环形布膜式垂直管内制冷剂R113降膜流动特性研究

Falling flow characteristics of R113 inside the vertical tube with an annular distribution

为研发高效余热蒸发制冷装置,采用RNG k-ε模型和VOF模型数值研究环形布膜式垂直管内制冷剂R113流动分布和不同喷淋密度对液膜分布和液膜厚度的影响。研究结果表明:在基本工况下,R113液膜流动沿管长方向呈现从平稳到波动的变化过程,出现平稳段、波动段和震荡段三种不同流动形态;管壁表面的液膜厚度随喷淋密度的减小而减小,在喷淋密度减小到一定值时,圆管壁面出现局部"干斑"现象。

To study the falling flow characteristics of Rl13 inside the vertical tube with an annular distribution, this paper carried out numerical simulation with RNG k - ε model and VOF model. The paper also reseached the influence of different spray density on film forming and film thickness distribution inside the tube. The study shows that the film flow changes from steady to fluctuant along the longitudinal direction. Three kinds of flow patterns are presented, which are the steady, the wave and the shock. Film thickness with the spray density gets smaller and smaller. When the spray density reduces to a certain value, dry spot will form on local area of vertical tube.