Computational Study of Heat Transfer in Bubbling Fluidized Beds with Geldart a Powder

Gas fluidization is widely used in industries and has been extensively studied either experimentally or mathematically. Recently, the coupled approach of discrete particle simulation (DPS) for solid phase and computational fluid dynamics (CFD) for gas phase has been proposed to study the heat transfer in fluidized beds at a particle level. The approach offers a convenient way to study the effects of key variables under controlled conditions. In this work, DPS-CFD is used to examine the effects of gas superficial velocity and cohesive force in bubbling fluidized beds with Geldart A powder. It is shown that the convective heat flux increases and the conductive heat flux decreases with the increase of gas superficial velocity. With the increase of cohesive force, the convective heat flux decreases and the conductive heat flux increases. The heat transfer characteristics are analysed in terms of the heat transfer mechanisms such as particle-fluid convection and particle-particle conduction. The related bed structures such as the bed porosity and the average coordination number are obtained and used to explain the heat transfer characteristics.