The 4-parameter Compressible Packing Model (CPM) including a new theory about wall effect and loosening effect for spheres
The 4-parameter Compressible Packing Model (CPM) including a new theory about wall effect and loosening effect for spheres
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DOI：
10.1016/j.powtec.2016.08.031
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发表时间：
2016-11
影响因子：
5.2
通讯作者：
G. Roquier
中科院分区：
文献类型：
--
作者：
G. Roquier
介绍了一种新的可压缩堆积模型(CPM)(De Larrard等)，即四参数可压缩堆积模型，用于预测双分散球形颗粒最大密度无序堆积的堆积密度。基于主导颗粒的假设，它考虑了堆积过程的效率和一个新理论的两个几何相互作用对象：壁面效应和松动效应。对于后者，引入了一个临界空腔尺寸比，在该比以下，可以将细小的微珠插入通过接触较粗颗粒而形成的小空腔中。当填充工艺完美时，填充密度达到最大虚拟密度，该最大虚拟密度定义为给定混合物可获得的最大填充密度。在这个参照系中，壁效应和松弛效应的理论是基于对一个被主导类相邻粒子包围的次要类粒子构型的具体处理。这四个参数是：壁面效应和松动效应系数，压实指数和临界空腔比，对于集料可以调整，但对于球体，其值为0.2，与四面体空穴理论一致。通过对320个计算结果的分析，证明了四参数CPM对预测二元混合物堆积密度的有效性。玻璃微珠的相关系数为99%(300值)，数值模拟的球形颗粒的相关系数为98.7%(20值)。
A new version of the Compressible Packing Model (CPM) (de Larrard et al.), the 4-parameter CPM, is introduced to predict the packing density of maximally dense disordered packings of bidisperse spherical particles. Based on the assumption of a dominant granular class, it takes into account the packing process efficiency and two geometrical interactions objects of a new theory: the wall effect and the loosening effect. For the latter, a critical cavity size ratio, below which a fine bead can be inserted into a small cavity created by touching coarser particles, is introduced. When the packing process is perfect, the packing density reaches a maximum virtual density defined as the maximum packing density attainable for a given mixture. In this reference frame, the theory for wall effect and loosening effect is based on a specific treatment of configurations of one secondary class particle surrounded by dominant class neighbours. The four parameters are: the wall effect and the loosening effect coefficients, the compaction index and the critical cavity size ratio which can be adjusted for aggregates, but whose value is 0.2 for spheres, in harmony with the tetrahedral cavern theory. The 4-parameter CPM demonstrates its efficiency to predict packing density of binary mixtures from the analysis of 320 results. Correlation coefficients are 99% for glass beads (300 values) and 98.7% for numerically simulated spherical particles (20 values).