Theoretical Studies of Near-Critical Fluids in Dilute Porous Media

稀多孔介质中近临界流体的理论研究

• 批准号: 9624090
• 负责人: Andrea Liu
• 金额: $ 32.95万
• 依托单位: University of California-Los Angeles
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1996
• 资助国家: 美国
• 起止时间: 1996-04-01 至 2000-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9624090&HistoricalAwards=false
• 关键词: Theoretical; Studies; Near; Critical; Fluids

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.

Andrea Liu得到了从理论和计算化学计划的教师早期职业发展奖的支持，以研究平衡相行为和近临界流体中的扩散运输，例如蒸气液系统或二进制液体混合物，限于稀释多孔介质（例如硅胶）。 通常，在多孔培养基中近临界流体的行为是一个极其困难的理论问题，因为培养基的表面强烈更喜欢流体的一个阶段，并且因为培养基的结构高度无序。 刘的方法集中在流体与表面之间的强相互作用上。以前的理论工作假设这种相互作用是弱的，而这种疾病是主要因素。 该提案的基石是限量介质作为圆柱链的简单周期网络的模型，刘在平均场近似中已解决。提出的工作是基于这种基本模型的基础，该模型通过使用分析和数值技术的协调组合来研究凝胶结构中关键波动和长波长障碍的影响，以及非平衡行为。 这种方法代表了隔离培养基几何形状的表面相互作用和无序的影响的最佳希望，以确定它们对平衡和非平衡行为的相对重要性。 拟议的教育计划围绕有效的科学交流。目的是使非裁判的科学神秘化，并说服他们化学是日常生活的重要而有趣的部分，并教授专业和研究生如何更有效地交流他们的工作。 稀释多孔培养基中的几乎关键流体（例如Liu研究的流体）是更真实的多孔培养基中更通用的多相流体的模型。 具有工业重要性的应用范围从多孔床的催化到多孔玻璃中的液体废物和液体燃料的储存，到从砂岩等多孔介质中提取液体（例如油）。 对多孔媒体中运输的理论理解的改进可能会在其中一些战略领域产生重大影响。