Mechanistic studies of initial deposition of fine adhesive particles on a fiber using discrete-element methods.

Abstract: The impaction-sticking mechanism of fine particulates plays a significant role in a wide range of applications from dust separation devices, thin-film deposition techniques to the astrophysics science, but the underlying physics still remains unclear. In this paper, a discrete element method (DEM) approach is established to investigate the impaction-sticking process during the initial deposition of fine particles on a single fiber. Starting from the JKR adhesive contact theory, the DEM well predicts the measured trend of single-fiber capture efficiency as a function of Stokes number in the literature, by the proper considerations of key dissipation terms including the first-contact energy loss, the linear-dashpot damping and the rolling friction resistance. The increasing work of adhesion not only dramatically increases the peak value of single fiber efficiency, but also causes the peak to move towards a much higher Stokes number. The DEM predictions further clarify that the sticking probability depends on the adhesion parameter, rather than Stokes number. An empirical power law between sticking probability and adhesion parameter is drawn as h =0.0558⋅Ad5/3 (for Ad<5.65). Finally, by using both adhesion parameter for the sticking and Stokes number for the impaction, four distinct deposition patterns during the initial stage of single fiber filtration are identified. [Copyright &y& Elsevier]