The Study Of The Tip Clearance Flow Of A Compressor Cascade

The flow at the compressor blade tip clearance has been a hot and difficult research field for national and international scholars in the field of aerothermodynamics. Fully understanding the flow development of tip clearance is favorable for improving compressor performance, increasing compression efficiency and enhancing compressor stability margin. Using a certain type of aero-engine compressor cascade as a datum model and without changing the length and the width of the winglet, this paper mainly emphasizes the influence of blade tip winglet on the tip clearance flow with various tip clearances by the calculated fluid mechanics(CFD) commercial software and the numerical simulation method.This paper applies compressible Navier-Stokes equation and Spalart-Allmars single equation turbulence model and numerically calculated the traditional blade(NW)(datum model) without blade tip winglet and the modified blade(SW)(modified model) with blade tip winglet of 0.5 of the blade maximum thickness as the tip clearances are 0.6%,1.2%,2.4% of the blade height.The predicted results show that as the increase of tip clearance, the minimum value of the cascade tip static pressure reduces and the location of this point moves towards downstream direction. As the rise of tip clearance, the pressure variation between the pressure side and suction side increases and the tip leakage flow enhances. With the suction side winglet, the static pressure coefficient at the blade suction side is significantly less than datum model, but there is almost no difference at the pressure side. By installing the suction side winglet, the formation of the blade tip leakage vortex has been delayed, the blade tip pressure variation obviously decreases, the tip leakage intensity has been weakened and the leakage velocity reduces. With the suction side winglet, the loss of total pressure decreases and the cascade efficiency increases.