混流式水泵水轮机驼峰区压力脉动特性

Pressure fluctuation characteristics of Francis pump turbine in Hump zone

为了研究混流式水泵水轮机在驼峰区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,对模型机组进行了全流道非定常数值计算.结合试验数据,分析了泵工况下驼峰区流道内不同位置处压力脉动特征和流态特征,讨论了流量变化对机组压力脉动特性的影响.结果表明:驼峰区工况下,蜗壳出口的压力脉动主要受到其内部流动特性的影响,同时受到上游双列叶栅作用的影响,在驼峰区极小值工况点处其压力时域变化周期性被扰动;导叶后转轮前的压力脉动主频为低频,第2主频为9倍转频和18倍转频,压力脉动幅值随着流量减小而增大;锥管内压力脉动都属于低频压力脉动,在驼峰区极小值工况点处,锥管上游压力脉动受下游转轮-尾水管动静干涉作用影响较大,出现了高频成分的压力脉动.

In order to study the pressure characteristics of Francis pump turbine flow in the peak zone inside,with a pumped storage station pump turbine as the research object,the whole flow channel unsteady numerical calculation was conducted for the model unit. Combined with the test data,the pressure fluctuation characteristics and flow characteristics at different positions in the hump flow under the pump operating conditions were analyzed,and the impact of the flow on the unit pressure fluctuation characteristics was discussed. The results show that under the hump zone operating condition,the pressure pulsation at the volute outlet is mainly affected by the internal flow characteristics,and also affected by the upstream dual cascade role. The pressure time domain change periodicity at the minimal value point in the hump zone is disturbed. The pressure pulsation frequency between the runner and the guide vane is the low frequency,and the second frequency is 9 times and 18 times conversion frequencies. The pressure fluctuation amplitude increases with the flow rate decreasing. Cone tube pressure pulsation is the low-frequency pressure pulsation. The upstream pressure fluctuation of cone tube is greatly influenced bythe dynamic interaction of the downstream runner-tail water pipe at the minimal value point in the hump zone,and there appears the pressure fluctuation of the high-frequency component.