Multiscale modeling of multiphase flows in chemical engineering processes

多相流可以在许多行业的化学过程中找到，例如制药，石油，汽车，食品和家庭护理。尽管实验和建模技术取得了重大进展，但与单相流相比，这种流动的行为方式复杂，人们对其了解甚少。例如，汽车微粒过滤器的行为在本质上既是多相的，也是瞬态的，因为它们涉及到在构成这些过滤器通道的多孔壁上捕获气体携带的小烟灰颗粒。由于对这些微粒的排放以及废气的排放有越来越严格的限制，因此需要更好地了解控制这种过滤器捕获机制的传输现象以及车辆排气管道催化转化器中的气体转化。在工业中发现的复杂系统的另一个例子包括固体形式药物制造的混合操作的设计和扩大，由于缺乏对控制机制的了解，通常是经验地实现的。我们还可以以洗发水、牙膏和个人护理用品的生产为例，这些产品都是由悬浮在载体液体中的非常小的颗粒组成的结构化液体。这是具有挑战性的，因为必须仔细控制这些最终用途产品的特性。

Multiphase flows can be found in the chemical processes of a wide range of industries such as pharmaceutical, petroleum, automotive, food and household care. Such flows behave in a complex manner and, in comparison to single phase flows, remain poorly understood despite significant progress in both experimental and modeling techniques. For instance, the behavior of automobile particulate filters is both multiphase and transient in nature, as they involve the capture of small gas-borne soot particles inside the porous walls that make up the channels of these filters. Owing to the increasing strict limits on the emission of these particles as well as that of exhaust gas, a better understanding of the transport phenomena governing the capture mechanisms of such filters and the gas conversion in catalytic converters along the exhaust lines of vehicles is needed. Another example of complex systems found in the industry includes the design and scale-up of blending operations for the manufacturing of solid form drugs often achieved empirically due to the lack of knowledge of the governing mechanisms. We can also cite the production of shampoos, toothpastes and personal care commodities, which are structured fluids comprised of very small particles suspended in a carrier liquid. This is challenging because the properties of such end-use products must be carefully controlled. The objective of this on-going research program is to pursue our efforts in the modeling of multiphase systems, with an emphasis on solid-fluid processes, by developing accurate, robust and usable multiscale models for the simulation of the flow dynamics and transport phenomena in such systems. Our interest is to apply these models to dry granular and solid-liquid mixing processes, and to applications involving porous media such as those in filtration operations. This research program will provide a better understanding of a variety of particulate systems of industrial relevance, involving varying distributions of solid particles and liquids of different rheological behaviors. It will also enable the training of highly qualified chemical engineers for the design, control and scale-up of chemical processes comprising powders and particles of all kinds.