Transport of colloids in unsaturated porous media: Explaining large-scale behavior based on pore-scale mechanisms

2004 ◽  
Vol 40 (12) ◽  
Author(s):  
Arturo A. Keller ◽  
Sanya Sirivithayapakorn
Keyword(s):  
Porous Media ◽  
Large Scale ◽  
Pore Scale ◽  
Unsaturated Porous Media ◽  
Behavior Based ◽  
Scale Behavior

Pore-scale Mixing and the Evolution from Anomalous to Normal Hydrodynamic Dispersion

2021 ◽  
Author(s):  
Marco Dentz ◽  
Alexandre Puyguiraud ◽  
Philippe Gouze
Keyword(s):  
Porous Media ◽  
Large Scale ◽  
Molecular Diffusion ◽  
Pore Space ◽  
Breakthrough Curves ◽  
Heterogeneous Porous Media ◽  
Hydrodynamic Dispersion ◽  
Pore Scale ◽  
Sandstone Sample ◽  
Flow Variability

<p>Transport of dissolved substances through porous media is determined by the complexity of the pore space and diffusive mass transfer within and between pores. The interplay of diffusive pore-scale mixing and spatial flow variability are key for the understanding of transport and reaction phenomena in porous media. We study the interplay of pore-scale mixing and network-scale advection through heterogeneous porous media, and its role for the evolution and asymptotic behavior of hydrodynamic dispersion. In a Lagrangian framework, we identify three fundamental mechanisms of pore-scale mixing that determine large scale particle motion: (i) The smoothing of intra-pore velocity contrasts, (ii) the increase of the tortuosity of particle paths, and (iii) the setting of a maximum time for particle transitions. Based on these mechanisms, we derive an upscaled approach that predicts anomalous and normal hydrodynamic dispersion based on the characteristic pore length, Eulerian velocity distribution and Péclet number. The theoretical developments are supported and validated by direct numerical flow and transport simulations in a three-dimensional digitized Berea sandstone sample obtained using X-Ray microtomography. Solute breakthrough curves, are characterized by an intermediate power-law behavior and exponential cut-off, which reflect pore-scale velocity variability and intra-pore solute mixing. Similarly, dispersion evolves from molecular diffusion at early times to asymptotic hydrodynamics dispersion via an intermediate superdiffusive regime. The theory captures the full evolution form anomalous to normal transport behavior at different Péclet numbers as well as the Péclet-dependence of asymptotic dispersion. It sheds light on hydrodynamic dispersion behaviors as a consequence of the interaction between pore-scale mixing and Eulerian flow variability. </p>

Pore-Scale Simulation for Predicting Material Transport Through Porous Media

2002 ◽  
Author(s):  
Goichi Itoh ◽  
Jinya Nakamura ◽  
Koji Kono ◽  
Tadashi Watanabe ◽  
Hirotada Ohashi ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Porous Media ◽  
Parallel Computation ◽  
Large Scale ◽  
Message Passing Interface ◽  
Complex Geometry ◽  
Data Communication ◽  
Porous Media Flow ◽  
Pore Scale ◽  
Material Transport

Microscopic models of real-coded lattice gas automata (RLG) method with a special boundary condition and lattice Boltzmann method (LBM) are developed for simulating three-dimensional fluid dynamics in complex geometry. Those models enable us to simulate pore-scale fluid dynamics that is an essential part for predicting material transport in porous media precisely. For large-scale simulation of porous media with high resolution, the RLG and LBM programs are designed for parallel computation. Simulation results of porous media flow by the LBM with different pressure gradient conditions show quantitative agreements with macroscopic relations of Darcy’s law and Kozeny-Carman equation. As for the efficiency of parallel computing, a standard parallel computation by using MPI (Message Passing Interface) is compared with the hybrid parallel computation of MPI-node parallel technique. The benchmark tests conclude that in case of using large number of computing node, the parallel performance declines due to increase of data communication between nodes and the hybrid parallel computation totally shows better performance in comparison with the standard parallel computation.

scholarly journals Pore-scale mechanisms for the enhancement of mixing in unsaturated porous media and implications for chemical reactions

2015 ◽  
Vol 42 (13) ◽  
pp. 5316-5324 ◽  
Author(s):  
Joaquín Jiménez-Martínez ◽  
Pietro de Anna ◽  
Hervé Tabuteau ◽  
Régis Turuban ◽  
Tanguy Le Borgne ◽  
...  
Keyword(s):  
Porous Media ◽  
Chemical Reactions ◽  
Pore Scale ◽  
Unsaturated Porous Media

scholarly journals Pore-Scale Behavior of Darcy Flow in Static and Dynamic Porous Media

2018 ◽  
Vol 9 (6) ◽  
Author(s):  
M. Aminpour ◽  
S. A. Galindo-Torres ◽  
A. Scheuermann ◽  
L. Li
Keyword(s):  
Porous Media ◽  
Darcy Flow ◽  
Pore Scale ◽  
Scale Behavior

scholarly journals Upscaling Mixing-Controlled Reactions in Unsaturated Porous Media

2021 ◽  
Author(s):  
Lazaro J. Perez ◽  
Alexandre Puyguiraud ◽  
Juan J. Hidalgo ◽  
Joaquín Jiménez-Martínez ◽  
Rishi Parashar ◽  
...  
Keyword(s):  
Experimental Data ◽  
Porous Media ◽  
Flow Field ◽  
Particle Tracking ◽  
Water Phase ◽  
Pore Scale ◽  
Unsaturated Porous Media ◽  
Reactive Mixing ◽  
The Impact ◽  
Random Walk Particle Tracking

AbstractWe study mixing-controlled chemical reactions in unsaturated porous media from a pore-scale perspective. The spatial heterogeneity induced by the presence of two immiscible phases, here water and air, in the pore space generates complex flow patterns that dominate reactive mixing across scales. To assess the impact of different macroscopic saturation states (the fraction of pore volume occupied by water) on mixing-controlled chemical reactions, we consider a fast irreversible reaction between two initially segregated dissolved species that mix as one solution displaces the other in the heterogeneous flow field of the water phase. We use the pore-scale geometry and water distributions from the laboratory experiments reported by Jiménez-Martínez et al. (Geophys. Res. Lett. 42: 5316–5324, 2015). We analyze reactive mixing in three complementary ways. Firstly, we post-process experimentally observed spatially distributed concentration data; secondly, we perform numerical simulations of flow and reactive transport in the heterogeneous water phase, and thirdly, we use an upscaled mixing model. The first approach relies on an exact algebraic map between conservative and reactive species for an instantaneous irreversible bimolecular reaction that allows to estimate reactive mixing based on experimental conservative transport data. The second approach is based on reactive random walk particle tracking simulations in the numerically determined flow field in the water phase. The third approach uses a dispersive lamella approach that accounts for the impact of flow heterogeneity on mixing in terms of effective dispersion coefficients, which are estimated from both experimental data and numerical random walk particle tracking simulations. We observe a significant increase in reactive mixing for decreasing saturation, which is caused by the stronger heterogeneity of the water phase and thus of the flow field. This is consistently observed in the experimental data and the direct numerical simulations. The dispersive lamella model, parameterized by the effective interface width, provides robust estimates of the evolution of the product mass obtained from the experimental and numerical data.

Pore-Scale Experimental Study of Boiling in Porous Media

2014 ◽  
Author(s):  
Paul SAPIN ◽  
Paul Duru ◽  
Florian Fichot ◽  
Marc Prat ◽  
Michel Quintard
Keyword(s):  
Experimental Study ◽  
Porous Media ◽  
Pore Scale
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