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Influence of Blade Lean on Performance and Shock Wave/Tip Leakage Flow Interaction in a Transonic Compressor Rotor
Author(s): Zhiyuan Cao, Xiang Zhang, Yuyuan Liang, Bo Liu
Keywords: Blade lean, Tip leakage vortex, Shock/Tip leakage flow interaction, Transonic compressor
Blade lean has been extensively used in axial compressor stators to control flow separations, but its influence mechanism on transonic compressor rotors remains to be revealed. The aim of this study is to explore the influence of blade lean on performance and shock wave/tip leakage flow interaction in a transonic compressor rotor numerically. The effects of leaned pattern (positively lean and negatively lean), leaned angle and leaned height are all studied. Results show that, for positively leaned rotor, both efficiency and total pressure ratio of the entire constant rotating speed line are decreased compared with baseline configuration; the peak efficiency is reduced by as much as 4.34% in absolute value at 20° lean angle, whereas the maximum reduction of peak total pressure ratio is 0.1 at 20° lean angle. The tip leakage flow streamlines of baseline transonic rotor can be divided into two parts, i.e., the primary vortex and secondary vortex which arises after the shock; because of shock/tip leakage vortex interaction, the primary vortex enlarges and low-momentum region shows up after the shock; at near stall (NS) condition, tip leakage vortex breakdown occurs after its interaction with shock. As positively leaned angle increases, the shock and the shock/tip leakage vortex interaction point move upstream; in addition, the tip leakage vortex breakdown phenomenon is enhanced. For negatively leaned rotors, as negatively leaned angle increases, the peak efficiency and total pressure ratio first increases and then decreases; the peak efficiency is increased by 0.8% at most, at 0° leaned angle. The maximum increment of total pressure ratio is 0.05 at 5° leaned angle; besides, the loading of blade tip reduces and the loading moves toward trailing edge, which results in the downstream moving of primary vortex, shock front and shock/tip leakage vortex interaction location. The results may help to improve the near tip flow field of transonic compressor rotor with leaned blade technology.

Journal of Applied Fluid Mechanics

The Journal of Applied Fluid Mechanics (JAFM) is an international, peer-reviewed journal which covers a wide range of theoretical, numerical and experimental aspects in fluid mechanics. The emphasis is on the applications in different engineering fields rather than on pure mathematical or physical aspects in fluid mechanics. Although many high quality journals pertaining to different aspects of fluid mechanics presently exist, research in the field is rapidly escalating.