Particulate Science and Technology, Vol.33, No.3, 273-289, 2015
A Comparative Study on Effect of Different Parameters of CFD Modeling for Gas-Solid Fluidized Bed
Simulated results from a commercial computational fluid dynamics (CFD) software package, Fluent 13.0, are compared with the experimental results obtained from fluidization experiments using red mud of size 77 mu m. Unsteady behavior of fluidized bed is simulated by using the Eulerian-Eulerian model coupled with kinetic theory of granular flow. Two equation standard k-E model has been used to describe the turbulent quantities. Momentum exchange coefficients are calculated using the Syamlal-O'Brien, Gidaspow, and Wen-Yu drag functions. The solid phase kinetic energy fluctuation is characterized by varying the restitution coefficient values from 0.9 to 0.99. The best model predictions are achieved, using Gidaspow drag model with restitution coefficient of 0.9, convergence criterions as 0.001, free-slip boundary condition of specularity coefficient and first-order discretization scheme. The modeling predictions are found to agree reasonably well with the experimentally observed values for pressure drop, bed expansion ratio, and qualitative gas-solid flow patterns under different operating conditions thereby giving sufficient information hydrodynamic behaviors of fluidized bed. Thus CFD simulation will be able to provide a strong base for the design and operations of bench scale as well as industrial catalytic fluidized bed reactors.