Vane Clocking Effects on Stator Loss for Different Compressor Loading Conditions

摘要

Vane clocking is the relative circumferential indexing of adjacent vane rows with similar vane counts, and it affects discrete frequency noise, forced response, and stage performance in axial compressors. The objective of this paper is to investigate vane clocking effects on stator 2 loss for many loading conditions in a three-stage axial compressor. Although previous studies have focused on two or three operating conditions, this is the first to investigate vane clocking effects over many loading conditions. Detailed circumferential traverses of stagnation pressure were acquired for six clocking configurations at six different loading conditions: a low-loading condition, two conditions near design point, two high-loading conditions, and a near-stall condition. Stator 2 wake widths and depths were similar for different clocking configurations at low loadings, but the high-loading cases exhibited larger changes associated with vane clocking, especially near the stator hub. This resulted in different radial total pressure profile shapes for different clocking configurations that, coupled with flow visualization, showed that vane clocking modulates the hub corner separation for the high-loading operating condition. For design-loading and low-loading conditions, the differences in area-averaged stator 2 loss coefficients with vane clocking were small, but changes in loss increased at the high-loading condition and resulted in a 20.6% difference in loss coefficient between the minimum and maximum clocking cases, with local changes near the hub as much as 46.6%. The effect of clocking on vane loss lessened as the stall boundary was approached.