Effects of Inlet Boundary Layer on Aerodynamic Performance of Tandem Cascade

In order to explore the effects of inlet boundary layer on the aerodynamic performance of the tan⁃ dem cascade，a high-subsonic compressor conventional cascade and its modified tandem cascade were investigat⁃ ed with numerical method in the current paper. The impacts of different inlet boundary layer thickness on the over⁃ all performance of the two cascades and their three-dimensional（3D）corner separations were compared and ana⁃ lyzed. The results show that as the thickness of the inlet boundary layer increases，the 3D corner separation range of the original cascade gradually increases along the span direction，while the increase of the 3D corner separa⁃ tion range in the tandem cascade is mainly reflected in the circumferential direction. For the tandem cascade，due to the existence of the inlet boundary layer，the passage vortex，induced vortex and corner vortex caused by the interaction between the jet-flow from the gap of the front and rear blades and the low-energy fluid near the endwall have primary responsibility for the loss increasing. Compared with the original cascade，the tandem cascade can effectively reduce the total pressure loss and increase the static pressure rise，while the increase in the inlet boundary layer thickness will reduce the advantage. When the ratio of the thickness of the inlet boundary layer to the blade height is 0%，5%，and 12.5%，compared with the original cascade，the total pressure loss coefficient of the tandem cascade is reduced by 11.1%，5.5%，and 4.1% ，respectively，and the static pressure rise coeffi⁃ cient increases by 7.4%，6.5% and 6.4%，respectively. © 2023 Journal of Propulsion Technology. All rights reserved.