Effects of k-ω shear stress transport turbulence model enhancements on axial compressor rotor performance and near-stall operation

Abstract

The three-dimensional (3D) Reynolds-Averaged Navier-Stokes (RANS) with turbulence viscosity modelling effectively brought Computational Fluid Dynamics (CFD) to everyone. The k −ω Shear Stress Transport (SST) turbulence model became particularly successful, providing robust solutions to various engineering problems. This paper presents a review of the SST model modifications’ effect on the flow structure in a transonic axial compressor rotor, with particular emphasis on the near-stall operation. The NASA Rotor 37 (R37) was used as test geometry. A range of meshes with increasing grid density was employed to validate the dependence on spatial discretisation. The results averaging methods were also evaluated. Following SST turbulence model enhancements were studied: Reattachment Modification (RM), increased shear stress limiter (a1), turbulence transition (γ −Reθ model), and the transition and RM combined. Furthermore, selected models were tested using isothermal wall treatment at the shroud casing. A wide range of results was discussed, from high-level compressor maps and spanwise parameters distribution to near-stall behaviour description dictated by the blockage, originating from the shockwave and tip leakage vortex interaction. Detailed investigation of the 3D flow field revealed that shear stress limiter (a1) reduction and RM combined with the γ −Reθ model provided the closest results to the experiment. Regardless of the turbulence closure method, casing heat transfer provided realistic spanwise temperature distribution. All of the CFD models are made available, allowing the reader to replicate the results easily.