An inter-particle contact area and time restoration for softening treatment in thermal discrete element modeling

The thermal discrete element method (TDEM), a coupling of the discrete element model (DEM) with the inter-particle heat transfer models, has been applied to the simulation of the particulate systems with heat transfer. Additionally, small normal spring stiffness coefficient has often been adopted instead of the real value in the softening treatment to improve the calculation efficiency. However, present research has indicated that the heat transfer thus simulated is exaggerated even though such softening treatment has almost no effect on the movement of particles. In this letter, we propose a restoration method to restore the inter-particle contact time and contact area in the real heat transfer process even when particle stiffness is softened by several orders. This restoration method keeps the merit of the softening treatment in the DEM simulation of the particulate systems with heat transfer and avoids the unreasonable heat transfer calculations using the softening treatment method.