Multiphase flows of particles in thin film systems

注[]指CCV中的期刊出版物。 这项研究的重点是在多相薄膜中，在工业上感兴趣的用于创建功能设备或薄膜涂层的流动中，颗粒填充流体的流动性质。本申请人的团队在浸涂和狭缝涂布以及微注塑成型方面具有相当丰富的经验，微注塑成型是开发高附加值设备的主要加工技术，其中涂层是功能性的（例如导电、光漫射）或保护性的（例如氧气或水屏障、损坏保护）。 电池、有机光电导体和微机电器件等器件的尺寸和复杂性要求在纳米至微米长度尺度的较小长度尺度上具有更高的精度。 研究目的是更好地理解多相系统中颗粒流动的机制，这些机制可能导致颗粒沉积、粘附和团聚。将研究颗粒-固体相互作用和颗粒-流体相互作用的性质，考虑颗粒上的力，并包括颗粒和流体之间的双向耦合。其中一个具有挑战性的领域将是非牛顿流体效应的结合，因为许多涂料是聚合物基质中的颗粒分散体。最近的研究集中在浸涂[7，10]使用流体模型，包括颗粒浓度，并在狭缝涂布[2，8]使用离散元法（DEM）跟踪单个颗粒。 在这两种应用中，使用开源CFD软件（OpenFOAM），在精确确定涂层膜界面的位置和捕获流动中颗粒的影响方面存在严重困难。 问题仍然出现的竞争力，由于流动，颗粒表面特性导致颗粒颗粒和颗粒壁的相互作用，以及自由表面的作用，存在于所有这些应用。模拟与实验验证将提供一个有价值的工具，在理解这些竞争效应的作用，并导致更好的设计和生产的设备，使用这些制造方法。 在不连续涂布技术（基本上是印刷）中也存在相当大的科学兴趣，用于诸如印刷电子、电池涂层和基材上的高价值功能材料的应用。 薄膜边缘的精确位置受到自由表面的影响：液-固接触线、局部表面张力、表面润湿性和颗粒的存在。 这种系统的模拟是一个科学感兴趣的领域，以更好地了解对颗粒分布的竞争影响，并且是设计和生产设备所必需的-这项研究将有助于为产品设计和工艺改进提供更好的建模工具。

Note [] refers to journal publications in CCV. The focus of this research is on the nature of flow of particle filled fluids, in multiphase thin films, in flows of industrial interest for the creation of functional devices or thin film coatings. The Applicant's group has considerable experience in dip coating and slot coating, as well as micro-injection molding - major processing technologies in the development of high value added devices where the coating is either functional (e.g. electrically conductive, light diffusion) or protective (e.g. oxygen or water barrier, damage protection). The size and complexity of devices such as batteries, organic photoconductors and microelectromechanical devices requires more precision at smaller length scales on the nano to microns length scale. The research objective is to better understand the mechanisms of particle flows in multiphase systems that may lead to particle deposition, adhesion, and agglomeration. The nature of the particle-solid interactions and particle-fluid interactions will be studied, taking into account the forces on the particles, and including two way coupling between the particles and the fluid. One of the challenging areas will be the incorporation of non-Newtonian fluid effects, as many coatings are particle dispersions in polymer matrices. Recent research has focused on dip coating [7,10] using fluid models that incorporate particle concentration, and in slot coating [2,8] using the discrete element method (DEM) to track individual particles. In both applications, using open source CFD software (OpenFOAM), there were serious difficulties in precisely determining the position of the interface of the coating film and in capturing the effects of particles within the flow. Questions still arise as to the competing forces due to flow, particle surface properties leading to particle-particle and particle wall interactions, and the role of free surfaces, which exist in all these applications. Simulation with experimental validation will provide a valuable tool in understanding the role of these competing effects and lead to better design and production of devices that use these manufacturing methods. There is also considerable scientific interest in discontinuous coating technologies (essentially printing) for applications such as printed electronics, battery coatings and high value functional materials on substrates. The precise location of the film edges are affected by the free surfaces: contact lines between liquid-solid, local surface tension, wettability of the surface and presence of particles. Simulation of such systems is an area of scientific interest to better understand the competing effects on the particle distribution, and necessary to design and produce devices - this research will contribute to better modeling tools for product design and process improvement.