Capillary equilibrium of bubbles in porous media

In geologic, biologic, and engineering porous media, bubbles (or droplets, ganglia) emerge in the aftermath of flow, phase change, or chemical reactions, where capillary equilibrium of bubbles significantly impacts the hydraulic, transport, and reactive processes. There has previously been great progress in general understanding of capillarity in porous media, but specific investigation into bubbles is lacking. Here, we propose a conceptual model of a bubble’s capillary equilibrium associated with free energy inside a porous medium. We quantify the multistability and hysteretic behaviors of a bubble induced by multiple state variables and study the impacts of pore geometry and wettability. Surprisingly, our model provides a compact explanation of counterintuitive observations that bubble populations within porous media can be thermodynamically stable despite their large specific area by analyzing the relationship between free energy and bubble volume. This work provides a perspective for understanding dispersed fluids in porous media that is relevant to CO2 sequestration, petroleum recovery, and fuel cells, among other applications.



Work Title Capillary equilibrium of bubbles in porous media
Open Access
  1. Chuanxi Wang
  2. Yashar Mehmani
  3. Ke Xu
License In Copyright (Rights Reserved)
Work Type Article
  1. Proceedings of the National Academy of Sciences of the United States of America
Publication Date April 27, 2021
Publisher Identifier (DOI)
Deposited July 16, 2021




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Work History

Version 1

  • Created
  • Added MainText_withFunding.pdf
  • Added Creator Chuanxi Wang
  • Added Creator Yashar Mehmani
  • Added Creator Ke Xu
  • Published
  • Updated
  • Updated
  • Updated