THEORETICAL AND EXPERIMENTAL INMSTIGATIONS ON AERODYNAMICALLY HIG HLY-LOADED COMPRESSOR BLADINGS WITH BOUNDARY LAYER CONTROL

The paper describes a semi-empirical calculation method for the design of blowing configurations for highlyloaded compressor cascades with boundary layer control by means of blowing. This method is based upon an inviscid velocity distribution on the profile for which at first a boundary layer calculation is carried out up to the slot location. The initial values for the boundary layer calculation downstream of the blowing point up to the trailing edge (or point of separation) supply empirical correlations for momentum loss thickness and form factor which take into account the blowing parameters. The losses are calculated with the boundary layer values at the trailing edge by means of a downstream flow calculation. Thus, boundary layer control can be optimised with regard to profile geometry, as well as position and shape of the blowing configuration. The results of the measurements carried out in the high speed cascade wind tunnel at the DFVLR, Institute of Aerodynamics, Brunswick, Germany, show an improvement in the cascade characteristics and, with reference to the effect of the influence on the boundary layer, good agreement with the design, so that the applicability of the analytical method is confirmed.