Deposition efficiency and location of aerosols in human lung under different transient breathing patterns

Abstract: With over 8 million people in Australia suffering from respiratory diseases, inhaler devices play crucial roles in improving people's breath. Inhaler devices deliver medicine to people as they inhale through the device. Breathing simulator devices are used to test inhaler devices by applying different breathing patterns to assess their performance under various circumstances. In this study, we investigated the deposition and trajectory of particles under different breathing patterns to understand how these patterns affect the deposition of aerosols when people inhale them through inhaler devices. To conduct this research, three common breathing patterns (sinusoidal, square, and triangular wave patterns) were applied as inlet boundary conditions in a realistic human lung model. We examined the impact of these patterns under different breathing volumes and peak inhalation flow rates on the deposition efficiency of 5 ?m size particles. The results indicate that the square flow pattern shows the lowest total deposition efficiency at tidal volumes below 1 L, but it exhibits the highest efficiency at tidal volumes greater than 1 L. Additionally, a regional deposition efficiency analysis was conducted to identify lung regions significantly impacting total deposition efficiency across different tidal volumes and transient flow patterns. Keywords: Computational Fluid Dynamics, Drug Delivery, Fluid Mechanics, Human Lungs, Aerosols