Computational model for stall inception and nonlinear evolution in axial flow compressors

This paper presents a computational model for axial compressor stall inception and its nonlinear evolution using unsteady Reynolds-averaged Navier - Stokes equations as an initial boundary value problem. The initial disturbance with the most unstable mode is obtained by a stall inception eigenvalue approach. To validate this computational model, several unsteady inlet boundary conditions with different frequencies are used as initial perturbations for full-annulus unsteady simulations of a transonic compressor rotor flow. Results reveal that the disturbance with the frequency near the most unstable mode can stimulate the objective rotating stall behavior, whereas the disturbances with the frequencies further away from the former cannot. The flow mechanism of rotating stall in a typical stalled case is also analyzed. It is found that severe tip clearance spillage and backflow form the stall inception disturbance, accompanied by a typical spike-type precursor. Based on comparison and analysis for different simulation examples, the present computational model provides a fast and reliable route to implement nonlinear simulation of compressor rotating stall.