进口畸变下缝式机匣处理改善轴流压气机性能的研究

Investigation of Performance Improvement for Axial Flow Compressor with Slots Casing Treatment with Inlet Distortion

关键词:  进口畸变  轴向倾斜缝机匣处理  轴流压气机  叶顶间隙泄漏流  气流分离

Key words:  Inlet distortion  Axial skewed slots casing treatment  Axial flow compressor  Tip clearance leakage flow  Flow separation

摘要:

为了研究进口畸变下缝式机匣处理改善轴流压气机性能的机理，以亚声速单级轴流压气机的孤立转子为研究对象，在53.4%设计转速下，采用10通道非定常的数值模拟方法，开展进口畸变下轴向倾斜缝机匣处理改善轴流压气机性能的机理研究。采取在进口径向延伸段中部沿周向设置栏杆的方式产生畸变。与进口均匀实体壁机匣相比，进口畸变实体壁机匣的失速裕度改进量和峰值效率改进量分别为-5.88%和-1.44%，而进口畸变带机匣处理的失速裕度改进量和峰值效率改进量分别为24.37%和-1.09%。进口均匀实体壁机匣时，压气机的失速类型为典型的突尖型失速，即由叶顶间隙泄漏流引起的堵塞所造成。进口畸变引发叶顶处吸力面的气流分离，且气流分离沿周向呈非轴对称分布，进口畸变后叶顶通道内的低速区在很大程度上还是由叶顶间隙泄漏流所造成，只不过相比于进口均匀，叶顶处吸力面的气流分离提前发生，并且反过来又加剧叶顶间隙泄漏流的负面影响，即进口畸变后压气机失速的主要诱因没有发生本质的变化。机匣处理上、下游的喷射、抽吸过程分别对叶顶通道上游、中部的低速区气流起到激励、吹除作用，其有效地抑制了由叶顶间隙泄漏流所造成的叶顶前缘溢流和叶顶通道内压力面附近的回流，进而提高了叶顶通道的流通能力。

Abstract:

In order to investigate the mechanism of performance improvement for axial flow compressor with slots casing treatment under inlet distortion， the isolated rotor of test rig for subsonic single stage axial flow compressor was chosen to investigate the mechanism of performance improvement for axial flow compressor with axial skewed slots casing treatment at 53.4% design rotating speed under inlet distortion with the help of 10 passages unsteady numerical simulation method， while taking the method of setting barriers along circumferential in the middle of inlet radial extension to produce distortion. Compared to inlet uniform with solid wall， the stall margin improvement and peak efficiency improvement of inlet distortion with solid wall were -5.88% and -1.44%， while the stall margin improvement and peak efficiency improvement of inlet distortion with casing treatment became 24.37% and -1.09%. As for inlet uniform with solid wall， the stall type of compressor was typical sudden stall， which resulted from the blockage caused by tip clearance leakage flow. Inlet distortion triggered flow separation at the suction surface of blade tip， and the flow separation distributed non-axisymmetrical along circumferential， the low velocity zone inside the blade tip passage was largely caused by the tip clearance leakage flow after inlet distortion， but compared to inlet uniform， the flow separation of the suction surface at the blade tip occurred in advance， and it exacerbated the negative effects of the tip clearance leakage flow in turn， i.e. the main cause of the compressor stall did not change in essence after inlet distortion. The injecting and pumping process from the upstream and downstream of casing treatment played a role in encouraging and pumping the flow of low velocity zone in the upstream and middle of blade tip passage， which restraining the leading edge spilled flow of blade tip and recirculation near the pressure surface of blade tip passage resulted by tip clearance leakage flow effectively， and improving the flow ability of blade tip passage.