The effect of side walls on particles mixing in rotating drums--颗粒学报PARTICUOLOGY

Jain, A., Evrard, F., & van Wachem, B. (2023). The effect of side walls on particles mixing in rotating drums. Particuology, 72, 112-121. https://doi.org/10.1016/j.partic.2022.02.011

The effect of side walls on particles mixing in rotating drums

Aman Jain, Fabien Evrard, Berend van Wachem ^*

Chair of Mechanical Process Engineering, Otto-von-Guericke-University Magdeburg, Universitaetsplatz 2, Magdeburg 39106, Germany

10.1016/j.partic.2022.02.011

Volume 72, January 2023, Pages 112-121

Received 29 October 2021, Revised 20 December 2021, Accepted 21 February 2022, Available online 14 March 2022, Version of Record 7 May 2022.

E-mail: Berend.van.Wachem@gmail.com

Highlights

• DEM study on the effect of side walls on mixing in rotating drums.

• Curved side walls induce a strong circulation.

• This circulation leads to segregation by particle size.

• The longer the drum, the less effect of side walls.

Abstract

In this paper, we study the effects of the presence and shape of side walls and of the overall length of rotating cylindrical drums on the mixing of particles with differing sizes by application of the discrete element method (DEM). By varying the semi-axis of the spheroidally shaped side walls and the length of the overall drum, we observe the formation of circulation patterns near the side walls. Although there is a vast amount of literature studying mixing regimes in rotating drums, little is known about the effect of the side walls of the drum on particle mixing. The results of our study demonstrate that introducing curved side walls induces a strong circulation pattern near these side walls, but has, paradoxically, a negative impact on mixing and actually promotes segregation. The cause for this segregation is the difference in velocity of differently sized particles near the curved side walls. Large particles accumulate at the curved side walls, whereas small particles move away from the curved side walls. When the length of the drum is increased, the overall effect of the side walls is decreased, although it does remain observable, even in very large drums.

Graphical abstract

Keywords

Discrete element method; Rotating drums; Particle mixing; Side walls of rotating drums

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