Electronic Thesis and Dissertation Repository


Master of Engineering Science


Mechanical and Materials Engineering


Anthony G. Straatman


The volume-averaged oxygen transport equation is closed using a volume-averaged form of Fick’s law of diffusion between the air and tissue to simulate species exchange within the lungs’ alveoli using a computational fluid dynamics (CFD) 3D conjugate domain model. Pore level simulations of a terminal alveolated duct are used to determine that the transport of inhaled oxygen from the cluster inlet to the alveolar walls is diffusion dominated. The resistance to oxygen diffusion into the tissue is found to be a function of the tidal volume and tissue transport properties, with a maximum respiration frequency at which the full amount of oxygen available can be exchanged per breath dependent on the tidal volume. The simulated exhaled oxygen and carbon dioxide compositions match experimental values for regular resting respiration. Therefore, this model provides a viable new approach to modelling species exchange within the alveoli.