Interfacial Controls on Dynamics and Equilibration in Porous Media

目前大多数多相流的宏观理论都是基于达西定律的联合方程和毛管压力与饱和度的经验关系。近年来，许多研究表明，这种状态并不一定是最佳的。然而，在给定的多孔介质中，饱和度和界面面积是独立的变量，也就是说，对于单一饱和度，许多不同的配置导致一系列界面面积是可能的。对界面力对多相流的影响的认识导致了基于基本热力学考虑的替代理论的发展，其中界面区域被作为单独的热力学实体引入。因此，毛细管压力成为饱和度和比流体-流体界面面积的函数，有人认为，该系统将由这种函数依赖来唯一地描述。最近的研究表明，一个独特的表面不能无可争议地描述非平衡条件下的两相流，这表明理论中可能还缺少其他一些东西。所提议的工作的目标是改善精密测量的缺乏，并产生高度独特的数据集，从中可以在多孔介质中多相流的基本动力学方面在许多方面取得战略进展。生成的数据将包括动态排水和渗吸实验，在此过程中，将捕获x射线层析图像，以便在三维空间上以前所未有的细节跟踪流体相。这将允许测量发展的界面面积、曲率和流体相的捕获行为。这种新颖的数据集可以用于验证基于多相理论的发现，并用于更广泛的界面动力学探索，特别是界面面积的形成和曲率演化。提高对多孔介质中多相流物理特性的理解，通过在地下水管理和修复、土壤和农业科学、石油工程和二氧化碳地质封存等各个领域的应用，对社会产生了影响。该项目旨在生成新的数据集，这些数据集不仅将首先支持理解界面的作用及其动态行为在多孔介质流动和传输中的进展，而且还将改进描述这些过程的现有理论。生成的高分辨率图像将通过数字存档提供给更广泛的科学界。最终，这将允许改进自然资源的管理和可靠地设计多孔系统的能力，从而改善用水和能源开发。

Interfacial Controls on Dynamics and Equilibration in Porous MediaMost current macroscopic theories of multi-phase flow are based on the combined equations of Darcy's Law and an empirical relationship between capillary pressure and saturation. In recent years, a number of studies have shown that this state of affairs is not necessarily optimal. However, in a given porous medium, saturation and interfacial areas are independent variables, i.e., many different configurations resulting in a range of interfacial areas are possible for a single saturation. Awareness of this effect of interfacial forces on multi-phase flow has led to the development of alternative theories based on fundamental thermodynamic considerations in which interfacial areas are introduced as separate thermodynamic entities. Thus capillary pressure becomes a function of both saturation and specific fluid-fluid interfacial area and it has been suggested that the system will be uniquely described by this functional dependence. Recent work has indicated that a single unique surface cannot indisputably describe two-phase flow under nonequilibrium conditions, suggesting that there may be something else missing from the theory. The goal of the proposed work is to improve on a paucity of delicate measurements and generate highly unique data sets from which strategic advances can be made on a number of fronts with respect to the fundamental dynamics of multi-phase flow in porous media. The data generated will consist of dynamic drainage and imbibition experiments during which x-ray tomographic images will be captured such that the fluid phases can be tracked in unprecedented detail in three dimensions. This will allow for measurement of developing interfacial areas, curvatures, and trapping behavior of the fluid phases. This novel data set can be used in a combined effort to validate findings based on multi-phase theories and for a broader exploration of interfacial dynamics, in particular the formation of interfacial area and curvature evolution. Improved understanding of the physics of multi-phase flow in porous media has societal impacts through applications in various fields such as groundwater management and remediation, soil and agricultural science, petroleum engineering, and geologic sequestration of CO2. This project aims to generate new data set that will not only first and foremost support progress in understanding the role of interfaces, and their dynamic behavior, on porous media flow and transport, but also improve on existing theories describing these processes. The generated high-resolution imagery will be made available to the broader scientific community through digital archiving. Ultimately, this will allow for improved management of natural resources and ability to reliably engineer porous systems leading to improvements in water usage and energy development.