移动端壁对压气机叶栅中叶尖泄漏流动的影响

对一压气机平面叶栅进行全三维数值模拟,分别对两种不同叶尖间隙情况下,移动端壁对叶栅性能及泄漏流流动结构的影响进行分析。详细对比了不同条件下,叶栅损失,泄漏涡传播轨迹及影响范围,泄漏流量等参数的变化,同时通过三维流线结构的对比,对泄漏流在间隙中的流动特点及其在通道中与主流的相互作用进行分析。结果表明:移动端壁加入使泄漏流量增加,泄漏涡传播轨迹向远离吸力面,靠近端壁的方向偏移,削弱通道流与泄漏流之间的剪切作用,改变通道中的各个二次流动结构所占比例。间隙较小时,移动端壁的影响主要集中在端壁附近,而间隙较大时,移动端壁能够抑制叶顶分离涡,从而影响整个间隙中泄漏流的速度分布,进一步削弱通道流与泄漏流动之间的剪切作用。 

Effects of moving endwall on tip leakage flowin compressor cascade

A numerical simulation was carried out to investigate the effect of the moving endwall on the tip leakage flow structure in a compressor cascade with different tip clearances. A detailed comparison of leakage flows loss, trajectory, size and mass flow rate, as well as the tip leakage flow features and its interaction with the mainstream, was conducted. Results showed that the moving endwall led to more leakage mass flow through the gap. The region of the tip leakage vortex was flattened away from the blade suction side. The interaction between the mainstream and the tip leakage flow was weakened. The structure of the vortexes inside the passage was altered. In the small clearance cases, the main effects of the moving endwall were focused on the near wall region. While in the large clearance cases, the moving endwall clearly suppressed the tip separation vortex, thus influencing the velocity distribution of the whole clearance, and further impacting the shear between the mainstream and the tip leakage flow.