Abstract:Due to the agglomeration effect between particles, the cohesive particles in the bubbling fluidized beds (BFBs), mainly in form of particles, agglomerates and multi-scale structures in beds, are more complicated than that of coarse particles in terms of the flow characteristics. Therefore, a system decomposition method has been introduced, with the bubble fluidized bed system with non-uniform flow structures divided into three homogeneous subsystems, i.e. the emulsion phase, the bubble phase and the inter-phase phase; and seven structural parameters have been introduced to describe the local flow structure of the system. Then a local structural parameter model of the system, based on the force balance model, has been constructed by using the continuity equation, the momentum conservation equation and the empirical formula. Finally, a case study has been made on the fluidization of the cohesive alumina particles in a bubbling fluidized bed, followed the global search algorithm used to solve the structural parameters to evaluate the feasibility of the proposed model. The experimental results show that the structural parameters help to correctly reflect the local flow structure of cohesive particles in a bubbling fluidized bed, which is consistent with the experimental data. Therefore, the drag force between phases, flow field simulation and flow characteristics of these structural parameters can be worked out finally.