采用VOF方法模拟了液滴以相同速度撞击到接触角分别为63°、90°、118°和160°的固体壁面上的形态演变过程。结果表明:固壁的亲憎水性对液滴撞击表面后形态的演化有较大影响,亲水壁面有利于液滴的铺展,在接触角为90°的壁面上液滴部分反弹,而当接触角为160°时,液滴完全反弹;当三相接触线开始回缩时,中心液体的表层部分在惯性力的作用下继续向铺展的液滴边缘聚集,导致近中心处液膜逐渐减薄至断裂,最终形成边缘较厚的液环;同时,液滴最大铺展系数随壁面接触角的增大而减小,达到最大铺展系数的时间也相应缩短。
Dynamic behavior of an impacting water droplet was simulated with the VOF(volume of fluid)method.Droplet diameter was 2.6 mm and impacting velocity was 0.5 m·s-1.Droplet dynamic behavior on simulated,hydrophilic and hydrophobic surfaces was simulated with an impacting angle of 63°,90°,118°and 160°.Simulation results showed reasonably good agreement with the experiment data.Surface wettability seriously affected droplet dynamic behavior.Droplet spread well and then sticked on the hydrophilic surface.On the surface with an impacting angle of 90°,droplet partly rebounded away from the surface.While droplet totally rebounded when impacting on the hydrophobic surface.There was an edge liquid ring for liquid sticking on the droplet edge when contact line draw back.The maximum spreading factor and the time needed to arrive at the maximum spread diameter were reduced with increasing contact angle.