高负荷氦气压气机矩形叶栅流动分离特性

Flow separation characteristics of rectangular cascade for a highly-loaded helium compressor

针对高负荷氦气压气机叶栅流动分离问题,以某高负荷氦气矩形叶栅为研究对象,采用SST湍流模型加γ-Reθ转捩模型进行了数值模拟。分析了不同负荷、弯角及弯高的高负荷氦气压气机矩形叶栅的流动分离结构和特性。研究结果表明,马蹄涡压力面分支是矩形叶栅角区集中脱落涡和壁角涡形成的主要原因;随着攻角和负荷的增加,叶栅吸力面的分离形式由开式分离向闭式分离转化;而采用恰当的弯高和弯角可以有效抑制流动分离,改善高负荷氦气压气机端部流动状况,减小流动损失。

Flow separation has great influence on high-loaded helium compressors. In this paper,high-loaded helium compressor rectangular cascades with different loads,bowed angles and bowed heights were studied to understand the flow separation structure in the cascades. The SST turbulence model and γ-Reθtransition model were used in numerical simulation. The results showed that the pressure-side leg of horseshoe vortex results in the generation of concentrated shed vortex and corner vortex at the corner of the rectangular cascade. Open separated flow will transform into closed separated flow with the increase of attack angles and loads. Flow separation will be suppressed in the cascade as well as the pressure loss will drop by using proper bowed angle and height.