(148d) Experimental and Numerical Study of Hydrodynamic Dispersion and Colloidal Transport in Solid Cellular Foam

Solid cellular structures are an important class of porous materials found throughout the industrial and natural world. Many highly optimized naturally occurring materials, e.g. lightweight woods, sponges, cancellous bone structures, are cellular in nature. Despite the advantageous utility of cellular materials for some transport applications there remains limited available data concerning either the time dependent or asymptotic features of dispersion within these structures. Characterization of these complex pore structures has, in the past, been achieved via a systematic analysis of the structure geometry. In the first section of this work we utilize nuclear magnetic resonance (NMR) to probe the stochastic dynamics of hydrodynamic dispersion resulting from the flow of water through high porosity polymer foam pore structures over a range of time scales. Three dimensional lattice Boltzmann simulations of a numerical foam sample supplement the NMR measurements. A short time spatial-temporal correlation, well known for mono-disperse packed beds, has been found within the stochastic dynamics of dispersion in solid cellular foam which can be interpreted as a direct measurement of the characteristic length scale of the structure. This efficient bulk measurement can be used as a characterization tool for commercial foams. In the second section of this work we utilize NMR to directly probe the stochastic dynamics of transport and deposition of a colloid suspension flowing through the cellular pore structure. The use of NMR ?active? core shell particles allows simultaneous measurement of the dynamics of both the suspended colloid particle phase and the suspending fluid. The process of colloidal deposition and the resultant effect on transport over a range of temporal and spatial scales is monitored.