Multiphase flows of particles in thin film systems

注[]指CCV的期刊出版物。 这项研究的重点是颗粒填充流体在多相薄膜中的流动性质，以及用于创建功能器件或薄膜涂层的工业流动。申请人的团队在浸渍涂层和缝隙涂层以及微注射成型方面拥有丰富的经验-在开发高附加值设备方面的主要加工技术，其中涂层要么是功能性的(例如导电、光扩散)，要么是保护性的(例如氧气或水的阻隔性、损伤保护)。电池、有机光导体和微电子机械设备等设备的大小和复杂性要求在纳米到微米的较小长度尺度上具有更高的精度。研究的目的是为了更好地了解多相系统中可能导致颗粒沉积、粘结和团聚的颗粒流动的机理。研究了颗粒-固体相互作用和颗粒-流体相互作用的性质，考虑了颗粒所受的力，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引入非牛顿流体效应，因为许多涂层是粒子在聚合物基质中的分散。最近的研究集中在使用包含颗粒浓度的流体模型的浸渍涂层[7，10]，以及在缝隙涂层[2，8]中使用离散单元法(DEM)来跟踪单个颗粒。在这两个应用中，使用开源CFD软件(OpenFOAM)，在精确确定涂层膜界面的位置和捕捉流动中颗粒的影响方面都存在严重困难。在所有这些应用中，仍然存在由流动引起的相互竞争的力、导致颗粒-颗粒和颗粒壁相互作用的颗粒表面性质以及自由表面的作用等问题。模拟和实验验证将为理解这些相互竞争的影响的作用提供宝贵的工具，并导致使用这些制造方法的设备的更好设计和生产。在印刷电子产品、电池涂层和衬底上的高价值功能材料等应用中，非连续涂层技术(主要是印刷)也引起了相当大的科学兴趣。薄膜边缘的精确位置受自由表面的影响：液-固之间的接触线、局部表面张力、表面的润湿性和颗粒的存在。对这类系统的模拟是一个很有科学意义的领域，可以更好地了解对颗粒分布的竞争影响，也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.