异常低水头下水泵水轮机压力脉动特性分析

发布时间：2018-10-21 14:04

【摘要】：为了研究水泵水轮机在异常低水头下内部流动的压力脉动特性,以某抽水蓄能电站模型水泵水轮机为研究对象,基于大涡模拟方法,对模型机组进行全流道非定常数值计算.结合试验数据,分析异常低水头下流道内不同位置处压力脉动特征和流态特征,讨论流量变化对机组压力脉动特性的影响.结果表明:异常低水头下,压力脉动主要由"导叶-转轮-尾水管"之间的两级动静干涉以及肘管段结构弯曲引起水流撞击等因素共同引起;流量变化对导叶后转轮前压力脉动的频率和幅值影响不大,仅在小流量区有所区别;尾水管内压力脉动的低频值和幅值受流量变化的影响较大,而高频值则在各种流量状况下均未出现.与正常运行工况相比,水泵水轮机在异常低水头工况下的压力脉动特性明显增强,对机组的稳定性和安全性造成了十分不利的影响.
[Abstract]:In order to study the pressure fluctuation characteristics of pump turbine flow under abnormal low water head, a model pump turbine of a pumped storage power station was studied. Based on the large eddy simulation method, the unsteady numerical calculation of the model unit was carried out. Based on the experimental data, the pressure pulsation characteristics and flow state characteristics at different locations in the downflow channel with abnormal low head are analyzed, and the influence of flow rate variation on the pressure pulsation characteristics of generating units is discussed. The results show that the pressure pulsation is mainly caused by the two-stage static and static interference between the guide vane, the runner and the draft tube, and the impact of the water flow caused by the bend of the elbow tube structure under the abnormally low water head. The change of flow rate has little effect on the frequency and amplitude of pressure pulsation in front of the back runner of guide vane, but only in the small flow region, and the low frequency and amplitude of pressure pulsation in draft tube are greatly affected by the change of flow rate. But the high frequency value does not appear under each kind of flow condition. Compared with the normal operation condition, the pressure pulsation characteristics of the pump turbine under the abnormal low head condition are obviously enhanced, which has a very adverse effect on the stability and safety of the unit.
【作者单位】：兰州理工大学能源与动力工程学院;兰州理工大学甘肃省流体机械及系统重点实验室;
【基金】：国家自然科学基金(51566009) 甘肃省自然科学基金(1310RJZA023)
【分类号】：TV734.1

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