Fibrous and Spherical Particle Transport and Deposition in the Human Nasal Airway: A Computational Fluid Dynamics Model

As the interface between the human respiratory system and the environment, the nose plays many vital roles. Not the least of which is filter. Resulting from numerous natural and anthropogenic processes, particulate matter becomes airborne. Should particulate matter reach the lower portions of the respiratory tract, a host of maladies may occur. In an attempt to further understand the physics behind particulate matter transitioning from the environment into humans a computational model has been developed to predict the efficiency with which human noses can remove particles before they reach the lungs. To this end computational fluid dynamics and Lagrangian particle tracking simulations have been run to gather information on the deposition behavior of both fibrous and spherical particles. MRI data was collected from the left and right passages of a 181.6 cm, 120.2 kg, human male. The two passages were constructed into separate computational volumes consisting of approximately 950,000 unstructured tetrahedral cells each. A steady laminar flow model was used to simulate the inhalation portion of a human breathing cycle. Volumetric flow rates were varied to represent the full range of human nasal breathing. General agreement was shared quantitatively and qualitatively with previously published in vitro studies on other nasal models. Lagrangian particle tracking was performed for varying sizes of fibrous and spherical particles. Deposition efficiency was shown to increase with fiber aspect ratio, particle size, and flow rate. Anatomy was also identified as effecting deposition.