How pore geometry affects the transition of non-Fickian to Fickian solute transport over various length scales
Pore scale solute transport is known to exhibit non-fickian solute transport characteristics related to pronounced tailing during asymptotic times. The tailing behavior is likely associated with large variability in pore fluid velocity, which is caused by diverging-converging pore channel geometry, and which further is magnified during inertial flows, as eddies or ‘recirculation zones’ form and grow in the dead-end part of pore channels. In this study we, at first, design a series of pore channel geometries and define them with a non-dimensional pore geometry parameter ‘γ’. We use these geometries to solve Navier-Stokes and Advection-Diffusion (ADE) equations and obtain ‘break through curves’. These curves are used to fit analytical solution to ADE and determine the degree of non-fickian to fickian transport characteristics for various range of Reynolds number (Re) flows. Finally, pore channels are systematically extended in the direction of flow to ‘length scales’ where the non-Fickian transport becomes Fickian transport. The relationships between ‘γ’, Re, and length scales for Fickian transport will be presented during the conference meeting.
Bradley, Jacob M. and Chaudhary, Kuldeep(2019). How pore geometry affects the transition of non-Fickian to Fickian solute transport over various length scales. Environmental Science & Design Research Initiative. Paper 7.