A helicopter gas turbine requires an overall compressor P.R. of 10:1. This is to be obtained using a two-spool layout consisting of a 4 stage axial compressor followed by a single-stage centrifugal compressor. The polytropic efficiency of the axial compressor is 92% and hat of the contrifugal is 83%
Assuming an axial velocity at the eye of the impeller, an impeller tip diameter of 33cm, a slip factor of 0.90 and a power input factor of 1.04, calculate the rotational speed required fo the centrifugal compressor. Ambient conditions are 1.01 and 288K.