Proceedings of the 9th World Congress on Momentum, Heat and Mass Transfer (MHMT 2024)
London, United Kingdom – April 11 – 13, 2024
Paper No. ICMFHT 175
DOI: 10.11159/icmfht24.175

Direct Numerical Modelling Of Capillary Driven Multiphase Flow at theEmbedded Steel - Porous Media Interface
Luka Malenica 1, Zhidong Zhang 1, Ueli Angst 1

Institute for Building Materials (IfB), ETH Zurich
Leopold-Ruzicka-Weg 4, 8093 Zurich, Switzerland
lmalenica@ethz.ch; zhidongz@ifb.baug.ethz.ch; ueli.angst@ifb.baug.ethz.ch
1

Extended Abstract

Multiphase flow through porous materials is an important field of study in a broad range of applications. One of suchapplications is understanding and predicting corrosion mechanisms inside reinforced porous materials, such as soil orconcrete, where air-water distribution at the steel surface is directly related to corrosion processes and has a great impact on
durability of reinforced structures [1].
Prediction of water transport and retention throughout pore systems is generally based on traditional models relying oneither Darcy scale modelling, such as Richards equation [2] or simplified pore scale modelling, such as bundle of capillarytubes or pore-network modelling [3]. However, such models are not capable of providing detailed insight into water
distribution at the steel-porous media interface which is crucial to understanding of relevant degradation mechanisms suchas corrosion.
One approach that can overcome mentioned limitation of traditional models is direct numerical modelling of multiphaseflow directly at pore scale [4]. Such an approach solves the full set of Navier-Stokes equations which accurately describes
multiphase flow by directly resolving fluid-fluid interfaces and contact lines of fluid phases with solid boundaries, such as
contact between air, water and solid (both porous skeleton and steel in our case). Moreover, these models are capable toaccount for complex microstructure heterogeneities of real pore structures obtained by pore-scale imaging, such as X-ray
microtomography or FIB-SEM techniques.
In this work, OpenFOAM based volume-of-fluid (VOF) solver is used to perform high-fidelity direct numericalsimulations of gas-liquid multiphase flow inside different reinforced porous media, such as reinforced soil or concrete. Bothsynthetic and realistic (imaged-based) pore structures, as well as different material properties were studied. Even that direct
numerical modelling approach cannot be used to predict flow over full scale of interest (mostly due to high computational
cost and size limitations of pore-scale imaging), combining detailed resolution of fully dynamic pore-scale multiphaseprocesses with realistic 3D geometries of pore space enables us deeper insight and consistent explanation of particular
processes that are still not well understood.

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Sep. 2022, doi: 10.1016/j.cement.2022.100043.
[2] L. Malenica, H. Gotovac, G. Kamber, S. Simunovic, S. Allu, and V. Divic, “Groundwater Flow Modeling in Karst
Aquifers: Coupling 3D Matrix and 1D Conduit Flow via Control Volume Isogeometric Analysis—Experimental
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[3] M. J. Blunt, Multiphase Flow in Permeable Media: A Pore-Scale Perspective. Cambridge: Cambridge University Press,2017. doi: 10.1017/9781316145098.
[4] J. Maes and S. Geiger, “Direct pore-scale reactive transport modelling of dynamic wettability changes induced by surface
complexation,” Advances in Water Resources, vol. 111, pp. 6–19, Jan. 2018, doi: 10.1016/j.advwatres.2017.10.032.

ICMFHT 175-1