CFD simulations of gas-solid flow in an industrial-scale circulating fluidized bed furnace using subgrid-scale drag models

Mesoscale flow structures such as clusters and streamers of particles are characteristic features of gas-solid flow in fluidized beds. Numerical simulations of gas-solid flows for industrial-scale fluidized beds are often performed using the Eulerian description of phases. An accurate prediction of this type of flow structure using the Eulerian modeling approach requires a sufficiently fine mesh resolution. Because of the long computational time required when using fine meshes, simulations of industrial-sized units are usually conducted using coarse meshes, which cannot resolve the mesoscale flow structures. This leads to an overestimation of the gas-solid drag force and a false prediction of the flow field. For these cases, a correction must be formulated for the gas-solid drag. We have simulated a large-scale circulating fluidized bed furnace using different gas-solid drag models and compared the model results with measurements. (C) 2014 Chinese Society of Particuology and Institute of Process Engineering, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.