The movement of the triple contact line plays a crucial role in many applications such as ink-jet printing, liquid coating and drainage (imbibition) in porous media. To design accurate computational tools for these applications, predictive models of the moving contact line are needed. However, the basic mechanisms responsible for movement of the triple contact line are not well understood but still debated. We investigate the movement of the contact line between water, vapour and a silica-like solid surface under steady conditions in low capillary number regime. We use molecular dynamics (MD) with an atomistic water model to simulate a nanoscopic drop between two moving plates. We include hydrogen bonding between the water molecules and the solid substrate, which leads to a sub-molecular slip length. We benchmark two continuum methods, the Cahn–Hilliard phase-field (PF) model and a volume-of-fluid (VOF) model, against MD results. We show that both continuum models reproduce the statistical measures obtained from MD reasonably well, with a trade-off in accuracy. We demonstrate the importance of the phase-field mobility parameter and the local slip length in accurately modelling the moving contact line.

三重接触线的移动在许多应用中起着至关重要的作用，例如喷墨打印，液体涂层和多孔介质中的排水（吸收）。为了为这些应用设计准确的计算工具，需要移动接触线的预测模型。但是，引起三重接触线运动的基本机制尚未得到很好的理解，但仍在争论中。我们研究了在低毛细管数条件下稳定条件下水，蒸气和二氧化硅样固体表面之间接触线的运动。我们使用带有原子水模型的分子动力学（MD）来模拟两个移动板之间的纳米滴。我们在水分子和固体基质之间包括氢键，这导致亚分子滑移长度。我们以两种连续体方法为基准，Cahn-Hilliard相场（PF）模型和流体体积（VOF）模型，与MD结果相对。我们表明，这两个连续模型都很好地再现了从MD获得的统计量，并在准确性上进行了权衡。我们展示了相场迁移率参数和局部滑移长度在精确地模拟运动接触线中的重要性。