ABSTRACT

The dynamic blockage behaviour of fine particles in a packed bed was simulated using the discrete element method (DEM). The influence of key variables are examined. The calculation results showed that fine particles blockage in packed bed are easy to occur in the area where fine particles just enter the bed. The mechanism of blockage formation is mainly due to mechanical interactions between fine particles, which can create arches on packed bed and stop the flow. When the fine particles form a bridge across the pore throat of the orifice, the bottleneck of void space becomes the starting point for blockage formation. The fine particles with a larger rolling friction coefficient have a higher clogging ratio. With the increase in charging fine particles, the fine particles experience more collisions with each other, and the clogging ratio increases. The initial velocity of fine particles also has an impact on the blockage behaviour.

摘要

使用离散元方法 (DEM) 模拟填充床中细颗粒的动态堵塞行为。检查了关键变量的影响。计算结果表明，在细颗粒刚进入床层的区域，很容易发生细颗粒堵塞床层。堵塞形成的机制主要是由于细颗粒之间的机械相互作用，可以在填充床上形成拱形并阻止流动。当细小颗粒在孔口的孔喉上形成桥梁时，空隙空间的瓶颈成为堵塞形成的起点。滚动摩擦系数较大的细颗粒具有较高的堵塞率。随着细小颗粒带电的增加，细小颗粒之间发生更多的碰撞，堵塞率增加。