Numerical Study on the Performance of a Centrifugal Impeller With Self-Adaptive Casing Treatment

Abstract

The stall margin and choke margin of centrifugal compressor could be increased by using Self-Adaptive Casing Treatment (SACT). The previous numerical research mainly focuses on making parametric optimization rather than the selection of turbulence model and flow field analysis of the compressor with SACT. In this work, the 3D steady state simulations were carried out to obtain the performance and flow field of the Krain impeller with and without SACT by ANSYS-CFX. Four turbulence models including k-Epsilon turbulence model, RNG k-Epsilon turbulence model, Shear Stress Transport (SST) turbulence model and BSL Reynolds Stress (BSL) turbulence model were used to simulate the Krain impeller with a vaneless constant area diffuser. The numerical data were validated by the experimental data in reference. The results of this study showed that different turbulence models led to differences in performance predictions and flow field characteristics, and the overall performance and flow field features could be predicted more accurately by using SST turbulence model. The bypass flow and reinjected flow were respectively observed in the hole when the Krain impeller with SACT worked at large and small mass flow rate conditions. And the stable working range of the Krain impeller was expanded by using SACT. In addition, the development of the low-velocity fluid at the blade tip region was restrained with the application of SACT.