液滴碰撞不同浸润性倾斜平板实验研究

Experimental Study of Droplet Impacting on Inclined Substrates With Different Wettabilities

采用高速摄像技术对液滴碰撞不同浸润性倾斜平板的动力学行为开展研究。系统分析了不同基板倾斜角度、浸润性及碰撞韦伯数对液滴撞击不同浸润性壁面动力学行为的影响规律,通过分析液滴撞击过程中的形态演化规律,阐述了不同分析变量对液滴撞击过程动力学行为的影响机制。结合沿斜面的切向力与垂直于基板的法向力作用关系,揭示了液滴与基板接触时间的变化规律,完成了液滴碰撞过程中的子液滴形成条件的定量划分。系统分析了韦伯数、接触角及基板倾斜角对液滴最大铺展直径与射流高度的影响规律,确立了各个分析变量对最大铺展直径及射流高度影响的定量关系。研究结果对揭示复杂工况下的液滴碰撞动力学行为机制,指导通过壁面改性实现液滴规律运移及定向调控具有一定理论及工程意义。

The dynamic behavior of droplets impacting on inclined substrates with different wettabilities is investigated via high-speed photography technology. The effects of different substrate inclination angle, wettability and Weber number on the dynamic behavior of liquid droplets impacting on inclined substrates are analyzed systematically. The influence mechanism of different analysis variables on the dynamic behavior of droplet impact process is revealed by analyzing the law of morphological evolution in the process of droplet impact. Combined with the relationship between the tangential force that along the inclined plane and the normal force perpendicular to the substrate,the variation law of the contact time between the droplet and the substrate is revealed. Meanwhile,the quantitative division of the parameters for the formation of daughter droplets in the process of droplet impact is conducted. The effects of Weber number, contact angle and substrate inclination angle on the maximum spreading diameter and jet height of droplets are analyzed systematically.Furthermore, the quantitative relationship between the influence of various analytical variables on the maximum spreading diameter and jet height is established. The investigation results have certain theoretical and engineering significance for revealing the dynamic behavior mechanism of droplet collision under complex conditions and guiding the regular movement and directional regulation of droplets by surface modified technique.