In this work we assess whether particle shape can induce radial segregation in a rotating cylinder. To this end, mixtures of spheres and non-spherical particles of equal-volume were modelled in a discrete element modelling framework. We could observe that particle-shape (alone) can induce radial segregation with the non-spherical particles accumulating in the centre of the cylinder. To probe the underlying segregation mechanism, a large number of particle trajectories and orientations were analysed. We observed that non-spherical particles, when segregating towards the centre of the bed, did not necessarily orientate themselves such that their projected area (in the sinking direction) was smaller than that of spheres. Instead, we found that there was a high probability that the avalanching, non-spherical particles are orientated such that their projected area in the direction perpendicular to the bed surface is maximal. Hence, particle-shape induced segregation cannot be explained by the conventional percolation mechanism. Instead, we propose that shape-induced segregation originates from the lower mobility of the non-spherical particles than spheres. We explain the lower mobility of non-spherical particles by their larger radius of gyration than equal-volume spheres, leading to an increased number of collisions and thus a higher rate of kinetic energy dissipation.

中文翻译：

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旋转圆柱体中的颗粒形状引起的径向偏析

在这项工作中，我们评估了颗粒形状是否会引起旋转圆柱体中的径向偏析。为此，在离散元素建模框架中对等体积的球体和非球形粒子的混合物进行了建模。我们可以观察到，颗粒形状（单独）可以引起径向偏析，而非球形颗粒则聚集在圆柱体的中心。为了探究潜在的分离机理，分析了许多粒子的轨迹和方向。我们观察到，非球形粒子朝向床中心偏析时，不一定会使其自身定向，以使它们的投影面积（在下沉方向上）小于球形的投影面积。相反，我们发现雪崩发生的可能性很高，对非球形颗粒进行定向，以使它们在垂直于床表面的方向上的投影区域最大。因此，颗粒状的偏析不能用常规的渗滤机理来解释。取而代之的是，我们提出形状诱导的偏析起因于非球形粒子的迁移率低于球形。我们解释了非球形粒子比等体积球体具有更大的回转半径，从而降低了迁移率，从而导致碰撞次数增加，因此动能耗散率更高。我们提出形状诱导的偏析起因于非球形粒子的迁移率低于球形。我们解释了非球形粒子比等体积球体具有更大的回转半径，从而降低了迁移率，从而导致碰撞次数增加，因此动能耗散率更高。我们提出形状诱导的偏析起因于非球形粒子的迁移率低于球形。我们解释了非球形粒子比等体积球体具有更大的回转半径，从而降低了迁移率，从而导致碰撞次数增加，因此动能耗散率更高。