中文摘要：

为了研究车辆发动机冷却风扇叶顶间隙泄漏流动特性,通过试验测量了典型叶顶间隙区域的3种流动结构在工作静压力50-250Pa、转速0-2 500r·min-1、叶顶间隙高度一定时的泄漏量和膨胀空腔内压力分布。通过与数值模拟计算结果对比分析,研究了压力和转速对叶顶间隙泄漏特性的影响规律及间隙泄漏流动机理。结果表明：数值计算可有效预测叶顶间隙的泄漏量和膨胀空腔压力;低压条件下,叶顶间隙泄漏量随导流环转速增加而降低,随着分隔翅片数增加到某一数值,转速对泄漏量的影响不再变化;膨胀空腔内压力沿流动方向逐渐减小,径向压力没有变化,导致泄漏射流流向改变的主要原因不是径向压力差驱动,而是粘性内摩擦力作用。

英文摘要：

In order to study the leakage flow behavior in blade tip clearance in vehicle engine cooling fan, the leakages and expansion cavity pressures distribution of three flow structures in blade tip clearance region of automotive engine cooling fan were measured when the static pressure was 50-250 Pa, the rotational speed was 0-2 500 r·min-1 , and the sealing gap was of certain value. The effects of the pressure and rotational speed on the leakage flow behavior and the mechanism of leakage flow in the blade tip clearance of vehicle engine cooling fan were studied by comparing the experiment with numerical simulation. The results show that numerical simulation can efficiently predict the amount of leakage and expansion cavity pressure under low pressure, the tip clearance leakage flow decreases as the deflector ring speed increases, and when the number of split fins increases to a certain value the impact of the rotational speed on the amount of leakage can be neglected~ and the expansion cavity pressure gradually decreases along the flow direction, whereas the radial pressure does not change, and the main reason for the change of leakage direction is not the radial pressure but the viscous internal friction.