Numerical study of drying process and columnar fracture process in granules-water mixtures

TL;DR

This numerical study explores the formation and evolution of columnar cracks in starch-water mixtures during drying, revealing complex water content dynamics and crack structures influenced by particle size and water distribution.

Contribution

It introduces a combined elastic porous medium model and phenomenological water potential model to simulate crack formation and water content evolution in drying mixtures.

Findings

Water content exhibits a propagating front not explained by simple diffusion.

Columnar crack structures are observed and their depth dependence studied.

Particle size influences the scale of the columnar cracks.

Abstract

The formation of three-dimensional prismatic cracks in the drying process of starch-water mixtures is investigated numerically. We assume that the mixture is an elastic porous medium which possesses a stress field and a water content field. The evolution of both fields are represented by a spring network and a phenomenological model with the water potential, respectively. We find that the water content distribution has a propagating front which is not explained by a simple diffusion process. The prismatic structure of cracks driven by the water content field is observed. The depth dependence and the coarsening process of the columnar structure are also studied. The particle diameter dependence of the scale of the columns and the effect of the crack networks on the dynamics of the water content field are also discussed.