重力影响下板间液桥断裂距离研究

运用实验测量和数值模拟两种方法对两平板间特征尺度为毫米量级的液桥断裂距离进行了研究,定量地给出了在有重力和无重力两种条件下,液桥断裂距离随着液桥体积和固体表面润湿性质变化的规律。结果显示,重力对液桥断裂距离的影响随着液桥特征尺寸的增大而增大,当特征尺寸达到毛细长度时,重力对亲水表面间液桥断裂距离的影响可达11%以上,对于疏水表面间的断裂距离影响更增加到20%以上。通过Surface Evolver软件可以很好地模拟准静态液桥拉伸-断裂过程,得到准确的液桥断裂距离。结果表明,即使在液桥特征尺寸小于毛细长度的条件下,液桥断裂距离也不能完全忽略重力的影响。

Study of Gravitation Effect on Rupture Distance of Liquid Bridge between Two Flat Substrates

Rupture distance of millimeter-scale liquid bridge between two flat substrates was experimentally and numerically studied. Quantitative relations between the rupture distances and the volume of liquid bridge and wetting property of solid surface were obtained under two conditions: with and without gravitation effect, respectively. Results show that gravitation has more effect on rupture distance along with the characteristic scale of liquid bridge increase. When characteristic scale has reached capillary length, the effect of gravitation on rupture distance between hydrophilic surfaces under gravitation are as high as more than 11%, and even more than 20% between hydrophobic surfaces. The quasi-static stretch-rupture process of liquid bridge was well simulated by Surface Evolver software. It indicates that the gravitation effect on rupture distance of liquid bridge is not completely ignored even though the characteristic scale of liquid bridge is shorter than capillary length.