Multiphase Mass and Heat Transport in Low Permeability Media

地下正迅速成为全球推动减缓气候变化、向后碳社会过渡、安全储存遗留能源废物以及通过棕地整治振兴城市地区的焦点。这些应用通常在低非均质渗透率介质中运行，由一组耦合物理（水和气体流动与能量动力学耦合）控制，但这些耦合过程的含义仍然知之甚少。如果不采取任何措施来更好地探索这些过程，那么所有这些应用程序可能都是出于好意，但无法实现。该研究计划旨在通过实验和建模任务来解决这一知识差距，这些任务将检查非均质低渗透域中热量和多相流之间的联系。该计划将在自然发生的低渗透介质和工程土壤（如粘土被压成特定密度或加工成颗粒，空隙或衬垫等形式）中检查这些过程，因为这两种类型的土壤在各种地下应用中都会遇到。实验将考察温度对重要土壤参数的影响，如导热系数和土壤水分特征。这些结果将用于一个新开发的模型，该模型将热动力学与非均质低渗透土壤中的气体和水运动联系起来。该模型将检验非均质性对水和气运动的影响，并确定孔隙间气和水动力学是否对这些类型域中的整体质量输运有影响。最后，模型和实验将比较自然和工程土壤在加热地下区域的性能。该研究项目的长期愿景是提高我们对低渗透系统中发生的耦合质量和能量过程的理解，从而提高污染场地的修复效率，最大限度地降低深层地质储存库中天然气运动带来的风险，并提高地能系统的能源效率。鉴于当前应对气候变化和营造更清洁环境的需要，这些应用具有特别重要的意义。本研究申请资助博士生2名，硕士生1名，本科生8名。

The subsurface is rapidly becoming the focus of a global push to mitigate climate change, transition to a post-carbon society, safely store legacy energy wastes, and revitalize urban areas through brownfield remediation. These applications are governed by a single set of coupled physics - water and gas flow coupled with energy dynamics - often operating in low heterogenous permeability media, yet the implications of these coupled processes remain poorly understood. If nothing is done to better explore these processes, then all these applications may be well intentioned but unattainable. This proposed research program aims to address this knowledge gap with the help of experimental and modelling tasks that will examine the linkage between heat and multiphase flow in heterogenous low permeability domains. The program will examine these processes in both naturally occurring low permeability media and engineered soils (such as clay that is pressed into specific densities or processed into forms such as pellets, gapfills, or liners) as both types of soils are encountered in the various subsurface applications. The experiments will examine the effect of temperature on important soil parameters such as thermal conductivity and soil water characteristics. These results will be used in a newly developed model that links heat dynamics with gas and water movement in heterogeneous low permeability soils. The model will examine the effect of heterogeneity on water and gas movement as well as determine whether inter-pore gas and water dynamics have an impact on the overall mass transport in these types of domains. Lastly, the model and experiments will compare the performance of both naturally and engineered soils in heated subsurface domains. The long-term vision of this research program is to improve our understanding of the coupled mass and energy processes that occur in low permeability systems, leading to an improvement in remediation efficiencies at contaminated sites, minimize risks posed by gas movement in deep geological repositories, and improve the energy efficiency of geo-energy systems. These applications are particularly relevant given the current need to fight climate change and foster a cleaner environment. Funds requested for this research will support two doctoral students, one masters student, and eight undergraduate students.