混流式转轮出口流速分布的PIV测试研究

转轮出口速度分布好坏直接影响尾水管内压力脉动的大小，是影响稳定性的内在因素之一。本文针对HL220改型的模型试验，对转轮出口的速度内流分布，采用2D-PIV激光内流速测试设备对锥管内径向面进行了内流测试，给出了最优工况下转轮出口处径向面的流动瞬态分布，清楚显示了尾水管进口位置在最优工况下的流动非定常特征与细节。试验结果表明，PIV内流测试是进行转轮出口流动测量的一种可靠方法，结果为研究尾水管内的流动分布提供了必要的依据和边界条件。

Study on PIV measurement of exit velocity distribution of Francis turbine runner

The pressure fluctuation in draft tube, which is one of the intrinsic influence factors for stability, highly depends on the quality of velocity distribution in runner exit. By using 2D-PIV, we measured the velocity distribution on the radial plane of tapered draft tube of HL220 renewed model. The test got the instantaneous velocity distribution on the runner exit radial plane under the best operating condition. The instantaneous-response characteristics and the details of flow at the position of draft tube entrance under the best operating condition can be clearly showed. This paper presents the results. The result offers important information and boundary condition for the research on velocity distribution in draft tube.