间隙流触发压气机内部流动失稳机制及周向槽扩稳机理

利用高频响动态压力传感器对某低速轴流压气机转子的失速先兆和顶部流场进行了详细的测试,探明该压气机内部存在与叶顶间隙泄漏流相关的突发型失速先兆,对压气机转子内部流场进行了单通道定常和非定常数值模拟,详细分析了压气机内部流动失稳过程中顶部流场结构的变化,揭示顶部间隙泄漏流触发轴流压气机内部流动失稳机理.在此基础上,利用周向槽处理机匣结构对顶部间隙泄漏流进行控制,并探讨了周向槽处理机匣结构提高压气机稳定工作裕度机理.

Role of tip leakage flow on flow instability and its control with circumferential groove casing treatment

In order to provide a state-of-the-art understanding of the flow field in axial-flow compressor in the perspective of enhancing its stability by using passive means,the detailed tip flow structure and inception of rotating stall were measured in a subsonic compressor rotor with high response pressure transducers.The inception of spike-type rotating stall that correlated with the tip leakage vortex was detected in this compressor.The physical processes occurring when approaching stall and the role of complex tip flow mechanisms on flow instability in current subsonic compressors were assessed by using time-accurate single blade passage computations.Based on these observations,circumferential groove casing treatment was introduced to control the tip leakage flow;and the physical mechanism responsible for stall margin improvement attributed to circumferential groove casing treatment was explored.