变工况下轴向非均匀凹槽叶顶的实验研究

Experimental Study of Axially Non-Uniform Clearances With a Squealer Tip Under Design and Off-Design Conditions

本文通过低速平面叶栅风洞实验的方法,将轴向非均匀间隙与叶顶凹槽进行结合,分析了其在不同工况下的性能及流场结构。结果表明:非均匀间隙适用于凹槽叶顶,在各个方案中均能显著降低能量损失系数(最高8.9%),并提高通流流量(最高1.53%);攻角的增大导致端壁处泄漏涡低压区增大,并延迟了泄漏涡抬离壁面,继而在下游引发了高损失区的扩大;轴向非均匀间隙下出口气流欠偏转现象更加明显,而正攻角条件下的欠偏转现象有所减轻。

This study combined axially non-uniform clearances and the squealer tip with experiments on a low-speed wind tunnel. The performance and flow structure were analyzed under design and off-design conditions. The results showed that the axially non-uniform clearances could be applied to the squealer tip. The energy loss coefficients were reduced in all cases considered in this study by axially non-uniform clearances （8.9% at most）. Meanwhile, the flow rate were strengthened. The low pressure zone of the leakage vortex went larger at the endwaU with the increasing of the attack angle, which delayed the leakage vortex raising from the endwall and induced a larger high-loss area downstream the cascade. Finally, the axially non-uniform clearances strengthed the level of under turning.