A Euler-Euler hydrodynamic modelling and simulation of dense particle flow in a small-scale fluidized bed

Abstract

Large eddy simulation of dense particle flow in fluidized bed is an advanced strategy to acquire a better understanding mechanism of gas-particle two-phase turbulent flow. A novelty particle stress model at subgrid scale level based on the Euler-Euler two-fluid frame is proposed to consider the effect of gas flow on particle dynamics. Anisotropic dispersion of interactions between gas and particle is modeled by a developed second-order moment approach, the four-way coupling is used to combine the particle–particle collisions by using the particle granular temperature based on the kinetic theory of granular flow. Numerical simulation is carried out in a small-scale fluidized bed and predictions are well agreed with the experimental data. Results show that the evolution of core-annular flow structure is captured. Increased superficial gas velocity is favorable for the enhancement of bubble hydrodynamics and anisotropic particle dispersions. At the 4u_mf, Bubblelike granular temperature is 11.2 times larger than particle granular temperature, and mean and standard deviation values of axial particle velocity are approximately 2.2 times and 1.5 times larger than those of 2u_mf. Bubble motions have a great effect on the heterogeneous flow pattern, particle dynamics and the redistribution of particle Reynolds stresses.