Unveiling Aerosol Deposition Dynamics in a Disease-Specific Lung Model Under Realistic Breathing Pattern

Abstract

This study examines the impact of tracheal stenosis on aerosol particle deposition (1, 5, and 10 μm) in a disease-specific human lung model. A computed tomography scan-based 3D airway model covering generations 0 to 4 (G0-G4) has been developed for a male adult. Two tracheal stenosis severity levels, mild (15%) and extreme (85%), were simulated. The airflow was modeled using the Reynolds-averaged Navier-Stokes (RANS) equations with the shear stress transport (SST) k-ω turbulence model, while particle transport was investigated using a combined Eulerian wall film (EWF) and discrete phase model (DPM) approach. Results indicate that extreme stenosis generates a narrow, high-velocity jet (~1.2 m/s), redirecting flow predominantly to the right lung, whereas mild stenosis maintains a low-velocity, symmetric profile (~0.3 m/s). Film thickness increases with particle size due to increased inertial impaction. In extreme cases of 10 μm particles, the right lung had a film thickness 2.37 times higher than the left lung, compared to 1.23 times higher in the left lung under mild stenosis. Deposition efficiency for 10 μm particles reached ~22% in the right lung under severe stenosis, while it remained below 5% in moderate instances. These findings highlight the impact of stenosis severity and particle size on drug delivery and provide crucial insights for developing targeted aerosol treatments in the obstructed airways.