Using sweep and dihedral to control three-dimensional flow in transonic stators of axial compressors

The paper describes an advanced 3D blading concept for highlyloaded transonic compressor stators. The concept takes advantage of the aerodynamic effects of sweep and dihedral. To the knowledge of the authors this is the first approach reported in open literature that combines those two basic types of lean in an engine-worthy aerofoil design. The paper makes a contribution to the understanding of the endwall effect of both features with special emphasis put on sweep. The advanced 3D blading concept was applied to an Engine Section Stator (ESS) of an aero-engine fan. In order to demonstrate how threedimensional flow can be controlled, numerical analysis of the flow structure in a conventional and an advanced stator configuration was performed using a 3D-Navier-Stokes solver. The numerical analysis showed the advanced blade improving the radial loading distribution as well as the three-dimensional endwall boundary layer development. In particular a strong hub corner stall could be largely alleviated. High-speed rig testing of the advanced ESS confirmed the concept and showed good qualitative agreement between measurement and prediction. The work presented was closely linked to the development the BR710 engine on which the advanced ESS is in service today.