An axial-flow compressor employed in gas turbine plant delivers air at the rate of 300 kg/s and develops total pressure ratio of 20. The inlet stagnation conditions are 300K and 1 bar. The isentropic efficiency of the compressor is 87%. The compressor is having 18 stages and the blade speed is kept at 200 m/s to minimize noise generation. The stage degree of reaction at the mean blade height is 50%. The axial velocity of flow is 160 m/s. The work done factor is 0.88. The hub-tip diameter ratio is 0.8. Assume actual temperature rise in each stage. Take R = 0.287kJ/kg-K and CP = 1.005 kJ/kg-K. Work out the following:
(i) Sketch the system, show the process on T-s diagram and draw velocity diagrams
(ii) All the fluid angles of the first stage
(iii) The hub and tip diameters including blade height
(iv) State the reasons why the pressure rise per stage in axial flow compressor is less than that of cengtrifugal compressor.