水泵水轮机泵工况旋转失速压力脉动特性及转动机理  

Pressure fluctuations characteristics and rotating stall propagation mechanism of a pumpturbine in pump mode

作　　者：张春泽[1,2] 夏林生 刁伟[1,2] 周家俞[1] 

机构地区：[1]重庆交通大学西南水运工程科学研究所,重庆400016 [2]武汉大学水资源与水电科学国家重点实验室,湖北武汉430072

出　　处：《水利学报》2017年第7期837-845,共9页Journal of Hydraulic Engineering

基　　金：国家自然科学基金面上项目(51579187);重庆市基础与前沿研究计划项目(cstc2016jcyj A1935;cstc2016jcyj A1937);重庆市教委科学技术研究项目(KJ1600514;KJ1600535);重庆交通大学内河航道整治技术交通行业重点实验室开放基金重点项目(NHHD-201501;NHHD-201505;NHHD-201513)

摘　　要：水泵水轮机在泵工况部分负荷下运行,叶道内易发生旋转失速,可诱发剧烈的低频压力脉动,严重影响水电站的安全稳定运行。本文采用尺度自适应(SST-SAS)湍流模型对某模型水泵水轮机泵工况进行全流道非定常数值模拟,得到不同工况点下旋转失速引起的压力脉动特性及失速涡团的周向转动机理。结果显示,在40%~80%设计流量下运行时,导叶区发生旋转失速,失速涡团的转动频率为叶轮转频的3.3%~8.1%。旋转失速发展强度越剧烈,转动越慢。旋转失速周向转动的机理是:失速与非失速相邻导叶流道内存在较大压力梯度,在其作用下,失速流道内流体从活动导叶与固定导叶之间通道流向非失速流道,加剧非失速流道内流动分离。被阻碍的水流与无叶区主流叠加流向下一流道,并在活动导叶吸力面进口前缘产生局部低压,导致当前非失速活动导叶流道在进口与出口之间的逆压梯度增强,使流体反向流动,流道产生失速。The pump-turbines have to be operated under off-design conditions to maintain the stability of the grid. The rotating stall usually occurs at part load in pump mode,which can cause severe pressure fluctuations and strong vibrations. To understand the pressure fluctuations and the stall cells propagation mechanism within turbine,the Scale adaptive simulation（SST-SAS） turbulence model and unsteady RANS approach were adopted to simulate a mode pump-turbine with different flow rate. The results show that thesimulated characteristics curves are in good agreement with the experiment results. The rotating stall occursin the region from 40% to 80% of the best efficiency point（BEP） flow rate. The stall cells rotating alongthe circumference and their rotating frequency is 3.3%~8.1% of the runner rotating frequency. The propagation of the stall cells is driven by the growth and the decay of the stall cell. The pressure gradient between the stalled and un-stalled channels make the fluids flow from the stalled channel into the unstalledchannel through the gap between the corresponding guide vane and stay vane,which will increase the flowseparations in the unstalled channel. The growth of flow blockage in the un-stalled channel will make theinflow deviate toward the downstream channel and pressure decrease around the leading edge of the guidevane suction side. Further,the adverse pressure gradient between the leading and the trailing edges of theun-stalled guide vane is enhanced. Consequently,the flow blockage continues to grow until the vortices occupy the entire un-stalled channel.

关 键 词：水泵水轮机 旋转失速 水泵工况 数值模拟 压力脉动 

分 类 号：TV741[水利工程—水利水电工程]