Boundary-induced inhomogeneity of particle layers in the solidification of suspensions

TL;DR

This study investigates how boundary effects influence particle layer inhomogeneity during suspension solidification, revealing a relationship between layer thickness, sample depth, and boundary-induced particle density variations.

Contribution

It introduces a mechanical model linking boundary-induced particle density inhomogeneity to layer thickness and sample depth in suspension freezing.

Findings

Layer thickness depends on sample depth due to boundary effects.

Particle density distribution is influenced by sample plates within nine particle diameters.

The model explains how boundaries affect suspension solidification processes.

Abstract

When a suspension freezes, a compacted particle layer builds up at the solidification front with noticeable implications on the freezing process. In a directional solidification experiment of monodispersed suspensions in thin samples, we evidence a link between the thickness of this layer and the sample depth. We attribute it to an inhomogeneity of particle density induced by the sample plates. A mechanical model enables us to relate it to the layer thickness with a dependency on the sample depth and to select the distribution of particle density that yields the best fit to our data. This distribution involves an influence length of sample plates of about nine particle diameters. These results clarify the implications of boundaries on suspension freezing. They may be useful to model polydispersed suspensions since large particles could play the role of smooth boundaries with respect to small ones.