Three Dimensional Modeling of the Human Respiratory System

JACKY ROSATI (1), Ray Burton (2), Rob McCauley (2), George McGregor (2)

(1) US EPA National Homeland Security Research Center, RTP, NC (2) Lockheed Martin, RTP, NC

     Abstract Number: 859
     Last modified: August 10, 2010

Abstract
We are developing a comprehensive computational fluid dynamics (CFD), morphologically-realistic model of the human respiratory tract (from nares to alveoli). The goal of this work is to model the inhalation, deposition, and clearance of contaminants, while making the model adaptable for age, race, sex, and health. The model will be used to predict dose from exposure to hazardous particulate-based contaminants, such as anthrax or ricin. The model will also assist in estimating thresholds and the need for prophylactic measures. Finally, this model may be used to better target therapeutics to the lung.
Extrathoracic airways were constructed using The U.S. National Library of Medicine Visible Human Project (http://www.nlm.nih.gov/research/visible/visible_human.html) imaging data. The branching airway, thoracic structures were modeled from Yeh and Shum data (1980), as well as additional data from the Lovelace Respiratory Institute. Five lobes were developed and a typical flow path was constructed to each of these lobes. Airflow rates of 7.5 and 40 liters per minute through these airways were modeled, and particle transport and deposition data for particle diameters of 1, 3, and 5 microns was collected. CFD studies were done for each of the typical path models independently and for a combined model of the five paths (five lobes). Solutions of the steady state laminar flow for the selected rates were considered as converged when the residual values were less than 10e-5.

Preliminary results of the combined model (five lobe) agree well with reported deposition data by Kim and Hu (2006). Comparisons between deposition data from the individual pathways and the combined pathway model indicate the combined model has better agreement with experimental data. Work is ongoing.