Numerical Stall Inception Predictions for Axial Compressors Using a Hybrid RANS/KES Turbulence Model

Abstract

A hybrid RANS/KES (HRKES) turbulence model is used for the stall predictions in a transonic axial compressor stage. This HRKES model solves Menter’s k-ω-SST model near walls and switches to Kinetic Eddy Simulation (KES) model away from walls. The KES model solves directly for local turbulent kinetic energy and local turbulent length scales, thus alleviating the grid spacing dependency found in other Detached Eddy Simulation (DES) and Hybrid RANS/LES (HRLES) models. The current methodology is used in the prediction of the performance map and the stall inception for the NASA Stage 35 compressor configuration as a representative of a modern compressor stage. The present approach is found to satisfactory predict the onset of stall. It is found that the rotor blade tip leakage vortex and its interaction with the shock wave is the main reason behind the stall inception in this compressor stage.