Pore-scale study of miscible density-driven mixing flow in porous media

Long Ju, Baochao Shan, Peiyao Liu, Zhaoli Guo*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

15 Scopus citations

Abstract

Two-dimensional density-driven convective mixing processes in synthetic porous media are simulated at pore-scale using lattice Boltzmann method with a rescaled version of the nonequilibrium extrapolation method in the present work. Numerical results demonstrate that the density-driven convective mixing process varies with the Rayleigh number (Ra). For low values of Ra, the numerical results at pore-scale are consistent with those at representative elementary volume (REV) scale. With the increase in Ra, the convective mixing process becomes different, which can be reflected by the time evolution of the dissolution flux and onset time of convection at different Rayleigh numbers. On the one hand, the flux growth regime in the time evolution of the dissolution flux can be divided into two sub-regimes, which are named early and late flux growth regimes in this study. In addition, for the shutdown regime, the dissolution flux can be scaled as J ∼ t - 1 rather than t - 2 for high Ra cases, which is consistent with our theoretical analysis. On the other hand, the existence of the early flux growth regime consumes the mass at the top diffusive layer, leading to a delay of convective onset time. Therefore, the onset time of the convection calculated at pore-scale is much higher than that predicted by the existing theory and REV scale studies. The present study shows practical implications for CO2 capture and storage.

Original languageEnglish (US)
Article number034113
JournalPhysics of Fluids
Volume33
Issue number3
DOIs
StatePublished - Mar 1 2021

ASJC Scopus subject areas

  • Computational Mechanics
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering
  • Fluid Flow and Transfer Processes

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