轴流泵装置反向发电的水力特性

为探究某泵站轴流泵装置反向发电的水力特性,对该轴流泵装置反向发电工况进行全流道数值模拟分析.结果表明:轴流泵装置在额定转速进行反向发电时,其最优工况相比于水泵模式,水头和流量分别提高43%和38%;随着转速增大,效率-流量曲线呈现向大流量方向偏移趋势,高效区范围逐渐增大;导叶进口、转轮进出口压力脉动呈周期性,转轮进出口压力脉动受转轮旋转影响更为显著;压力脉动系数幅值沿径向由轮毂至轮缘逐渐增大,转轮出口的压力脉动幅值最大,约为转轮进口的2倍;在频域方面,压力脉动主频为叶频,次频为2倍叶频,在转轮进出口主频所对应的压力脉动系数幅值沿径向由轮毂至轮缘逐渐增大;在小流量工况,随着轴流泵反向发电运行时的流量越小,出水流道流线越混乱且涡带越明显.研究结果可为泵站轴流泵装置反向发电提供一定的理论支撑和工程运行参考.

Hydraulic characteristics of reverse power generation of axial-flow pump

In order to investigate the hydraulic characteristics of reverse power generation of axial-flow pump device in a pumping station, the full flow channel numerical simulation analysis of reverse power generation of the axial-flow pump device was carried out. The results show that when the axial-flow pump device generates reverse power at rated speed, the head and flow are increased by 43% and 38% respectively compared with the pump mode. At the same time, with the increase of rotating speed, the flow-efficiency curve tends to shift to the direction of large flow, and the width of high efficiency zone increases gradually. The pressure fluctuation at the inlet and outlet of guide vane and runner is periodic. The pressure fluctuation at the guide vane inlet and the inlet and outlet of runner is periodic, and the pressure pulsation at the in and outlet of runner is more significantly affected by the rotation of the runner. The amplitude of pressure fluctuation coefficient increases gradually from hub to rim along the radial direction, the pressure fluctuation amplitude of runner outlet is the largest, which is nearly two times of that at the runner inlet. In the frequency domain, the main frequency of pressure fluctuation is the blade frequency, the secondary frequency is 2 times blade frequency. The amplitude of the pressure fluctuation coefficient corresponding to the main frequency at the inlet and outlet of runner increases gradually from the hub to the rim along the radial direction. In small flow condition, with the decrease of the flow rate of the reverse power generation of the axial-flow pump, the more chaotic the streamline of the outlet passage is, and the more obvious the vortex zone presented. The paper provides theoretical support and engineering operation reference for reverse power generation of axial-flow pump in pump station.