Feedback Coupling Between Flow and Reactions in Heterogeneous Porous and Fractured Media:Computational and Experimental Studies (CAREER)

针对多孔和裂缝介质中反应-输运-流动耦合这一特定领域，提出了一项综合研究和教育计划。研究计划侧重于可溶岩石中裂隙的溶蚀生长和沉淀/溶蚀反应对多孔和裂隙介质渗透率的影响的计算和实验研究。教育计划包括与流体力学和水文学教育相关的观测部分的发展，以及与水文学研究生课程相关的课程发展。流体流动和化学反应之间的反馈耦合在岩溶管道和溶洞形成等地质过程以及“酸化”提高渗透率以采收率等工程应用中非常重要。虽然以前已经研究过反应-流动耦合，但对地质非均质性对非线性耦合动力学影响的系统研究才刚刚开始。由P.I.和一名研究生进行的初步研究表明，裂缝孔径的随机变化加速了方解石中管道的生长，其速度可达一个数量级。本研究的目的是在对照实验和计算研究的基础上，量化非均质性对多孔和裂缝介质中流动-反应耦合动力学的影响。实验将在用巴黎石膏铸造的骨折中进行。测量过的表面粗糙度将被用来组装裂缝。高分辨率孔径测量（通过与桑迪亚国家实验室的罗伯特·j·格拉斯博士合作）将伴随着溶解实验。计算研究将集中于局部系统，如岩溶演化、石膏和硬石膏的溶解、裂缝中石英脉的沉积和碳酸盐结核的生长。碳酸盐结块的研究将支持dr。Matt Davis （EAR-9725194）和Peter Mozley （EAR-9726416）。从他们的工作中获得的关于混凝土生长历史和方向的数据将被用来评估关于混凝土生长的不同假设。继续教育活动包括开发互动式本科流体力学课程和用于定性和定量可视化的台式分水岭模块。拟议的模块开发活动侧重于简单的实验，以说明非均质性对多孔和裂缝介质中流动和输运过程的影响。课程开发包括一门新的反应输运模拟综合课程，作为水文科学研究生课程的核心课程。本课程将提供大气、海洋、地表和地下水系统中反应-输运相互作用的综合视角，强调不同媒介之间的统一方面。感兴趣的空间/时间尺度与所使用的模型类型之间的关系也将是一个主题。本课程将包括一个关于小溪流水质的实验改造（通过与Diane McKnight博士合作）和实验研究的实地部分。

9734404 Rajaram An integrated research and education plan is proposed in the specific area of reaction-transport-flow coupling in porous and fractured media. The research plan focuses on computational and experimental studies of the dissolutional growth of fissures in soluble rock and the impact of precipitation/dissolution reactions on permeability of porous and fractured media. The educational plan involves the development of observational components relevant to education in fluid mechanics and hydrology, and curriculum development relevant to the graduate program in hydrologic sciences. Feedback coupling between fluid flow and chemical reactions is important in the context of several geological processes such as conduit and cave formation in karst, and engineering applications such as "acidization" to increase permeability for oil recovery. Although reaction-flow coupling has been examined previously, a systematic study of the influence of geologic heterogeneity on the nonlinearly coupled dynamics is only beginning. A preliminary study carried out by the P.I. and a graduate student indicated that random variations in the fissure aperture accelerate conduit growth in calcite by up to an order of magnitude. The objective of the proposed research is to quantify the influence of heterogeneity on the dynamics of flow-reaction coupling in porous and fractured media, based on controlled experiments and computational studies. Experiments will be carried out in fractures cast with plaster-of-paris. Surfaces with measured roughness will be used to assemble the fractures. High-resolution aperture measurements (through collaboration with Dr. Robert J. Glass, Sandia National Laboratories) will accompany dissolution experiments. Computational studies will focus on topical systems such as karst evolution, dissolution of gypsum and anhydrite, deposition of quartz veins in fractures and the growth of carbonate concretions. The studies on carbonate concretions will support the work of Drs. Matt Davis (EAR-9725194) and Peter Mozley (EAR-9726416). The data on concretion growth history and orientation obtained from their work will be employed to evaluate different hypotheses on concretion growth. Continuing educational activities include development of an interactive undergraduate fluid mechanics course and a bench-top watershed module to be used for qualitative and quantitative visualization. Proposed module development activities focus on simple experiments to illustrate the impact of heterogeneity on flow and transport processes in porous and fractured media. Curriculum development involve a new integrative course on reactive transport modeling, to serve as a core course for the graduate program in hydrologic sciences. The course will provide an integrated perspective on reaction-transport interactions in atmospheric, oceanic, surface and groundwater systems, emphasizing the unifying aspects across different media. The relationship between spatial/temporal scales of interest and the types of models used will also be a theme. The course will include a field component on experimental modification of water quality in small streams (through collaboration with Dr. Diane McKnight) and experimental studies.