The Application of 3D Blading and Non-Axisymmetric Hub Endwall Contouring in a Dual-stage Axial Flow Counter-Rotating Compressor

Abstract

D blading and non-axisymmetric endwall contouring technologies are effective ways to control secondary flows in cascades. 3D blading can effectively reduce the secondary flows near the blade surface, but it has little impact on the endwall region. Non-axisymmetric endwall contouring is widely used in the control of endwall secondary flows in turbines. However, the use of non-axisymmetric endwall contouring in compressors is rarely. The effect of non- axisymmetric endwall contouring on compressors is not clear. The research object of the report is an axial flow dual-stage counter-rotating compressor. In order to further improve the performance of the compressor and to explore the method of reducing secondary flow loss, the two rotor blade rows and the hub endwall of the secondary rotor row are redesigned by 3D blading and non-axisymmetric endwall contouring technologies based on optimization algorithm. The flow fields of original compressor and redesigned compressor are also compared. After 3D blading optimization, the secondary flows near the suction surface of the rotor blades are obviously reduced and the efficiency of the optimization point increases. Nonetheless, the secondary flows at the hub endwall improve scarcely any. Based on the 3D blading optimization, the second row rotor hub endwall are parameterization designed, and non- axisymmetric endwall contouring is designed by optimization algorithm. After non-axisymmetric endwall contouring optimization, the hub endwall consist of a hill near the rotor pressure surface and a valley near the suction surface. The contouring reduces the pressure gradient at 0~40% axial chord near the hub. And the secondary flow loss is reduced effectively. This paper successfully combines the advantages of both 3D blading and non-axisymmetric endwall contouring technologies; the performance of the counter-rotating compressor is improved