Numerical investigation of positive dihedral application conditions in compressor cascades

This study attempts to make a contribution to the understanding of dihedral application conditions and their aerodynamic mechanisms. The present efforts have finished contrastive investigations on several dihedral blades to their corresponding straight ones with different geometric or aerodynamic conditions including aspect ratio, solidity, aerofoil turning angle, inlet boundary layer configuration and inlet Mach number. A dihedral with the angle between the suction side and the endwall to be obtuse, i.e., positive dihedral, is chosen. The result reveals the dihedral application conditions consist of aerofoil turning angle, inlet boundary layer, inlet Mach number and so on. The further analysis indicates: in a transonic cascade, two considerations are needed on the contrastive relationship between intensities of the two shocks, namely detached shock and passage shock, and the interaction of the shocks with the corner separation.