Chapter 7, Problem 7.99P

Home work dulmalel An axial flow compressor having eight stages and with (50%) reaction design compresses air in the pressure ratio of 4:1. the enters the compressor at (200.C) and flows through it with a constant speed of (90 m/s). The rotating blades of compressor rotate with a mean speed of (180 m/s). isentropic efficiency of compressor may be taken as 82%. Calculate: (i) Work done by the machine (ii) Blades angles. If y=1.4. Cp=1.005 kj/kg K.

In an ammonia refrigerator , the pressure in the evaporator is 267. 58 KPa and theammonia at is 0.14 dry while at the exit is 0.86 dry . During compression the work done per kgof ammonia is 20 ,000 kg .m . Calculate volume of the vapor entering the compressor per minuteif the rate of ammonia circulation is 6.54 kg. The compressor has a volumetric efficiency of 90%and it runs at 150 rpm .The ratio of stroke to bore is 1 .Latent enthalpy of ammonia at basedon its evaporating pressure is 320 Kcal per kg and its latent specific volume of ammonia basedon its evaporating pressure is 0.436 m3 per kg .Specific volume of ammonia .A) 2.23 C) 2.46B) 3.23 D) 4.62

A four-stage single-acting air compressor running in an atmospheric at 87 kPa and 15°C has a F.A.D of 2.83 m³/min. The section pressure and temperature are 80 kPa and 32 °C respectively, the delivery pressure is to be 7 MPa. The temperature at the start of compression in each stage is 32 °C, take n=1.3  for all stages. calculate: 1. The intermidiate pressure ratio 2. The intermidiate pressure at first, second and third stages in kPa