(460f) CFD Simulations of Air-Particle Dynamics in the Respiratory System

Majji, M. V., Stanford University
Geisler, T. S., Stanford University
Kesavan, J., ECBC
Shaqfeh, E. S. G., Stanford University
Iaccarino, G., Stanford University
To assess the health risks that arise due to breathing in airborne particles such as bacteria, pollen and smoke and the effectiveness of aerosolized drug delivery, it is essential to understand the dynamics of airflow and inhaled particles through the human airways and lungs. We use Computational Fluid Dynamics (CFD) simulations to study air-particle dynamics through such airways. Various research groups employ non-human primates such as monkeys and rabbits as test subjects for inhalatory delivery experimentsto determine the effect of chemicals and organisms, and to determine the effectiveness of vaccines and drugs. Knowing the amount and region of particle deposition will allow for the study of dose response, effectiveness of vaccines and treatment, and extrapolation of animal data to humans. We use the results of these experiments to calibrate our CFD simulations tool and thereby improve the confidence level of simulations in all (including human) airways. In this work, we present the results of CFD simulations in the anatomically-accurate rabbit airways comprising the nasal cavity, larynx, and trachea. The airway is obtained from computed tomography (CT) scan of the animal. The averaged flow quantities and particle deposition at various locations in the airway will be reported as a function of Inhalation and Exhalation rates and particle size. The air flow rate is varied between the resting state (0.5 lpm) and that corresponding to sniffing (2 lpm) and the particle size is varied between 0.5 micron and 10 microns. We will report the effect of unsteadiness in the flow caused by the narrow cross sections in the pharynx and larynx regions on the local particle deposition and compare it to previous results involving Rhesus monkey inhalation.