Experimental investigation of Stator hub treatment in an axial flow compressor

Abstract

An experiment was carried out to examine the effects, on stator stall margin and performance, of a slotted hub treatment rotating beneath the stator of an axial flow compressor. The compressor was run with this hub treatment and the results compared to those taken with a smooth rotating hub. It was determined that, for the configuration tested, the hub treatment was ineffective in the improvement of stall margin but resulted in a measurably higher static pressure rise across the stator and a significant decrease in flow deviation and blockage in the stator midspan region. Although it is the hub section of the stator that sets the stall limit in this configuration, measurements of the stator exit flow field indicated that the type of stall that is occurring is a blade stall rather than a pure wall stall. Absence of a wall stall is thus seen as a key possibility for the lack of stall margin improvement.