Effects of Periodic Wakes on Unsteady Aerodynamic Performance of High-Lift Low-Pressure Turbine Cascade

At low Reynolds number, incoming wakes were produced through moving rods upstream of the cascade. The effects of upstream wakes on endwall secondary flow and profile losses within the high-lift LPT cascade were researched by experiment, and the interaction mechanisms between the upstream wakes and secondary flow were studied by numerical simulation. Upstream wakes can significantly suppress endwall secondary vortical structures. The interaction between vorticity of the wakes and the passage vortex decrease the time-averaged result of the secondary vortex in an upstream wake-passing period. Additionally, upstream wakes have both positive and negative effects on the flow of LPT. The periodic wakes can decrease the size of the separation bubble, but increasing mixing losses. If appropriate wakes passing frequency was chose, aerodynamic performance of turbine cascade can be improved more.