【力耕强农】Analysis of the impact of interparticle forces on bulk behaviours of cohesive powders using DEM(颗粒间作用力对粘性粉末行为的DEM分析)
发布时间:2024-04-09
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报 告 人:
Prof. Charley Wu(邬传宇 教授)(萨里大学)
时 间:
2024年4月12日(星期五)9:30~11:30
地 点:
理学院逸夫楼302会议室
主办单位:
理学院 应用力学系
联系人:
陈雪冬
联系方式:
010-62736990,chenxuedong@cau.edu.cn
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Powders consist of collections of individual particles that interact with each other and their surrounding media, such as gases or fluids. It is widely acknowledged that the behaviour of bulk powders on a macroscopic scale is influenced by the microscopic interactions between individual particles and their dynamics. Therefore, it is crucial to develop tools capable of predicting bulk powder behaviour based on the properties of individual particles. The discrete element method (DEM) is one such tool that directly links the behaviour of the bulk powder with the properties of its constituent particles. In DEM, the motion of each particle is explicitly modelled using Newton's second law and the resulting forces acting on the particles that determine the collective (or bulk) behaviours. DEM has the capacity to include various interparticle forces, such as mechanical contact forces, van der Waals forces, electrostatic forces, and liquid bridge forces, which enables a comprehensive description of the behaviour of powders with distinct characteristics. In this talk, a systematic evaluation of DEM models incorporating various inter-particle forces, including mechanical interactions, cohesive forces induced by van der Waals interactions, liquid bridges and electrostatic interactions, will be presented. Typical bulk behaviours observed in powders involving these particle interactions will be demonstrated. Furthermore, how particle properties are taken into account in these force models will be explained, and their influence on bulk behaviour will be illustrated. 粉末由单个颗粒的集合组成,这些颗粒相互作用,并与周围的介质(如气体或流体)相互作用。人们普遍认为,散装粉末在宏观尺度上的行为受到单个颗粒及其动力学之间微观相互作用的影响。因此,开发能够根据单个颗粒的性质预测散装粉末行为的工具至关重要。离散元法(DEM)就是这样一种工具,它直接将散装粉末的行为与其组成颗粒的性质联系起来。在DEM中,每个粒子的运动都是用牛顿第二定律和作用在颗粒上的力来明确地建模的,这些力决定了群体(或整体)的行为。DEM能够包含各种粒子间力,如机械接触力、范德华力、静电力和液桥力,从而能够全面描述具有不同特征的粉末的行为。在本次演讲中,将系统地评估包含各种粒子间力的DEM模型,包括机械相互作用,由范德华相互作用引起的内聚力,液体桥和静电相互作用。在涉及这些颗粒相互作用的粉末中观察到的典型群体行为将被证明。此外,将解释如何在这些力模型中考虑颗粒特性,并说明它们对群体行为的影响。
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邬传宇(Charley Wu)教授是英国萨里大学化学与过程工程系的化学工程教授。先后主持欧洲FP7和H2020联盟IPROCOM(2013-2016, 380万欧元)、MATHEGRAM(2019-2023, 420万欧元)等重大项目,研究领域涉及药物和颗粒材料的计算工具的开发。邬教授是《粉末技术》的执行主编,并先后主编《颗粒介质离散元建模》和《颗粒材料:合成、表征、加工与建模》两本专著(RSC出版),与人合著《粒子技术与工程》专著(2016年由爱思唯尔出版),先后发表了150多篇高水平学术论文。他曾在世界各地的国际会议、工业公司和大学做过80多次受邀演讲并参与研讨。现为《颗粒学报》(Particuology)、《药物学报B》(APSB)及《工程学报》(Journal of Engineering)的顾问及编委会成员。
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