Application of positron emission particle tracking (PEPT) to validate a discrete element method (DEM) model of granular flow and mixing in the Turbula mixer

M. Marigo*, M. Davies, T. Leadbeater, D. L. Cairns, A. Ingram, E. H. Stitt

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

36 Citations (Scopus)

Abstract

The laboratory-scale Turbula mixer comprises a simple cylindrical vessel that moves with a complex, yet periodic 3D motion comprising of rotation, translation and inversion. Arising from this complexity, relatively few studies to obtain fundamental understanding of particle motion and mixing mechanisms have been reported. Particle motion within a cylindrical vessel of a Turbula mixer has been measured for 2 mm glass spheres using Positron Emission Particle Tracking (PEPT) in a 2 l blending mixing vessel at 50% fill level. These data are compared to results from Discrete Element Method (DEM) simulations previously published by the authors. PEPT mixing experiments, using a single particle tracer, gave qualitatively similar trends to the DEM predictions for axial and radial dispersion as well as for the axial displacement statistics at different operational speeds. Both experimental and simulation results indicate a minimum mixing efficiency at ca. 46 rpm. The occupancy plots also show a non-linear relationship with the operating speed. These results add further evidence to a transition between two flow and mixing regimes. Despite the similarity in overall flow and mixing behaviour measured and predicted, including the mixing speed at which the flow behaviour transition occurs, a systematic offset between measured and predicted result is observed.

Original languageEnglish
Pages (from-to)46-58
Number of pages13
JournalInternational Journal of Pharmaceutics
Volume446
Issue number1-2
DOIs
Publication statusPublished - 25 Mar 2013

Keywords

  • DEM
  • Particle mixing
  • PEPT
  • Turbula mixer

ASJC Scopus subject areas

  • Pharmaceutical Science

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