Airflow and Particle Transport Prediction through Stenosis Airways.

Parth Singh,Suvash C Saha,Vishnu Raghav,Mohammad S Islam,Gunther Paul,Vignesh Padhmashali

doi:10.3390/ijerph17031119

Abstract

Airflow and particle transport in the human lung system is influenced by biological and other factors such as breathing pattern, particle properties, and deposition mechanisms. Most of the studies to date have analyzed airflow characterization and aerosol transport in idealized and realistic models. Precise airflow characterization for airway stenosis in a digital reference model is lacking in the literature. This study presents a numerical simulation of airflow and particle transport through a stenosis section of the airway. A realistic CT-scan-based mouth–throat and upper airway model was used for the numerical calculations. Three different models of a healthy lung and of airway stenosis of the left and right lung were used for the calculations. The ANSYS FLUENT solver, based on the finite volume discretization technique, was used as a numerical tool. Proper grid refinement and validation were performed. The numerical results show a complex-velocity flow field for airway stenosis, where airflow velocity magnitude at the stenosis section was found to be higher than that in healthy airways. Pressure drops at the mouth–throat and in the upper airways show a nonlinear trend. Comprehensive pressure analysis of stenosis airways would increase our knowledge of the safe mechanical ventilation of the lung. The turbulence intensities at the stenosis sections of the right and left lung were found to be different. Deposition efficiency (DE) increased with flow rate and particle size. The findings of the present study increase our understanding of airflow patterns in airway stenosis under various disease conditions. More comprehensive stenosis analysis is required to further improve knowledge of the field.

Highlights

IntroductionAmbient air pollution is a global problem which has affected all countries across the world
Ambient air pollution is a global problem which has affected all countries across the world.Developing countries suffer from environmental air pollution, as they often derive inexpensive energy from burning natural fossil resources
The velocity profiles at the mouth–throat sections (Lines 1 and 2), trachea (Line 3), and stenosis section (Line 4) of the bifurcating airway portions are plotted for better understanding of the flow field

Summary

Introduction

Ambient air pollution is a global problem which has affected all countries across the world. Developing countries suffer from environmental air pollution, as they often derive inexpensive energy from burning natural fossil resources. They do not have access to technologies to mitigate potential air pollution. Air pollution is an important environmental risk factor with global health implications. The respiratory system becomes a target of harmful air pollutants, including ozone, nitrogen dioxide, volatile organic compounds, and particulate matter, affecting the lungs [1]. The overall impact of exposure to pollutants on lung health and the treatment of respiratory diseases have become of

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Conclusion