Fine and cohesive powders typically exhibit low packing density, with solid volume fraction around 0.3. Discrete element modelling (DEM) of particulate materials and processes typically employs spherical particles which have much larger solid fractions (e.g. 0.64 for dense random packing of frictionless spheres). In this work a range of quasi-spherical particles are designed, represented by a number of small satellites connected rigidly to a larger centre sphere. Using DEM, packing density is found to be controlled by the interplay between particle shape, size and inter-particle cohesion and friction. Low packing density is obtained for an appropriate combination of (1) particle shape that allows the creation of geometrically loose structures via separation of the central particles by the satellites, (2) particle size that should be sufficiently small so that adhesive forces between particles become dominant over gravity, (3) adhesive forces, determined from surface energy, should be sufficiently large, and (4) friction (static friction was found to have a dominant role compared to rolling friction, but negligible compared to adhesive forces for small particle size). By using the proposed quasi-spherical particle designs it becomes possible to calibrate more realistic DEM models for particulate processes that reproduces not only packing, but also other behaviours of bulk powders.

细粉和粘性粉末通常具有较低的堆积密度，固体体积分数约为0.3。颗粒材料和工艺的离散元素建模（DEM）通常使用球形颗粒，该球形颗粒的固体成分要大得多（例如，对于无摩擦球的密集无规堆积，其密度为0.64）。在这项工作中，设计了一系列准球形粒子，这些粒子由刚性连接到较大中心球体的许多小卫星代表。使用DEM，发现堆积密度受颗粒形状，大小，颗粒间内聚力和摩擦之间的相互作用控制。对于（1）粒子形状的适当组合，可以获得较低的堆积密度，该形状允许通过卫星分离中心粒子来创建几何上松散的结构，（2）粒径应足够小，以使粒子之间的粘附力超过重力；（3）由表面能确定的粘附力应足够大；以及（4）摩擦（发现静摩擦具有与滚动摩擦力相比起主要作用，但对于小粒径，与粘附力相比则可忽略不计）。通过使用拟议的准球形颗粒设计，可以为颗粒过程校准更实际的DEM模型，该模型不仅可以重现堆积，还可以重现散装粉末的其他行为。但与小颗粒的粘附力相比微不足道）。通过使用拟议的准球形颗粒设计，可以为颗粒过程校准更实际的DEM模型，该模型不仅可以再现堆积，还可以再现散装粉末的其他行为。但与小颗粒的粘附力相比微不足道）。通过使用拟议的准球形颗粒设计，可以为颗粒过程校准更实际的DEM模型，该模型不仅可以再现堆积，还可以再现散装粉末的其他行为。