Three-dimensional simulations of reactive gas uptake in single airwaybifurcations.
Taylor,AB; Borhan,A; Ultman,JS
Abstract The pattern of lung injury induced by the inhalation of ozone (O(3)) dependson the dose delivered to different tissues in the airways. This study examined the distribution ofO(3) uptake in a single, symmetrically branched airway bifurcation. Reaction in the epitheliallining fluid was assumed to be so rapid that O(3) concentration was negligible along the entiresurface of the bifurcation wall. Three-dimensional numerical solutions of the continuity,Navier-Stokes and convection-diffusion equations were obtained for steady inspiratory and expiratoryflows at Reynolds numbers ranging from 100 to 500. The total rate of O(3) uptake was found toincrease with increasing flow rate during both inspiration and expiration. Hot spots of O(3) fluxappeared at the carina of the bifurcation for virtually all inspiratory and expiratory Reynoldsnumbers considered in the simulations. At the lowest expiratory Reynolds number, however, thelocation of the maximum flux was shifted to the outer wall of the daughter branch. For expiratoryflow, additional hot spots of flux were found on the parent branch wall just downstream of thebranching region. In all cases, O(3) uptake in the single bifurcation was larger than that in astraight tube of equal inlet radius and wall surface area. This study provides insight into theeffect of flow conditions on O(3) uptake and dose distribution in individual bifurcations.
Keywords Air Pollutants; Lung; Microfluidics; Models, Biological; Ozone; Pulmonary GasExchange
Annals of Biomedical Engineering
0090-6964, Volume 35, Issue 2, 2007, Pages 3-249
