Three-dimensional Monte Carlo model of the coffee-ring effect in evaporating colloidal droplets
Date of Issue2014
School of Mechanical and Aerospace Engineering
The residual deposits usually left near the contact line after pinned sessile colloidal droplet evaporation are commonly known as a “coffee-ring” effect. However, there were scarce attempts to simulate the effect, and the realistic fully three-dimensional (3D) model is lacking since the complex drying process seems to limit the further investigation. Here we develop a stochastic method to model the particle deposition in evaporating a pinned sessile colloidal droplet. The 3D Monte Carlo model is developed in the spherical-cap-shaped droplet. In the algorithm, the analytical equations of fluid flow are used to calculate the probability distributions for the biased random walk, associated with the drift-diffusion equations. We obtain the 3D coffee-ring structures as the final results of the simulation and analyze the dependence of the ring profile on the particle volumetric concentration and sticking probability.
DRNTU::Engineering::Mechanical engineering::Fluid mechanics
This work is licensed under a Creative Commons Attribution- NonCommercial-NoDerivs 3.0 Unported license. To view a copy of this license,visit http://creativecommons.org/licenses/by-nc-nd/3.0