Computer simulation of fluid flow and particle diffusion within human upper airways system

Computer simulation of air flow and particle transport phenomenon within the human upper respiratory system has important applications in inhalation toxicology, aerosol medicine delivery as well as basic medical science research.;A three-dimensional physiologically realistic computer model of the human upper respiratory tract has been developed. The respiratory tract consists of nasal airways, oral airways, laryngeal airways and the first two generations of tracheobronchial airways. A rubber mold of the airway system was first cast from the impression of the human head airway teaching model. The rubber cast was sliced into 2mm-apart parallel pieces. The cross-sectional geometry of the sliced rubber pieces were then scanned into the computer to be stored as the digital information.;A body-fitted three-dimensional curvilinear grid system and a multi-block method have been employed to mimic the complex head airway. A total of 280,000 grid node was used for the entire respiratory tract.;Air flow patterns within the human upper airways are investigated by numerically solving the corresponding full Navier-Stokes equations using the flow simulation software CFX-F3D. Effects of human breath patterns on respiratory flow distribution and ultrafine particle deposition are investigated. Results of ultrafine particle deposition generated by computer simulation show reasonable agreements with the experimental measurements.