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Particulate flows with charged particles under electric flow field exist in many practical applications, including metal particles in Gas Insulated Switchgear (GIS) or manipulation of powders in fluidized bed. The motions of these particles are affected by the electrical field, ambient flow and collisions. This work further develops the four-way coupled CFD-DEM framework under electric field, which not only computes the coupling of flow field, electric field with particle motion and particle charge, the particle-occupied solid fractions on CFD cell, particle-particle interactions and particle-wall interactions, but also considers the dielectrophoretic force, particle-particle Coulomb force, virtual mass force and Magnus force. Particle electrification on its contact with electrode is computed as well. Besides, the multi-sphere model is also introduced into the present framework in order to simulate particles of irregular shapes. The model is validated with theoretic solutions and experiments, and is applied to GIS and fluidized bed. Based on the framework, statistic information from the particulate flow in GIS, e.g., time-averaged solid fraction, time-averaged electric field or particles' velocity and charge distribution are analyzed. A dimensionless number is proposed to predict the particle motion in GIS with Alternating Current (AC), which is further conducive to reducing the parameter window in relevant simulations and studies. • The four-way coupled CFD-DEM modeling framework for charged particulate flows is extended with more concerned forces. • Fluid fraction is counted in the standard four-way coupling. • Multi-sphere model is introduced for modeling irregular-shaped particles. • Interesting phenomena of charged particles in GIS are revealed and discussed. • A dimensionless number is proposed to predict the particle motion in GIS. [ABSTRACT FROM AUTHOR]

The rigid motions of powders widely exist in powder-based laser additive manufacturing, like powder deposition, entrainment and spattering. These phenomena simultaneously happen as the laser melts these powders, and can have significant impacts on the quality of the printed products. However, existing models can hardly efficiently reproduce the co-existence of melting and rigid motion which greatly influences the molten pool and molten track evolution. The bottleneck therein lies in the demand that unresolved Computational Fluid Dynamics-Discrete Element Method (CFD-DEM) has on the CFD grid size, that is, larger than 3 times of the particle diameter. However, this large size ratio (CFD grid cell vs particle diameter) handicaps the description of the particle deformation during melting. Hence in this paper, a kernel approximation-based semi-resolved CFD-DEM numerical model that allows the refinement of CFD grid is employed, and then coupled with the Volume of Fluid (VOF) method to reproduce the molten metal-gas interface. On this basis, the rigid motions of the powders, like entrainment and spattering, are finally simultaneously realized as the molten pool evolves at high efficiency. Powders remained in the unclosed molten pool trail defect are well explained with the proposed model as well. This model can also be applied to simulate the particle-fluid interactions in Directed Energy Deposition. It is believed that this semi-resolved VOF-DEM Additive Manufacturing model will serve as a good tool for future investigations into the particle behaviors in powder-based additive manufacturing. [Display omitted] • Semi-resolved VOF-DEM Additive Manufacturing model is developed. • Particle rigid motion is simultaneously modeled with molten pool evolution. • Spattered powders left in the defect are well explained. • Modeling of complex particulate flows in Directed Laser Deposition is realized. [ABSTRACT FROM AUTHOR]