Modelling the wetting / dewetting of solid particles.

在工业中，涉及固体颗粒的液体涂层(“润湿”)或从颗粒中去除液体涂层(“去湿”)的过程是很常见的。加拿大最著名的例子来自艾伯塔省，在那里，油砂被加工成分离覆盖在沙子上的沥青。类似的分离过程可以在许多其他行业找到，包括食品、制药和采矿。另一方面，有些工艺的目标是在固体颗粒上涂覆一层液体涂层。尽管过程看起来很简单，但颗粒润湿和去湿现象非常复杂，关于这些过程是如何发生的，许多问题仍然没有答案。这项建议是为了开发一个复杂的计算机模型来模拟这些基本现象，然后使用该模型在基本层面上检查润湿和除湿，更多地了解它们是如何工作的，并将这种理解应用于在工业规模上开发更有效率和效果的过程。与其从头开始构建计算机模型，我们将在一个名为OpenFOAM(Openfoam.org)的开源软件中开发模拟能力，该软件已经被全球数千名工程师和科学家使用。该提案涉及两项主要任务。首先是增加该软件的功能：引入不同形状的固体颗粒，允许它们随水流移动；以及模拟润湿和除湿现象的算法。第二项任务是使用新的软件来研究一些基本现象：从单个球形颗粒和椭球体等非球形颗粒中分离出一层薄薄的液体；两个或多个有涂层的颗粒的行为，以检查何时以及是否从一个颗粒上移除涂层只会导致另一个颗粒的涂层；一组涂层颗粒在不同类型的流动中的行为；最后，一个未被涂层的颗粒在从一个液体到另一个液体时的行为，以及该颗粒何时以及在多大程度上保留了一些第一种液体作为涂层。

Processes that involve a liquid coating a solid particle ("wetting"), or the removal of a liquid coating from a particle ("dewetting"), are commonplace in industry. The best-known Canadian example comes from Alberta, where oil sands are processed to separate the bitumen that coats sand. Similar separation processes can be found in many other industries, including the food, drug, and mining. On the flip side, there are processes where the goal is to apply a liquid coating to a solid particle. Despite what may appear to be simple processes, particle wetting and dewetting phenomena are very complex, and many questions remain unanswered about how such processes take place. This proposal is for the development of a sophisticated computer model to simulate such basic phenomena, and then to use the model to examine wetting and dewetting at a fundamental level, to learn more about how they work, and to apply that understanding to the development of more efficient and effective processes at the industrial scale. Rather than build the computer model from scratch, we will develop the simulation capabilities within an open-source software called OpenFOAM (openfoam.org) that is already used by thousands of engineers and scientists worldwide. The proposal involves two main tasks. The first is to add capabilities to this software: the introduction of solid particles of different shapes, that will be allowed to move with a flow; and algorithms to mimic wetting and dewetting phenomena. The second task is to then use the new software to examine a number of basic phenomena: the separation of a thin film of liquid from a single spherical particle, and from non-spherical particles like ellipsoids; the behaviour of two or more coated particles, to examine when and whether removing a coating from one particle simply leads to the coating of another; the behaviour of a cluster of coated particles in different kinds of flows; and finally, the behaviour of an uncoated particle as it passes from one liquid to another, and when and to what extent the particle retains some of the first liquid as a coating.