Time step criteria in DEM simulation of wet particles in viscosity dominant systems

Abstract

Discrete element method (DEM) has been applied to simulate particulate flows with wet particles by taking into account the liquid bonding forces between particles. However, there is only limited work available in literature which applies DEM to simulate wet particles with highly viscous liquid. In this paper, the currently used DEM framework is assessed and the limitations are revealed for simulations of wet particles with highly viscous liquid in terms of the time step required for stable simulations, i.e. the time step decreases with increasing liquid viscosity. Semi-empirical time step criteria based on the viscous force decay time are proposed which determine the stable time step limit for given simulation conditions.