Particulate Systems

Key features of the DEM model to analyse behaviour and interaction of particles in various small or large scale processes

Cohesive particles

Wet particles with liquid bridges

  • Liquid bridge force (capillary and viscous forces) model

  • Improved viscous force model for pendular liquid bridges

  • Newtonian and power-law fluids

[Video] Flow of dry (left) and wet (right) particles in a mixer

Improved liquid bridge viscous force model (Washino et al., 2017a and 2017b) for Newtonian fluid. Models are compared with Direct Numerical Simulation (DNS) results.

Improved liquid bridge viscous force model (Washino et al., 2018 and 2021) for power-law fluid. Models are compared with Direct Numerical Simulation (DNS) results.

Surface adhesion

  • Full (with negative overlap force) and simplified JKR models for adhesive contacts

  • Adhesive rolling friction model

[Video] Dry cohesive powder flow in a twin screw mixer

System simplification, computational time reduction

Scaled-up particle model

  • Particle size scaled-up to reduce number of particles for faster computation

  • All types of particle interaction forces (contact, cohesion etc.) are scaled accordingly to maintain system dynamics


[Video] Pile formation of dry cohesive particles with scaled-up particle model

Reduced particle stiffness (RPS) model for cohesive particles

  • Particle stiffness reduced (softer particle) to increase simulation time step while maintaining system dynamics

Wet particle velocities in mixer: solid line indicates the original particle stiffness while the red filled circles are results for reduced particle stiffness with RPS scaling

Dynamic load balancing

  • Dynamic adjustment of processor sub-domains sizes to balance number of particles and thus, computational cost evenly across processors

  • Particularly useful for systems with spatially-varying particle distribution

[Video] Particles falling on a chute simulation with dynamic load balancing

[Video] Particles falling on a chute simulation without dynamic load balancing