Passive control of shock-boundary layer interaction in transonic axial compressor cascade flow

Abstract

The object of this investigation is the ventilated flow through an axial transonic/supersonic compressor cascade. It is a joint research project between the Chinese Academy of Sciences, Institute of Engineering Thermophysics and the University of Karlsruhe (TH), Institute for Fluid Mechanics and Fluid Machinery. Losses in the cascade flow can be reduced by passive control of the shock-boundary layer interaction. The passive control is realized by a cavity covered with a porous plate which is located at the interference region of the shock at the suction side of the blade. The static pressure gradient along the porous surface initiates a flow through the cavity which smoothes the pressure jump across the shock automatically. Experiments are performed in a cascade wind tunnel of the Chinese Academy of Sciences and in a cascade element being installed in the supersonic wind tunnel of the Institute for Fluid Mechanics and Fluid Machinery. Numerical results are obtained at the University of Karlsruhe by solving the 2-D Reynolds averaged Navier-Stokes equation with an explicit, time-dependent finite volume method. Experimental results in the cascade and in the cascade element yield a relative reduction of the total loss of 14 – 15% and an improvement of the isentropic efficiency of about 2%. In the numerical simulation of stationary viscous flow the total loss reduces by more than 5% and the isentropic efficiency increases by nearly 1%.