周向槽调控轴流压气机非定常间隙泄漏流机理初探

Exploring the manipulation of the tip clearance flow's unsteadiness via circumferential groove

以某压气机转子为载体,针对其顶部间隙泄漏流的非定常特性,设计了一种周向槽处理机匣,利用数值模拟的方法研究了其对压气机转子性能及顶部非定常间隙泄漏流动特性的影响,结果表明:该处理机匣的引入能够在不恶化压气机性能的前提下使得其流量裕度提高约6.5%。与实壁机匣结构相比,周向槽处理机匣减小了间隙泄漏流轴向动量,抑制了叶顶间隙泄漏流非定常性的出现,从而提高了压气机的稳定工作裕度。

The use of slots and grooves in the shroud over the tips of compressor blades,known as casing treatment,is a powerful method to control tip leakage flow through the gap and enhance the flow stability in compressors.This paper presents a contribution to the understanding of the physical mechanism by which circumferential groove casing treatment manipulates the tip clearance flow＇s unsteadiness.A series of computational studies were carried out to understand the physical mechanism responsible for improvement in stall margin of a high subsonic axial-flow compressor rotor due to the circumferential groove casing treatment from an unsteady viewpoint.Detailed analyses of the flow visualization at the tip have exposed the different tip flow topologies between the cases with circumferential groove and with untreated smooth wall.It was found that the primary stall margin enhancement afforded by the circumferential groove casing treatment is a result of the unsteady tip clearance flow manipulation.