Effect of a Bionic Blade Rib on the Loss Characteristics of a Highly Loaded Compressor Cascade

To effectively reduce cascade loss and further improve compressor performance, spanning bionic blade ribs are built and positioned on the suction surface of a highly loaded compressor cascade based on the flow separation control mechanism of a peregrine falcon in high-speed flight. The effect of several kinds of bionic blade ribs on the loss of the cascade as well as the mechanism of their action are studied using numerical approaches with experimental calibration. The investigation shows that the bionic blade rib structure can lower the corner loss of the cascade to varying degrees in the range of a - 9(o) to +6 (o )attack angle, with the T-shaped cross-section blade rib having the best overall loss reduction impact. The open trapped vortices generated inside the blade rib suck the energy of the corner region wall boundary layer into the low-energy fluid in the corner region. Consequently, the size and intensity of the passage vortices decrease, while losses are reduced by up to 9.87%. Within the midrange of the blade, a closed trapped vortex forms within the bionic blade-rib structure. The kinetic energy of the near-wall flow is continually consumed by closed trapped vortices along the flow passage, leading to a greater velocity differential between the suction and pressure surface flows as they converge at the trailing edge. Thus, the mixing scale increases, and the loss rises. Finally, the blade rib structure also increases the accumulation of low-energy fluid in the near-end wall region of the blade and increases the end wall loss.