Effect of interface contamination on particle-bubble collision

This study focuses on the impact of the interface contamination on the collision efficiency between bubbles and inertial particles. The bubble's surface mobility has been integrated into the collision modelling by using the hydrodynamics stagnant-cap model, in which the clean angle θclean is used to characterise the interface contamination level. Direct numerical simulations have been performed for various bubble's Reynolds numbers (1≤Reb≤100), particle to bubble size ratio (0.001≤rp/rb≤0.02) and particle's Stokes numbers (0.001θcrit, the contact point of the “grazing trajectory” can only be situated on the mobile interface, while for θclean<θcrit, the contact point may be on both mobile and immobile part of the interface and only the positive inertial effect is observed. A simple model has been proposed that makes possible the description of collision efficiency for clean or contaminated bubbles.