Numerical simulation of air and particle motions in bubbling fluidized bed of small particles

Air and particle motions in a bubbling fluidized bed of about 100,000 particles of 310 μm in diameter, which are classified as the B particles in the Geldart map, are numerically simulated. Particle–particle interactions were calculated, using the three-dimensional distinct element method (DEM). The Navier–Stokes equation and the Lagrangian type particle equation were simultaneously solved, where the drag and lift forces on particles, the multi-body collisions among particles and the mutual interaction between air and particles were taken into account. The corresponding experiments were also performed. It was found that the calculated results describe well the experimental instantaneous particle positions, and enable us to know the mechanisms of bubble formation, bubble coalescence and bubble disruption in a bubbling fluidized bed.