Effect of geometry on the dewetting of granular chains by evaporation

TL;DR

This study explores how the packing geometry of granular chains influences the stability and height of liquid film networks during evaporation, combining experiments and simulations to understand the underlying physics.

Contribution

It introduces a controlled experimental and simulation approach to analyze the impact of granular packing on film network stability during evaporation.

Findings

Liquid film height varies with packing density.

Model predictions agree with experimental results.

Granular packing geometry significantly affects evaporation dynamics.

Abstract

Understanding evaporation or drying in granular media still remains complex despite recent advancements. Evaporation depends on liquid transport across a connected film network from the bulk to the surface. In this study, we investigate the stability of film networks as a function of granular packing. Using a controlled experimental approach, we vary the granular packing geometry and show the changes in the height of the liquid film network during evaporation as packing shifts from a loose-packed to a close-packed arrangement. This height can be calculated from an equilibrium between hydrostatic pressure and the pressure difference between two points in the vertical film network. We use a simulation approach to calculate the pressure in both the percolating front and evaporating front within the two-phase zone of air/water mixture. Results show good agreement between the model and the experiment.