端壁抽吸位置对压气机叶栅角区分离控制的影响

Effect on corner separation control for high load compressor cascade with different end-wall BLS position

关键词:  压气机叶栅  角区分离  通道涡  端壁  附面层抽吸

Key words:  Compressor cascade  Corner separation  Passage vortex  End-wall  Boundary layer suction

摘要:

以某高负荷压气机叶栅为研究对象,应用数值模拟方法探索了叶栅端壁不同抽吸位置对角区流动结构、通道漩涡发展过程以及叶栅性能的影响规律,寻求控制角区分离的可行方法。研究结果表明:在叶栅前缘上游5%C(弦长)位置实施抽吸,延缓了通道涡的形成,但导致叶栅来流攻角发生改变,在角区形成角区分离涡,并且该漩涡与通道涡相互促进,进一步恶化叶栅流场,导致叶栅落后角增大,损失增加;在叶栅通道激波后25%C端壁抽吸,吸除了上游端壁积累的高熵低能气流,制约了通道涡的迅速发展,改善了叶栅通道的流场结构,降低了流动损失,但并未对上游流场产生较大影响,是一种可行的方案。然而25%C处抽吸后,未能完全消除分离,在端部与叶栅通道主流之间存在较高损失区域。

Abstract:

A high load compressor cascade with boundary layer suction(BLS) at end-wall has been investigated by numerical simulation to explore a better way to control the corner separation.The effects of two schemes of different BLS location to the cascade performance,flow structure of corner and passage vortex have been analyzed.The results show that when the suction slot is located 5% C(chord) upstream of leading edge,onset of the passage vortex is decayed due to the boundary layer suction.However,the inlet flow angle has been changed,which lead to separation vortex happening near the cascade corner.In addition,the interaction of the separation vortex and the passage vortex deteriorates the flow structure,which increases the deviation angle and the total pressure loss.When the suction slot is located at 25% C downstream of the cascade leading edge,BLS removes the higher entropy flow near the end-wall,which may restrict the development of passage vortex,ameliorate the flow structure of cascade passage and decrease the total pressure loss.Moreover,it does not affect the upstream flow field.However,there is a higher total pressure loss area between the cascade corner and main stream flow when the suction slot is located at 25% C because the separating flow near the corner is not eliminated absolutely.