1. Applied Thermodynamics and Heat Engines
S.Y. B.Tech. (Production)
Assignment - III
1. Prove that the volumetric efficiency of a single-stage compressor is given by :
1/ n
P 
 vol  1 k _ k  2
P 
 …..k = Vc / Vs
 1 
2. A single-stage, single-acting air compressor running at 1000 rpm delivers air at 25 bar.
For this purpose, the induction and free air conditions can be taken as 1.013 bar and
15 °C, and the free air delivery as 0.25 m3/min. The clearance volume is 3 % of the swept
volume and the stroke / bore ratio is 1.2 : 1. Calculate the bore and stroke and the
volumetric efficiency of this machine. Take the compression and expansion as 1.3. Also
calculate the indicated power and the isothermal efficiency.
(ANS : bore = 73.2 mm, bore = 87.84 mm, ηvol = 67.6 %, I.P. = 2 kW, ηiso = 67.5 %)
3. Explain the working of an Intercooler. Explain the physical significance with help of P-V
diagram.
4. A single-acting two-stage compressor with complete intercooling delivers 10 kg/min of
air at 16 bar. The suction occurs at 1 bar and 15 °C. The compression and expansion
processes are reversible polytropic with index n = 1.25. Calculate :
(i) Power Required (iii) Thermal Eficiency
(ii) FAD (iv) Heat transferred in Intercooler.
(ANS : Power = 44.0 kW, FAD = 8.266 m3/min, ηth = 86.8 %, Qint = 15.41 kW)