当前位置: X-MOL 学术Chem. Eng. Sci. › 论文详情
Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)
Discrete element method based analysis of mixing and collision dynamics in adhesive mixing process
Chemical Engineering Science ( IF 4.7 ) Pub Date : 2018-11-01 , DOI: 10.1016/j.ces.2018.06.043
Xiaoliang Deng , Kai Zheng , Rajesh N. Davé

Abstract When small amounts of fine particles are mixed with coarser particles, they tend to form ordered or adhesive mixtures. In order to understand the effect of fine particle amount and cohesion on the adhesive mixing process, discrete element method (DEM) simulations are carried out in which cohesion is represented by surface energy. High-intensity vibrational mixing was used to examine two important and related dynamic processes; fine particle deagglomeration and their subsequent adhesion to coarse particles, by analyzing normalized fine-fine (FF) and coarse–fine (CF) particle contact numbers, respectively, along with the mixing quality. It is found that FF contacts decreases with the mixing time, indicating deagglomeration, before reaching equilibrium; while CF contacts, an indicator of coating, as well as mixing quality increase before reaching equilibrium. A major new finding is that the number of fine particles per coarse particle at equilibrium follows lognormal distribution. The time scales to reach equilibrium FF contact number and mixing quality are comparable, indicating that deagglomeration is the dominant factor for achieving a uniform adhesive mixture. As expected, increasing surface energy of fine particles leads to decreased mixing quality due to stronger agglomerates that cannot be broken by collisions. On the other hand, collision rate can dictate mixing quality, as long as the collision energy is greater than the corresponding detachment energy of fine particles agglomerates. Selected experimental results validate the DEM simulations and their ability to describe the adhesive mixing process.

中文翻译:

基于离散元法的粘合剂混合过程混合与碰撞动力学分析

摘要 当少量细颗粒与较粗颗粒混合时,它们往往会形成有序或粘合的混合物。为了了解细颗粒数量和内聚力对粘合剂混合过程的影响,进行了离散元法 (DEM) 模拟,其中内聚力由表面能表示。高强度振动混合用于检查两个重要且相关的动态过程;通过分别分析归一化细-细 (FF) 和粗-细 (CF) 颗粒接触数以及混合质量,细颗粒解聚及其随后对粗颗粒的粘附。发现FF接触随着混合时间的增加而减少,表明在达到平衡之前解聚;而CF触点,涂层指标,以及在达到平衡之前混合质量增加。一个主要的新发现是平衡时每个粗颗粒的细颗粒数量遵循对数正态分布。达到平衡 FF 接触数和混合质量的时间尺度是可比的,表明解聚是实现均匀粘合剂混合物的主要因素。正如预期的那样,由于无法通过碰撞破碎的更坚固的团聚体,细颗粒的表面能增加会导致混合质量下降。另一方面,碰撞速率可以决定混合质量,只要碰撞能量大于细颗粒附聚物的相应脱离能量。选定的实验结果验证了 DEM 模拟及其描述粘合剂混合过程的能力。一个主要的新发现是平衡时每个粗颗粒的细颗粒数量遵循对数正态分布。达到平衡 FF 接触数和混合质量的时间尺度是可比的,表明解聚是实现均匀粘合剂混合物的主要因素。正如预期的那样,由于无法通过碰撞破碎的更坚固的团聚体,细颗粒的表面能增加会导致混合质量下降。另一方面,碰撞率可以决定混合质量,只要碰撞能量大于细颗粒团块的相应脱离能量。选定的实验结果验证了 DEM 模拟及其描述粘合剂混合过程的能力。一个主要的新发现是平衡时每个粗颗粒的细颗粒数量遵循对数正态分布。达到平衡 FF 接触数和混合质量的时间尺度是可比的,表明解聚是实现均匀粘合剂混合物的主要因素。正如预期的那样,由于无法通过碰撞破碎的更坚固的团聚体,细颗粒的表面能增加会导致混合质量下降。另一方面,碰撞率可以决定混合质量,只要碰撞能量大于细颗粒团块的相应脱离能量。选定的实验结果验证了 DEM 模拟及其描述粘合剂混合过程的能力。
更新日期:2018-11-01
down
wechat
bug