Aerodynamic characterization of a transonic axial flow compressor stage – with asymmetric tip clearance effects

Abstract

This manuscript discusses the performance of a single-stage transonic axial flow compressor with non-uniform/asymmetric rotor tip clearance. Detailed steady and unsteady experimental measurements are carried out for a compressor with non-uniform clearance over the rotor. Measurements are focused at the peak clearance region of the compressor annulus where stall inception is likely to occur. A sector-based steady-state CFD simulation is performed on the compressor stage with uniform averaged rotor running clearance obtained from the blade growth estimates at design speed using structural analysis. The role of the tip leakage vortex on the stall dynamics of the compressor is elucidated. The stall events/disturbances occurring at every two rotor revolutions are shown using hotwire measurements. Varied flow features of the transonic compressor stage are discussed for different compressor speeds investigated. The level of clearance eccentricity/asymmetry existing in this compressor due to its complex spread does not degrade the overall compressor performance behavior.