Investigation of 3D Blading and Non-Axisymmetric Hub Endwall Contouring to a Dual-Stage Counter-Rotating Compressor in Multistage Environment

Abstract

3D blading technique is an effective way to mitigate flow separation and improve the performance of turbomachinery. Non-axisymmetric endwall contouring technique is widely used to reduce transverse secondary flows near the endwall region in turbines, while the application of non-axisymmetric endwall contouring to compressors is rare. The investigation rig is the Northwestern Polytechnical University dual-stage counter-rotating compressor. In order to further improve the aerodynamic performance of the compressor, 3D blading optimization of the two rotors and outlet guide vane (OGV) was done in multistage environment at near stall condition. After 3D blading optimization, the radial secondary flows of the two rotors and the separation vortex at the tip of OGV are obviously reduced. However, the transverse secondary flows at the hub endwalls of the two rotors are scarcely improved. Based on the 3D blading optimization, non-axisymmetric hub endwall contouring optimization of the two rotors was carried out afterwards and the circumferential secondary flow losses of the two rotors are reduced effectively. The efficiency of the counter-rotating compressor on optimization point increases and the aerodynamic performance is improved largely after 3D blading and non-axisymmetric hub endwall contouring optimization.

Effective strategy of non-axisymmetric endwall contouring in a linear compressor cascade

“…The optimal endwall geometry differed greatly between cases with and without inlet boundary layer skew, and the endwall designed with boundary layer skew involved showed greater flow control capability. Zhang 18 carried out the design optimization in a counter-rotating compressor with endwall contouring and 3D blading combined and obtained performance improvement. Varpe 19 studied the endwall contouring on a linear compressor cascade with tip clearance and showed that the influence of CEW could expand to the tip region.…”

Numerical investigation of non-axisymmetric end wall contouring effects in a low-speed compressor tandem stator

“…They performed a parametric study on contouring in a stator, where they achieved an increase of efficiency and the suppression of the stator hub-corner stall, defining how to suppress separation in transonic compressors it is better to use a 3-D blade shaping based on the total pressure loss reduction. Zhang et al (2014) applied a double process of optimization coupling the 3-D blade generator with a non-axisymmetric hub contouring routine, on a double stage counter-rotating compressor. They find how both techniques can improve the performances of the compressor, but they act on two different span ranges.…”