EXPERIMENTAL AND NUMERICAL STUDY OF HYDRODYNAMIC DISPERSION AND COLLOIDAL TRANSPORT IN SOLID CELLULAR FOAM

摘要

The transport of a colloidal suspension through a porous material is an important process found within a broad range of disciplines; e.g. geophysics, engineering, and medicine. The importance of colloidal transport (e.g. microbe, radio-nuclide, etc.) in the subsurface has motivated much theoretical and experimental work focused upon understanding the mechanisms of colloid transport and deposition in porous media; e.g. [1,2]. The practical challenges associated with experimentally observing the transport of colloids in opaque media have limited past techniques to classic breakthrough methods [2-4]. This work presents results from nuclear magnetic resonance (NMR) measurement of moderate concentration (volume fraction Ф = 0.15), neutrally charged, Brownian (hard sphere particle radius of 1.25μm), colloidal suspension transport through a high porosity open cell polymer foam. The recent development of core shell oil filled particles [5] has allowed for the separation of liquid and solid-phase dynamics in NMR measurements of colloidal suspensions [6-8]. The proven application of NMR in the study of single phase transport in porous media, [9], coupled with recent developments in NMR active colloidal suspensions have established all the experimental details necessary to directly probe the transport of colloidal suspensions in porous media. The experimental observations of colloid transport in this work are limited to the long time limit of transport; times much greater than the transient so-called “clean-bed removal” filtration phase [3]. In this “stationary” regime the interplay of colloid attachment and flow has equilibrated so that the solute and colloid dynamics are stationary.