On the Impact of the Turbulence Model on the Secondary Flow Structure of a Highly-Loaded Compressor Stage

Abstract

RANS turbulence models still represent a weak point of industrial simulations of turbomachinery flows. In presence of a large blade loading the turbulence model can impact severely on the prediction of the end-wall flow and secondary structures in the blade passage, with an important effect on the computed global performance and flow stability. This paper presents a turbulence model comparison for the characterization of a highly-loaded low-pressure compressor at multiple operating points using 3D RANS simulations. The turbulence models mostly employed for the design and analysis of axial compressors are considered, with the aim of providing a clear physical description of their impact on the critical flow features of the machine. It will be shown that no single turbulence model is generally better than others and the prediction depends on the operating point, with increasing discrepancies as the mass-flow is reduced.