Potential Discrete Element Simulation Applications Ranging from Airborne Fines to Pellet Beds

Under micro-gravity, lack of sedimentation allows all scales of airborne particulates to participate in the formation of clusters and aggregates. As observed in the International Space Station (ISS), the resulting very-low-density dust aggregates can collect on ventilation inlet screens and duct walls. Discrete Element Method (DEM) simulations, utilizing cohesive interparticle forces and bending-moment interactions, are a tool that can assist in understanding the build-up, compaction, and removal of such agglomerate beds. At a different length-scale, high pellet-pellet contact stresses can be developed in the thermally cycled packed granular beds of air revitalization equipment (possibly fracturing pellets and/or producing unwanted fines). The limits and capabilities of DEM models to simulate these and other particulate systems is discussed.