小流量下周向弯曲叶片叶顶泄漏流动的PIV研究

对带有周向前弯和周向后弯叶片的低压轴流风机,采用PIV技术测量小流量工况下叶顶区域瞬态速度场。基于小流量压力峰值工况下的瞬态测量结果,详细阐述了周向弯曲叶片叶顶泄漏涡的演化过程。结果表明：小流量压力峰值工况下,周向弯曲叶片叶顶泄漏涡存在瞬态特性,泄漏涡起源向前缘方向迁移,涡核在向下游发展的过程中不断破碎,沿端壁向通道中部迁移,并发生径向迁移;周向后弯叶片的泄漏涡较周向前弯叶片迁移明显,涡核破碎过程剧烈;周向前弯叶片有利于叶顶泄漏涡的控制。

The investigation of tip leakage flow of circumferential skewed axial fan at off-design condition by PIV

In this paper,the instantaneous velocity and vorticity distributions in the tip region of lower pressure axial fans with circumferential forward-skewed,backward-skewed blades are successfully measured with the PIV system at off-design condition.Based on the measurement results,the evolution of the tip leakage vortex in circumferential skewed blades is discussed.The measurement results show that at peak pressure condition,the instantaneous characteristic of the tip leakage vortex in circumferential skewed blades is observed;the tip leakage vortex of circumferential backward-skewed blade generates and breaks down earlier and interacts more violently with mainstream than that of forward-skewed blade,which causes large blockage and much loss.The circumferential forward-skewed blade seems to be efficient to control the tip leakage flow.