非能动安全壳竖直平板降膜流动特性数值模拟

Numerical simulation on falling film properties of vertical plate in passive containment

核电安全日益受到关注,非能动系统作为第三代核电系统具有很高的安全性。采用FLUENT流体体积分数(volume of fraction,VOF)模型和k-ε湍流模型对非能动安全壳冷却系统(passive containment cooling system,PCCS)三维平板降膜流动进行数值模拟。结果表明:1)在降膜过程中有波动现象,最终波动趋于平缓;2)水与空气逆流流动过程中发生轻微的液滴夹带;3)降膜流动受重力、表面张力与壁面黏滞力共同作用,液膜厚度沿横向分布均匀,沿高度方向平均液膜厚度越来越小,并且受进口水流速度与入口宽度影响,水流量一定时增加进口水流速度与入口宽度,平均液膜厚度增大,空气入口流速对水膜厚度影响相对较小。

The Safety of nuclear power plants are becoming more and more important,passive containment has high security as the generation of nuclear power system.In this paper,numerical simulation on falling film properties of three-dimensional vertical plate in the passive containment cooling system with Volume of Fluid（VOF）model k-εturbulence model by FLUENT.The numerical results show that：1）The wave phenomenon appears in the process of falling film,eventually flatten out fluctuations;2）Entrained droplets appears when water and air counter-currently pass the channel;3）Falling film flow by gravity,surface tension and viscous force wall work together,uniform thickness of liquid film along the lateral distribution,and the average thickness of liquid film along the height direction become thin,in addition,the import flow velocity and the import width have a significant impact on the thickness of liquid film,when the water flux remains constant,the greater the import flow speed and the import width,the greater the thickness of liquid film,and the influence of that is more powerful than that of air inlet velocity.