压气机叶栅角区分离中速度PDF双峰现象的DES数值模拟

Detached-Eddy Simulation of Velocity PDF Bimodal Phenomenon of Corner Separation in Linear Compressor Cascades

关键词:  双峰现象  角区分离  脱体涡模拟  混合高斯分布  相关性分析

Key words:  Bimodal phenomenon  Corner separation  Detached-eddy simulation  Gaussian mixture distribution  Correlation analysis

摘要:

为了研究在实验中发现的角区分离区域内速度概率密度分布(PDF)双峰现象并探索其机理，利用脱体涡模拟(DES)对压气机叶栅中角区分离流动进行数值模拟，成功模拟出双峰现象，并讨论了双峰现象的可能机理。DES模拟结果中，双峰点位置以及内外峰随双峰点位置变化而此消彼长的发展趋势与实验结果一致。对来流攻角脉动特性的分析表明，角区分离中双峰现象与叶栅前缘附近非定常来流和角区内分离流动的相互作用有关。

Abstract:

To study the velocity probability density distribution (PDF) bimodal phenomenon of corner separation in linear compressor cascade which was found in experiment and investigate its mechanism， Detached-eddy simulation (DES) is used to simulate the corner separation flow field. DES successfully captures the locations and development of bimodal points in the linear compressor cascade that have been found in previous experiment. And the evolution trend of bimodal PDFcorresponding to the location change of bimodal points is same with the experimental results. From the analysis of instantaneous flow field， it can be inferred that bimodal phenomenon in corner separation is induced by the interaction between high unsteady incoming flow just upstream blade leading edge and high unsteady separation flow in corner region.