摘要：采用离散单元法对垂直螺旋输送机中颗粒流动进行模拟计算,提出运用周期边界条件解决垂直螺旋输送机中计算效率问题,选用全尺寸模型和应用了周期边界条件的周期模型2种计算模型,计算得到2种模型中颗粒的流动特征,包括颗粒运动形态、正向接触力的力链网络和轴向速度的大小及其概率密度分布,讨论输送机在结构、颗粒流动形态、正向接触力的力链网络和轴向速度上的周期性。结果表明:2种模型在填充率较大且转速为300~1 700 r/min时模拟的颗粒流动特征一致;在一些工况中应用周期边界条件的仿真模型可以用来探寻垂直螺旋输送机中颗粒流动特征。

关键词：垂直螺旋输送机； 周期边界条件； 颗粒流动形态； 力链网络； 轴向速度

Abstract：The particle flow in a vertical screw conveyor was simulated by the discrete element method. Periodic boundary conditions were proposed to solve the problem of computing efficiency in the vertical screw conveyor. Two simulation models of a full-sized model and a periodic model applied periodic boundary conditions were adopted. Flow characteristics of particles including particle movement form,normal contact force network,axial speed and its probability density distribution were obtained in the simulation. The periodicity of the conveyor was discussed in respect of the structure,particle movement form,normal contact force network and size and proportions of axial speed. The results show that simulated flow features in the two models with suitable periodic boundary conditions are consistent when the fill level is large and rotating speed is between 300 and 1 700 r/min. The proposed model with periodic boundary conditions can be generally used to investigate the granular flow in vertical screw conveyor in some case.

Keywords: vertical screw conveyor； periodic boundary condition； particle movement form； force network； axial speed