Convection behavior of non-spherical particles in a vibrating bed: Discrete element modeling and experimental validation

This paper proposes a discrete element method (DEM) model to simulate the convection phenomenon of non-spherical particles in a vibrating bed. The corresponding physical experiments were carried out in our previous study. The discrete element simulation results were validated with the experimental results. The non-spherical particles were paired particles, composed of two single beads. The proposed discrete element model adopted Hertz–Mindlin no slip contact force model to model particle collision and multi-sphere method to exactly represent the shape of paired particles. The local damping as well as contact friction and contact damping were incorporated to properly dissipate the system energy of non-spherical granular assemblies. To attain a high level quantitative validation, the important particle properties required for DEM simulation were not simply assumed but measured directly in laboratory tests. The transport properties of paired particles in a vibrated bed, involving local average velocity, local fluctuation velocity, granular temperature, fluctuation velocity distribution and self-diffusion coefficient, were analyzed. The comparison between the DEM results and experimental results was made and discussed in this paper. Both results show the convection phenomena of paired particles in a vibrating bed and the majority of transport properties show good to excellent match, thus giving a quantitative validation for the discrete element simulation of the problem studied here. This proposed discrete element model is shown to provide plausible results and can directly be applicable to realistic industrial problems comprising many non-spherical particles.

This paper proposes a DEM model to simulate the convection phenomenon of non-spherical particles in a vibrating bed. The following figure shows the local translational velocity fields of POM paired particles for experiment and simulation. The DEM predicted translational velocity field matched well with the measured velocity field.Figure optionsDownload as PowerPoint slideHighlights
► Simulate the convection phenomena of non-spherical particles in a vibrating bed
► Propose a DEM model with local damping as well as contact damping and friction
► Use the local damping to account for the air drag force induced by vibration
► Simplify this two-phase flow problem into one-phase flow problem
► Predict the translational velocity field within 8% difference to the test results