InterPore2026

Development of an Image-Data-Driven Flow Solver for Investigating Intermittency Effects in Multiphase Flow

21 May 2026, 09:35

15m

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

Speaker

Karlijn Smeulders (Eindhoven University of Technology)

Description

The movement of multiple fluids through porous media is commonly described through phenomenological extension of Darcy's law for single phase flow, assuming the different fluids follow distinct and stable pathways. However, experimental studies have shown that this is frequently violated: fluids can undergo intermittent rearrangements. These rapid events promote phase fragmentation and can ultimately lead to fluid trapping. Despite extensive study, debate remains regarding the onset and spatial extent of these fluid rearrangements [1,2,3].

Enabled by recent advances in synchrotron X-ray imaging and microvelocimetry, it is now possible to directly observe 3D intermittent events at pore scale and associated velocities in opaque porous materials [2]. Building on these experimental developments, this work presents a numerical tool that enables investigation of the onset and spatial extent of intermittent multiphase flow events and addresses the computational complexity associated with modelling this phenomenon. This is achieved through the reconstruction of local pressure and velocity fields, as well as viscous dissipation, from the fluid arrangement observed in X-ray imaging data. Combined with 4D microvelocimetry, direct validation of the computed velocity fields is possible. The model integrates several existing approaches into a single workflow, comprising three main components. First, pressure analysis based on interface reconstruction of image data in porous media [4]. Second, the pull-force method, which directly calculates the net tensile forces acting on triangular interface elements [5,6,7]. Finally, a flow solver that takes as input the forces determined by the pull-force method, using the finite volume method.

Test cases for both the pull-force method and the flow solver were first evaluated independently to verify their correctness, and all showed the expected behavior. The coupled approach was then validated using a static droplet, yielding a 3% deviation from the expected Laplace pressure. However, at the small length scales typical of porous media ($10^{-4}$ m), high parasitic currents were observed, on the order of $10^{-1}$ m/s.

To assess the applicability of the method to real porous media flow, X-ray imaging data from Bultreys et al. [2] were analyzed. Pressure analysis using the pull-force method on the interface shows that the pressure is within the expected order of magnitude based on the average contact angle and pore size. No significantly elevated pressure is found on the interface over which a Haines jump was observed, supporting findings from previous literature that Haines jumps are not localized events [3, 8,9].

Overall, these preliminary results indicate that the method provides a promising framework for investigating intermittency effects in multiphase porous media flows beyond Darcy’s law. Ongoing pressure analysis could provide insight into the effect of surrounding pore pressure and fluid distribution on the onset of these jumps. A notable challenge is that strong surface forces at small length scales can lead to high parasitic currents, which presently limit the use of the flow solver at this scale. Addressing these effects is therefore an important direction for future work.