在工业生产过程中,液滴碰撞的控制和利用对于涂覆、喷涂、沉积等工艺有着重要意义.为了分析不等大液滴在不同湿润性壁面碰撞聚结的过程,制备了体积比为1∶2的不等大液滴,利用高速摄像技术,开展了不同润湿性基板上小液滴撞击大液滴的碰撞实验,对液滴碰撞聚结动力学行为进行分析.实验结果表明,在韦伯数为8.07≤We≤40.38与基板接触角α=100°、120°、145°、160°的实验范围内,液滴出现反弹聚结和接触聚结两种现象.双液滴碰撞聚结后,液滴的最大铺展直径与韦伯数呈正相关,与基板接触角呈负相关.最大射流高度随韦伯数增加先升高后降低,随接触角增加而增加.实验范围中,双液滴碰撞聚结过程中最大铺展直径为dp,max=8.41 mm,最大射流高度hs,max=6.92 mm.
Abstract
The control and utilization of droplet collisions in industrial production processes is of great importance for coating,spraying,deposition,et.al.In order to analyze the process of collision agglomeration of unequal droplets on different wettability wall surfaces,unequal droplets with a volume ratio of 1∶2 were prepared,the collision experiments of small droplets hitting large droplets on substrates with different wettability were carried out by using high-speed camera technology to analyze the dynamic behavior of droplet collision agglomeration.The results show that two types of droplet aggregation phenomena,rebound aggregation and contact aggregation,are found in the experimental range of 8.07≤We ≤40.38 and substrate contact angle α=100°,120°,145°,160°.The maximum spreading diameter of droplets after collisional aggregation of double droplets is positively correlated with the Weber number and negatively correlated with the substrate contact angle.The maximum jet height increases first and then decreases with the increase of Weber number,and increases with the increase of contact angle.In the experimental range,the maximum spreading diameter of the double droplet collision aggregation process is dp,max=8.41 mm and the maximum jet height hs,max=6.92 mm.
关键词
液滴碰撞/不等大液滴/聚结/接触角/韦伯数
Key words
droplet collision/unequal droplets/coalescence/contact angle/Weber number
维普
万方数据