Eulerian-Lagrangian Simulation of the Heat Transfer Behavior of Particles with Different Diameters in Fluidized Bed with Immersed Tube

A kind of new coupling method,CFD-DEM-FEM method,was established by combining finite element method,computational fluid dynamics based on unstructured mesh,and discrete element method. The flow and heat transfer behaviors in the fluidized bed with an immersed tube were simulated by the programs based on the new method when the k-e turbulence model and the multi-way coupling heat transfer model among particles,walls and gas were employed. The micro-scale mechanism of heat transfer in the fluidized bed was explored by the simulation and the critical factors that influence heat transfer between the tube and the bed were discussed. The profiles of average solids fraction and heat transfer coefficient around the tube were obtained and the influences of particle size on the transfer coefficient were revealed by simulations. The computational results agree well with the experiments,which shows that the CFD-DEM-FEM method is feasible and accurate for the simulation of complex gas-solid flow with heat transfer.