Multiscale Modelling of Particle Motion by Means of DEM and DPM

We report on the synthesis of the Discrete Element Method (DEM) modelling the behaviour of individual grains and a Discrete Phase Model (DPM) for disperse particle flow. Since in many cases different granular regimes occur within one simulation, a synthesis of dedicated models operating at different scales is considered to be the best trade-off between describing the physics and ensuring computability. DEM captures the physics of granular materials at the particle scale but is computationally time-consuming. We show that complementing the DEM by a Discrete Phase Model (DPM) can considerably accelerate the overall simulation. This is because the DPM approach tracks the trajectory of groups (parcels) of particles. It neglects interparticle collisions and is thus valid when the particle volume fraction is low. This DEM-DPM synthesis can also be complemented by the fluid dynamics of a continuous phase, resulting in a fully coupled DEM-DPM-CFD approach. We finally demonstrate the efficiency and validity of our approach by applying our approach to a lab-scale particle charging experiment.