Kinetic Monte Carlo method applied to micrometric particle detachment mechanisms by aerodynamic forces

VILLAGRÁN OLIVARES, MARCELA C.; BENITO, J.G.; UÑAC, RODOLFO O.; VIDALES, A. M.

JOURNAL OF PHYSICS CONDENSED MATTER

IOP PUBLISHING LTD

Año: 2021 vol. 34

0953-8984

The formulation of a kinetic Monte Carlo simulation to account for the different possiblemechanisms present in the problem of resuspension of aerosol particles is addressed as anextension of a former model Benito et al (2016 J. Aerosol Sci. 100 26?37). The re-entrainmentof micrometer particles to airflow when detached from a surface by aerodynamic forces ismodeled using the similitude of the problem with the desorption process from heterogeneoussurfaces. Depending on the relative role of the intervening forces, three main mechanisms formovement initiation can be present: rolling, sliding and lifting-off . Three different transitionprobabilities are defined for each mechanism and the corresponding transition rates calculatedfor the kinetic process to be simulated. The decisive factor for the development of the model isto set an appropriate dynamical hierarchy to simulate correctly the evolution of the transitionrates as the airflow velocity increases, reflecting the stochastic nature of the process, notalways fully captured by other Monte Carlo approaches. The model is applied to spherical andelongated particles on a flat surface, reproducing qualitatively well the experimental trendsfound by other authors for the case of particles with different shapes. It is also demonstratedthat, for elongated particles, the main mechanism assisting the detachment is not rolling butsliding, underscoring the need for an adequate choice of the particles shape and detachmentmechanism when looking for the critical conditions for particle removal from surfaces.