Experimental and numerical investigation of corner separation control in highly loaded compressor cascades using leading-edge micro-vanes

Based on linear cascade wind tunnel experiments and unsteady numerical simulations, this study investigates the potential of a passive control technique using leading-edge micro-vanes (LEMVs) to mitigate corner separation in compressor cascades. The experimental results demonstrate that the optimal LEMV scheme with a percent pitch of 0.2 significantly extends the operating range of the cascade. By alleviating open corner separation at a 0° incidence angle and suppressing full trailing-edge separation at a 6° incidence angle, the total pressure loss is reduced by 15.64% and 26.05%, and the static pressure rise is increased by 10.77% and 3.76%, respectively. The LEMVs act as turbulence promoters that shorten the extent of the laminar separation bubble and delay the onset of turbulent separation on the suction surface. Furthermore, the strong shear effect associated with the passage vortex (PV), which rolls up within the blade passage and develops downstream into a hairpin-shaped structure, leads to intense viscous dissipation. The LEMV enhances mixing between the mainstream and low-energy corner flow through both the jet effect between the LEMV and main blades and the induced vortices, while also suppressing the development of the PV via a vortex generated near the vane tip. As a result, the flow unsteadiness and viscous dissipation are significantly reduced.