Simulation of Heat Transfer in Moving Granular Material by the Discrete Element Method With Special Emphasis on Inner Particle Heat Transfer

Physical processes involving static or dynamic granular assemblies are best modeled on the particle scale by Discrete Element Methods (DEM) rather than continuum approaches. Due to the high computational effort of DEM simulations, present studies assume the inner particle temperature to be spatially uniform and neglect the inner particle heat transfer. For this reason the Radial Temperature Model was introduced [1, 2] It assumes radial temperature distributions within the particles and is based on an analytical solution of the heat conduction equation in a spherical particle. The scope of this paper is to present the further development of the Radial Temperature Model that allows to simulate granular systems of particles of different sizes and materials, enabling the use of DEM in various applications. The contact heat transfer is modeled making additional material-specific data unnecessary. It is shown that a very good accuracy for the contact heat transfer between different spherical particles is achieved for binary contacts. DEM simulations were performed using the Radial Temperature Model and uniform particle temperatures, respectively. The results demonstrate that the Radial Temperature Model that has been developed and incorporated in the Discrete Element Method allows for an improved calculation of the transient thermal behavior of granular assemblies even for large numbers of particles.