预开导叶下水泵水轮机S特性及其压力脉动分析

可逆式水泵水轮机兼具了发电以及储能的特点既满足人们环保意识的需求也满足对功率的平衡与控制。但水泵水轮机在S特性区内运行会发生机组并网困难或者甩负荷过程中水压异常上升,使机组振动加剧。为探究预开启导叶的方法对水泵水轮机S特性的改善,对水泵水轮机模型分别在同步导叶和不同预开启导叶条件下进行能量试验及全流道内流场的(Computational fluid dynamics,CFD)数值计算;通过试验数据与计算结果的对比分析预开导叶后水泵水轮机S特性及其压力脉动特征。CFD计算结果及模型试验数据表明,预开导叶的方法能有效解决水泵水轮机S特性问题,但是预开导叶后,飞逸工况下的单位流量变大,造成转轮内的流动轴对称特性较差,导致机组的脉动加大,尾水管压力脉动幅值较大,运行稳定性较差,所以通过预开导叶的方法来改善S特性仍然存在弊端。

Analysis of S Characteristics and Its Pressure Pulsation of Pump-turbine under Pre-opening Guide Vanes

Due to the growing environmental awareness and demanding for the balancing power and frequency control,the renewable energy sources reversible pump-turbine seem to have the both characteristics of power generation and energy storage.While the Pump-turbine operates in the S characteristics,the difficulty in loading rejection process and unusual increase in water pressure will occur,which due to the machine vibration.In order to explore the pre-opening guide vane on the improvement of the S characteristics of pump-turbine.Firstly,uses the synchronization guide vane and pre-opening guide vane to do the energy test and the whole flow of CFD numerical flow;Secondly,by comparing the experimental data with the CFD results to analysis the S characteristics and its pressure pulsation;Then concluded that: by pre-opening part guide vanes the pump-turbine can avoid the influence of the S characteristic under the steady flow.While after pre-opening guide vanes,the increase of unit flow in the runway condition destroyed the symmetry of the flow in the runner,which due to the increase of the pressure pulsation and the unstable of the unit operation.So there is still some abuse improving the S characteristics by pre-opening part guide vanes.