通道前缘小叶片对轴流压气机叶栅气动性能的影响研究

Effects of Little Blades at Leading Edge of Passage on Axial Compressor Cascade Aerodynamic Performance

关键词:  压气机  叶栅  翼刀  涡流发生器  角区分离  气动性能  失速

Key words:  Compressor  Cascade  Fence  Vortex generator  Corner separation  Aerodynamic performance  Stall

摘要:

为了更好地控制压气机静叶角区分离，结合翼刀和涡流发生器的流动控制思想，提出一种在通道前缘端壁处设置小叶片的新型流动控制方法。以某高负荷轴流压气机叶栅为研究对象，基于数值方法深入分析了不同周向位置和安装角的小叶片对流场的影响。结果表明：小叶片存在提升叶栅气动性能的最佳周向位置和安装角范围。在近失速工况附近，小叶片可减缓角区分离，提高全叶高的扩压能力，但会不可避免地增加中间叶高位置处的流动分离和气动载荷；小叶片可减少角区分离损失和尾迹损失，提高各流向位置处的静压系数；小叶片能阻碍马蹄涡压力面分支发展，减缓叶栅前缘附近的横向二次流动；从小叶片叶顶泄漏的诱导涡可将马蹄涡压力面分支推向流向，带走端壁和角区附近的低能流体，从而削弱通道涡强度。

Abstract:

To control the corner separation of compressor stator blades better， a new flow control method with little blades at the end wall of the leading edge of the passage were proposed， which combined the flow control idea of the end wall fence and the vortex generator. Taking a high-load axial compressor cascade as the research object， the influence of the little blades with different pitchwise positions and stagger angles on the flow field were analyzed in depth based on numerical methods. The results show that the little blades have the best pitchwise position and stagger angle range to improve the aerodynamic performance of the cascade. At the near stall condition， the little blades can alleviate corner separation and improve the diffuser capacity of the whole span， but inevitably increase the flow separation and the aerodynamic load near the middle of span. The little blades can reduce the corner separation loss and wake loss， and increase the static pressure coefficient at each axial cross section. The little blades can prevent the development of the pressure surface branch of horseshoe vortices and alleviate the cross secondary flow near the leading edge of the cascade. The induced vortices leaked from the tip of the little blades can push the pressure surface branch of horseshoe vortices toward the streamwise， take away the low-energy fluid near the end wall and corner area， thus weakening the strength of the passage vortices.