THE EFFECT OF AN ENTIRELY ERODED AIRFOIL ON THE AERODYNAMIC PERFORMANCE OF A SUPERSONIC COMPRESSOR CASCADE

In-service performance of modern axial compressors of aircraft engines is strongly dependent on deterioration processes such as solid particle erosion. So far the resulting aerodynamic losses have been studied by analyzing pre-set shape changes of locally eroded airfoil regions with a focus on the leading edge contours. However, the aerodynamic losses caused by solid particle erosion are the result of the entire shape change of the deteriorated airfoils. These shapes are assignable to the particular erosive conditions and the amount of particles ingested. The midspan airfoil shapes of the NASA Rotor 37 experimentally deteriorated in a linear cascade form the basis of the presented numerical study. The shapes of the eroded airfoils are used to perform supersonic numerical simulations at near stall conditions. The losses and flow patterns caused by different degrees of erosion are discussed. Cascade performance is deteriorated up to 25% due to solid particle erosion. The shock systems for different erosion shapes are evaluated and their influence on the overall losses is demonstrated. It is concluded that the analysis of isolated erosion phenomena such as leading edge changes in shape provide an incomplete understanding of the aerodynamic losses caused by solid particle erosion. The interaction of the entire shape change of the airfoils is needed to fully understand the losses in turbomachines caused by erosion.