为探究水泵水轮机转轮和导水机构的动应力特性,通过建立水泵水轮机导水机构(固定导叶与活动导叶)及转轮的固体域模型,并基于流固耦合的方法对转轮、导水机构在水泵水轮机发电、抽水等多工况展开计算分析,以获得转轮及导水机构的应力特性.计算结果表明:转轮叶片与上冠"T"型连接处的应力集中与转轮进口处旋涡发展状态有关;转轮与活动导叶间的动静干涉是无叶区压力脉动的主要来源,且主频为叶片通过频率;较小开度或低水头工况下机组运行靠近不稳定区,活动导叶与转轮的动应力均较大,但活动导叶对水流的约束引导作用使其动应力值相比于转轮更高,且流量的增大有利于降低转轮所受动应力.因此可考虑通过改变导叶尾端与转轮进口间距,调整无叶区宽度或调整机组运行区域,避免长时间运行在低负荷、小开度工况下可进一步改善转轮所受动应力情况.
In order to investigate the dynamic stress characteristics of runner and distributor of pump-turbine,this paper establishes the solid domain models of stay vanes,guide vanes and runner,and carries out the FSI-based computation of runner and distributor.The calculation results show that the stress concentration at the"T"junction between the runner blade and crown is related to the vortex development state at the runner inlet;the dynamic and static interference between runner and guide vanes is the main source of pressure pulsation in the vaneless zone,where the main frequency is the blade passing frequency;the dynamic stress of guide vanes and runner is generally high because the pump-turbine is easily involved in the unstable area while working under smaller GVO(guide vanes opening)or low head conditions.The dynamic stress of guide vanes is greater than that of the runner owing to its constraint guidance effect on water flow,and increased flow rate is beneficial to reducing the dynamic stress of the runner.So for the purpose of improving the dynamic stress of runner,the measures could be taken,such as changing the distance between the guide vanes tail and runner inlet,i.e.changing the width of vaneless zone,or adjusting the unit operation area,i.e.avoiding working in low road or small opening conditions for long.