Fluid flow and particle diffusion in the human upper respiratory system

Airflow patterns within the human upper airways, including nasal airway, oral airway, laryngeal airway, and the first two generations of tracheobronchial airway, are investigated by numerically solving the corresponding full Navier-Stokes equations using the flow simulation software CFX-F3D. A body-fitted three-dimensional curvilinear grid system and a multiblock method have been employed to mimic the complex head airway geometry and to match the computational domain with the outline of a semirealistic nasal sagittal cross-section geometry. Effects of human breath patterns, i.e., nasal breath, oral breath and simultaneous nasal and oral breath, on airflow and ultrafine particle deposition are investigated. Results of ultrafine particle deposition generated by computer simulation show reasonable agreements with the experimental measurements. (C) 1998 American Association for Aerosol Research.