模型水泵水轮机的尾水管旋涡空化流动分析
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摘要
为研究水泵水轮机的空化性能,文章采用基于SST k-ω湍流模型和Zwart空化模型的两相流计算方法,对某抽水蓄能电站的模型水泵水轮机进行定常计算,并将计算结果与试验结果进行了对比。对不同导叶开度下3个非设计工况的数值计算结果进行了对比分析,结果表明:随着流量增大,涡带形状有所不同,小流量工况下涡带形状较为复杂,中流量工况下涡带为螺旋形,大流量工况下涡带为柱状;涡带半径越来越小,涡带中心的压力越来越低,当涡带内部压力低于汽化压力时,就会产生空腔空蚀,反而使得效率下降。当转轮出口处外侧存在圆周速度分量,中心区域速度较小时,会形成涡带,交界区域速度急剧变化的位置与涡带半径相对应,涡带形状与速度分布情况有关。
In order to investigate the cavitation performance of the pump turbine,the flow in a model turbine of a pumped storage power station was simulated based on SST k-ω turbulence model and Zwart cavitation model.The simulation results and experiment data were compared.Three non-design conditions under different guide vane opening degrees were simulated and the results showed that:as the flow rate increases,the structure of the vortex rope changed.The structure of the vortex rope is relatively complex under low flow conditions,while it is spiral under medium flow conditions and columnar under large flow conditions.The radius of the vortex rope and the pressure inside the vortex rope decreases.When the pressure of the vortex rope core is lower than the vaporization pressure,cavitation occurs and the efficiency reduces.The vortex rope will be formed when there are circumferential velocity component in the runner outlet and a small center region velocity.The position where the velocity of the boundary region changes rapidly is related to the radius of the vortex rope,and the velocity distribution is connected with the shape of the vortex rope.
In order to investigate the cavitation performance of the pump turbine,the flow in a model turbine of a pumped storage power station was simulated based on SST k-ω turbulence model and Zwart cavitation model.The simulation results and experiment data were compared.Three non-design conditions under different guide vane opening degrees were simulated and the results showed that:as the flow rate increases,the structure of the vortex rope changed.The structure of the vortex rope is relatively complex under low flow conditions,while it is spiral under medium flow conditions and columnar under large flow conditions.The radius of the vortex rope and the pressure inside the vortex rope decreases.When the pressure of the vortex rope core is lower than the vaporization pressure,cavitation occurs and the efficiency reduces.The vortex rope will be formed when there are circumferential velocity component in the runner outlet and a small center region velocity.The position where the velocity of the boundary region changes rapidly is related to the radius of the vortex rope,and the velocity distribution is connected with the shape of the vortex rope.
引文
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[15]周凌九,王正伟,黄源芳.转轮出口流态对尾水管内压力脉动的影响[J].清华大学学报(自然科学版),2002(12):1670-1673.
[2]韩芳.我国可再生能源发展现状和前景展望[J].可再生能源,2010,28(4):137-140.
[3]贾宏新,张宇,王育飞,等.储能技术在风力发电系统中的应用[J].可再生能源,2009,27(6):10-15.
[4]R T柯乃普,J W戴利,F G哈密脱.空化与空蚀[M].北京:水利出版社,1981.1.
[5]阮辉,罗兴锜,廖伟丽,等.叶片低压边厚度对水泵水轮机空化性能与强度的影响[J].农业工程学报,2015,31(15):32-39.
[6]郑建兴,张俊芝,曾再祥,等.黑麋峰蓄能电站水泵水轮机模型验收试验及性能分析[J].水力发电,2010,36(7):63-65.
[7]徐宇,吴玉林,刘文俊,等.用两相流模型模拟混流式水轮机内空化流动[J].水利学报,2002(8):57-62.
[8]张梁,吴玉林,刘树红,等.混流式水轮机内部流场的三维空化湍流计算[J].工程热物理学报,2007(4):598-600.
[9]施卫东,李通通,张德胜,等.轴流泵叶轮区域空化特性数值模拟[J].农业工程学报,2012,28(13):88-93.
[10]张德胜,施卫东,陈斌,等.轴流泵叶轮汽蚀两相流的数值模拟与分析[J].流体机械,2013,41(4):16-20.
[11]郝宗睿,刘锦涛,王乐勤.水泵水轮机临界空化系数的数值预测[J].排灌机械工程学报,2013,31(9):774-777.
[12]李琪飞,刘超,王源凯.部分负荷工况下水泵水轮机的空化特性[J].排灌机械工程学报,2017,35(8):680-684.
[13]Menter F R.Two-equation eddy-viscosity turbulence models for engineering applications[J].AIAA Journal,1994,32(8):1598-1605.
[14]张大本,李吉川.混流式水轮机尾水管涡带引起的水力振动[J].广西电力技术,1996(4):18-22.
[15]周凌九,王正伟,黄源芳.转轮出口流态对尾水管内压力脉动的影响[J].清华大学学报(自然科学版),2002(12):1670-1673.