Direct simulations of two-phase flow experiments of different geometry complexities using Volume-of-Fluid (VOF) method

Two-phase flow in three porous media with different geometry complexities are simulated using the Volume-of-Fluid (VOF) method. The evolution of the flow pattern, as well as the dynamics involved are simulated and compared to experiments. For a simple geometry and smooth solid surface, like single capillary rise experiment, VOF simulation gives results which are in good agreement with the experiments. For a micromodel, with a relatively simple geometry, we can predict the flow pattern while we cannot effectively capture the dynamics of the process in terms of the temporal evolution of flow. With an increase in the geometry complexity in another micromodel, we fail to predict both the flow pattern and the flow dynamics. The reasons for this failure are discussed: interface modeling, pinning of contact line, 3D effects and the sensitivity of the system to initial and boundary conditions. More work regarding benchmarking of pore-scale methods in combination with experiments with different geometry complexities is needed. Also, possibilities and the potential to make better use of the porous media structure data from advanced visualization methods should be addressed.