| Dense gas-particle flows are frequently encountered in a variety of industrially important gas-solid contactors. Due to their favorable mass and heat transfer characteristics, gas-fluidized beds are often applized in the chemical, petrochemical, metallurgical, environmental and energy industries. The research is not only of academic interest, but would also significantly contribute to a better design of industrial reactors.An LES/FDF model of two-phase flow was developed, in which a filtered density function (FDF) transport equation was used to describe the fluid velocity seen by the particles in two-phase flows and the interaction between the two phases was considered. Numerical simulation of a gas-particle two-phase backward-facing flow was carried out with the LES/FDF model. The numerical results were compared with the experimental data. The comparison shows that the LES/FDF model can distinctly improve the precision of the simulation. Further investigation has been carried out on the turbulence modification by particles with different particle Stokes and shows that the improvement of Stokes number can not always improve the effect on the turbulence modification of the gas.A new stochastic particle stochastic collision model based on LES/FDF model was developed in which the LES/FDF model was used to solve gas-solid two-phase flow and stochastic particle stochastic collision model was used to deal with interaction between particles. The developed stochastic particle stochastic collision model relies on the generation of collision partners and the calculation of the collision probability according to kinetic theory. The advantage of this model is that it does not require information on the location of the surrounding particles and the collision probability is instantaneous. Numerical simulation of 2D fluidized bed and 3D fluidized was carried out with Stochastic particle stochastic collision model. The numerical results were compared with the experiment data. |
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