Comparative analysis of turbulence model influence in numerical simulation of an experimental radial compressor stage

Abstract

The accuracy of a CFD model of a turbo-machine might depend on a number of factors: turbulence model, quality of the mesh model, boundary conditions, solver settings, consideration of secondary geometric factors, etc. The purpose of this work is to develop practical recommendations for CFD calculations of centrifugal compressors based on the validation of a model of NASA High Efficiency Centrifugal Compressor experimental radial compressor stage. Results of a grid independence test are presented, and the optimal grid size for the High Efficiency Centrifugal Compressor stage is identified as comprising 3 million elements. CFD-calculations of an experimental stage were performed with different turbulence models. The obtained data was compared with the NASA experimental data considering integral (total pressure ratio, mass flow rate, adiabatic efficiency) and differential parameters (static pressure distribution downstream the vaned diffuser). The required CFD computational time for different turbulence models was calculated. Based on the results of this research, recommendations were formulated for the application of SST, k–ε, BSL EARSM and GEKO turbulence models for numerical modeling of centrifugal compressors.