Dynamics of droplet impact on solid surface with different roughness
Dynamics of droplet impact on solid surface with different roughness
复制标题
液滴撞击不同粗糙度固体表面的动力学
DOI：
10.1016/j.ijmultiphaseflow.2017.07.002
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发表时间：
2017-11-01
影响因子：
3.8
通讯作者：
Huang, Zuohua
中科院分区：
文献类型：
--
作者：
Tang, Chenglong;Qin, Mengxiao;Huang, Zuohua
本文报道了一项实验研究水滴（水、癸烷、乙醇和十四烷）对平面不锈钢表面的冲击动力学，使用高速显微摄影技术，并对表面粗糙度对冲击动力学的影响特别感兴趣。结果表明：冲击水滴在表面上以边缘有界的片层形式扩散，到达最大扩散后边缘收缩，而燃料液体则不存在这种收缩运动；随着韦伯数（We）和表面粗糙度的增加，二次液滴的喷射有利于溅射。液滴的扩散速度随着We的增大而加快，表面粗糙度和Ohnesorge数（Oh）的增大则减慢了液滴的扩散速度。此外，最大归一化扩散直径beta（max）主要取决于（We/Oh），表面粗糙度的增加会略微降低beta（max）。随着We或R-a或两者的增加，从扩散到飞溅的转变会增强。根据目前的实验数据，导出了β (max)作为表面粗糙度函数的经验相关性。此外，从扩散到飞溅的转变可以用临界（We/Oh）（1/2）来表示，该临界（We/Oh）是表面粗糙度的函数。所有提出的经验相关性都与文献数据很好地吻合，并且被认为对喷雾/壁面相互作用建模很重要。(C) 2017年Elsevier Ltd.出版
This paper reports an experimental investigation on the impact dynamics of droplets (water, decane, ethanol, and tetradecane) onto a flat stainless steel surface, using high-speed microphotography and with a particular interest in the effect of surface roughness on the impact dynamics. Results show that the impacting water droplet spreads on the surface in the form of a rim-bounded lamella and the rim contracts back after reaching the maximum spreading, while this contraction motion is absent for the fuel liquids. With the increase of Weber number (We) and surface roughness, splashing, evidenced by the ejection of secondary droplets, is favored. The droplet spreading, which is characterized by a normalized diameter beta, is accelerated with increasing We, while the surface roughness and Ohnesorge number (Oh) tend to slow down the spreading process. Furthermore, the maximum normalized spreading diameter, beta(max), depends primarily on the (We/Oh) and the increase in the surface roughness slightly reduces beta(max). The transition from spreading to splashing is enhanced with increasing We or R-a or both. An empirical correlation of beta(max) as a function of the surface roughness was derived based on the present experimental data. In addition, the transition from spreading to splashing can be represented by a critical (We/Oh)(1/2), which was fitted as a function of the surface roughness. All the proposed empirical correlations show good agreement with literature data and are believed to be of importance for the spray/wall interaction modelling. (C) 2017 Published by Elsevier Ltd.