端壁倒圆对高负荷压气机叶栅性能及流场影响的机理探究

Mechanism Study of End-Wall Fillet’s Influence on Performance and Flow Field of High-Load Compressor Cascade

关键词:  压气机叶栅  端壁倒圆  数值模拟  角区流动  损失

Key words:  Compressor cascade  End-wall fillet  Numerical simulation  Corner flow  Loss

摘要:

为了改善压气机端壁区流动状况，减小流动损失，对一大尺度低速(不可压)压气机叶栅设计了五种倒圆结构。通过Numeca全三维数值方法进行模拟，结果表明，在原叶栅失速工况下，损失降低最多的达到了5.22%，但在设计工况下增加了1.12%。分析了此叶栅端壁区性能及流场改善的机理，给出了其余四种结构效果不佳的原因。对于效果最好的叶栅，倒圆的存在将失速因子降低了41.29%，使其能够适应更大的来流攻角范围。近端壁处吸力面的流动分离得到明显抑制，马蹄涡强度和逆流区减小，出口流动更加均匀，二次流能量显著减小，从而在整体上降低了损失，改善了角区流动。

Abstract:

For the purpose of improving compressor’s flow condition in end-wall region and reducing flow loss， five different fillet structures around blade root were designed on a large-scale low speed compressor cascade， which was investigated by full 3D numerical simulation of Numeca. Results show that the highest loss reduction reached up to 5.22% on original cascade’s stall condition， while the loss increased by 1.12% on design point. For the best case， the mechanism of improvement on performance and flow field was analyzed， and the reason that the other four structures made little promotion was given. With the fillet， the cascade reduced the stall factor by 41.29% and could adapt a larger range of incidence angle. The flow separation on suction side near the end-wall is evidently restrained and the strength of horse-shoe vortex and reverse flow region are diminished. Moreover， the outlet flow becomes more uniform and secondary flow energy decreased. Finally， both the total loss and the corner flow are significantly improved.