水轮机尾水管内部压力脉动试验研究

EXPERIMENTAL STUDY ON PRESSURE SURGE IN HYDRAULIC TURBINE DRAFT TUBE

水轮机尾水管内部的水压力脉动是影响水轮机组运行稳定性和发电效益的重要因素之一。对水轮机模型,测取了从直锥段进口至尾水管出口8个截面共26个测点在6个稳定运行工况下的水压力脉动数据。通过水压力脉动数据的FFT频谱分析,研究了直锥段和尾水管内部在不同位置不同工况下的压力脉动在时域及频域上的变化规律。结果显示,尾水管内部的压力脉动在不同位置不同工况都有区别,直锥段内的压力脉动与转轮出口流态密切相关,尾水管肘管之后的压力脉动与尾水管本身的形状关系较大。这对改善尾水管设计、提高机组运行稳定性具有参考价值。

It's one of the most important causes that pressure surge occurs in the draft tube, which results in the units operation instability and power losses. In the experimental study, the pressure surge data are acquired at 26 points from the taper pipe intake to the draft tube exit distributing at 8 sections under 6 stable operating conditions. With the FFT analysis it is analyzed that the pressure surge changing laws in the taper pipe and draft tube in time domain and frequency domain. It shows that the pressure surge is different at different position and operation conditions. In the taper pipe it is closely related to the flow field of rotating runner exit, and it is more interrelated to the draft tube form behind the elbow. These results afford reference on the draft tube design in order to improve the operation stability.