The effect of different clearance geometry configurations on aerodynamic performance in a high-load compressor cascade

Abstract

The clearance flow of compressor variable stator vanes has a significant impact on compressor performance. Most clearance flow experimental research work has been carried out in compressor cascades with lower turning angle (lower load). The clearance flow in a higher load compressor cascade is relatively more complicated due to three-dimensional (3D) flow separation. In the present work, the effects of different heights and locations of clearances in a compressor cascade on aerodynamic performance and separation flow were investigated experimentally in a low-speed plane cascade wind tunnel. The objective of this investigation is to study the characteristics of different clearance configurations depending on the clearance height and the clearance axial position, and make an attempt to verify the possibility of a local clearance flow that improves the performance. The cascade outlet section aerodynamic parameters were measured by ''L'' five-hole probe. The ink-trace flow visualizations on the cascade surface and lower end wall were performed. The results show that with the increase in clearance size, the core area of high loss is moving to the end wall and the morphology of limiting streamlines on the suction surface changes gradually from separation lines to reattachment lines. The separation lines on end wall gradually moved to the middle of the cascade and the separation area increased gradually. The above reasons caused high loss zone gradually extended to the end wall. Thus, the loss at mid-span declined slightly while the loss on the end wall was increasing. Otherwise, cascade load reduced significantly when the clearance height became 3 mm, and the change magnitude of limiting streamline morphology in the flow field which was influenced by clearance flow at the rear of the blade reached to a minimum. So the loss and load came to a minimum, respectively. The impact of the clearance in the rear of a blade on loss and flow is weaker than the other schemes, with a slightly larger loss and separation with respect to the original scheme without a clearance. It may be expected to improve the cascade performance further by an appropriate design of clearance near the trailing.

Effect of hub clearance of cantilever stator on aerodynamic performance and flow field of a transonic axial-flow compressor

“…The shape of the clearance affected the development of the HLF by influencing the blade load distribution. 13 Barankiewicz et al 14 studied the effect of HLF in different chordwise ranges on compressor performance by adjusting the hub clearance geometry. The results indicated that the HLF within the full chord length range could positively weaken the serious separation near the SS/hub corner area, but at the same time, it increased the flow turning angle near the hub and reduced the diffusion factor.…”

Impact of Boundary Layer Suction on Clearance Leakage Flow in a Cantilever Stator of Transonic Compressor

“…But inappropriate clearance may result in enhancement of TLF, which makes the compressor efficiency decline and the stall margin reduce (Wheeler et al, 2012;Zhong et al, 2013;Chen et al, 2013;Acharya et al, 2013). Kang and Hirsch (1994) measured the TLF in detail and studied the vortex structures in the endwall region.…”

Numerical Research on the Impact of Axial Position of Endwall Suction Slot on Tip Leakage Flow

“…The results of some pieces of literature showed that the performance of compressor and cascade could be improved as the separation flow was controlled by introducing an appropriate clearance size. While a larger clearance size led to the enhancement of the TLF, which would decrease the performance of the compressor (Zuo et al 2011;Chen et al 2012Chen et al , 2013Gottschall et al 2012;Gao et al 2017). In addition, Liu et al (2016a) and Mao et al (2019) explored the effect of tip clearance of the rotors on the performance of a counter-rotating axial flow compressor.…”