Assessment of a bubble-based bi-disperse drag model for the simulation of a bubbling fluidized bed with a binary mixture

In the simulation of a bubbling fluidized bed, it is necessary to consider the bubble effect on interphase drag force. In this work, the bubble-based drag model is extended to a binary mixture system. A bi-disperse gas-solid drag model considering the bubble effect is developed and implemented into the multi-fluid model. Three simulations of a bubbling fluidized bed with a binary mixture are carried out. The mixing and segregation performance of binary mixture is investigated. Meanwhile, the sensitivity analysis of drag model to local structure parameters is conducted. The results reveal that the bi-disperse drag model does not only depend on the voidage, but also on the solid component. With consideration of bubble effects, the predicted bed expansion is reduced and the model can obtain a better agreement with experimental results.