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Center for Nonlinear Studies |
Although there is a wide adoption of Discrete Element Modeling (DEM) of particulate systems in academic research, there is a general lack of consensus on the usage and applicability of DEM within industry. DEM modeling has successfully modeled granular beds versus fine powder beds. However, simulation of full-scale processes is difficult (due to increased number of particles to model). There are examples of qualitative full-scale processes with “meso” particles. Calibration is difficult; better for “granules,” although lacks consistency in the method. Calibration for fine powders is poor to non-existing. Recently identified industrial DEM technological gaps are: lack of standardized calibration/benchmarking approaches, representative contact models/physics, simulation of “meso” particles link to continuum, lack of a clear understanding of the evolution of Molecular Dynamics (MD) and Computational fluid dynamics (CFD) – how they managed practical limitations of their techniques, and limited understanding of additional physics – electrostatics, humidity, temperature, micro-structural effects. Experientially, particle level correlations to product structure-property outcomes are well studied, while the influences of bulk powder effects (powders as used) on structure-property functions remain elusive. Bulk powder effects depend on multi-scale characterization of the ensemble of particles packing and require evaluation at the meso-scale (pre-bulk powder level) to bridge nano/micro particle scale characteristics and bulk powder macro-scale behavior. A review of bulk powder characterization challenges, i.e. multi-scale characterization and its relationship to DEM calibration of simulation parameters will be discussed, which includes: meso-scale (dynamic) particle characterization, powder flow mechanics of cohesive powders, quantifying segregation and electrostatic effects, milling utilization and predictability, and nanoparticle processing and handling as it relates to the technical gaps surrounding the use of DEM and its industrial relevance.
Host: Duan Zhang