CFD-DEM-IBM simulation of fluidized bed direct reduction of magnetite
Magnetite is an important raw material for direct reduced iron in mineral processing.Fluidized bed direct reduction of magnetite is widely used in metallurgical industry because of its advantages of significantly reducing carbon emission,efficient heat and mass transfer and high speed reaction.Based on the unreacted shrinkage core model of the multi-resistance network,the coarse-grained CFD-DEM-IBM(computational fluid dynamics-discrete element method-immersed boundary method)coupling method was used to simulate the fluidized reduction of magnetite in a hydrogen atmosphere.In the process,the effects of different coarse-graining rates on particles,gas flow,and reaction characteristics were investigated.It is shown that when the coarse-graining ratio is less than 4,the reduction characteristics of the whole particles in the coarse-grained system and the real system are similar,but the local flow characteristics of the gas and particles are different.When the coarse-graining ratio is 3,the calculation accuracy is within the allowable range,and the calculation amount can be significantly reduced.