Coarse graining DEM simulations of a powder die-filling system
Coarse graining DEM simulations of a powder die-filling system
复制标题
粉末模具填充系统的粗粒 DEM 模拟
DOI：
10.1016/j.powtec.2020.05.063
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发表时间：
2020
影响因子：
5.2
通讯作者：
Sakai Mikio
中科院分区：
文献类型：
--
作者：
Widartiningsih Putri Mustika;Mori Yuki;Takabatake Kazuya;Wu Chuan-Yu;Yokoi Kensuke;Yamaguchi Akira;Sakai Mikio
为了提高粉末产品的质量，优化粉末模具填充的生产工艺，需要应用数值模拟技术。在粉末充模过程中，固体颗粒受动壁边界下气体流动的影响较大，因此需要模拟复杂的气固相互作用。离散元法（DEM）与计算流体力学（CFD）相结合在气固流动模拟中得到了广泛的应用，并通过无数的研究证明了其充分性。另一方面，现有的DEM-CFD方法难以模拟壁面边界移动时的气固流动。此外，在现有的DEM-CFD方法中，无法在一台PC上模拟大量的计算粒子。因此，从DEM-CFD方法发展的角度来看，工业粉末充模的数值模拟成为一个具有挑战性的课题，因为需要同时考虑移动壁面边界的建模和大量计算颗粒的建模。最近，作者小组开发了包括任意形状壁面边界模型和标度律模型在内的DEM-CFD集成方法。在DEM- cfd集成方法中，采用带符号距离函数和浸入边界法对壁面边界进行建模，并采用粗粒化DEM作为标度律模型。通过验证试验，证明了DEM-CFD综合方法的充分性。在本研究中，检验了DEM-CFD集成方法在粉末模具填充中的适用性。在粉末充型过程中，原始颗粒系统与粗粒颗粒系统的一致性证明了DEM-CFD方法的充分性。通过验证试验，采用DEM-CFD集成方法再现了粉末充型过程的宏观特征。结果表明，采用DEM-CFD方法对工业粉末充模系统进行数值模拟是有效的。
Application of numerical simulations are desired to improve the quality of powder products and to optimize the production process in powder die-filling. In the powder die-filling, complex gas-solid interaction should be simulated since the solid particles are significantly influenced by the gas flow under moving wall boundary. The discrete element method (DEM) coupled with computational fluid dynamics (CFD) has been widely utilized in the simulation of gas-solid flows, and the adequacy has been proved through countless studies. On the other hand, the existing DEM-CFD method is extremely difficult to simulate the gas-solid flow where the wall boundary is moving. Besides, in the existing DEM-CFD method, huge number of computational particles cannot be simulated on a single PC. Hence, numerical simulations of the industrial powder die-filling becomes a challenging topic from a viewpoint of evolution of the DEM-CFD method, because modeling of the moving wall boundary as well as modeling of large number of computational particles should be considered simultaneously. Very recently, the authors' group has developed the Integrated DEM-CFD method including the arbitrary shape wall boundary model and the scaling law model. In the Integrated DEM-CFD method, the wall boundary is modeled by the signed distance functions and the immersed boundary method, and besides the coarse graining DEM is employed as the scaling law model. Adequacy of the Integrated DEM-CFD method has been proved through verification tests. In the current study, applicability of the Integrated DEM-CFD method is examined in the powder die-filling. Adequacy of the Integrated DEM-CFD method is shown by agreement between the original particle system and the coarse graining particle system in the powder die-filling. Through the verification tests, macroscopic characteristics of the powder die-filling are shown to be reproduced by the Integrated DEM-CFD method. Consequently, the Integrated DEM-CFD method is illustrated to be effective for the simulation of the industrial powder die-filling systems.