Multiscale Modeling of the Three-Dimensional Meniscus Shape of a Wetting Liquid Film on Micro-/Nanostructured Surfaces.
Multiscale Modeling of the Three-Dimensional Meniscus Shape of a Wetting Liquid Film on Micro-/Nanostructured Surfaces.
复制标题
DOI：
10.1021/acs.langmuir.7b02837
复制
发表时间：
2017-10
期刊：
影响因子：
--
通讯作者：
Han Hu;Monojit Chakraborty;Taylor P. Allred;J. Weibel;S. Garimella
中科院分区：
文献类型：
--
作者：
Han Hu;Monojit Chakraborty;Taylor P. Allred;J. Weibel;S. Garimella
用于增加在沸腾和蒸发过程期间经由增强的液体再润湿耗散的热通量的结构化表面的设计需要预测这些表面上的液体弯月面形状。在这项研究中，一个通用的连续模型来预测微/纳米结构表面上的液体膜的三维弯月面形状的基础上最小化的系统自由能，包括固液货车德瓦尔斯相互作用能，表面能和重力势。在纳米尺度上对水膜的分子动力学模拟与金字塔压痕的金表面上的连续模型进行了验证，并对硅V形槽通道上的水膜在微观尺度上的实验测量。验证模型被用来研究膜厚和表面结构深度对弯月面形状的影响。的弯月面被示出成为更符合与表面结构作为膜厚度的减小和结构深度的增加。假设小的界面斜率和膜厚度的小变化，连续介质模型可以线性化以获得弯月面形状的显式表达式。这种线性化模型的误差进行了定量评估，并显示出增加结构深度和减少结构间距。开发的模型可以用于精确预测的三维弯月面形状的结构化表面与微/纳米尺度的功能，这是必要的，以确定液体输送速率和薄膜蒸发过程中耗散的热通量。当结构深度小于或等于液膜厚度时，线性化模型可用于快速预测弯月面形状。
The design of structured surfaces for increasing the heat flux dissipated during boiling and evaporation processes via enhanced liquid rewetting requires prediction of the liquid meniscus shape on these surfaces. In this study, a general continuum model is developed to predict the three-dimensional meniscus shape of liquid films on micro/nanostructured surfaces based on a minimization of the system free energy that includes solid-liquid van der Waals interaction energy, surface energy, and gravitational potential. The continuum model is validated at the nanoscale against molecular dynamics simulations of water films on gold surfaces with pyramidal indentations, and against experimental measurements of water films on silicon V-groove channels at the microscale. The validated model is used to investigate the effect of film thickness and surface structure depth on the meniscus shape. The meniscus is shown to become more conformal with the surface structure as the film thickness decreases and the structure depth increases. Assuming small interface slope and small variation in film thickness, the continuum model can be linearized to obtain an explicit expression for the meniscus shape. The error of this linearized model is quantitatively assessed and shown to increase with increasing structure depth and decreasing structure pitch. The model developed can be used for accurate prediction of three-dimensional meniscus shape on structured surfaces with micro/nano-scale features, which is necessary for determining the liquid delivery rate and heat flux dissipated during thin-film evaporation. The linearized model is useful for rapid prediction of meniscus shape when the structure depth is smaller than or comparable to the liquid film thickness.