Discrete element method based analysis of mixing and collision dynamics in adhesive mixing process

Document Type

Article

Publication Date

11-23-2018

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.

Identifier

85048723191 (Scopus)

Publication Title

Chemical Engineering Science

External Full Text Location

https://doi.org/10.1016/j.ces.2018.06.043

ISSN

00092509

First Page

220

Last Page

231

Volume

190

Grant

EEC-0540855

Fund Ref

National Science Foundation

This document is currently not available here.

Share

COinS