Unsteady Effects of Wake on Downstream Rotor at Low Reynolds Numbers

In a compressor, the periodic wake is an inherently unsteady phenomenon that affects downstream flow conditions and loading distribution. Thus, understanding physical mechanisms of these effects important for eliminating losses improving compressor performance, particularly at low Reynolds numbers. To understand influence upstream on field structure, this paper describes numerical simulations one-stage high-pressure altitudes 10–20 km. The rotor blockage different numbers analyzed, interaction between boundary layer or tip leakage discussed. results indicate has beneficial effect efficiency high numbers, but weakens becomes negative as number decreases. can reduce in mainflow region. Due to wake, length laminar separation bubble decreases increases. addition, unsteadiness causes bubbles appear periodically induces open Kelvin–Helmholtz instability dominate transition process layer, which also affected by disturbance vortex induced wake. Regarding flow, increase double-leakage finally leads large-scale suction surface layer. region prevents from propagating downstream. On contrary, pass through clearance inhibit reflected larger amplitude one blade passage frequency. Therefore, loss significantly reduced