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Q2. Air enters an open cycle gas turbine at an atmospheric temperature and pressure of 15℃ and 1.013 bar respectively. The compressor operates on a pressure ratio of 8.5: 1 with isentropic efficiency of 0.78.

The temperature of gas leaving the combustion chamber is 925℃ and it expands through the turbine to the atmosphere with an isentropic efficiency of 0.83. The net power output of the plant is 1800 kW.

The mass flow of fuel may be ignored.

(a) Sketch The cycle on a Temperature-specific entropy diagram. (2)

(b) Calculate EACH of the following:

(i) The temperature at the end of compression; (3)

(ii) The temperature at the end of expansion; (3)

(iii) The mass flow rate of air through the plant; (3)

(iv) Thermal efficiency; (3)

(v) The work ratio. (2)

Note: for air cp=1.005 kJ⁄(kg K) and cv=0.718 kJ⁄(kg K) .