Theoretical Studies of Near-Critical Fluids in Dilute Porous Media

Andrea Liu获得了学院早期职业发展奖， 理论和计算化学计划来研究平衡 近临界流体中的相行为和扩散输运，例如 气液系统或二元液体混合物，限制在稀释多孔 介质如硅胶。 一般来说，近临界的行为 多孔介质中的流体是一个极其困难的理论问题， 因为介质的表面强烈地偏好流体的一个相 并且因为介质的结构是高度无序的。 的 刘所使用的方法侧重于流体之间的强相互作用 和表面;以前的理论工作已经假设， 相互作用较弱，无序是主导因素。 的 该建议的重点是一个模型的约束介质作为一个简单的 圆柱形股线的周期性网络，刘已经解决了在 平均场近似拟议的工作建立在这一基本模型的基础上， 使用分析和数值技术的协调结合， 研究临界波动和长波长的影响 在凝胶结构中的无序，以及非平衡行为。 这种方法代表了隔离 表面的相互作用和无序的几何形状的介质， 为了确定它们对平衡的相对重要性， 非平衡行为 教育计划围绕 有效的科学沟通。目标是揭开 科学，并说服他们，化学是一个 重要和有趣的日常生活的一部分，并教专业和 研究生如何更有效地沟通他们的工作。 稀释多孔介质中的近临界流体，例如， 刘，是更一般的多相流体的模型，更真实 多孔介质。 具有工业重要性的应用范围从 在多孔床中的催化，到液体废物和液体燃料的储存， 多孔玻璃，从多孔玻璃中提取液体，如油， 像砂岩一样的介质。 提高对运输的理论认识 在多孔介质中， 战略领域。

Andrea Liu is supported by a Faculty Early Career Development Award from the Theoretical and Computational Chemistry Program to study equilibrium phase behavior and diffusive transport in near-critical fluids, such as vapor-liquid systems or binary liquid mixtures, confined in dilute porous media such as silica gels. In general, the behavior of a near-critical fluid in a porous medium is an extremely difficult theoretical problem, because the surface of the medium strongly prefers one phase of the fluid and because the structure of the medium is highly disordered. The approach used by Liu focuses on the strong interaction between the fluid and the surface; previous theoretical work has assumed that the interaction is weak and that disorder is the dominant factor. The keystone of the proposal is a model of the confining medium as a simple periodic network of cylindrical strands, which Liu has solved within the mean-field approximation. The proposed work builds on this basic model by using a coordinated combination of analytic and numerical techniques to investigate the effects of critical fluctuations and long-wavelength disorder in the gel structure, as well as the nonequilibrium behavior. This approach represents the best hope of isolating the effects of surface interactions and of disorder in the geometry of the medium in order to determine their relative importance for equilibrium and nonequilibrium behavior. The proposed education plan is centered around effective scientific communication. The objectives are to demystify science for non-majors and to convince them that chemistry is an important and interesting part of daily life, and to teach majors and graduate students how to communicate their work more effectively. Nearly critical fluids in dilute porous media, such as those studied by Liu, are models for more general multiphase fluids in more realistic porous media. Applications that are of industrial importance range from catalysis in porous beds, to storage of liquid wastes and liquid fuels in porous glasses, to the extraction of liquids such as oil from porous media like sandstone. An improved theoretical understanding of transport in porous media could have a significant impact in several of these strategic areas.