Thursday 20 March 2025
Drying complex fluids in porous media is a crucial process that occurs in various natural and industrial contexts, such as consolidating damaged stones or removing water from soil. However, this process is often hindered by the formation of a skin at the surface, which slows down evaporation rates significantly.
Researchers have long sought to understand and predict the drying kinetics of complex fluids undergoing phase changes in porous media. To tackle this challenge, scientists have developed pore network models that simulate the behavior of fluids in these systems. But these models often neglect the critical role played by skin formation during the drying process.
A recent study published in Physical Review Letters sheds new light on this phenomenon. By developing a novel pore network model that incorporates spatial gradients in pore size distribution and localized skin formation, researchers have been able to accurately predict the drying kinetics of complex fluids undergoing sol-gel transition in porous media.
The model takes into account the air invasion path and the interplay between capillary-driven liquid flows, space-dependent viscosity increases, and localized skin formation. By simulating the evaporation process under different conditions, the researchers were able to demonstrate that the model can successfully capture the slowdown of drying kinetics caused by skin formation.
One of the key findings of this study is that the air invasion path remains primarily governed by the pore size distribution, even when viscosity increases during the sol-gel transition. This suggests that the formation of a skin at the surface does not significantly alter the overall flow pattern in the porous medium.
The researchers also investigated the influence of thin films on the drying process and found that their presence does not have a significant impact on the drying kinetics. However, they do trap less liquid than other throats, leading to a more gradual onset of skin formation.
This study has important implications for various fields, including materials science, environmental engineering, and cultural heritage conservation. By better understanding the drying process and its relationship with skin formation, researchers can develop more effective strategies for consolidating damaged structures or removing pollutants from soil.
The development of this novel pore network model is a significant step forward in our ability to predict and control complex fluid behavior in porous media. It has the potential to inform a wide range of applications, from preserving ancient artifacts to designing more efficient water treatment systems.
Cite this article: “Unraveling Skin Formation during Drying of Complex Fluids in Porous Media”, The Science Archive, 2025.
Pore Network Models, Drying Kinetics, Porous Media, Skin Formation, Complex Fluids, Phase Changes, Sol-Gel Transition, Air Invasion Path, Viscosity Increases, Thin Films
