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.
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