轴流压气机端壁失速的耦合扩稳方法及机理研究

The study was to investigate the method of stability enhancement to control effectively endwall stall in an axial flow compressor. The coupled design took advantage of slot-type casing treatment and tip injection, and the effects on compressor performance of slot length, location and angle were parametrically studied. The flow mechanism of stability improvement and the effect on compressor efficiency were analyzed for the ‘coupled casing treatment’ in the unsteady simulation. The results show that compressor stability margin is improved by 18% with a penalty of 0.21% on compressor efficiency at the design point, and the compressor efficiency is improved slightly at the operating conditions of lower mass flow rates. The slot length is the key to the compressor performance, and the maximum length should not exceed 50% of the axial chord length of the blade tip. The influence of the slot position and slot angle are limited. There are two types of flow circulation in the ‘coupled casing treatment’, i. e. the inner circulation in slots and the circulation from slots to injectors. The two circulations can depress effectively the tip leakage vortex and lower the blade tip loading, which mainly accounts for the stability enhancement. The interaction between the ‘coupled casing treatment’ and compressor is self-adaptive, which reduces its negative effect on the compressor efficiency at the design point and ensures the positive effect on the blade tip blockage. The coupling design of slots and injector has the potential to greatly increase the stall margin of compressor without penalty on compressor efficiency.