Multiphase multilayer viscoplastic displacement flows: Controlling interfacial patterns

在各种自然和工业应用中，一种流体被另一种通常具有不同性质的流体所取代。很难实现的目标通常是通过施加的驱替流体完全去除原位驱替流体，而流体-流体界面积极参与流动动力学。与这个具有根本性挑战的流体力学问题相关，我们的研究项目的长期愿景围绕着开发先进的流动模型/模拟和新颖的实验，以改善加拿大处理位移流动的工业过程，其复杂，多相，多层，界面和非牛顿性质至关重要。例子包括油气井堵塞和废弃的移除/清洗过程中的置换流，以及铝生产、清洗/移除和去污以及注塑成型中的各种过程。在这些和类似的工业过程中使用的流体和材料经常表现出非牛顿粘塑性特性，当考虑触变性和粘弹性瞬态响应时，流变性变得更加复杂。这些复杂性，以及高度非线性和难以预测的界面行为，使得控制这些复杂的界面位移流动变得极其困难。在此背景下，我们的愿景是开发突破性的方法和策略，以有效控制多相、多层粘塑性流体的发展和渗透。这可以实现，例如，通过控制/操纵时空界面的演变和阻碍/触发界面现象，以实现所需的位移流动模式/制度，根据我们的设计和需要。反过来，这使我们能够在广泛的工业过程中精确预测/设计复杂的位移行为，并减少这些流动的不可预测性/不可控性带来的负面影响。在此框架下，我们的短期目标是通过分析(i)旋转管道中的非混相粘塑性位移，（ii）具有超疏水壁的流动几何形状中的位移，以及（iii）触敏-弹性-粘塑性位移流动，提出变异性控制位移策略。通过新颖的复杂流体实验（例如激光/相机/超声成像），严格的半解析数学模型（润滑，渐近和稳定性分析模型）以及依靠开源代码的先进计算流体动力学方法来研究这些引人入胜的研究课题。通过研究生和本科生的参与，这些高素质的人才在我们的研究项目中经历了一个独特的教育环境，为复杂流动的数学和实验建模而设计，即一个对专业知识和技能需求不断增加的研究领域。

The displacement of one fluid by another fluid of usually different properties occurs in a variety of natural and industrial applications. The hard-to-achieve objective is typically to completely remove the in-situ displaced fluid, via the imposed displacing fluid, while the fluid-fluid interface participates actively in the flow dynamics. Relevant to this fundamentally-challenging fluid mechanics problem, our research program's long-term vision revolves around developing advanced flow models/simulations and novel experiments, to improve Canadian industrial processes dealing with displacement flows, whose complex, multiphase, multilayer, interfacial and non-Newtonian nature are critical. Examples include displacement flows in removal/cleaning processes in the plug and abandonment of oil&gas wells, as well as various processes in aluminum production, cleaning/removal and decontamination, and injection molding. The fluids and materials used in these and similar industrial processes frequently exhibit non-Newtonian viscoplastic properties, for which the rheology becomes even more complex when thixotropy and viscoelastic transient responses are considered. These complexities, along with highly non-linear and hard-to-predict interfacial behaviour, make it extremely hard to control these complex interfacial displacement flows. In this context, our vision is to develop ground-breaking methods and strategies to effectively control the advancement and penetration of multiphase, multilayer viscoplastic fluids into one another. This can be realized, for example, via controlling/manipulating the spatiotemporal interface evolution and hindering/triggering interfacial phenomena, to achieve desired displacement flow patterns/regimes, according to our design and needs. This in return enables us to precisely predict/design complex displacement behaviours in a broad range of industrial processes, and reduce concomitant negative impacts of unpredictability/uncontrollability of these flows. In this framework, our specific short-term objectives are to propose transformative controlling displacement strategies, via the analysis of (i) immiscible viscoplastic displacements in rotating pipes, (ii) displacements in flow geometries with superhydrophobic walls, and (iii) thixo-elasto-visco-plastic displacement flows. These fascinating research topics proposed are investigated through novel complex fluid experiments (e.g. laser/camera/ultrasound imaging), rigorous semi-analytical mathematical models (lubrication, asymptotic and stability analysis models), and advanced computational fluid dynamics methods relying on open-source codes. Through engaging both graduate and undergraduate students, these highly qualified personnel trained in our research program experience a unique educational environment, designed for mathematical and experimental modeling of complex flows, i.e. a research area for which the demand for expertise and skills is increasing.