Study of particle deposition in human airway models
In this dissertation, the deposition of particles in human airway models is studied. The dissertation consists of three parts: ^ In the first part, an analytical model of particle nasal airway deposition by diffusion considering effects of both laminar and turbulent flows is proposed. It appears in the literature that neither laminar nor turbulent analytical models alone works well for the entire range of diffusion parameters. A simplified turbulent particle diffusion equation is first developed and then a new combined turbulent/laminar diffusion model is proposed. The results predicted from the new model show improved accuracy when compared with available experimental data from the literature. ^ In the second part, the trajectories of particles within a three-dimensional integrated human upper respiratory system by the nasal inhalation are simulated. The airway system includes the nasal, nasopharyngeal, laryngeal and tracheobronchial airways. Array of evenly distributed particles is launched at the nostril cross-section. Uniform inlet flow profile is assumed. Each of the particles is carefully traced all the way down and its destination recorded. The fraction of particles deposited in each individual airway segments is calculated. The demographical distributions of these particles are presented. It has been found that respiratory flow rates have significant effects on the demographical distribution of particles at the airway entrance while the effects of particle size is not dominant. The particle demographical distribution patterns have many important implications to site prediction and probability of particle deposition for the application of inhalation toxicology and aerosol therapy. ^ In the last part, an approximated mapping theory of particle deposition in human lower airways is proposed. Preliminary experimental studies of particle deposition based on this theory in the human pulmonary airway models are conducted. The objective of this study is to qualitatively investigate the phenomena of enhanced particle local deposition. In the experiments, the volume expansion and contraction of the hollow latex airway model are controlled by varying the surrounding vacuum pressures inside the chamber. The local distribution patterns of particle deposition in the airway models are measured by fluorescence spectrophotometer. ^
Engineering, Biomedical|Engineering, Mechanical
"Study of particle deposition in human airway models"
Dissertations and Master's Theses (Campus Access).