关键词: 旋转流化床, 数值模拟, CFD-DEM联合仿真, 混合, 优化设计

Abstract: In order to get structure optimal design of a rotating fluidized bed powder mixer, the mixing progress of spherical powder granules in a rotating fluidized bed powder mixer was simulated by a combined approach of computational fluid dynamics (CFD) and discrete element method (DEM). Lacey mix index was used to quantitatively analyze the mixing degree of granules in the mixer. The effects of different parameters including the tilt angle of the intake pipe, the arrangement of the intake pipe and intake method were studied respectively. To verify the mixing performance of the rotating fluidized bed powder mixer, a granule mixing experiment was carried out. Simulation results showed that the most appropriate angle of intake pipe should ensure the area of airflow is just half of the area of granular materials in the bottom of the mixer. Besides, if the intake pipe is horizontal arranged, effective mixing quality and mixing rate could be achieved. Moreover, whether the intake is continuous or pulsed, spherical granules could achieve uniform mixing. Compared with the continuous intake, the air comsumption of pulsed intake was less. Finally, the powder mixing experimental results showed a positive mixing quality, which were in good agreement with the numerical data. It could be drawn that it is a structure with superior mixing effect if the intake pipe is tilted at an angle of 35 degrees and horizontal arranged.

Key words: rotating fluidized bed, numerical simulation, computational fluid dynamics-discrete element method coupling, mixing, optimal design