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Q8. A single stage single acting reciprocating air compressor has a bore of 250 mm and stroke of 400 mm. The inlet pressure and temperature are 95  and 30°C respectively, the delivery pressure is 950 .

The compressor has a volumetric efficiency of 82.5% at a speed of 300 rev/min.

The polytropic index of expansion and compression is 1.28.

The mechanical efficiency of the drive train is 90%.

(a) Sketch the cycle on a Pressure-volume diagram identifying the volumes. (3)

(b) Calculate EACH of the following:

(i) The clearance ratio;(3)

(ii) The compressor input power;(4)

(iii) The rate of heat rejection during the compression process.(6)

Note: for air γ = 1.4