颗粒对混流式水轮机内流场及外特性的影响

Effect of Particles on Internal Flow Field and External Characteristics in Francis Turbine

为了研究颗粒对混流式水轮机内部流场和外特性的影响,采用单相和固液两相流模型对某电站的高水头混流式水轮机进行全流道非定常数值模拟,分析水轮机运行在典型工况(小流量工况、额定工况、大流量工况)时的外特性和压力脉动特性。结果表明:颗粒的存在会不同程度降低水轮机效率,平均降低1%左右。在监测点P_1(转轮与活动导叶的交界面)处,颗粒的存在不同程度增加了此处的压力脉动,小流量工况下增加幅度最大;监测点P_5(尾水管)处,小流量工况下颗粒的存在增加了此处的低频压力脉动,大流量下颗粒的存在略微削弱了此处的压力脉动幅值。

To study the influence of particles on the internal flow field and external characteristics of Francis turbines,the unsteady numerical simulation of full passage of a high-head Francis turbine was carried out based on single-phase and solid-liquid two-phase models. The external characteristics and pressure pulsation of the turbine are analyzed in three typical conditions: low flow rate,rating condition,and high flow rate. It showed that the existence of the particles reduces efficiency of turbine with the average reduction of about 1%. At the monitoring point P_1( at the interface between the runner and the guide vane),the presence of particles increases the pressure pulsation,with the largest increase occurring under the low flow rate condition. At the monitoring point P_5( draft),the presence of particles increases the low-frequency pressure pulsation for the low flow rate,while it slightly weakens the pressure pulsation for the high flow rate.