Loss and Stall Analysis of Compressor Cascades

Abstract

A simple equation expressing the wake momentum thickness as a primary function of the suction-surface diffusion ratio (ratio of maximum surface velocity to outlet velocity) of coaventional low-speed cascade blades is derived from boundary-layer theory in conjunction with simplifying approximations. The derived equation is utilized to gain an insight into qualitative effects on stalling diffusion ratio of such factors as Reynolds number, transition location, and extent of local laminar separation. Use of parameters suggested by the analysis is shown to result in generalized experimental loss and stall correlations and in means for estimating total-pressure loss and unstalled range of operation for commonly used blades.