Numerical Investigation of an Axial Compressor Cascade with Corner Separation Control by Aspiration

To explore the effectiveness and mechanisms of different aspiration schemes in controlling the three-dimensional corner separation in an axial compressor cascade, four slotted aspiration schemes have been investigated numerically. AUTOGRID5 in NUMECA is used to generate the grid of O4H topology. At the same time, the software solver of FINE/Turbo is used for 3D RANS calculation, and S-A turbulence model is applied. It is found that corner separation can be controlled more effectively on the endwall at its early development stage without considering the loss coefficient caused by the slots, while it is more favorable for the enhancement of cascade performance when applying aspiration on the suction surface near the hub at the middle development stage of corner separation. After aspiration, the total pressure loss and flow blockage in the corner region are decreased obviously to different extent at different blade span due to the spanwise coverage difference of the aspiration slots. The starting location of the corner separation, the trajectory of the horseshoe vortex on the pressure side and the vortex core location of the passage vortex are all affected remarkably in the aspiration schemes. Considering the slot-related loss, the control scheme (EW1) on the endwall is the most effective in decreasing the total loss of the cascade, and its total loss and flow blockage compared with the original cascade reduced by 17.702% and 72.6%. Among the aspiration schemes on the blade suction surface in the corner region, the aspiration scheme (SPW2, DEC2) that occupies more spanwise extent is better than the scheme of STW2 which covers more streamwise range.