导叶开度对水泵水轮机调相运行水环流动的影响

水泵水轮机运行在泵工况压水启动过程或压水调相工况时,需要在转轮腔体内注入空气以降低转轮的启动功率.为了避免转轮室内的压缩空气泄漏到蜗壳内,需要在无叶区内形成一定厚度的水环进行密封,以减少压水时的用气量.为了研究导叶开度对水泵水轮机的水环内部流动特性的影响规律,利用ANSYS CFX软件对3种不同的导叶开度(全关闭、1%最优导叶开度、2%最优导叶开度)水泵水轮机模型两相流进行非定常数值计算分析.研究结果表明:水环的厚度随导叶的关闭而增大,从而增大了转轮的阻力,加大了轴功率的消耗;无叶区内的压力脉动特征频率为叶频及其倍频,呈现出明显的动静干涉现象.研究结果可为水泵水轮机在泵工况压水启动过程或压水调相工况下的水环控制提供一定的依据.

Influence of guide vane opening on water-ring flow characteristics of pump-turbine in synchronous condenser mode

It is necessary to inject air into the runner passage to reduce the starting power, when pump turbine operates under the starting process in pump mode or under the synchronous condenser mode. In order to prevent the compressed air in the runner passage from leaking into the casing, it is necessary to form a certain thickness of water-ring in the vaneless space for sealing to reduce the air consumption. In order to investigate the water-ring characteristics of pump-turbine in synchronous condenser mode by different guide vane openings, the ANSYS CFX software was employed to conduct the unsteady state analysis with two-phase flow. The pump-turbine model was adopted to investigate the internal flow characteristics on the water-ring with three guide vane openings(full closed, 1% GVO, 2% GVO). The research shows that the thickness of the water-ring increases with decrease in guide vane opening, which results in increasing the resistance of the runner and the consumption of the shaft power. At the same time, the dominate frequency of pressure fluctuation in the vaneless space is the blade pass frequency and harmonics, which represents the phenomenon of rotor-stator interaction obviously. The research results can provide a reference for controlling water-ring of pump-turbine in the process of synchronous condenser mode and sump start-up mode.