旋转滚筒离散崩塌中被动层颗粒重排机制

Passive layer particle rearrangement mechanism in discrete avalanche of rotating drum

旋转滚筒中颗粒物质离散崩塌的触发与传播机制是十分复杂的问题,被动层颗粒在其中起到非常重要的作用。为进一步研究被动层颗粒局部重排触发与传播机制,对旋转滚筒中颗粒的离散崩塌进行离散元模拟,运用改进的颗粒温度计算方法获得更详细的被动层颗粒运动信息。通过被动层颗粒温度空间分布识别出颗粒重排,得到颗粒重排点在崩塌周期中的时间与空间分布,针对具体颗粒重排区域考察颗粒重排的传播速度、颗粒堆积结构以及力学特性。结果表明:颗粒重排广泛存在于整个崩塌周期的被动层中,且在被动层靠上位置发生最为频繁;颗粒重排以弹性波的形式由触发点向四周传播,并且在主力链方向上具有更快的传播速度;颗粒重排的区域在重排后距离库伦失效准则更远,整个区域发生细微的压实。

The triggering and propagation mechanisms of discrete avalanche of granular matter in a rotating drum are complex,with the passive layer of particles playing a crucial role.In order to further investigate the triggering and propagation mechanisms of localized rearrangements of passive layer particles,discrete element simulations were conducted to study the discrete avalanche of particles in a rotating drum,and an improved granular temperature calculation method was used to obtain more detailed information about the motion of passive layer particles.First,the particle rearrangement was identified by the spatial distribution of the passive layer granular temperature,and the time and spatial distribution of the particle rearrangement region in the avalanche period were obtained.Then,the propagation speed of particle rearrangement,particle stacking structure,and mechanical properties were investigated in specific particle rearrangement regions.The results show that particle rearrangement is widespread in the entire passive layer during the avalanche period and occurred most frequently in the upper part of the passive layer.Particle rearrangement propagates in the form of elastic waves from the triggering point to the surroundings,with a faster propagation speed in the direction of the main force chain.The particle rearrangement area is further away from the Coulomb failure criterion after rearrangement,and the entire area experiences slight compaction.