In the present work, the location effect of single grooved casing treatment (CT) on the compressor performance and flow stability are numerically studied at a large tip clearance in a two-stage counter-rotating axial flow compressor. The results show that the first stall stage is changed from the rear rotor (R2) to the front rotor (R1) as the tip clearance is increased from the normal design tip clearance (τ) to a large tip clearance of 2τ. The compressor stability can only be improved by the CT schemes in R1 without obvious change of compressor efficiency, while the compressor efficiency at near stall point can be increased remarkably for the effective CT configurations in R2 without stall margin improvement (SMI). The stall inception type may be changed for the least effective CT configuration in R1 due to the drastic change of flow structure of the tip leakage flow (TLF) released from near the blade leading edge. Detailed analysis of TLF structure shows that it is advisable to improve the compressor flow stability by controlling the TLF part which is released from the blade chord range away from the blade leading edge. After the application of effective CT schemes, the tip flow field is improved in the corresponding rotor and the interface is pushed further downwards to a different extent resulting in the reduction of the TLF intensity and loss generation.

在目前的工作中，在两级反向旋转轴流式压缩机的大叶尖间隙处，对单槽套管处理（CT）对压缩机性能和流动稳定性的位置影响进行了数值研究。结果表明，在第一失速阶段从后转子（R2）改变到前转子（R1）为顶间隙从正常设计顶端间隙（增加的τ）至2的一个大顶端间隙τ。只有通过R1中的CT方案才能改善压缩机稳定性，而不会明显改变压缩机效率，而对于R2中的有效CT配置，无需失速裕度（SMI），就可以显着提高接近失速点的压缩机效率。由于在叶片前缘附近释放的叶尖泄漏流（TLF）的流动结构发生了急剧变化，因此对于R1中最无效的CT配置，可以将失速开始类型更改为。对TLF结构的详细分析表明，建议通过控制从叶片翼弦范围远离叶片前缘释放的TLF部分来提高压缩机的流量稳定性。应用有效的CT方案后，