CFD–DEM SIMULATION OF HEAT TRANSFER DURING THE BIOMASS COMBUSTION PROCESS IN FLUIDIZED BEDS

In this paper, based on CFD–DEM, several heat transfer models were coupled with dense gas-solid flow and chemical reaction to simulate the heat transfer characteristics of biomass combustion in bubbling fluidized bed. The results show that for fuel particles, heat of reaction is dominated, and radiation and convection also play an important role, but heat conduction has little effect. With the increase of volatile content of fuel, the contributions of convection and particle-particle conduction increase, but the contribution of particle-wall conduction decreases. The local hot spot in the bed is mainly caused by the volatiles combustion, which is generated from the bed surface and rises to the freeboard. The biomass particle temperature generally increases with the decrease of local particle concentration.