DEM–CFD simulation of the particle dispersion in a gas–solid two-phase flow for a fuel-rich/lean burner

The objective of this study was to numerically investigate the particle dispersion mechanisms in the gas–solid two-phase jet for a fuel-rich/lean burner by means of coupling the discrete element method (DEM) with the computational fluid dynamics (CFD). The DEM was employed to deal with the particle–particle and the particle–wall interaction in the computation of solid flow; while gas flow was computed by CFD based on the commercial software package Fluent. The particles with various Stokes numbers equal to 0.1, 0.5, 1, 2 and 3 (corresponding to particle diameter 10.8, 24.17, 34.18, 48.38 and 59.21 μm, respectively) in the gas–solid fuel-rich/lean jet were investigated in this study. The particle–particle collision was simulated and its effect on the fuel-rich/lean separating performance was evaluated. The results show that the particle–particle collision occurred more frequently with the increasing of Stokes numbers from 0.1 to 3. The particle dispersion became more uniform between the fuel-rich side and the fuel-lean side for particles with small Stokes number; while for particles at St > 1, a better fuel-rich/lean separating performance was achieved. The efficiency of the DEM–CFD coupling method was validated by the corresponding experiments, and a good agreement between the simulation and experiments was achieved as a result of the particle–particle collision.