液滴碰撞亲-疏水性组合壁面的数值分析

采用VOF方法对液滴碰撞亲-疏水性组合壁面过程进行数值模拟。通过量纲1化，在Reynolds数不变的情况下，研究Weber数和亲水性区域直径对液滴碰撞动态特性的影响，绘制了液滴碰撞结果分区图。结果表明：随着Weber数从1增加至100，液滴呈现出附着、短液滴一次破碎和长液滴多次破碎3种状态；液滴破碎过程受到表面张力、壁面黏附力及Rayleigh不稳定性的影响，亲水性区域直径增加时，液滴破碎所对应的临界Weber数随之增大；此外，Weber数较大时，液滴最大铺展因子不受亲水性区域直径的影响，Weber数较小时，最大铺展因子随亲水性区域直径的增大而增大。

Numerical simulation of droplet impact on hybrid surfaces with different wettabilities

Surfaces with patterned domains of different wettabilities can be used for controlling the impact process. The dynamic behavior of droplet impact on hybrid surfaces with different wettabilities is simulated using the VOF method by dimensionless. Effects of Weber number and hydrophilic region diameter are studied with constant Reynold number. A drop impact regime map is generated, in which the impact dynamics is characterized as a function of Weber number and relative diameter of hydrophilic region. With the increase of Weber number, the droplet presents three different status: deposition, pinch-off as a short liquid column and break up as a long liquid column. The threshold Weber number where pinch-off occurs will increase with the increase of hydrophilic region diameter. For high Weber number, the maximum spreading factors are the same for different hydrophilic region diameter. While for low Weber number, the maximum spreading factors will increase with it.