Flow characterization in healthy airways and airways with chronic obstructive pulmonary disease (COPD) during different inhalation conditions

Justus Kavita Mutuku, Wei Hsin Chen

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1 Citation (Scopus)

Abstract

The flow of air in the central and lower generations of the human airways results in complex secondary flows, which heavily affect the deposition of aerosol such as PM2.5 in the human airways. To figure out the flow dynamics in healthy airways and airways with chronic obstructive pulmonary disease (COPD), the flow distributions were predicted numerically. In a bronchial tube geometry (G5-G8), COPD was represented by an axisymmetric constriction in G6-2 of a four-generation airway. Real and unsteady breathing inhalation curves under rest, light activity, and moderate exercise were applied in the simulations. The velocity distribution, recirculation, and stagnation zones in the generation G6-2 affected by COPD together with the effects of sudden pressure drop in the constriction were investigated. Two symmetrical vortices (Dean vortices) were formed at the cross-sections of the geometry affected by COPD and their intensities were dependent on the Reynolds number. The mas flow rates in the healthy generation (G6-1) went to as high as 3.10 times the mass flow rate in the generation affected by COPD (G6-2). The simulations showed that inflammation of the bronchus greatly affected pressure distribution and the rates of mass flow in the human airway during inhalation. The overall pressure drop in the bifurcation affected by COPD was 3.38 Pa for rest, 10.91 Pa for light activity and 21.39 Pa for moderate exercise. A combination of these factors make COPD patients very susceptible to adverse health effects caused by inhalation of PM2.5.

Original languageEnglish
Pages (from-to)2680-2694
Number of pages15
JournalAerosol and Air Quality Research
Volume18
Issue number10
DOIs
Publication statusPublished - 2018 Oct

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Pulmonary diseases
pressure drop
Pressure drop
vortex
Vortex flow
Flow rate
geometry
secondary flow
Geometry
Secondary flow
bifurcation
pulmonary disease
Velocity distribution
Aerosols
Reynolds number
Pressure distribution
simulation
cross section
Health
aerosol

All Science Journal Classification (ASJC) codes

  • Environmental Chemistry
  • Pollution

Cite this

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abstract = "The flow of air in the central and lower generations of the human airways results in complex secondary flows, which heavily affect the deposition of aerosol such as PM2.5 in the human airways. To figure out the flow dynamics in healthy airways and airways with chronic obstructive pulmonary disease (COPD), the flow distributions were predicted numerically. In a bronchial tube geometry (G5-G8), COPD was represented by an axisymmetric constriction in G6-2 of a four-generation airway. Real and unsteady breathing inhalation curves under rest, light activity, and moderate exercise were applied in the simulations. The velocity distribution, recirculation, and stagnation zones in the generation G6-2 affected by COPD together with the effects of sudden pressure drop in the constriction were investigated. Two symmetrical vortices (Dean vortices) were formed at the cross-sections of the geometry affected by COPD and their intensities were dependent on the Reynolds number. The mas flow rates in the healthy generation (G6-1) went to as high as 3.10 times the mass flow rate in the generation affected by COPD (G6-2). The simulations showed that inflammation of the bronchus greatly affected pressure distribution and the rates of mass flow in the human airway during inhalation. The overall pressure drop in the bifurcation affected by COPD was 3.38 Pa for rest, 10.91 Pa for light activity and 21.39 Pa for moderate exercise. A combination of these factors make COPD patients very susceptible to adverse health effects caused by inhalation of PM2.5.",
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