轴流压气机静子角区分离流动的DDES数值研究

为进一步加深对压气机静子角区分离流动非定常性和湍流特性的认识,以某台用于低速模拟的多级低速轴流压气机的第3级改型静子为研究对象,采用延迟脱落涡模拟(DDES)方法进行详细的数值研究。结果表明:压气机静子角区分离流动受到叶片几何参数和来流条件的综合影响;通道涡是引起静子角区分离的主要涡系结构,其发展过程伴随着大小尺度发簪涡的交替出现;通道涡、发簪涡和尾迹脱落涡的相互作用是引起静子角区分离流动非定常性的主要来源;静子角区存在高度各向异性和能量反传的湍流特征;角区分离区的频率幅值强于主流区,振幅较大的区域位于500 Hz以下的低频区。 

Investigation of corner separation in axial compressor stator using DDES

In order to investigate the unsteady behavior and turbulence characteristics of corner separation, the delayed detached-eddy simulation (DDES) method was performed on a modified third-stage stator of a multistage low-speed axial compressor, which was used for low-speed model testing of a rear stage embedded in a modern high-pressure compressor.The results showed that the corner separation in the compressor stator was influenced by the geometric parameters of blade and the inlet flow conditions.Passage vortex as the main vortex structure caused stator corner separation, and the development of passage vortex was accompanied by the alternations of large and small hairpin vortices.The interaction among passage vortex, hairpin vortex and wake vortex was the main source of the unsteadiness of the corner separation flow.Turbulence anisotropy and energy backscatter were found in the corner separation region.The frequency amplitude of the separation region was stronger than that of the mainstream region, and the region with large amplitude was located in the low-frequency region below 500 Hz.