水泵水轮机同步启动过程内部流场分析

Inner Flow Field Analysis on the Process of Synchronous Initiation of Pump Turbine

为了研究水泵水轮机水轮机工况同步启动过程中的瞬态流动特性和能量转换机理,基于FLUENT动网格模型对模型水泵水轮机同步启动过程进行了三维全流道数值模拟。根据模拟结果,重点分析了活动导叶、转轮内部流场结构的演变过程。结果表明:水轮机启动过程大体可分为两个阶段,第一阶段导叶开度较小时,从活动导叶出来的高压水流在活动导叶与转轮之间的区域沿活动导叶形成的内环面作圆周运动,转轮以较小的角加速度缓慢加速;第二阶段当导叶开度足够大时,高压水流开始直接作用在叶片上,并且高压区面积不断增大转轮转速急剧增大。

In order to study the transient flow characteristic and mechanism of energy conversion on the process of synchronous initiation of working condition of water turbine of pump turbine,three-dimensional numerical simulation of full flowpath of the process of synchronous initiation of pump turbine model is conducted based on FLUENT dynamic mash model.Movable guide vane and evolution process of inner flow field structure of turning wheel are emphatically analyzed based on simulation results,which indicates that starting process of water turbine can be generally divided into two phases.On the first phase,guide vane opening is smaller.Water flow with high pressure from movable guide vane has circling motion along the inner ring surface formed by movable guide vane on the region between movable guide vane and turning wheel.The turning wheel is slowly accelerated at a smaller angular acceleration.On the second phase,water flow with high pressure starts to directly influence vane with continuously increase of area of high pressure and rapid increase of revolving speed of turning wheel when the guide vane opening is large enough.