InterPore2026

Pore-network modeling of buoyancy-driven microbubbles in a supergravity field

21 May 2026, 10:05

1h 30m

Poster Presentation (MS09) Pore-Scale Physics and Modeling Poster

Speaker

Mr Kristoffer Skjelanger (Western Norway University of Applied Sciences)

Description

Decreasing the production cost of hydrogen is a key challenge in the hydrogen economy, and one of the obstacles is the overpotential caused by bubble effects \cite{swiegers_prospects_2021}. Experimental studies have shown that rotating an electrolyzer promotes bubble detachment from the electrode surface of an alkaline electrolyzer; however, the mechanism within the porous medium remains largely unknown \cite{wang_water_2010}. In this talk, we will present a pore-network model with discrete bubble tracking as a way of understanding the bubble transport within a porous medium under the influence of a supergravity field.

The pore-network model is chosen for its discrete mass conservation, well-defined geometry, and computational efficiency \cite{michalkowski_modeling_2022}. In addition to the capillary-driven phase transport, we will allow buoyancy driven microbubbles to move through the pore-network. This buoyancy-driven bubble transport can appear in strong gravitational fields where the bubble detachment radius is smaller than the average pore-size. In a rotating system, the supergravity field can easily exceed 100 G.

Using classical nucleation theory and bubble detachment sizes, we can estimate the minimum size of a mobile bubble in the porous medium. We can then track their movement and behavior through the pore-network by formulating suitable rules for bubble transport and numerically determining the rising velocity of bubbles in simple pore-throat geometries \cite{bico_rise_2002}. The model is implemented in DuMux \cite{koch_dumux_2021}.

Finally, we discuss the observed flow-patterns in the pore-network model and how this microbubble flow impacts the overall system. The respective importance of continuous phase capillarity-dominated transport and bubble-like transport driven by buoyancy is then evaluated for different gravitational fields.