亲水微结构倾斜表面上液滴形态的数值模拟

Numerical simulation of droplet shape on hydrophilic microstructure inclined surface

本文基于能量最小原理,建立了重力场中亲水微结构倾斜表面上液滴的数值模型。当系统总能量取到最小值时,液滴达到最终的平衡状态;采用有限差分法和非线性优化算法,对倾斜表面上的液滴形态进行数值模拟。讨论了表面倾角、液滴体积以及微结构尺寸对液滴形态的影响,并以实验结果验证数值结果。结果表明,倾角和液滴体积的增大会增加液滴前向接触角,减小后向接触角,同时增大了三相接触线长度和液滴高度;当微结构的相对高度较大且相对间距较小时,表面呈现超亲水的趋势,此时液滴三相线长度长、液滴高度低。该研究可以指导设计合理的亲水表面,或应用于微流控芯片中液滴的控制。

Based on the principle of minimum energy,this paper establishes a mathematical model of droplets on the inclined surface of hydrophilic microstructures in the gravitational field.When the total energy of the system reaches the minimum value,the droplet reaches the final equilibrium state.Finite difference method and nonlinear optimization algorithm are used to numerically simulate the droplet shape on the inclined surface.The effects of surface inclination,droplet volume and microstructure size on droplet morphology are discussed,and the numerical results are verified by experimental results.The results show that the increase of inclination angle and droplet volume will increase the forward contact angle of the droplet,reduce the backward contact angle,and increase the length of the three-phase contact line and the height of the droplet.When the relative height of the microstructures is large and the relative spacing is small,the surface shows a tendency of super-hydrophilicity.In this situation,the length of the three-phase line of the droplet is long and the height of the droplet is low.This research is promising to guide the design of a reasonable hydrophilic surface,or be applied to the control of droplets in a microfluidic chip.