压气机微小损伤叶型流动特性及边界层发展机制研究

Study on flow characteristic and boundary layer development mechanism for compressor blade profile with minor damage

压气机在运行过程易受到砂石等外来物冲击,致使叶片产生轻微损伤,进而导致气动性能下降。本文以某轴流压气机进口级静子中基元级为研究对象,利用数值模拟方法分析了“凹坑”型损伤尺寸、位置对压气机叶片基元级性能的影响规律,揭示了叶型损伤对边界层流动演化的影响机制。研究表明:随损伤位置向前缘靠近,叶型性能恶化程度呈非线性增大;损伤特征尺寸可以影响边界层转捩的形式,进而影响叶型损失;型面损伤增强了边界层流体与主流区的掺混程度,使损伤区域附近边界层流体动能增强,进而影响分离泡转捩位置,在特定条件下可以减小叶型损失。

The performance of compressor will be degraded when minor damage occurs on the compressor blade hit by foreign objects such as sand and gravel during operation.In this paper,the numerical simulation was conducted on the baseline stage of medium blade of the inlet stage stator of an axial compressor with minor profile damage to analyze the influence rule of the size and location of the"dimple"type damage on its performance,which reveals the inluencing mechanism of blade profile damage on the boundary layer flow development.The results show that the deterioration of the blade performance increases nonlinearly with the shortening distance between the damage location and the leading edge;the damage characteristic size can affect the boundary layer transition form obviously,and then affect the balde profile loss;the profile damage enhances the mixing degree between the boundary layer and the mainstream fluid,and the kinetic energy of the boundary layer fluid near the damage area is enhanced,which furtherly affects the transition position of the seperation bubble.Under the certain operating conditions,a damage with favorable size and location can reduce the blade profile loss.