(159b) Comparison of Liquid Bridge Volume Models in DEM Simulations

Liquid bridge forces play an important role in many processes that handle particulates, such as wet granulation and spray coating.  Although there is little disagreement on models for predicting the normal force and the maximum extensional length of liquid bridges, there has been considerably less work investigating how much liquid participates in a liquid bridge.  In many DEM simulations that include liquid bridges, it is assumed that liquid covers the surface of the particle uniformly and that all of the liquid on the particle instantly participates in a newly formed liquid bridge.  If subsequent liquid bridges form, the liquid on the particle is frequently assumed to instantly divide so that equal volumes of liquid participate in all of the liquid bridges.  Another recent model also assumes that liquid is uniformly distributed on particles, but that the volume participating in a liquid bridge is a function only of the geometry of the contact, with the liquid bridge volume from the partnering particle consisting of the liquid volume contained within the angle subtended by the particle center and the tangent surface of the partnering particle.  Still other models have proposed that liquid does not uniformly coat a particle’s surface, but instead is distributed in drops.  This talk will describe the implementation of these various liquid bridge volume models in separate DEM simulations and then compare the distributions of liquid volume as functions of time for the various models.