Reynolds Number Effects in Cascades and Axial Flow Compressors

Abstract

A series of tests on guide vane and compressor cascades is reported. The Reynolds number was varied in the guide vane cascade tests, and the Reynolds number and the cascade aspect ratio were varied in the compressor cascade tests. The substantial laminar separation observed in the compressor cascades at high aspect ratio (and low Reynolds number) was suppressed in the cascade tests at low aspect ratio, 2:1. Effects of Reynolds number variation on the performance of a single stage axial flow compressor are also given, and compared with predictions of performance using the cascade tests. Calculations of laminar separation points agree quite well with the experimental observations. It appears that transition due to laminar boundary layer instability is unlikely to occur on compressor blades, in the normal operating range of Reynolds number.