Experimental assessment of a new combined flow control approach in compressor cascade

A new combined flow control approach is put forward in this paper using blade slot and vortex generator, which increase the flow control benefits by the combining their effects. A preliminary parameter study is conducted to select the geometry parameters of the vortex generator, and then experiments are performed to assess the gains and to reveal the mechanisms. The measured flow fields show that the cascade separation is significantly reduced and the outlet flow field is more ordered due to the combined approach. The cascade performance, the total pressure loss, the flow turning angle and the static pressure rise averagely increase by −30.9%, +2.0° and +69.9% respectively. The stable margin of the cascade rises +3° regarding the incidence angle. The mechanisms should be concluded that high-speed slot jet induced reduces trailing edge separations and concentrates remaining separations to the cascade corner, and the vortex generator further decreases the corner separations by deflecting the passage vortex. Combining the benefits of two devices, the combined approach achieves better flow control effects than the individual two.