雷诺数对跨声速压气机转子内部流动失稳触发机理的影响

Effects of Reynolds Number on the Instability InceptionMechanism of a Transonic Compressor

关键词:  低雷诺数  径向迁移  间隙泄漏流  低能流体

Key words:  Low Reynolds number  Radial movement  Tip leakage flow  Low-energy flow

摘要:

利用带有先进转捩模型的数值模拟方法,对高低两种雷诺数下的跨声速压气机转子NASA Rotor67的内部流动进行了数值模拟。对比了不同雷诺数下叶片内部复杂三维流动,剖析了雷诺数影响风扇转子流动失稳的机制。研究发现:雷诺数降低使得叶片表面低能流体增多,径向迁移加剧,造成叶片顶部吸力面分离加剧；且雷诺数降低使得叶顶间隙泄漏流强度减弱,间隙泄漏流和主流相互作用造成的叶片顶部流场堵塞减弱。雷诺数通过上述两种作用影响压气机转子的失稳机制。 

Abstract:

By using the advanced transition model, the inflow was simulated for NASA Rotor67 both at high Reynolds number and low Reynolds number. Detailed analysis of the flow visualization exposed the different flow topologies of the complicated secondary flow. It is found that the Rotor 67 is prone to tip stall behavior. The tip section flow field is controlled by two low momentum zones. One is generated by the interaction of the tip leakage flow and incoming flow and the other one is attributed to the suction surface flow separation. When the Reynolds number is reduced, the core leakage flow is weaken. Thereafter,its influence on the tip section flow is reduced. The rear zone of low-energy fluid is dominant in the tip section flow field.Thus,decreasing Reynolds number changes the dominant factor affecting the tip section flow field. 