Grain Scale Modeling of Arbitrary Fluid Saturation in Random Packings

TL;DR

This paper introduces a comprehensive model for simulating liquid saturation in granular packings, capturing complex liquid structures and dynamics beyond traditional regimes, validated against experimental data.

Contribution

The model uniquely integrates capillary bridges, menisci, and saturated pores, enabling detailed simulation of liquid redistribution at various saturation levels.

Findings

Model accurately predicts liquid structures and flow patterns.

Matches experimental observations at both microscopic and system levels.

Captures dynamic phenomena like Haines jumps.

Abstract

We propose a model for increasing liquid saturation in a granular packing which can account for liquid redistribution at saturation levels beyond the well-studied capillary bridge regime. The model is capable of resolving and combining capillary bridges, menisci and fully saturated pores to form local liquid clusters of any shape. They can exchange volume due to the local Laplace pressure gradient via a liquid film on the surfaces of grains. Local instabilities like Haines jumps trigger the discontinuous evolution of the liquid front. The applicability of the model is demonstrated and compared to benchmark experiments on the level of individual liquid structures as well as on larger systems.