Study of combined flow control strategies based on a quantitative analysis in a high-load compressor cascade

Abstract

Micro-vortex generator and a jet flow control technique are combined to improve the flow performance of a high-load compressor cascade, and the injection position is further investigated. The calculated results showed that the reverse flow region of baseline grows with the increment of incidence, and an unstable flow phenomenon rapidly occurs near the leading edge when the incidence rises to +7.9°. Meanwhile, two critical points occur on the end-wall, that is considered to be the main reason for occurring stall. When an injection tube is applied to remove the low energy fluid, the total pressure loss appears drastic reduction, and the occurrence of stall shows a slight delay from +7.9° to +8.7° incidence compared with the baseline. With the micro-vortex generator is introduced in the baseline, the occurrence of stall is delayed from +7.9° to +10.0° incidence due to the mixture of low energy fluid and main flow. The combined application shows an excellent effect in delaying the occurrence of stall and reducing the total pressure loss, and the sudden deterioration of the cascade performance occurs at +9.8° incidence. A quantitative analysis of total pressure loss shows that the secondary flow loss and wake loss contribute to the reduction of total pressure loss, the former is reduced by 31.0% and the latter is decreased by 24.1% at the near stall condition. Moreover, the spanwise injection position can affect both the total pressure loss and stall incidence, and the wider operating range is accompanied by the increment of total pressure loss.