基于CFD-DEM模型的喷动流化床内颗粒流动特性的研究

Research on particle flow characteristics in spoutedfluidized bed based on CFD-DEM model

采用稠密离散相模型与离散单元法耦合模型对工程塑料颗粒在流化床中的运动及混合行为进行数值模拟研究,获得了颗粒流型、温度分布、颗粒速度分布等,计算结果表明该模型能合理地模拟稠密气固两相流的颗粒弥散特性,颗粒动态分布特性在喷动区、喷泉区、环隙区各不相同;初始气流温度对颗粒间的传热效果影响显著,对提高干燥效果起到明显作用;通过模拟结果,探讨了气固流化床内多相流动的耦合作用机制对传热的影响,结果为工业流化床的工艺参数设定、结构优化及缩放提供参考依据。

The mixing behavior of engineering plastic particles in the fluidized bed are numerically simulated by using the dense discrete phase model coupling with the discrete element method,and the results show that the model can reasonably simulate the particle flow type,temperature distribution and particle velocity distribution.The dynamic distribution characteristics of particles are different in the spray area,fountain area and ring gap area;the initial air flow temperature has a significant effect on the heat transfer effect between the particles,which plays a significant role in improving the drying effect,and through the simulation results,This paper discusses the influence of the coupling mechanism of multi-phase flow in gas-solid fluidized bed on heat transfer,and the results provide reference for the process parameter setting,structure optimization and scale of industrial fluidized bed.