Modeling the heat transfer between fluid-granular medium

Fluidized bed processes to have various applications, where knowledge of temperature fields is very important (combustion, drying, freezing, etc.). Thermal behavior of solid-fluid in fluidized beds has been studied through the simulation by means of coupling Discrete Element Method (DEM) and Computational Fluid Dynamics (CFD). A thermal approach (conduction-convection) based on the finite volume method is proposed to calculate the heat transfer between particles-fluid and particle-particle, the effects of dissipation by friction and impact (collision) were also taken into account. Validation of results depicted that the thermal model has proven its effectiveness whether on a fixed or fluidized bed. A thermal indicator is proposed, which allows knowing the ratio of particles that have reached the temperature of the fluid imposed, which is difficult to access in practice. Finally, an evaluation of heat transfer in fluidized bed has been done, through inlet fluid velocity to the fluidization column. The evaluation revealed the effect of fluid velocity on the mechanisms of heat transfer (conduction and convection) energy in the fluidization processes. The simulations results were agreed and consistency with the experimental data in the literatures, which will allow in the longer term; to add heat transfer models and mass transfer ones between the fluid and particles (for example during a drying process) in simulations. (C) 2017 Elsevier Ltd. All rights reserved.