基于CFD-DEM方法的柱状颗粒在弯管中输送过程的数值模拟

针对物料在气力输送过程中特别是弯管部分易破碎的问题,采用计算流体力学(CFD)和离散单元法(DEM)耦合模拟弯管内的柱状颗粒气力输送过程,对弯径比k分别为1、2、3、4、6的90°弯管内柱状颗粒的运动状态、碰撞特性、破碎原因及相关的力学特性进行研究。结果表明:球形颗粒与柱状颗粒在输送过程中遵循基本一致的变化规律,同样外部条件下,柱状颗粒的悬浮速度小于球形颗粒。当k=3时气力输送过程颗粒的破碎率最低。同时,颗粒与管壁的碰撞是造成颗粒破碎的主要原因。

Numerical Simulation of Cylindrical Particles Conveying in Curved Ducts Using CFD-DEM Coupled Approach

For the particle breakage during the pneumatic conveying,the process of cylindrical particles conveying in the curved ducts was simulated using CFD-DEM coupled approach and the particles movement,features of collision,causes of breakage and relevant mechanics features of cylindrical particles in 90° curved duct were studied whose the ratio of curvature and diameter k was separately as 1,2,3,4,6.The results showed that the spherical particles had the similar law as the cylinder particles during the pneumatic conveying,and the suspended velocity of spherical particles was higher on the same conditions.When k was 3,it could cause the least breakage in the pneumatic conveying.The collision of particles and tube wall contributed the most to the cause of the particle breakage.