Effect of Diffuser Vane Height and Position on Diffuser Wall Static Pressures in a Centrifugal Compressor

Abstract

The present paper reports experimental investigations on the effect of diffuser vane height and its position on diffuser wall static pressures of a low speed centrifugal compressor. Apart from the standard types of diffusers, namely, vaneless, vane and low solidity vane diffusers, a partial vane diffuser, whose height is less than the diffuser width is also tested. The vane height of the partial vane diffuser is varied from 0.3, 0.4 and 0.5 times the diffuser width in vane and low solidity vane diffuser configurations. In addition, the effect of vane position is examined by fixing the partial vanes to the hub, shroud or hub and shroud. It is found that there is an optimum height for the diffuser vane height, which is found to be 0.3 times the diffuser width. The effect of position of the partial vanes on the hub or shroud on the diffuser wall static pressures is found to be negligible. However when partial vanes are fixed on the hub and shroud staggered at half spacing, the diffuser performance based on wall static pressures is improved substantially.