Periodically Unsteady Flow in an Imbedded Stage of a Multistage, Axial-Flow Turbomachine

Abstract

A periodic-average flow measurement technique involving a hot-wire sensor was used to measure the periodically unsteady velocity field in the first stage of a low-speed, multistage, axial-flow research compressor. In portions of the compressor annulus, the periodic-average velocity patterns for imbedded rotor and stator exit flows showed appreciable sequential variation with the systematically changed data sampling position of the rotor blades. Representative examples of periodic-average flow field variation with rotor blade sampling position in stop-action sequence are shown for various locations in the compressor. A simple, first-order approximation physical description of blade wake flow transport and interaction based on experimental data interpretation is proposed to organize and thus help understand the data obtained.