TY - JOUR
T1 - Three-dimensional simulations of reactive gas uptake in single airway bifurcations
AU - Taylor, Adekemi B.
AU - Borhan, Ali
AU - Ultman, James S.
N1 - Funding Information:
This work was supported by the National Institute of Environmental Health Sciences research grant 1P01 ES 11617.
PY - 2007/2
Y1 - 2007/2
N2 - The pattern of lung injury induced by the inhalation of ozone (O 3) depends on the dose delivered to different tissues in the airways. This study examined the distribution of O3 uptake in a single, symmetrically branched airway bifurcation. Reaction in the epithelial lining fluid was assumed to be so rapid that O3 concentration was negligible along the entire surface of the bifurcation wall. Three-dimensional numerical solutions of the continuity, Navier-Stokes and convection-diffusion equations were obtained for steady inspiratory and expiratory flows at Reynolds numbers ranging from 100 to 500. The total rate of O3 uptake was found to increase with increasing flow rate during both inspiration and expiration. Hot spots of O3 flux appeared at the carina of the bifurcation for virtually all inspiratory and expiratory Reynolds numbers considered in the simulations. At the lowest expiratory Reynolds number, however, the location of the maximum flux was shifted to the outer wall of the daughter branch. For expiratory flow, additional hot spots of flux were found on the parent branch wall just downstream of the branching region. In all cases, O3 uptake in the single bifurcation was larger than that in a straight tube of equal inlet radius and wall surface area. This study provides insight into the effect of flow conditions on O3 uptake and dose distribution in individual bifurcations.
AB - The pattern of lung injury induced by the inhalation of ozone (O 3) depends on the dose delivered to different tissues in the airways. This study examined the distribution of O3 uptake in a single, symmetrically branched airway bifurcation. Reaction in the epithelial lining fluid was assumed to be so rapid that O3 concentration was negligible along the entire surface of the bifurcation wall. Three-dimensional numerical solutions of the continuity, Navier-Stokes and convection-diffusion equations were obtained for steady inspiratory and expiratory flows at Reynolds numbers ranging from 100 to 500. The total rate of O3 uptake was found to increase with increasing flow rate during both inspiration and expiration. Hot spots of O3 flux appeared at the carina of the bifurcation for virtually all inspiratory and expiratory Reynolds numbers considered in the simulations. At the lowest expiratory Reynolds number, however, the location of the maximum flux was shifted to the outer wall of the daughter branch. For expiratory flow, additional hot spots of flux were found on the parent branch wall just downstream of the branching region. In all cases, O3 uptake in the single bifurcation was larger than that in a straight tube of equal inlet radius and wall surface area. This study provides insight into the effect of flow conditions on O3 uptake and dose distribution in individual bifurcations.
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U2 - 10.1007/s10439-006-9195-4
DO - 10.1007/s10439-006-9195-4
M3 - Article
C2 - 17131171
AN - SCOPUS:33846278015
SN - 0090-6964
VL - 35
SP - 235
EP - 249
JO - Annals of Biomedical Engineering
JF - Annals of Biomedical Engineering
IS - 2
ER -