Liu Zhongmin, Lu Zezhao, Zhang Chengwei, Lang Heng, Zhai Xin
School of Mechanical Engineering, Hangzhou Dianzi University, Hangzhou 310018, China.
Langmuir. 2023 Aug 22;39(33):11520-11528. doi: 10.1021/acs.langmuir.2c03448. Epub 2023 Aug 10.
The capillary force is critical to the moving and breaking of droplets on fibers. This study brings forward a 3-D model reconstruction method for a clam-shell droplet on fibers and obtains the capillary force by the surface integral of Laplace pressure on the whole droplet. The capillary force results are verified by the droplet gravity and axial drag force, respectively. Moreover, the tensile tangential stresses are analyzed to illustrate the top limits of Laplace pressure against droplet breaking or sliding on the fiber. The experiment shows that the capillary force obtained by the 3-D model accurately describes the vertical and tangential forces of the clam-shell droplet on the fiber. Sharp shrinking of the cross-section on the droplet's upper part results in an exponential increase in tensile and tangential stresses, which makes the droplet break or move on the fiber.
毛细力对于液滴在纤维上的移动和破裂至关重要。本研究提出了一种针对纤维上蚌壳状液滴的三维模型重建方法，并通过对整个液滴上拉普拉斯压力的表面积分获得毛细力。分别通过液滴重力和轴向阻力对毛细力结果进行了验证。此外，还分析了拉伸切向应力，以说明拉普拉斯压力对液滴在纤维上破裂或滑动的上限。实验表明，通过三维模型获得的毛细力准确地描述了蚌壳状液滴在纤维上的垂直力和切向力。液滴上部横截面的急剧收缩导致拉伸应力和切向应力呈指数增加，这使得液滴在纤维上破裂或移动。
