Department of Mechanical and Nuclear Engineering, Virginia Commonwealth University , Richmond, Virginia 23284-3015, United States.
Langmuir. 2016 Dec 20;32(50):13333-13339. doi: 10.1021/acs.langmuir.6b03198. Epub 2016 Dec 8.
Determining the force required to detach a droplet from a fiber or from an assembly of fibers is of great importance to many applications. A novel technique is developed in this work to measure this force experimentally by using ferrofluid droplets in a magnetic field. Unlike previous methods reported in the literature, our technique does not require air flow or a mechanical object to detach the droplet from the fiber(s); therefore, it simplifies the experiment and also allows one to study the capillarity of the droplet-fiber system in a more isolated environment. In this article, we investigated the effects of the relative angle between intersecting fibers on the force required to detach a droplet from the fibers in the in-plane or out-of-plane direction. The in-plane and through-plane detachment forces were also predicted via numerical simulation and compared with the experimental results. Good agreement was observed between the numerical and experimental results. It was found that the relative angle between intersecting fibers has no significant effect on the detachment force in the out-of-plane direction. However, the detachment force in the in-plane direction depends strongly on the relative angle between the fibers, and it increases as this angle increases.
确定从纤维或纤维束上分离液滴所需的力对于许多应用都非常重要。本工作开发了一种新的技术，通过在磁场中使用铁磁液滴来实验测量该力。与文献中报道的以前的方法不同，我们的技术不需要气流或机械物体将液滴从纤维上分离；因此，它简化了实验，也允许人们在更隔离的环境中研究液滴-纤维系统的毛细现象。在本文中，我们研究了相交纤维之间的相对角度对沿面或离面方向从纤维上分离液滴所需力的影响。还通过数值模拟预测了面内和贯穿面的分离力，并将其与实验结果进行了比较。数值和实验结果之间观察到了良好的一致性。结果表明，相交纤维之间的相对角度对离面方向的分离力没有显著影响。然而，面内方向的分离力强烈依赖于纤维之间的相对角度，并且随着该角度的增加而增加。
