凹槽叶尖受限空间内流动特性的实验研究

Experimental Research on Flow Characteristics in Confined Space of Squealer Tip

关键词:  涡轮  凹槽叶尖  端壁运动  概率分布  脉动速度

Key words:  Turbine  Squealer tip  Endwall motion  Probability distribution  Velocity fluctuation

摘要:

为了深入理解叶尖泄漏流动机理及凹槽控制泄漏损失的物理机制，围绕叶尖凹槽内部旋涡相互作用及能量分布等问题进行实验研究。介绍了一种可模拟端壁相对运动且考虑多因素的低速叶栅试实验台，并发展了适用于凹槽叶尖受限空间的热线测量技术，利用该技术精确捕捉了多工况下叶尖区域的流动结构及演化过程。结果表明：端壁相对运动可促进叶尖区域内的湍流发展，增强掺混和耗散作用，从而控制泄漏流；负荷分布可改变流场的湍流脉动统计规律，影响刮削涡的堵塞效果和控制范围；间隙高度大小对凹槽腔流动结构的产生和发展有直接的影响，从而改变了凹槽对叶尖泄漏流的控制效果。

Abstract:

In order to deeply understand the tip leakage flow mechanism and the physical mechanism of the squealer tip control leakage loss， experimental research was carried out around the vortex interaction and energy distribution inside the squealer tip. A low-speed turbine cascade testing facility is introduced that can model the relative motion of end wall. The turbine cascade testing facility can consider multiple factors， and has developed a hot-wire measurement technology suitable for the confined space of the squealer tip， and used the technology to accurately capture the flow structure and evolution process of the blade tip under multiple working conditions. The results show that the relative motion of the end wall can promote the development of turbulence in the tip area， enhance mixing and dissipation， and control leakage flow. Load distribution can change the statistical law of turbulence pulsation in the flow field， and affect the clogging effect and control range of the scraping vortex. The size of gap height directly affects the generation and development of the flow structure in the squealer tip， thereby changing the control effect of the squealer tip on the leakage flow.