不同转速下叶尖间隙流对跨声速压气机失速的影响

Effects of Tip Leakage Flow on Transonic Compressor

关键词:  跨声速压气机  换算转速  叶尖间隙  泄漏涡  失速机制

Key words:  Transonic compressor  Corrected rotation speed  Tip clearance  Leakage vortex  Instability mechanism

摘要:

为了研究不同换算转速下叶尖间隙流对转子失速的影响，对不同工况下叶尖间隙流动的特点进行了分析，讨论了压气机转子叶顶两个低速区的形成机理，以及该转子在多种换算转速下的失速机制。研究表明，转子失速是近压力面前缘和吸力面尾缘两个低速堵塞区共同作用的结果。二者的形成都与泄漏涡关系密切，前者是泄漏涡受激波干扰破裂而形成，后者是吸力面气流在泄漏流、吸力面二次流以及激波相互作用下而形成。不同换算转速下压气机失速机制不尽相同:在70% ~ 100%换算转速，压气机叶顶失速主要是由于叶尖泄漏涡与激波相互作用而破裂；在115%换算转速，失速的主要触发因素为径向涡导致吸力面附面层低速气流向叶顶堆积。

Abstract:

In order to study the effects of tip leakage flow on compressor instability at different corrected rotation speed，the feature of tip clearance flow in different working condition was simulated to analyze how the two low-speed areas in tip clearance develop，and the instability mechanism of the rotor in different corrected rotation speed. The results show that the instability of rotor is caused by two low-speed areas near leading edge of PS and the trailing edge of SS respectively，which are both influenced by leakage vortex. The former is developed because of leakage vortex breakdown caused by shock wave，while the latter is formed by the combined action of leakage vortex，span-wise underflow and shock wave. The instability mechanism in different corrected rotation speed varies from each other: breakdown of leakage vortex is the major triggering factor of compressor’s instability at 70% ~ 100% corrected rotation speed，while the congeries of low-speed flow in boundary layer caused by span-wise underflow is the major triggering factor at 115% corrected rotation speed.