Flow and Particle Deposition in Asymmetric Human Airways

Transport and deposition of particles in human upper thoracic airways is important to understand their toxicology and the effect of exposure to environmental particulate matter as well as in the design of inhalation drug delivery devices. In the past, limited studies have employed 3-D asymmetric models to study the airflow through human lung, although tracheobronchial branching is generally asymmetric. Also limited work has been devoted to the study of particle deposition in upper airways where turbulence is important to particle depositions. It is also known that the asymmetry of the airways has a profound effect on the airflow fields and particle transport and deposition. The present study is concerned with providing a more accurate computational model for lung deposition. A realistic 3-D asymmetric bifurcation representation of human upper tracheobronchial tree has been developed to simulate the airflow field characterizing the inspiratory flow conditions using a turbulence Reynolds stress transport model. A Lagrangian particle trajectory analysis was also used for analyzing particle transport and deposition patterns in the upper tracheobronchial tree.