Yuu Shinichi, Umekage Toshihiko
Ootake R. and D. Consulting Office, 1-17-27-508 Ootake, Higashiku, Fukuoka 811-0322, Japan.
Department of Mechanical Engineering, Kyushu Institute of Technology, 1-1 Sensuicho, Tobataku, Kitakyushu 804-8550, Japan.
Materials (Basel). 2011 Aug 22;4(8):1440-1468. doi: 10.3390/ma4081440.
Granular flows of 200 μm particles and the pile formation in a flat-bottomed hopper and bin in the presence of air and in a vacuum were predicted based on three-dimensional numerically empirical constitutive relations using Smoothed Particle Hydrodynamics and Computational Fluid Dynamics methods. The constitutive relations for the strain rate independent stress have been obtained as the functions of the Almansi strain including the large deformation by the same method as Yuu et al. [1]. The constitutive relations cover the elastic and the plastic regions including the flow state and represent the friction mechanism of granular material. We considered the effect of air on the granular flow and pile by the two-way coupling method. The granular flow patterns, the shapes of piles and the granular flow rates in the evolution are compared with experimental data measured under the same conditions. There was good agreement between these results, which suggests that the constitutive relations and the simulation method would be applicable for predicting granular flows and pile formation with complex geometry including free surface geometry. We describe the mechanisms by which the air decreases the granular flow rate and forms the convergence granular flow below the hopper outlet.
基于使用光滑粒子流体动力学和计算流体动力学方法的三维数值经验本构关系，预测了200μm颗粒在平底料斗和料仓中在有空气和真空条件下的颗粒流及堆积形成情况。通过与Yuu等人[1]相同的方法，获得了与应变速率无关的应力的本构关系，该关系是包括大变形在内的阿尔曼西应变的函数。本构关系涵盖了包括流动状态在内的弹性和塑性区域，并表征了颗粒材料的摩擦机制。我们采用双向耦合方法考虑了空气对颗粒流和堆积的影响。将演化过程中的颗粒流模式、堆积形状和颗粒流速与在相同条件下测量的实验数据进行了比较。这些结果之间有很好的一致性，这表明本构关系和模拟方法可用于预测具有复杂几何形状（包括自由表面几何形状）的颗粒流和堆积形成。我们描述了空气降低颗粒流速并在料斗出口下方形成汇聚颗粒流的机制。
