The impact of asymmetric branching on particle deposition in conducting airways

• Published in: International journal of multiphase flow Vol. 179; p. 104935
• Main Authors: Ghorui, Shouvik, Kundu, Debjit, Chakravarty, Aranyak, Panchagnula, Mahesh V.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01-09-2024
• Subjects: Airborne diseases; Computational fluid dynamics; Drug delivery; Human airways; OpenFOAM; Particle deposition; OpenFOAM; Particle deposition; Human airways; Airborne diseases; Drug delivery; Computational fluid dynamics
• ISSN: 0301-9322
• DOI: 10.1016/j.ijmultiphaseflow.2024.104935

Inhalation exposes individuals to a diverse range of airborne particles carrying potential health risks. Airflow and particle transport behavior is highly sensitive to airway geometry. Therefore, it is a huge source of inter-subject variability — in both disease development as well as inhalation therapy outcomes. Numerical simulations of multi-phase flow of particle-laden air within the respiratory system has emerged as a key tool in assessing these complex physical phenomena. This study investigates the implications of bifurcation asymmetry in airway geometry on the fate of inhaled particles by employing Computational Fluid Dynamics (CFD) calculations. To that end, we use single generation ‘Y-units’. Then we extend the study to multi-generation (G5−G11) bronchial tree networks, both symmetric and asymmetric. An Eulerian–Eulerian approach was employed to solve for the coupled air-flow and particle transport equations, utilizing the OpenFOAM® CFD package. The relationship between lung structure and particle dynamics is revealed by analyzing the effects of asymmetry on particle transport and deposition. Our results show that although geometric asymmetry may not have a significant impact on the deposition fractions of single Y-units, its effects keep accumulating over multiple generations. This study also sheds light on local deposition patterns, identifying the specific deposition hot spots, leading to a comprehensive understanding of inhaled particle behavior in distinct lung geometries.
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•Airflow and particle transport in the central airways were simulated using CFD.•Symmetric and asymmetric bifurcations (Y-units) as well as multi-generation bronchial trees (G5–G11) were compared.•Branching asymmetry in human airways influences particle deposition.•Mechanisms through which asymmetry has an impact on particle deposition was explained.