Effects of Surface Roughness on Aerodynamic Performance of a High Subsonic Compressor Airfoil under Low Reynolds Number Conditions

In order to investigate the effects of surface roughness Ra on the aerodynamic performance of a high subsonic compressor airfoil under low Reynolds number Re conditions, three roughness locations and fifteen roughness magnitudes were applied on the suction surface, respectively. At the Reynolds number of 1.5×105, the boundary layer separation and transition on the suction surface covered with different roughness locations and magnitudes were compared in detail, then the underlying physics of boundary layer development of compressor airfoil affected by roughness under low Reynolds number conditions were detected. Results showed that the trends of profile loss varied with the roughness magnitudes were similar to each other for the three roughness locations. In the transitionally rough region, the negative displacement effect of laminar separation bubble (LSB) over the suction surface on the airfoil performance was suppressed or even eliminated by the increased roughness magnitude, and the maximum reduction in profile loss were approximately 10.16%, 16.4% and 15.58% for the three roughness locations, respectively, at Ra=157μm. On the other hand, with the further increase of roughness magnitude in the fully rough region, the airfoil performance was degraded gradually by the strong turbulent dissipation instead. Within the entire region of roughness magnitudes, the roughness covering from leading edge to the transition point on the suction surface has the potential to effectively control the boundary layer development, and the aerodynamic performance of compressor airfoil operating at low Re conditions was improved more distinctly. © 2020, Editorial Department of Journal of Propulsion Technology. All right reserved.