An Investigation of Rotating Stall Phenomena in Turbine Engine Compressors

摘要

The work encompasses both theoretical and experimental studies of rotating stall and an investigation of the requirements for a stall control system. The theoretical studies approached the problem primarily from the point of view that rotating stall is the consequence of an instability of the mean flow to small disturbances. Both two-dimensional flows and a certain class of three-dimensional flows with wheel-type swirl were studied. In addition, numerical experiments were performed with a computer program for a two-dimensional cascade of discrete flat plate blades. Of the theoretical models, only the two-dimensional small disturbance approach exhibited an instability which might lead to rotating stall. The experimental program was performed to provide fundamental data prior to and during rotating stall for comparison with theory and for use as a guide in improving the theoretical model. Extensive investigations of the conditions for inception and the properties of rotating stall were performed on a row of stator blades in an annular cascade. The effects of blade profile shape, blade stagger angle and blade row spacing were studied in the cascade. In addition, several methods for detecting unsteady pressures were studied to determine their suitability as a generator of a rotating stall signature which could be used in a closed loop control system. It was found that a pressure tap located on the suction surface of a stator blade near the quarter-chord showed promise of providing a satisfactory signal. (Author)