A high pressure axial compressor for a jet engine rotates at 15000 rpm with an overall stagnation pressure ratio of 8.5. The mass flow rate of air through the compressor is 16kg/s^-1 and the stagnation conditions at inlet are 200 kPa and 450K. The polytropic efficiency is 91%.
(a)If the mean radius is .24m and this is constant throughout the compressor, calculate the total-to-total isentropic efficiency of the compressor and show that, for the stage loading to be less than .4 in all stages, eight stages are required.
(b) The compressor is designed with repeating stages and zero inlet swirl. If the inlet axial Mach number is .52, calculate the mean flow coefficient and sketch the velocity triangles for one stage. Show that the blade height at exit from the compressor is about 7.8mm.