In this work, the droplet impact and rebound behaviors on a flat substrate are comprehensively investigated by using the consistent and conservative phase-field based lattice Boltzmann method, which is robust for the multiphase flow problems with the large density ratios and long-time dynamics. The dynamic behavior of the droplet considered here is governed by five key factors: the contact angle, droplet size, the Bond number, the Reynolds number and the density ratio. The effects of these parameters on the barycenter motion trajectory, contact time, the maximum spreading factor and rebound height are studied, and the results show that the Bond number and the density ratio play the critical roles in the droplet morphology when it impacts the substrate. After the impact process, there are three typical patterns: fragmentation, deposition and rebound, which are mainly controlled by the wettability, the size of droplet and the Bond number. In the rebound process, we focus on the rebound height and the number of rebound, and also give the distribution of pressure inside the droplet and the evolution of pressure before fragmentation. Finally, it is also found that under some certain conditions, the air density has a positive effect on the droplet rebound behavior and a large density ratio of 6400 can be achieved.

中文翻译：

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液滴撞击和反弹的动力学：晶格玻尔兹曼研究

在这项工作中，采用一致且保守的基于相场的格子玻尔兹曼方法全面研究了液滴在平坦基底上的撞击和反弹行为，该方法对于大密度比和长时间动态的多相流问题具有鲁棒性。这里考虑的液滴的动态行为由五个关键因素控制：接触角、液滴尺寸、键合数、雷诺数和密度比。研究了这些参数对重心运动轨迹、接触时间、最大铺展因子和回弹高度的影响，结果表明键合数和密度比对液滴撞击基底时的形貌起着关键作用。撞击过程后，存在破碎、沉积和反弹三种典型模式，主要受润湿性、液滴尺寸和键合数控制。在回弹过程中，我们重点关注回弹高度和回弹次数，并给出了液滴内部压力的分布以及破碎前压力的演变。最后还发现，在某些特定条件下，空气密度对液滴反弹行为有积极影响，可以实现6400的大密度比。