines. (3 pts)

Answer 1

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