Corner Separation Control by Boundary Layer Suction Applied to a Highly Loaded Axial Compressor Cascade

Jinjing Sun,Yangwei Liu,Lipeng Lu

doi:10.3390/en7127994

Abstract

Control of corner separation has attracted much interest due to its improvement of performance and energy utilization in turbomachinery. Numerical studies have been performed under both design and off-design flow conditions to investigate the effects of boundary layer suction (BLS) on corner separation in a highly loaded compressor cascade. Two new BLS slot configurations are proposed and a total of five suction slot configurations were studied and compared. Averaged static pressure rise, exit loss coefficient, passage blockage and flow turning angle have been given and compared systematically over a range of operation incidence angles. Distributions of significant loss removal, blade loading, exit deviation and total pressure loss at 3 degree and 7 degree incidence have also been studied. Under the same suction mass flows of 0.7% of the inlet mass flows, the pitchwise suction slot on the endwall shows a better optimal performance over the whole operation incidence among single suction slots. By using of the new proposed compound slot configuration with one spanwise slot on the blade suction side and one pitchwise slot on the endwall, the maximum reduction of total pressure loss at 7 degree incidence can be 39.4%.

Highlights

Corner separation, which has been identified as an inherent flow feature of the corner formed by the blade suction surface and the endwall, is a high loss structure in axial compressors [1]
Numerical simulations were conducted to study the effects of boundary layer suction (BLS) on corner separation in a highly loaded axial compressor cascade
(b) For BLS with the single slot configurations tested, the endwall suction gives better incidence characteristics compared with suction on the blade suction surface, especially at the higher incidence angles

Summary

Introduction

Corner separation, which has been identified as an inherent flow feature of the corner formed by the blade suction surface and the endwall, is a high loss structure in axial compressors [1]. It has a great impact on the total pressure ratio, loading, efficiency and operating range of aero-engines, restricting the development of high performing ones. In 1997 the concept of an aspiration compressor was put forward by Kerrebrock et al [5], who pointed out that BLS on the suction surfaces of the blade could increase the flow turning angle in a transonic compressor. Qiang et al [10] studied BLS on a single-stage, low-speed axial compressor based on the concept of an aspirated compressor and they found the approach is effective and the 3D separation can be controlled by the suction

Methods

Results

Conclusion