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bioRxiv · 10.64898/2026.10.15.759419

Coupled Effects of Airway Deformation and Carrier Gas on Pulmonary Gas-Particle Flow Dynamics Using an Euler-Lagrange Method with Dynamic Mesh

Yi, H.·Feng, Y.
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Abstract

Physiologically realistic prediction of inhaled aerosol deposition in the airways requires simultaneous consideration of airway deformation kinematics and carrier-gas properties. This study developed a 3D deformable lung airway model (DLAM) using an experimentally validated computational fluid particle dynamics (CFPD) model coupled with a dynamic mesh method. Both the DLAM and a conventional static lung airway model (SLAM) were used to predict and compare inhaled gas-particle transport and deposition in a subject-specific mouth-to-generation 9 (G9) human respiratory system. To assess the significance of airway deformation, SLAM and DLAM were compared under identical 12 breaths per minute (BPM) inhalation-exhalation waveforms for both conventional air and heliox (70% He-30% O2), considering particle sizes of 1, 5, and 10 um. The effects of carrier gas and breathing frequency were further evaluated using the more physiologically realistic DLAM, comparing air and heliox at 12, 16, and 20 BPM for the same particle sizes. Results showed that the influence of airway deformation on aerosol transport is strongly dependent on particle size. Differences between SLAM and DLAM were negligible for 1 um particles. In contrast, for 5 and 10 um particles, SLAM consistently underpredicted beyond-G9 delivery and overpredicted G0-G9 local deposition for both air and heliox. For example, for 10 um particles at 12 BPM, accounting for airway deformation kinematics increased the beyond-G9 delivery fraction by an absolute 3.76% with air and 5.55% with heliox. After establishing the size-dependent deformation effect, DLAM was further used to evaluate the influence of carrier gas and breathing frequency on inhaled aerosol transport and deposition. Compared with air, heliox reduced turbulence kinetic energy, wall shear stress, and pressure drop, and enhanced beyond-G9 delivery of larger particles. Specifically, for 10 um particles, the absolute increases in beyond-G9 delivery were 16.82%, 20.25%, and 22.90% at 12, 16, and 20 BPM, respectively. Increasing breathing frequency reduced distal delivery, particularly for 5 and 10 um particles, whereas 1 um particles maintained approximately 99% beyond-G9 penetration across all investigated conditions. These findings indicate that DLAM is essential for accurate regional dosimetry of higher-inertia aerosols, for which the static airway simplification can significantly bias predicted deposition and distal delivery.

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Yi, H., Feng, Y.. 2026-10-16. Coupled Effects of Airway Deformation and Carrier Gas on Pulmonary Gas-Particle Flow Dynamics Using an Euler-Lagrange Method with Dynamic Mesh. https://doi.org/10.64898/2026.10.15.759419

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