Advective trapping in the flow through composite heterogeneous porous media

We study the mechanisms of advective trapping in composite porousmedia that consist of circular inclusions of distributed hydraulic con-ductivity embedded in a high conductivity matrix. Advective trappingoccurs when solute enters low velocity regions in the media.Transportis analyzed in terms of breakthrough curves measured at the outlet ofthe system. The curve’s peak behavior depends on the volume frac-tion occupied by the inclusions, while the tail behavior depends onthe distribution of hydraulic conductivity values. In order to quantifythe observed behaviors we derive two equivalent upscaled transportmodels. First, we derive a Lagrangian trapping model using the con-tinuous time random walk framework that is parameterized intermsof volume fraction and the distribution of conductivites in the inclu-sions. Second, we establish a non-local partial differential equation forthe mobile solute concentration by volume averaging of the microscaletransport equation. We show the equivalence between the two modelsas well as (first-order) multirate mass transfer models. Theupscaledapproach, parameterized by medium and flow properties captures allfeatures of the observed solute breakthrough curves, and sheds newlight on the modeling of advective trapping in heterogeneous media.

Bibliographic Details

Main Authors:	Hidalgo, Juan J., Neuweiler, Insa, Dentz, Marco
Other Authors:	Dentz, Marco [0000-0002-3940-282X]
Format:	artículo biblioteca
Language:	English
Published:	Springer 2022
Subjects:	Porous media, Continuous Time Random Walks, Multirate MassTransfer, Stochastic Modeling,
Online Access:	http://hdl.handle.net/10261/270041
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