Fragmentation dynamics of single agglomerate-to-wall impaction

A. Lowe, G. Singh, H.-K. Chan, A. R. Masri, S. Cheng, A. Kourmatzis*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

7 Citations (Scopus)


The de-agglomeration characteristics of single agglomerate-wall impaction are examined using high-resolution shadowgraph imaging. Experiments are performed to investigate the effects of constituent particle size (D50 from 3 to 7 μm) and air velocity on the individual size and velocity of de-agglomerated fragments at conditions relevant to dry powder inhalation systems. De-agglomerated fragment area and trajectories were used to differentiate between pseudo-elastic and inelastic collisions during de-agglomeration. Advanced image processing techniques have enabled provision of joint population distributions of fragment area and aspect ratio, which identify a bimodal dispersion of fragments during de-agglomeration. The bimodality is destroyed with increasing air velocity and also generally diminishes with time after impact. The experiment presented forms a platform for the detailed quantitative characterisation of de-agglomeration behaviour and can be useful towards the development and validation of related computational models for pharmaceutical dry powder inhalers.

Original languageEnglish
Pages (from-to)561-575
Number of pages15
JournalPowder Technology
Issue numberPart A
Publication statusPublished - 22 Jan 2021


  • Dry powder inhalers
  • Pharmaceutical powders
  • De-agglomeration


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