Modeling on Core-Annulus-Wall Structure in Fluidized Bed near Choking
Student: Qun Yu
Advisor: Dr. I. Joga Rao
An analytical model has been developed to interpret the formation mechanisms of the core-annulus-wall structure in circulating fluidized bed, which was discovered recently by a novel Electrical Capacitance Tomography (ECT) technique. This model also could be used to interpret the mechanism of the initiation of choking. The model assumes that the solids transport across the interfaces between core and annulus region, and the transport between annulus and wall region, is resulted by the solid particle collisional diffusion and the turbulent convection induced by the motion of gas. The initiation of the choking transition is due to the solids suspension instability, which is induced by the imbalance of local forces acting on the solid particles and clusters. The numerical results by using this model agree well with the previous experimental discoveries.