Abstract: The experimental and numerical investigations of three kinds of circumferential grooved casing treatment(CT)were performed to explore the mechanism of affecting the ability of casing treatment of improving stall margin with changing axial position of circumferential grooves. The experimental and numerical results show that the CT of unchanging axial position has the best ability to improve stall margin among three kinds of CT，and the ability of CT with forward axial position is better than that of CT with backward axial position. The experimental stall margin improvement is 10.3%，7.82% and 5.65%，respectively. The detail analysis of flow-field in compressor tip indicates that the inlet blockage caused by the low energy tip clearance leakage flow appears near the leading edge of blade tip because there are not the positive effect made by grooves on leading edge of blade tip，when the CT moves backward along axial direction. Similarly，tip clearance leakage flow results in the outlet blockage due to the absence of the positive action of grooves near the tip blade tail when the CT moves forward along axial direction. The air flow status in blade tip is the best among three kinds of casing treatments when the axial position of casing treatment is unchanged，so the corresponding effect of improving stable operating range is optimal.

Key words: Axial-flow compressor；Casing treatment；Axial position；Clearance leakage flow；Blockage

摘要： 为了揭示周向槽机匣处理轴向位置影响压气机稳定性的流动机理，采用试验与数值方法研究了三种不同轴向位置对机匣处理扩稳能力的影响。试验与数值结果均表明机匣处理轴向位置不变时扩稳能力最强，轴向位置前移次之，轴向位置后移最弱，对应的试验综合裕度改进量分别为10.3%，7.82%及5.65%。通过详细分析压气机叶顶流场表明，周向槽机匣处理轴向位置后移使叶顶前缘区域没有受到到周向槽的作用，叶尖部分间隙泄漏流在叶顶前缘形成低速带并造成进口堵塞。轴向位置前移使叶顶后部区域没有受到周向槽的作用，在叶顶通道出口部分叶高范围内形成低速堵塞区，流通能力弱。轴向位置不变的机匣处理对应的叶顶通道流通能力最强，因此扩稳效果最好。

关键词: 轴流压气机；机匣处理；轴向位置；间隙泄漏流；堵塞；