화학공학소재연구정보센터
Chemical Engineering Research & Design, Vol.82, No.7, 918-926, 2004
Numerical simulation of the turbulent gas-particle flow in a fluidized bed by an LES-DPM model
The turbulent gas-particle flow in a bubbling fluidized bed is numerically studied using large eddy simulation and discrete particle method (LES-DPM). The gas-phase model is based on locally averaged two-dimensional Navier-Stokes equations for two-phase flow with fluid turbulence calculated by LES, in which the particle effect on subgrid-scale (SGS) gas flow is taken into account. The particle motion is treated by a DPM, in which the particles are assumed to interact through binary, instantaneous and non-elastic collisions. The gas-particle turbulent flow structures are predicted. The distributions of the simulated particle anisotropic velocity show that the particles in the fluidized bed do not have any local equilibrium. The vertical components of both the gas and particle turbulent intensities are higher near the walls than in the centre, whereas these horizontal components are always low. The prediction results indicate that the profiles of the mean gas and particle velocities and of the turbulent intensities are rather insensitive to C-k value, whereas the instantaneous particle structure and individual trajectories are sensitive to it in this turbulent model.