Computer simulation of aerosol transport and deposition in multi-generation airway models

Laminar dilute suspension flows of micron-particles in rigid tubular double and triple bifurcations, representing segments of human respiratory airways, have been simulated with a finite-volume code for the air flow and an ODE-solver for the aerosol trajectories. Of interest are the local particle deposition characteristics with respect to inlet conditions, particle size, and branching geometry. Particle diameters of 3, 5, and 7 μm were considered while the inlet Reynolds and Stokes numbers varied from 500 to 2000 and 0.037 to 0.23, respectively. Results were successfully compared with measured particle deposition efficiencies for single and double bifurcations. Particle deposition occurs mainly in the carinal regions, the amount declining with each downstream bifurcation, and the patterns becoming asymmetric due to the highly vortical air flow fields after the first bifurcation. The results of the study will provide necessary information for algebraic dosimetry models of the lung as well as quantitative health risk assessment of inhaled air pollutants