APPLIED THERMODYNAMICS (SKMM 2423)

TEST 2 (Sem 1 2016/2017)

06/11/2016

(9:00 am – 10:00 am)

ANSWER THE QUESTIONS

Question 1 (5 marks)

a) What is the function of air compressor?

b) List two types of positive displacement air compressor and describe three different comparisons

between them.

Question 2 (10 marks)

A single-stage, single-acting air compressor operates at 1000 rpm delivering air at 25 bar. Conditions at the

entrance and during induction are assumed the same at 1.013 bar and 15°C, and the free air delivery (FAD) is

0.25 m3/min. The clearance volume is equivalent to 3% of swept volume and the stroke/bore ratio is 1.2/1. Index

of compression and expansion is 1.3.

a) Sketch and label the pressure-volume (P-V) diagram.

b) Calculate the size of cylinder bore and stroke, [m].

c) Calculate the volumetric efficiency, [%].

d) Determine the indicated power, [kW].

e) Calculate the isothermal efficiency, [%].

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