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喷雾液滴撞击液膜影响参数及流动机理分析-2021增刊

鲍俊,王瑜,牛潜,朱锡冬,程建杰   

  1. 南京工业大学
  • 收稿日期:2021-09-10 修回日期:2021-10-05 出版日期:2021-10-09 发布日期:2021-10-09
  • 通讯作者: 王瑜
  • 基金资助:
    国家自然科学基金青年基金项目;中国博士后科学基金面上项目;南京航空航天大学飞行器环境控制与生命保障重点实验室项目

Influencing Parameters and Film Flow Mechanism of Spray Droplet Impacting Liquid Film

  • Received:2021-09-10 Revised:2021-10-05 Online:2021-10-09 Published:2021-10-09

摘要: 液滴撞击壁面是喷雾冷却中最常见的现象。使用Volume of Fluid (VOF)模型对液滴撞击壁面过程进行了模拟研究,研究了不同参数的液滴撞击壁面液膜过程的水花形态特点,针对水花高度和直径进行了分析,通过运动间断理论和无量纲参数Re的变化分析了不同参数对液膜的流动特征和水花形态的影响及水花产生机理。结果表明:大液滴撞击液膜时能够改善液膜的流动状态;过大的液滴速度会产生大量飞溅及表面干涸;液滴撞击薄液膜时,液膜的流动性较好,当0.6<h*<1.2时,液膜的流动性不随液膜厚度改变。

关键词: 喷雾冷却, 数值模拟, 计算流体力学, VOF, 液膜, 水花参数

Abstract: The impact of droplets on the wall is the most common phenomenon in spray cooling. The volume of fluid (VOF) method was used to simulate the process of droplets impacting the wall surface, and the splash shape characteristics of the process of droplets impacting the wall surface liquid film with different parameters were studied. According to the height and diameter of splash, the influence of droplet parameters and film thickness on splash parameters were analyzed. Combined with the change of splash parameters, the motion discontinuity theory and the change of the dimensionless parameter Re and We were used to analyze the effects of different parameters on the flow characteristics of the liquid film, the shape of the splash and the mechanism of the splash generation. The results showed that when large droplets hit the liquid film, the fluidity of the liquid film can be improved, but the film thickness will be increased. Excessive droplet velocity will produce a lot of splashing and dry up the surface. In-creasing the surface tension properly can reduce the formation of secondary droplets and promote the flow of liquid film. Better fluidity of the liquid film can be achieved when the droplets hit a thin liquid film. When the non-dimensional film height is be-tween 0.6 and 1.2, the fluidity of the liquid film does not change with the thickness of the liquid film.

Key words: Spray cooling, Numerical Simulation, Computational Fluid Dynamics, VOF, Liquid films, Splash parameters

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