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Q8. A three stage single acting reciprocating compressor is designed for minimum work with perfect intercooling.

The inlet pressure and temperature are 1 bar and 17℃ respectively and the discharge pressure is 64 bar.

In all stages, the polytropic index of expansion and compression is 1.3 and the clearance ratio is 0.05.

The low-pressure cylinder bore is 250 mm and the stroke is 300 mm.

(a) Calculate EACH of the following:

(i) The interstage pressure;(2)

(ii) The induced volume in litres per revolution;(3)

(iii) The indicated work;(3)

(iv) The heat removed in the intercoolers. (5)

(b) Sketch the cycle on a Pressure- volume diagram showing the pressure and the work saved by intercooling.(3)

Note: for gas C_P = 0.5203  kJ⁄(kg K), molecular mass M = 39.948  kg⁄kmol  .

The universal gas constant = 8.3145  kg⁄(kmol K)