Modeling the Transition between Localized and Extended Deposition in Flow Networks through Packings of Glass Beads

We use a theoretical model to explore how fluid dynamics, in particular, the pressure gradient and wall shear stress in a channel, affect the deposition of particles flowing in a microfluidic network. Experiments on transport of colloidal particles in pressure-driven systems of packed beads have shown that at lower pressure drop, particles deposit locally at the inlet, while at higher pressure drop, they deposit uniformly along the direction of flow. We develop a mathematical model and use agent-based simulations to capture these essential qualitative features observed in experiments. We explore the deposition profile over a two-dimensional phase diagram defined in terms of the pressure and shear stress threshold, and show that two distinct phases exist. We explain this apparent phase transition by drawing an analogy to simple one-dimensional mass-aggregation models in which the phase transition is calculated analytically.

Automated summary

This study explores the deposition of particles flowing in a microfluidic network under the influence of fluid dynamics, specifically the pressure gradient and wall shear stress in a channel. Experimental observations show that particles deposit locally at the inlet at lower pressure drop, while they deposit uniformly along the direction of flow at higher pressure drop. A mathematical model and agent-based simulations are developed to capture and explain these qualitative features. The deposition profile is explored over a two-dimensional phase diagram defined by the pressure and shear stress threshold, revealing the existence of two distinct phases.