Particle-particle heat transfer in thermal DEM: Three competing models and a new equation

Abstract

Simulation of transient heat transfer from the wall of contact equipment (e.g. rotary drum) to a mechanically agitated bed of particles in gas atmosphere by the discrete element method (DEM) requires knowledge of the particle-particle heat transfer coefficient. A simple analytical equation is proposed in order to calculate this quantity from the effective thermal conductivity of the respective packed bed for the described class of problems. Comparison with other calculation methods that assign particle-particle heat transfer exclusively to either the solid or the gas phase shows that large differences can occur. It stresses the need for further work on the fundamentals of thermal DEM for such applications, and for a critical attitude until those have been clarified.