Micro-particle deposition and lobar distribution of mass flow in human upper respiratory tract model

Abstract

A representative human upper respiratory tract model consisting of oropharyngeal and asymmetric tracheobronchial (TB) airways from the trachea (G0) to the main lobar bronchi (G2) was constructed. Laminar-to-turbulent airflow for typical inhalation modes as well as micro-particle transportation, wall deposition and mass flow to lobes was simulated using the CFX10.0 software from Ansys Inc. The numerical particle deposition efficiency of the oropharynx region and two generations (G1 and G2) of TB airways shows great agreement with the experimental data obtained from realistic casts. The particle deposition pattern indicates that inertial impaction is the primary mechanism in the human upper airway, and turbulence dispersion performs crescent influence especially for small particles. The initial positions of particles with different fates are confined to specifically concentrated zones. The particle mass distributions of five lobes are close to airflow distributions. The upper lobes receive fewer particles than lower lobes and the right middle lobe receives the least.upper respiratory tract, asymmetric tracheobronchial airways, transportation and deposition, lobar differences, computational fluid dynamics simulation Citation:Huang J H, Zhang L Z. Micro-particle deposition and lobar distribution of mass flow in human upper respiratory tract model. Chinese Sci Bull, 2011Bull, , 56: 380−385, doi: 10.1007 Inhaled particle deposition in the human respiratory tract is a concern in lung diseases. Accurate investigation of aerosol deposition in the human upper respiratory tract (URT) and lobar distribution are important for the analysis of "filtering effects" of human URT and correct air/particle inlet conditions to the deeper bronchial airways. The human upper respiratory tract consists of the oral cavity, nasal cavity, pharynx/larynx airway and tracheobronchial (TB) airways. Numerous investigations have been carried out in experimental or numerical methods on one part or several parts of the human respiratory tract. Previous particle deposition investigations in the oropharyngeal airway have used realistic replicas from cadavers [1], idealized oral models [2] and idealized mouth-throat models [3,4]. In TB airway studies, the effective methods *Corresponding author (email: zhanglz@nankai.edu.cn) include theoretical predictions on symmetrical bifurcation [5], experimental measurements on realistic replicas [6][7][8], Monte Carlo stochastic simulations [9,10] and computational fluid dynamics (CFD) determinate simulations [11,12].Most studies have focused on one part or several separated parts of human URT, but a few studies investigate the particle deposition in the whole region of human URT [13] or predict the lobar distribution of air and particle mass flow into the five lobes. Whole region URT studies avoid any assumptions of boundary conditions between separate parts. A more precise human URT model will improve the accuracy of prediction.In this study, we construct a representative human URT model with oropharyngeal a...

Airflow and Aerosol-Drug Delivery in a CT Scan based Human Respiratory Tract with Tumor using CFD

“…They obtained significant effects on the particle deposition in downstream of the obstruction. Micron size particle distribution in human upper respiratory tract based on regular pipes was studied by Huang and Zhang (2011). They mentioned inertial impaction is the main mechanism for deposition of particles in both oropharynx and primal generation of respiratory tract.…”