摘要
颗粒系统堆积的休止角是颗粒学中一个基础性的科学问题,深入认识其影响因素和变化规律对于土木、化工等工程优化具有重要意义.目前基于实验测量的研究受限于可用的颗粒种类和测量手段,难以完备地揭示各种物理参数对休止角的影响规律.离散元(Discrete element method,DEM)是一种可直接对复杂的大型颗粒系统的运动进行仿真的数值方法.本文借助DEM方法对颗粒系统的休止角问题开展了高精度数值研究,揭示了影响颗粒堆积休止角的重要颗粒物性参数.在DEM建模方面,为了表征非球形度对仿真的影响,本研究采用了滚动摩擦系数,并利用既有的实验数据进行了模型验证.同时,本文利用堆积体在垂直平面内投影的二值化图像来合理计算休止角.仿真结果表明,滑动和滚动摩擦系数均与休止角的大小呈正相关,滑动摩擦系数的增加可将休止角提升一倍,而滚动摩擦系数对休止角的影响存在一个上限阈值,达到该阈值后将不能继续增加休止角的大小;颗粒的杨氏模量、回弹系数对休止角的影响不显著.此外,本文利用DEM方法研究了堆积体的传热特性,发现在加热过程中,堆积体内部具有最高热流率的区域从堆积体的底部迁移到上部.
The angle of repose of granular accumulation is a fundamental issue in granulometry,and our current understanding of its influencing factors and variation patterns is still incomplete.Experimental research methods are limited by the existing types of granules and measurement means,making it difficult to comprehensively reveal the influence of individual physical parameters on the angle of repose.The Discrete Element Method(DEM)is a commonly used computer simulation method for studying granular systems,allowing for direct modeling and calculation of the transient behavior of complex large-scale granular systems.In this paper,the DEM method was used to conduct a systematic numerical study on the angle of repose of granular accumulation,exploring the important granular physical parameters that can affect the angle of repose.Simulation results show that both sliding and rolling friction coefficients are positively correlated with the size of the angle of repose.The sliding friction coefficient can double the angle of repose,while the influence of the rolling friction coefficient on the angle of repose has an upper threshold value.Once this threshold is reached,it will no longer increase the size of the angle of repose;the effects of Young's modulus and the coefficient of restitution on the angle of repose are relatively minor.
作者
阎顺
Shun Yan(Electrified Design Institute,China Railway Siyuan Survey and Design Group Co.,Ltd.,Wuhan,430070)
出处
《固体力学学报》
CAS
CSCD
北大核心
2024年第3期416-426,共11页
Chinese Journal of Solid Mechanics
基金
精细爆破国家重点实验室开放基金项目(42172286)资助。
关键词
离散元方法
休止角
控制变量法
颗粒堆积体
discrete element method
angle of repose
control variable method
granular heaps
