TITLE:
CFD Simulation of Particles Mixing and Segregation in a Rotary Coating Disk: Influence of Drag Models and Restitution Coefficient
AUTHORS:
Salma Awad Nouh, Ku Zilati Bt Ku Shaari, Lau Kok Keong, Shafirah Bt Samsuri, Tigabwa Yosef Ahmed
KEYWORDS:
Rolling Mode, Drag Model, Restitution Coefficient, CFD
JOURNAL NAME:
Open Journal of Applied Sciences,
Vol.12 No.3,
March
14,
2022
ABSTRACT: In this paper, the dynamics of a transverse plane of a rotary coating
disk of a binary mixture system comprising
sand and urea particles were simulated using the two-fluid model along
with the kinetic theory of granular flow in Fluent 19.1. Although some
parameters relating to the material properties and size of the rotary coating disk have been researched, the
effects of both drag force and restitution
coefficient on the flow characteristics have yet to be examined. Thus,
this paper numerically examines the effect of the inclusion of drag models and
particle-particle restitution coefficients on particle dynamics in a rotary disk operating in the rolling regime of the
granular bed. Three particle-particle drag models were considered: the
Schiller-Naumann, Syamlal-O’Brien, and Gidaspow. The Syamlal-O’Brien and
Gidaspow models were both able to successfully simulate particle segregation in
a perfect rolling regime, whereas the Schiller-Naumann drag model appeared to
be unable to predict the segregation of the particles and the rolling flow
regime under the assumed conditions. Four different values of the restitution
coefficient were also investigated: 0.7, 0.8, 0.9, and 0.95. The higher
restitution values of 0.9 and 0.95 were found to substantially affect flow
characteristics, ensuring suitable rolling regime behaviour for the bed during
the rotational movement. The lower restitution coefficients of 0.7 and 0.8, on
the other hand, indicated that irregular velocity vectors could be obtained in
the active region of the granular bed.