TY - JOUR
T1 - Discrete element method based analysis of mixing and collision dynamics in adhesive mixing process
AU - Deng, Xiaoliang
AU - Zheng, Kai
AU - Davé, Rajesh N.
N1 - Funding Information:
We gratefully acknowledge partial financial support from the National Science Foundation (NSF) through grants # EEC-0540855 and EEC-0951845 .
Publisher Copyright:
© 2018 Elsevier Ltd
PY - 2018/11/23
Y1 - 2018/11/23
N2 - 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.
AB - 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.
KW - Adhesive mixing process
KW - Collision dynamics
KW - Discrete element method (DEM)
KW - Mixing dynamics
UR - http://www.scopus.com/inward/record.url?scp=85048723191&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85048723191&partnerID=8YFLogxK
U2 - 10.1016/j.ces.2018.06.043
DO - 10.1016/j.ces.2018.06.043
M3 - Article
AN - SCOPUS:85048723191
SN - 0009-2509
VL - 190
SP - 220
EP - 231
JO - Chemical Engineering Science
JF - Chemical Engineering Science
ER -