带周向单槽的低速轴流压气机失速起始过程

为了深入认识周向槽轴向位置对压气机失速机制的影响规律,针对某叶尖敏感的低速单转子压气机开展实验测量与数值模拟相结合的研究。实验与计算结果均表明,位于叶片弦长中部的周向单槽扩稳效果最好,而位于叶片前缘下游20%~30%轴向弦长位置的周向单槽扩稳效果最差。进一步分析了利用非定常、多通道计算模型获得的数值结果,发现对于光壁机匣和扩稳效果最好的周向单槽机匣,泄漏流与主流交界面在近失速工况下到达叶片前缘位置,压气机通过突尖型失速先兆进入失速状态;对于扩稳效果最差的周向单槽机匣,泄漏流与主流交界面在近失速工况下仍位于叶片通道内部距离叶片前缘20%的轴向弦长位置,压气机经历了由准模态型失速先兆向突尖型失速先兆转换的失速起始过程。

Prestall process in low-speed axial compressor with single circumferential casing groove

In order to further understand the impact of circumferential casing groove axial location on stall mechanism of compressor, a tip sensitive low-speed single rotor is tested and numerically simulated. The results show that the location with the maximum stall margin improvement (SMI) is near the mid-chord of blade tip and the location with the minimal SMI is around 20%-30% axial tip chord aft of blade leading edge. Numerical results are acquired from an unsteady multi-passage numerical scheme. For smooth casing and the optimal groove, the interface between the tip leakage flow and main flow reaches blade leading edge under the near stall condition and spike stall inception appears; but for the worst groove, the interface is away from blade leading edge under the near stall condition, around 20% axial tip chord aft of blade leading edge, and a conversion between quasi-modal stall inception and spike stall inception is captured.