摘要
射流放水阀是水电站和水坝放水系统中广泛应用的流量控制装置。目前关于射流放水阀的数值模拟均为静止状态下的流场分析,运动状态下的流场数值模拟还未见报道。本文采用温度体模型和重叠分区背景网格方法生成射流阀动态关闭过程中的计算域网格,首次采用数值模拟方式对其动态过程进行研究。数值模拟结果显示,射流阀流量与开度呈近似线性变化规律,但在大开度和小开度范围内,流量随开度的变化较为平缓。水流经阀针后发生分离,在其背部形成主流区、剪切层区和回流区。在阀针外缘处、阀壳喉部及阀针后侧的压力远远低于阀针头部及正面压力,将导致这些区域发生汽蚀。数值模拟结果与实验观测到的现象非常吻合。
Hollow-jet valve is widely used in water discharging system of hydropower station and dam. At present, the computational fluid dynamics of hollow-jet valve is under the static analysis. In this thesis, grids＇ reference temperature distribution and division of background grid are used to generate the dynamic grid during the closing process. The computational fluid dynamics obtain the flow rates at different valve opening. The pressure at the outer margin and backside of valve needle, throat of valve shell is much lower than front side, which will case the vortex cavitation. This result is highly identical with the phenomenon observed by experimental methods.
出处
《流体机械》
CSCD
北大核心
2009年第12期9-13,共5页
Fluid Machinery
基金
国家自然科学基金项目(50776052)
水沙科学与水利水电工程国家重点实验室自主研究课题项目(2008-ZY-2)
关键词
射流放水阀
温度体模型
重叠分区背景网格
旋涡空化
hollow-jet valve
temperature analogy
division of background grid
vortex cavitation
