液滴碰撞不同湿润性表面的行为特征

摘要

Four types of surfaces were prepared in order to analyze the influence of wettability on the droplet collision behavior.They were superhydrophilic,hydrophilic,low adhesive superhydrophobic and high adhesive superhydrophobic surface.Collision experiment was conducted on four surfaces over a wide range of height.Droplet diameters were 1.96 mm,2.61 mm,3.06 mm respectively.Droplets exhibited different behavioral characteristics on four surfaces under different We.Droplets mainly exhibit spreading characteristics on hydrophilic and superhydrophilic surfaces,but the extension is more thorough on the superhydrophilic surface.Droplets mainly exhibit rebounce characteristics on low adhesive and high adhesive surface,and droplets can rebound entirely on low adhesive surface.Droplet behaviors could be divided into different regions in the coordinates of We versus Re.The tendency of expansion coefficient β with dimensionless time τ almost does not change and the maximum value of β can increase with the increase of We.%为了探究湿润性对液滴撞击行为特性的影响,制备超亲水、亲水、超疏水高黏附、超疏水低黏附4类湿润性表面.利用直径为1.96、2.61、3.06 mm的液滴,在不同的高度下开展液滴碰撞4类湿润性表面的实验.结果表明,在不同We下,液滴碰撞特性受撞击表面湿润性的影响较大,在亲水以及超亲水表面主要表现为铺展特性,但在超亲水表面扩展更显著;在超疏水低黏附以及高黏附表面主要表现为弹跳特性,但当表面为低黏附时,液滴主要表现为完全弹跳.在We-Re坐标下,4类表面各自的液滴碰撞特性可以划分为差异明显的不同铺展或者弹跳现象.4类表面各自的扩展系数β随无量纲时间τ的变化趋势随We的变化基本保持不变,但β的最大值随We的增大而增大.