Numerical study of near-stall flow feature on transonic compressor

Three-Dimensional full-annulus time-accurate numerical simulation of the NASA Rotor 37 flow at near-stall condition has been carried out for the purpose of exploring the evolution pattern and feasible detection method of spike-like rotating stall inception in the transonic axial flow compressor. Simulation results show that there is a stage when stalling perturbations grow slowly in approximately 2 revolutions before the first stall cell appears. The leading edge spillage, which eventually leads to the formation of stall cells, is actually the result of continuously decreased mass flow rate which appears at earlier moments. Static pressure signals from numerical probes located on the casing just upstream of the blade leading edge were processed and carefully studied by various methods. It is shown that a new cross-correlation method developed by the author shows better capability in the identification of pre-stall perturbations among the studied methods.