摘要：为了研究热熔融流化床包衣的影响因素，优化包衣过程，采用计算流体力学(CFD)与离散单元法(DEM)耦合的方法，在4种流化速度下(u_mf，1. 5 u_mf，2. 5 u_mf，3. 5 u_mf)模拟熔融液滴与流化粉体的接触过程；研究热熔融流化床包衣过程中的参数变化对包衣过程的影响。结果表明，当液滴与粉体接触成粒时，产生聚并和破碎现象；顶喷流化床比中喷流化床的液滴与粉体的接触次数更多更充分；较理想的流化速度为1. 5 u_mf。

关键词：热熔融流化床；包衣；离散单元法

Abstract: The purposes of this paper were to study the factors which affected the coating characteristics in hot-melt fluidized bed and further to optimize its the coating process．The computational fluid dynamics ( CFD) and discrete element method ( DEM) were used to simulate the contact process between droplets and powders at four fluidization velocities ( u_mf，1．5u_mf，2．5u_mf，3．5u_mf ) ．Through the coupling of CFD and DEM，the effects of parameters changes during the coating process in hot-melt fluidized bed on the coating process were studied．The results show that the droplets are more fully contacted with the powders under the condition of top spray fluidized bed rather than the middle spray．When the droplets contacting with the powders，the combination of the particles and the droplets causes the phenomenon of aggregation and breakage．The optimal condition is 1．5 u_mf in this study for the performance of coating． 

Keywords: hot-melt fluidized bed; coating; discrete element method (DEM)