The role of particle collisions in enhancing resuspension

Abstract

The resuspension of fine particles from surfaces exposed to airflow is a phenomenon of greatrelevance in various scientific and engineering contexts. While traditional models often focus onsingle-particle detachment driven by aerodynamic forces overcoming adhesion, recent studieshave highlighted the significant role of particle–particle interactions, especially in systems withmoderate to high surface concentrations. In this work, we develop a Monte Carlo numericalmodel to investigate the role of collisions as an additional mechanism for particle detachment.The model introduces a probabilistic rule for inter-particle collisions based on particle surfaceconcentration and collision force effect. A parametric study is performed to evaluate how particlesurface concentration, particle size, flow velocity, collision efficiency (ε) and the number ofmultiple particle impacts influence the resuspension rates. The results show that at low concentrations,collisions are negligible, and resuspension is governed by direct aerodynamicdetachment. However, as the surface becomes more populated, collisions increasingly contributeto particle removal, especially when the velocity and size of moving particles allow sufficientmomentum transfer. The efficiency parameter ε controls the fraction of successful detachmentsupon impact, and even modest values lead to noticeable increases in collisional contributions toresuspension rates. The model also captures the non-linear behavior of resuspension curves andreproduces key experimental trends reported in the literature. Comparisons with experimentaldata from other authors show that incorporating collisions significantly improves the predictionof resuspension rates at higher deposition densities. In particular, the introduction of multipleparticle impacts is crucial to match the sharp increase in detachment observed experimentally.These findings underscore the importance of including particle–particle interactions in theoreticalmodels and suggest that even in relatively dilute regimes, collisions can enhance detachmentunder appropriate flow conditions.