摘要
Abstract
Considering the effects of bubbles and clusters on the transport between gas and particles for the Geldart A particles in the bubbling fluidized beds,the structural parameters model and structural drag model were built.Meanwhile the behavior of fine particles in bubbling fluidized beds was predicted by incorporating the structural parameters model and structural drag model into the two-flow model.According the flow behavior of Geldart A particles in bubbling fluidized beds,the flow structure in beds could be divided into three homogeneous dispersed phases:bubble phase,interphase and emulsion phase (cluster phase).Then,through the force balance and mass balance,the structural parameters model and drag model which are based on the bubbles and clusters are built to consider the effects of bubbles and clusters on the flow behavior synthetically.The structural parameters (fb,Ub,db,Ugb,fi,Ugi,εi,fe,Uge,εe,dc)are obtained by solving seven independent equations made up of momentum conservation equation,mass conservation equation,and empirical correlations.The structural parameter model and structural drag correlation are incorporated into the two-fluid model to simulate the hydrodynamics of Geldart A particles in bubbling fluidized beds.Comparing the structural parameters in the result,it could be found that the structural parameters describe the flow structure correctly and reflect the relationship among the flow structural parameters.The simulation results show that the drag model based on the bubbles and clusters could predicted the flow behavior of fine particles well.In the comparison of the radial solid concentration,it could found that,compared to the drag model based on the bubbles,the radial solid concentration is more consistent with the experimental data when the drag model based on the bubbles and clusters is used.关键词
流化床/介尺度/两相流/细颗粒/团聚Key words
fluidized-bed/mesoscale/two-phase flow/fine particle/agglomeration分类
化学化工
