| People may inhale 100 millions of particles each day, including toxic particulate matter as well as drug aerosols. Some of those deposited in the respiratory system can be either harmful or therapeutic to humans depending upon the particle material, deposition site, and local concentration. These transport and deposition phenomena as well as the resulting biomedical processes are greatly determined by the airflow field, particle properties, breathing pattern, and geometric airway characteristics.;Realistic models of tracheobronchial and nasal/oral-tracheobronchial airways were built. Airflow and particle transport and deposition in these airway models were investigated in detail by mainly using the validated, in-house FORTRAN code CFPD (computational fluid-particle dynamics), which is a cell-centered, finite volume multi-block code. Both laminar and transitional-turbulent-laminar flows were considered for different transient and steady inhalation flow rates and inlet velocity profiles. The resulting effects of transients, upstream conditions and geometric characteristics, i.e., spatial angle and/or cartilaginous rings, are fully discussed.;A new code based on the lattice-Boltzmann method (LBM) has been developed and validated to investigate airflow patterns and pressure changes in representative alveolar structures of the human respiratory zone.;The new idea of targeted drug aerosol delivery technology was numerically tested for a more realistic human airway configuration and thereby addressing the problem of inter-subject variability. Specifically, controlled air-particle streams were studied using the oral and asymmetric tracheobronchial airway models. The results were compared with data obtained for a symmetric Weibel Type A tracheobronchial airway model. |
