平面闸门有压出口段突扩突跌三维流场数值模拟

高水头平面闸门后接平坡明流段,且出口采用突扩突跌的掺气设施,其水力特性复杂,实际工程中研究及运用较少.结合设计采用该形式的龙开口水电站冲沙底孔,应用标准双方程紊流模型和VOF多相流方法对其流道流场进行了三维数值模拟,对闸门出口突扩突跌段特性、平坡泄槽段水力特性进行研究,并将部分结果与模型试验成果进行比较,两者符合较好.通过数值模拟与模型试验相互验证对其体型进行优化,提出闸门段压力分布均匀的出口收缩方式、出口加挑坎的跌坎掺气体型,在平坡泄槽上取得了良好的掺气效果,为工程设计提供参考.

Numerical simulation of 3D flow field at plane gate region with suddenly lateral enlargement and bottom drop

There has little report on the plane gate region with suddenly lateral enlargement and bottom drop in the outlet of pressured spillway tunnel.In this paper,a three-dimensional two-phase flow model based on standard k-ε two-equation turbulence model and volume of fluid(VOF)model for simulating the flow field in sand flushing bottom outlet of Longkaikou Hydropower Station are developed.The flow characteristics of open channel and the outflow of suddenly lateral enlargement and bottom drop are simulated;and the data show a good agreement with the physical model test.The optimized shape which has a plunge and flip bucket can have a better pressure distribution and intensive air entrainment on the flat-bottomed channel.The conclusion will provide reference data for the design of projects.It can be used for reference in similiar projects.