The Study Of The Tip Clearance Flow Of A Transonic Compressor Cascade

In order to enhance the overall performance of aero-engines, increasing the efficiency ofthe compressor has always been the direction of many scholars’ research. The flow ofcompressor blade tip clearance has been a hot and difficult research field for national andinternational scholars in the field of aerothermodynamics. Fully understanding the flowdevelopment of tip clearance is favorable for improving compressor performance, increasingcompression efficiency and enhancing compressor stability margin. Using a certain type ofaero-engine compressor cascade as a datum model and without changing the length and thewidth of the winglet, this paper mainly emphasizes the influence of blade tip winglet on thetip 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 singleequation turbulence model. The results of numerical simulation for the NASA Rotor37werecompared to the measured data. The results show good agreement. Furthermore, numericallycalculated the traditional blade (CB)(datum model) without blade tip winglet and the modifiedblade (WB)(modified model) with blade tip winglet of0.5of the blade maximum thicknessas the mach number are0.7and1.1and the tip clearances are1.2%，2.4%of the blade height.The predicted results show that as the increase of tip clearance, the minimum value ofthe cascade tip static pressure reduces and the location of this point moves towardsdownstream direction. As the rise of tip clearance, the pressure variation between the pressureside and suction side increases and the tip leakage flow enhances. With the suction sidewinglet, the static pressure coefficient at the blade suction side is significantly less than datummodel, but there is almost no difference at the pressure side. By installing the suction sidewinglet, the formation of the blade tip leakage vortex has been delayed, the blade tip pressurevariation obviously decreases, the tip leakage intensity has been weakened and the leakagevelocity reduces. With the suction side winglet, the loss of total pressure decreases and thecascade efficiency increases.