带分流叶片水泵水轮机特殊工况内部流场特性

Internal flow characteristics of pump turbine with splitter blades under special conditions

基于国内某抽水蓄能电站建立的水力模型并结合该模型试验报告,采用SST/Uo模型计算带分流叶片水泵水轮机7.5°导叶开度下零流量工况附近的制动工况和反水泵工况,进行定常和非定常数值模拟,研究其内部流场压力分布、速度流线分布及径向力分布规律.结果表明:计算流体动力学数值计算可以很好地模拟分析带分流叶片水泵水轮机的内部流场特性;制动工况下的流态很差,涡结构充满整个流道引起水流拥堵且成不对称分布;反水泵工况导叶和转轮出现了严重的流动分离,水流在叶片中上游发生冲击;分流叶片的存在减小了负压区域,降低了汽蚀现象发生的可能性,有助于水轮机内部水流流动更加平稳;带分流叶片水泵水轮机的径向力在一个周期内的变化规律与转轮叶片数强关联,峰谷值个数与叶片数相对应.

Based on the hydraulic model established by a domestic pumped storage power station and the test report of the model test,the shear stress transfer(SST)k-co model was used to calculate the steady and unsteady numerical simulation of the braking and reverse pump conditions near the zero-flow condition of the 7.5°guide vane of the pump turbine with shunt vanes.The pressure distribution,velocity streamline distribution and radial force component of the internal flow field were studied.The results show that the computational fluid dynamics(CFD)numerical calculation can simulate and analyze the internal flow characteristics of the pump turbine with splitter blades well.The flow pattern under braking condition is very poor,and the vortex structure fills the whole flow passage causing the flow congestion and asymmetrical distribution.The flow separation between the guide vane and the runner under reverse pump condition occurs seriously,and the presence of splitter blades reduces the negative pressure zone.The existence of splitter blades reduces the possibility of cavitation phenomena and helps to make the flow more stable inside the turbine.In the distribution of radial force,the variation of radial force of pump turbine with splitter blades in a period is closely related to the number of runner blades,and the number of peak and valley values corresponds to the number of blades.