Heat conduction in granular materials

Heat transfer in particulate systems is important to a vast away of industr ies, yet is poorly understood even in the simplest case - conduction throug h the solid phase. This is due in part to the stress and contact heterogene ities inherent to these systems. Heat conduction in a packet bed of cylinde rs is investigated both experimentally and computationally. A novel model i s developed based on the Discrete Element Method, which not only sheets lig ht on fundamental issues in heat conduction in particles, but also provides a valuable test bed for existing theories. By explicitly modeling individu al particles within the hulk material, bed heterogeneities ave directly inc luded and dynamic temperature distributions are obtained at the particle le vel. Comparison with experiments shows that this model yields a quantitativ ely accurate temperature field without the need for adjustable parameters o r detailed microstructural information. This simple system may also provide insight into such phenomena as reactor hot spot formation and spontaneous combustion of bulk reactive materials.