锯齿尾缘翼型近场湍流试验研究

基于锯齿尾缘结构在航空发动机上的应用,对其降噪机理进行研究。通过3维热线风速仪测量2种尾缘结构的尾迹流场揭示锯齿降噪的流动本质,其结果显示出锯齿尾缘后流场的细微湍流结构变化规律,并在尾迹流场可见单个锯齿的齿峰和齿谷。结果表明:锯齿尾缘后尾迹中心线速度的衰减率比直尾缘的高;湍流峰值因为锯齿尾缘的存在出现在离翼型更远处,锯齿在近尾迹区产生了额外的马蹄涡。

Experimental Investigation on Near-field Turbulence of an Airfoil with Trailing-edge Serrations

The mechanism of noise reduction for the trailing-edge serrations applied in the aeroengine was studied. Two kinds of serrated trailing structure for turbulence flow field were measured by three dimensional hot -wire anemometer in order to reveal the characteristics of serrations noise reduction. The results show the change rules of small turbulence structure behind the trailing-edge serrations flow field, and the individual trailing-edge serrations tips and valleys occur in the trailing-edge flow field. The experiment result shows that the decay rate of the centerline velocity behind the tailing is higher than its on the straight edge, the turbulence peak occurs further fromthe airfoil surface in the presence of the serrations, and the serrations generate additional horseshoe vortices shed in the tail region