纳米液滴撞击高温平板壁的分子动力学模拟  

Molecular dynamics simulation of nanodroplet impacting on high-temperature plate wall

作　　者：冯山青 龚路远[1] 权生林[1] 郭亚丽[1] 沈胜强[1] Feng Shan-Qing;Gong Lu-Yuan;Quan Sheng-Lin;Guo Ya-Li;Shen Sheng-Qiang(National and Local Joint Engineering Research Center for Comprehensive Utilization of Thermal Energy,School of Energy and Power Engineering,Dalian University of Technology,Dalian 116024,China)

机构地区：[1]大连理工大学能源与动力学院,热能综合利用技术国家地方联合工程研究中心,大连116024

出　　处：《物理学报》2024年第10期126-135,共10页Acta Physica Sinica

基　　金：国家自然科学基金重点项目(批准号:51936002)资助的课题。

摘　　要：采用分子动力学的方法对纳米液滴撞击高温平板壁面产生的Leidenfrost现象进行了探究,分析了液滴撞击不同温度壁面对Leidenfrost现象的影响.结果表明,随着壁面温度的提升,液滴蒸发的速度更快,脱离壁面的时刻越早,脱离壁面时的速度也越大,最终悬浮时液滴体积也越大.通过分析脱离壁面前一时刻液滴内部的密度、温度分布发现,由于高温壁面具有更高的热通量致使蒸发过程更快进而产生更厚的蒸气层,该蒸气层将阻碍换热,使得液滴在壁面温度更高时液滴内部的平均温度越低,且平均密度越小.The process of droplet impacting on a high-temperature wall is widely existent in daily life and industrial applications.Most of scholars mainly have focused on experimental and macroscopic research on this phenomenon.In this work,molecular dynamics simulation is conducted to investigate the evolution of droplet and the influence of surface temperature on its evolution,in order to explore the heat transfer mechanism of nanodroplet impacting on high-temperature surface.Droplet containing 10741 argon atoms impacts on the copper plates at temperatures of 85,150,200,250 and 300 K,respectively.The number of droplet evaporation atoms is statistically obtained,the droplet barycenter displacement is analyzed,and the density distribution and temperature distribution inside the droplet are acquired.It is shown that the droplet exhibits different characteristics on the wall at different temperatures.The droplet finally stabilizes on the wall at 85 K as shown in Fig.(a),but when the temperature of the wall rises to 150 K,the droplet evaporates slowly and finally completely as shown in Fig.(b),and for the wall temperatures 200,250 and 300 K,the Leidenfrost phenomenon is found:the droplet is suspended above the wall as displayed in Figs.(c)-(e).Fig.(f)shows the number of evaporated atoms at different wall temperatures.It also can be seen that the Leidenfrost phenomenon occurs at wall temperatures 200,250 and 300 K,because for the three conditions there are rise steps and then the numbers of evaporated atoms almost keep constant.For the temperature conditions under which the Leidenfrost phenomenon can occur,the higher the wall temperature,the faster the droplet evaporates,the earlier the detachment occurs from the wall,the greater the droplet detaching velocity,and the larger the final suspending droplet volume.The analyses of the density distribution and temperature distribution of the droplet at the moment when it detaches from the wall show that the evaporation process is faster and a thicker vapor layer is generated due to

关 键 词：分子动力学 液滴 Leidenfrost现象 

分 类 号：O561[理学—原子与分子物理]