A Coarse-Grained Discrete Element Model (CG-DEM) based on parameter scaling for dense wet granular system
Roxana Saghafian Larijani, Vanessa Magnanimo, Stefan Luding
Abstract
The Discrete Element Model (DEM) is widely used for studying wet granular systems, where particles experience liquid bridge forces. However, due to its high computational cost, DEM is not a viable approach for industrial scale simulations. A potential solution is offered by coarse-graining (CG), where a group of particles is substituted by a larger particle, thereby increasing the computational efficiency of the simulations. However, it is essential to consider appropriate scaling rules to properly apply CG-DEM and conserve the material’s rheological behaviour. Two scaling approaches based on constant dimensionless groups, Weber (We) and Bond (Bo) numbers, are compared. The We-based CG-DEM simulation can reproduce the volume fraction, velocity, apparent viscosity and macroscopic friction fields properly, but not granular temperature. The effect of CG on the liquid convection and migration patterns, as well as wall coverage is explored. In addition, the applicability of the CG-DEM model in the wet slumping regime is investigated. • CG-DEM for wet particles in a drum is explored in rolling and wet slumping regimes. • Scaling rules for dry forces and liquid bridge related parameters are reviewed and tested. • The CG-DEM model can reproduce most of the system’s macroscopic rheological state variables. • Invariant and variable restitution coefficient-based scalings are compared for the dry system. • The effect of CG modelling on the liquid convection and migration is studied.