THE EFFECT OF GRAVITY ON PARTICLE DEPOSITION PATTERNS IN BRONCHIAL AIRWAY BIFURCATIONS

Inspiratory particle deposition patterns within three-dimensional mode ls of asymmetric bronchial airway bifurcations in the human lungs are simulated by a numerical model in which the Navier-Stokes equations fo r the air velocity field are solved by numerical methods and trajector ies of aerosol particles entrained in the airstream are modeled by Mon te Carlo techniques. In this note, the effect of the spatial orientati on of a bronchial bifurcation relative to the gravity vector has been explored for situations where gravitational settling is the primary mo de of particle deposition. Resulting inspiratory deposition patterns a nd efficiencies for five different orientations are distinctly differe nt from each other, emphasizing the significance of the gravity angle for the determination of localized doses and their distribution among different regions of the human lungs.