Collision dynamics of wet particles: Comparison of literature models to new experiments

Abstract Collision dynamics of wet particles are often investigated in literature, since their knowledge is important for the design and modeling of granular process involving liquid layers or moisture. Several models were already reported predicting rebound behavior of wet particles. However, most of them are either developed for a viscous dominant regime, neglecting capillary effects all together, or capillary effects are strongly simplified. This work summarizes the various models and compares them to new experimental results for liquids at small and moderate viscosities, to check for applicability also for these materials. Several discrepancies between experiments at small liquid viscosities and models were found and reasons for these differences are discussed. Mainly, the negligence or simplification of capillary forces regarding energy dissipation during the collision leads to an overprediction of rebound velocities compared to the experiments reported in this work. Furthermore, selection of appropriate models for viscous forces during wet particle collisions has to be conducted with care.