Modelling the wetting / dewetting of solid particles.

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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.