低雷诺数下粗糙度对高亚声速压气机叶型气动性能的影响

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

关键词:  低雷诺数  压气机  叶型  粗糙度  边界层  叶型损失  气动性能

Key words:  Low Reynolds number  Compressor  Airfoil  Roughness  Boundary layer  Profile loss  Aerodynamic performance

摘要:

为了探究低雷诺数Re 下粗糙度Ra 对一高亚声速压气机叶型气动性能的影响，在其吸力面 布置三种粗糙度分布，每种分布对应15种粗糙度大小。在Re=1.5×105时，利用数值模拟手段详细对比了 不同粗糙度分布及大小下压气机叶片吸力面边界层分离、转捩规律，揭示了低Re 下粗糙度调控压气机 叶型边界层发展特性的机理。研究表明，三种粗糙度分布下，叶型损失随粗糙度大小的变化趋势类似。 在转捩粗糙区，吸力面分离泡“位移效应”对叶型性能的不利影响随粗糙度增大而被抑制乃至完全消 除，Ra=157μm时叶型损失最大分别降低10.16%，16.4%，15.58%；在完全粗糙区，随粗糙度进一步增 大，强烈的湍流耗散作用反而致使叶型性能不断下降。在整个粗糙度大小范围内，粗糙度布置在吸力面 前缘到转捩点之间时对边界层调控效果较好，能够较大限度地提升低Re 下压气机叶型的气动性能。

Abstract:

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 for the three roughness locations. In the transitionally rough region, the negative displacement effect of laminar separation bubble (LSB) of 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 regime 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.