TY - JOUR
T1 - Scale-up and flow behavior of cohesive granular material in a four-bladed mixer
T2 - effect of system and particle size
AU - Boonkanokwong, Veerakiet
AU - Khinast, Johannes G.
AU - Glasser, Benjamin J.
N1 - Funding Information:
The authors would like to thank Dr. Brenda Remy for her insightful and helpful suggestions on this work. We appreciate the assistance of Dr. Clara Hartmanshenn, Benedict J. S. Benque, Rohan P. Frank, Pavithra Valliappan, and Yashmitha Ravindra for their assistance with the DEM simulations. The authors wish to thank DEM Solutions Ltd. for the technical support regarding EDEM? for this research project.
Publisher Copyright:
© 2021 The Society of Powder Technology Japan
PY - 2021/12
Y1 - 2021/12
N2 - Flow of cohesive granular materials with different moisture contents was examined in a four-bladed mixer via the discrete element method (DEM). Firstly, the mixer diameter (D) was increased while keeping the particle diameter (d) constant. It was observed that when the mixer diameter to the particle diameter ratio (D/d) was larger than a certain critical size (D/d ≥ 75), granular flow behaviors and mixing kinetics followed simple scaling relations. For D/d ≥ 75, flow patterns and mixing kinetics were found to be independent of system size, and velocities of particles scaled linearly with the tip speed of the impeller blades and particle diffusivities scaled with the tip speed of the blades and mixer diameter. These results suggest that past a certain system size the flow and mixing of cohesive particles in large-scale units can be predicted from smaller systems. Secondly, system size was kept constant and particle diameter was changed and it was observed that by keeping the Bond number constant (by changing the level of cohesion) the flow behavior and mixing patterns did not change, showing that larger particles can be used to simulate flow of smaller cohesive particles in a bladed mixer by matching the Bond numbers.
AB - Flow of cohesive granular materials with different moisture contents was examined in a four-bladed mixer via the discrete element method (DEM). Firstly, the mixer diameter (D) was increased while keeping the particle diameter (d) constant. It was observed that when the mixer diameter to the particle diameter ratio (D/d) was larger than a certain critical size (D/d ≥ 75), granular flow behaviors and mixing kinetics followed simple scaling relations. For D/d ≥ 75, flow patterns and mixing kinetics were found to be independent of system size, and velocities of particles scaled linearly with the tip speed of the impeller blades and particle diffusivities scaled with the tip speed of the blades and mixer diameter. These results suggest that past a certain system size the flow and mixing of cohesive particles in large-scale units can be predicted from smaller systems. Secondly, system size was kept constant and particle diameter was changed and it was observed that by keeping the Bond number constant (by changing the level of cohesion) the flow behavior and mixing patterns did not change, showing that larger particles can be used to simulate flow of smaller cohesive particles in a bladed mixer by matching the Bond numbers.
KW - Cohesive granular material
KW - Discrete element method
KW - Pharmaceutical mixing/blending process
KW - Scale-up of bladed mixer
KW - Solid particulate flow
UR - http://www.scopus.com/inward/record.url?scp=85117363433&partnerID=8YFLogxK
U2 - 10.1016/j.apt.2021.09.044
DO - 10.1016/j.apt.2021.09.044
M3 - Article
AN - SCOPUS:85117363433
SN - 0921-8831
VL - 32
SP - 4481
EP - 4495
JO - Advanced Powder Technology
JF - Advanced Powder Technology
IS - 12
ER -