Flow Measurements in the Passages of Different Types of Diffusers of a Centrifugal Compressor at Off Design Conditions

Abstract

Flow measurements in the passages of different types of diffusers of a centrifugal compressor at off design flow coefficients are presented and compared with those at design flow coefficient in this paper. The measurements are carried out using a precalibrated three hole pressure probe. The measurements are carried out in the passages of the following diffusers: vaneless, vane, low solidity vane and partial vane diffusers. The results are presented as contours, axially averaged and mass averaged flow parameters. The partial vane diffuser shows slightly improved flow field. At the above design flow coefficient, both vane and low solidity vane diffusers suffer large losses due to high incidences causing large drop in static pressure.