Transport Processes in Two-Phase Macroscopically Homogeneous Systems

9318820 Acrivos这个项目涉及两相宏观均质材料中传输过程的理论研究。利用各种分析和数值方法，将S关于无限稀悬浮液的工作推广到浓悬浮液，并将他们关于剪切诱导的颗粒纵向和横向自扩散系数的工作推广到剪切诱导的梯度扩散系数。这项工作可能导致悬浮体扩散输运领域的根本性进展，因为它从基本的、简化的和渐近的理论极限情况转移到潜在应用所在的更复杂的系统。由于拟议的研究具有非常根本的性质，因此有许多潜在的应用。潜在的应用范围包括沉积、在非均匀剪切流中形成堵塞和沉淀颗粒的再悬浮、在接近失重的条件下通过热电泳法将气泡从液体中分离出来(在太空中生产超高纯度材料)，以及预测两相介质中的有效导热系数、渗透率和其他传输特性。确定复合材料有效性能的有效介质技术将建立在更坚实的理论基础上，并将建立计算流动悬浮液中颗粒分布函数的动力学模型。该项目的理论研究将与P.I.S实验计划(由美国国防部资助)协调进行。和文献中的数据将被用来检验理论结果。***

9318820 Acrivos This project involves the theoretical study of transport processes in two-phase, macroscopically homogenous materials. A variety of analytical and numerical techniques are used to extend the prior work of the P.I.'s on infinitely dilute suspensions to concentrated suspensions and to extend their work on the shear-induced longitudinal and transverse self-diffusivity of particles to the shear-induced gradient diffusivity. This work may lead to fundamental advances in the field of diffusive transport in suspensions because it moves from the basic, simplified, and asymptotic theoretical limiting cases toward the more complex systems in which the potential applications lie. There are many potential applications because of the very fundamental nature of the proposed study. The range of potential applications includes sedimentation, formation of plugs in non-homogeneous shear flow and the re-suspension of settled particles, separation of gas bubbles from liquids under near weightless conditions (production of ultra high purity materials in space) by thermophoresis, and prediction of effective thermal conductivity, permeability, and other transport properties in two-phase media. The effective medium technique for determining the effective properties of composite materials will be put on a firmer theoretical foundation and a kinetic model for computing particle distribution functions in flowing suspensions will be developed. The theoretical studies in this project will be coordinated with the P.I.'s experimental program (funded through U.S. Dept. of Energy) and the data form the literature will be used to test the theoretical results. ***