Numerical Study of Aerosol Deposition in a Realistic Human Lung in Different Body Orientations

Abstract

The success of targeted drug delivery through inhalation largely depends on the efficient deposition of aerosols across different regions of the human lung. Factors such as particle size, airflow dynamics, lung geometry, and body posture have a significant influence on aerosol transport and deposition. This computational fluid dynamics (CFD)-based study investigates the combined effects of body orientation and particle size on aerosol deposition using a realistic lung geometry reconstructed from computed tomography (CT) images and a realistic aerosol breathing profile derived from patient data. Simulations were conducted in ANSYS Fluent using the Discrete Phase Model (DPM) for five particle sizes (3, 5, 7, 9, and 10 µm) across three body orientations: upright, dorsal, and lateral. Results showed that total deposition efficiency increased with particle size, while regional deposition varied noticeably with posture. The right lung consistently exhibited higher deposition than the left, and the upper lobes of both lungs received the majority of particles, particularly for larger aerosols. Although overall deposition efficiency remained similar across orientations, regional redistribution was evident. These findings highlight how body posture influences aerosol transport within the lungs and offer valuable insights for optimizing posture based inhalation strategies and improving targeted drug delivery.