Quantitative investigation of the turbulence model effect on high-pressure-ratio centrifugal compressor performance prediction.

The accuracy of centrifugal compressors performance and flow field prediction by Computational Fluid Dynamics (CFD) is a serious problem facing in the design and analysis process due to its complex flow feature inside. Different turbulence models choosing in the Reynolds-Averaged Navier-Stokes Equations (RANS) leads to different simulation results. In this paper, a high-pressure-ratio centrifugal compressor was used as the simulation object to discuss the effect of common turbulence models, including a one-equation model (Spalart-Allmaras model), a two-equation linear model (Shear Stress Transport model) and a two-equation nonlinear model (Explicit Algebraic RSM model), on performance prediction under design speed. By introducing the calculation method of local entropy generation rate, an improved method of dividing different types of loss in centrifugal compressors was proposed. After comparing with the experiment results, the effect of turbulence models on loss prediction inside the compressor was quantitative investigated. Further, the flow mechanism underlying was discussed. The results show that the secondary flow loss have the largest impact on the components' prediction performance, also, the reasons for different magnitudes of secondary flow loss inside the impeller and the diffuser are different. These comparisons hope to help designers choose an appropriate turbulence model in further compressor design process and may benefit future turbulence modelling development. • The predicted performance of SA, SST and EARSM models and the experimental results were compared. • An improved losses dividing method in centrifugal compressors was introduced. • Combining with the local entropy generation rate computation method, difference in predicted value of various types of loss under different turbulence models were quantitative analyzed. • The decisive role of secondary flow losses in performance prediction was revealed. • The different reasons for the different prediction of secondary flow loss in the impeller and diffuser were discussed linking to the flow mechanism respectively. [ABSTRACT FROM AUTHOR]