针对空天发动机压气机内流的改进 SA 湍流模型研究

To address the accuracy problems of standard SA (Spalart-Allmaras) turbulence model when predicting complex rotating flows in aviation compressors，how the SA-helicity modified turbulence model performed in rotating flows was analyzed. It showed how the helicity correction helped compensate for strain rate through eddy viscosity mechanisms，leading to better predictions of corner separation and tip leakage flow while maintaining good boundary layer accuracy. Three turbulence models: standard SA，SA-helicity，and SA-QCR (quadratic constitutive relation)，were tested，using NASA Rotor 67，a 3.5-stage axial compressor，and a publicly released high-load single-stage axial compressor from AECC Shenyang Engine Research Institute. Their performance at different rotational speeds was analyzed by focusing on performance characteristic curves， tip stall prediction， secondary flow prediction， and near-stall point prediction. Results showed that both the SA-helicity and SA-QCR models accurately predicted the trends of the characteristic curves. The SA-helicity model increased eddy viscosity in the corner separation region under adverse pressure gradients， thereby suppressing excessive corner separation. It also reasonably predicted the channel secondary flow induced by root separation，leading to an increased pressure ratio in the lower half of the blade. Compared with the QCR model， the helicity model better predicted the development and extent of tip leakage flow，significantly expanding the flow range，pressure ratio and efficiency，and showing better agreement with experimental results. Furthermore，the boundary layer flow predicted by the helicity model resisted adverse pressure gradients better，resulting in separation bubble reattaching earlier，thereby enhancing diffusion capability near the tip region and expanding the pressure ratio and flow range. Overall，the SA-helicity model overcame the limitations of traditional turbulence models in predicting how rotating secondary flows interacted with main flows in complex compressor environments.