Performance and Flow Regime of Annular Diffusers With Axial Turbomachine Discharge Inlet Conditions

Abstract

An experimental investigation of the flow regime and the performance of straight-core annular diffusers operating immediately downstream of an axial compressor was carried out. Features of the compressor’s discharge including the size of the blade wakes, the streamwise relative turbulence intensity and the periodic streamwise component of velocity induced by the rotor blades were studied. The periodic streamwise velocity component was found to be quite small and it decayed as the flow proceeded through the diffusers. The relative turbulence intensities were comparatively large and increased along the diffusers. The statistical distribution of the stall periods for the diffuser with transitory stall had characteristics similar to those found for two-dimensional diffusers.