A gas enters a turbine at an inlet state of 800 kPa. The gas expands and leaves the turbine at an outlet state of 100 kPa and 497 Celcius. The amount of heat transferred out from the turbine to the surrounding is 10 kJ/kg. The surrounding is at a temperature of 28 Celcius. The actual work output from the turbine is 484 kJ/kg. Properties of the gas: R = 0.287 kJ/kg.K; cp = 1.138 kJ/kg.K; cv = 0.851 kJ/kg.K; k = 1.337; i) Write the energy balance equation for the turbine and state your assumptions. ii) Determine the temperature of the gas at the turbine inlet, K. iii) Determine the entropy generation, sgen during the expansion process, kJ/kg.K.
A gas enters a turbine at an inlet state of 800 kPa. The gas expands and leaves the turbine at
an outlet state of 100 kPa and 497 Celcius. The amount of heat transferred out from the turbine to
the surrounding is 10 kJ/kg. The surrounding is at a temperature of 28 Celcius. The actual work
output from the turbine is 484 kJ/kg. Properties of the gas: R = 0.287 kJ/kg.K;
cp = 1.138 kJ/kg.K; cv = 0.851 kJ/kg.K; k = 1.337;
i) Write the energy balance equation for the turbine and state your assumptions.
ii) Determine the temperature of the gas at the turbine inlet, K.
iii) Determine the entropy generation, sgen during the expansion process, kJ/kg.K.
iv) Is the expansion process possible? Briefly explain your answer.
v) Determine the isentropic efficiency of the turbine, %.
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