Authors: Florian Huchet Nicolas Roquet Bogdan Cazacliu
Publish Date: 2014/06/05
Volume: 104, Issue: 2, Pages: 299-313
Abstract
Advection–dispersive phenomena inside two geometries of porous media corresponding to a structured and unstructured network of minichannels are studied from a combination of analytical numerical and electrodiffusion techniques The instantaneous limiting diffusion current connected to the concentration of electroactive species flowing in the porous matrix is recorded and measured during flow experimentation Transport phenomena investigation consists of the step injection of a tracer of higher concentration than the bulk flow in order to characterize the mixing of electrolyte species inside two arrangements of network so called times network and T network The experimental results are supported by 2Dnumerical simulations performed in the times network A pore model is proposed in order to predict the pore velocity which is used within the resolution of the diffusion–convection balance The numerical simulations based on a secondorder finite difference scheme give rise to a good agreement in terms of mixing index and the methodology employed for the numerical injection concentration appears suitable The numerical experiments are quitewell representative in laminar regime below the critical Reynolds number Re mathrmcritapprox 200 Above Re mathrmcrit the inertial effects are not negligible and the momentum transfer needs to be taken into account This latter phenomenon is analyzed at the porescale in term of local skin friction measured at the channels crossing then compared and discussed from analytical solutions
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