密集颗粒流中的速度波动及自扩散特征

摘要/Abstract

摘要： 密集颗粒流是颗粒介质中非常重要的一种运动状态,其内部单个粒子的速度波动通常是导致系统出现输运、混合、分离等宏观过程的微观基础,因此,如何对其进行定量描述是颗粒介质研究中一个非常关键的问题。基于所建立的环形剪切颗粒流的离散元模型,首先分析了系统达到剪切稳定状态时不同局部区域内微观粒子速度波动的宏观统计特征;通过引入自扩散系数定量研究了剪切颗粒流内粒子扩散运动过程中的局部化和各向异性特征;最后讨论了局部剪切率、初始体积分数以及粒子间的摩擦系数对系统自扩散系数的影响规律。

关键词: 密集颗粒流, 离散单元法, 速度波动, 自扩散系数

Abstract: The dense granular flow is a very important state in granular materials movement. In such granular system, the velocity fluctuation of a single particle is the basis of many macroscopic processes such as transporting, mixing and segregating, etc. How to quantitatively characterize such fluctuating features becomes a very key issue in granular materials research. Based on the established discrete element model of annular shear granular flow, this paper mainly focuses on the macroscopic statistical features of particle velocity fluctuation within different sub-regions when the system approaches the shearing steady state. By introducing the self-diffusion coefficient, we investigate the localized and anisotropic features of diffusion processes of particles in a shear granular flow. Finally, the influences of local shear rate, initial packing fraction and friction coefficient between particles on self-diffusion coefficients in a shear granular flow are also discussed.

Key words: dense granular flow, DEM, velocity fluctuation, self-diffusion coefficient

中图分类号:

O368
X169

王等明;周又和. 密集颗粒流中的速度波动及自扩散特征[J]. 中国沙漠, 2011, 31(3): 618-625.

WANG Deng-ming;ZHOU You-he. Velocity Fluctuation and Self-diffusion of Particles in a Dense Shear Granular Flow[J]. JOURNAL OF DESERT RESEARCH, 2011, 31(3): 618-625.

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