Numerical Simulation of Transport and Deposition of Dust Particles in Human Tracheobronchial Airways

Abstract

Dust is a common pollutant of the air we breath. If dust particles are inhaled and deposited in human airways, they can cause a variety of respiratory disorders. The inhaled dust particles motion in human airways goes along with the airflow. The transport process can be considered as a two-phase flow of a gas phase and a particle phase. In this study, we investigated the airflow and dust particles transport and deposition in human tracheobronchial airways using computational fluid dynamics (CFD) techniques. A steady simulation was performed in asymmetric tracheobronchial airway mode consisting of 19 outlets to observe the characteristics of airflow fields. The discrete phase model (DPM) was employed to predict the particle trajectories and deposition in the airway model. Deposition resulted from inertial impaction and gravitational sedimentation was considered. In the simulation, the airflow characteristics differences in the right and left bronchial trees were observed. The influence of secondary flow on dust particles motion was great. More dust particles were deposited in the right bronchial tree than in the left. The deposition fraction of dust particles in human tracheobronchial airways was high. This study can provide awareness on deposition of dust particles passing beyond the larynx and enhance prevention of their entry into the respiratory system. It can also contribute a convenient way on the location of deposition of particles of a given type in human respiratory tract to be used for respiratory disease preventions.