ADVANCED ENDWALL CONTOURING FOR LOSS REDUCTION AND OUTFLOW HOMOGENIZATION FORAN OPTIMIZED COMPRESSOR CASCADE

Abstract

The following paper deals with the development of an optimized non-axisymmetric endwall contour for reducing the total pressure loss and for homogenizing the outflow of a highly loaded compressor cascade. In contrast to former studies using a NACA-65 K48 cascade airfoil this study starts with the design of a new high performance airfoil which is based on the aerodynamic boundary conditions of the NACA-65 K48 cascade. This new airfoil is then used as a basis. Optimizations of the airfoil and of the endwall contour are performed using the DLR in-house tool AutoOpti and the RANS-solver TRACE. Three operating points at an inflow Mach number of 0.67 with different inflow angles are used to secure a wide operating range of the optimized design. The optimized endwall contour changes the secondary flow in such a way, that the corner stall is reduced, which in turn significantly reduces the total pressure loss. The endwall contour in the outflow region leads to a considerable homogenization of the outflow in the near wall region. Using non-axisymmetric endwall shaping can give a contribution to enhancing axial vane rows with already highly efficient blading.