Steam enters a turbine at 120 bars and 440C and expands to 1 bar. At the...

 

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Steam enters a turbine at 120 bars and 440°C and expands to 1 bar. At the exit the entropy is 0.650 kJ/kg K greater than at the inlet. The process is adiabatic and changes in kinetic and potential energies may be neglected. a. Determine the work done by the steam, in kJ/kg. b. Now, for the same initial conditions and the same final pressure the turbine is run without insulation. It is found that the entropy increase of the steam is now 0.600 kJ/kg · K, and that the heat transfer from the steam occurs to the environment, which is at 300 K. The entropy change of the environment is 0.0850 kJ/K per kilogram of steam. Determine the heat transfer and the work output for the steam turbine under these new conditions, in kJ/kg. Steam enters a turbine at 120 bars and 440°C and expands to 1 bar. At the exit the entropy is 0.650 kJ/kg K greater than at the inlet. The process is adiabatic and changes in kinetic and potential energies may be neglected. a. Determine the work done by the steam, in kJ/kg. b. Now, for the same initial conditions and the same final pressure the turbine is run without insulation. It is found that the entropy increase of the steam is now 0.600 kJ/kg · K, and that the heat transfer from the steam occurs to the environment, which is at 300 K. The entropy change of the environment is 0.0850 kJ/K per kilogram of steam. Determine the heat transfer and the work output for the steam turbine under these new conditions, in kJ/kg.