锯齿尾缘对叶片尾迹特性的影响

Effect of Sawtooth Tail Edge on Wake Characteristics of Blade

对某型轴流压气机叶片尾缘进行三角锯齿建模,利用Fluent软件对基准叶片、短锯齿叶片、长锯齿叶片进行数值模拟研究。研究表明:锯齿尾缘可以有效加强尾迹区与主流区之间的流动掺混,且长锯齿尾缘尾迹区流动掺混程度比短锯齿尾缘更强;流动掺混的增强使得叶片出口速度更均匀,从而减小速度亏损。同时,由于长锯齿尾缘叶片显著地降低了尾缘附近的湍流强度,导致湍流与叶片尾缘相互干涉作用降低,因而能有效降低压气机叶片噪声,相比于基准叶片及短锯齿尾缘叶片,长锯齿叶片在降低噪声和减小流动损失方面效果更佳。

The tail flange of a certain axial compressor blade is modeled by triangle saw tooth,and the Fluent software is applied to the numerical simulation of the base blade,the short serrated blade,and the long sawtooth blade.The results show that the jagged trailing edge can effectively strengthen the flow mixing between the wake region and the main stream,and the flow mixing degree of the long serrated tail edge is stronger than the short serrated tail edge;the flow mixing enhancement makes the blade exit speed more uniform and thus reduces the speed loss.At the same time,the blade noise of the compressor can be reduced effectively because of the lower turbulent intensity near the tail edge of the long sawtooth edge,which reduces the interaction of the turbulence and the tail edge of the blade.In conclusion,compared with reference blades and short serrated trailing edge blades,long serrated blades have better effects in reducing noise and reducing flow losses.