Emulsion and Soft Colloid Transport in Porous Media and Confined Systems

乳液滴是软胶体的例子。油水乳状液常见于油田采出水中。这些乳状液对采出水的处理提出了许多挑战，人们试图破坏油和水的稳定，并将其分成两个相。相反，乳液和软胶体用于几种工艺工程应用中，即使在剪切力或其他不稳定力的影响下，它们也需要保持稳定。我们的研究重点是在电场和/或压力的影响下，这种乳状液或可变形胶体在高度狭窄的通道或孔隙中的流动。在这种流动过程中，在剪切力和电场力的影响下，液滴可能变形、破裂或合并。此外，狭窄通道的壁会对这些乳液滴施加作用力。拟议研究的短期目标是从机理上了解影响乳液滴和可变形胶体的流动、变形和稳定性的各种电气、流体动力学和胶体效应。这里提出的理论模拟研究将建立在我们过去模拟电强迫下的胶体传输、薄膜排水和液滴变形的经验的基础上。这些模型将使用流体流动、电场和带电物种分布的控制方程来确定液滴或软颗粒的流动性。随后，这些模型将被合并到宏观胶体传输模型中，以预测乳状液或软胶体分散体通过捕收剂填充床的宏观传输行为。各种理论模型将通过将它们的结果与适当设计的微流控和柱层析实验进行比较来验证。这些研究成果有望从根本上理解乳状液在多孔介质中的输送方式，并将有助于开发更有效的过滤、破乳、气浮、分离以及最终的采出水处理技术。9名研究生将通过这一项目进行培训。

Emulsion droplets are examples of soft colloids. Oil-water emulsions are commonly found in produced water in oil field applications. These emulsions pose numerous challenges in treatment of produced water, where one attempts to destabilize and separate the oil and water into two phases. Conversely, emulsions and soft colloids are used in several process engineering applications where they need to remain stable even under the influence of shear or other destabilizing forces. Our proposed research focuses on the flow of such emulsions or deformable colloids in highly constricted channels or pores under the influence of electric field and/or pressure. The droplets can deform and break, or coalesce under the influence of shear and electrical forces during such flows. Furthermore, the walls of the constricted channels can impose forces on these emulsion droplets. The short-term objectives of the proposed research are to develop mechanistic understanding of the various electrical, fluid dynamic, and colloidal effects influencing the flow, deformation, and stability of emulsion droplets and deformable colloids. The theoretical modeling studies proposed here will build on our past experience in modeling colloid transport, thin film drainage, and droplet deformation under electrical forcing. These models will employ the governing equations of fluid flow, electric fields, and charged species distribution to determine the mobility of the droplets or soft particles. Subsequently, these models will be incorporated into a macroscopic colloid transport model to predict the macroscopic transport behavior of the emulsion or soft colloidal dispersion through a packed bed of collectors. The various theoretical models will be validated by comparing their results against suitably designed microfluidic and column chromatography experiments. The research outcomes are expected to provide a fundamental mechanistic understanding of the pertinent modes of emulsion transport in porous media, and will help develop more efficient techniques for filtration, de-emulsification, flotation, separation, and ultimately, produced water treatment. Nine graduate students will be trained through this program.