Fragmentation dynamics of single agglomerate-to-wall impaction

• Published in: Powder technology Vol. 378; no. Pt A; pp. 561 - 575
• Main Authors: Lowe, A., Singh, G., Chan, H.-K., Masri, A.R., Cheng, S., Kourmatzis, A.
• Format: Journal Article
• Language: English
• Published: Switzerland Elsevier B.V 22.01.2021
• Subjects: De-agglomeration; Dry powder inhalers; Pharmaceutical powders; Dry powder inhalers; De-agglomeration; Pharmaceutical powders; pharmaceutical powders; de-agglomeration
• ISSN: 0032-5910; 1873-328X
• DOI: 10.1016/j.powtec.2020.10.021

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. [Display omitted] •A new approach to study de-agglomeration of single agglomerate-to-wall impaction.•De-agglomeration at conditions relevant to dry powder inhalation are studied.•A bimodal behaviour in the de-agglomeration process is found.•Transient behaviour of fragment formation is investigated for different conditions.