Eulerian multiphase CFD analysis of particle transport and deposition in the human

The authors' recent research in the application of three-dimensional, multiphase Computational Fluid Dynamics (CFD) analysis of particle transport and deposition in the human lung is summarized in this paper. A physically accurate representation of the trachea and upper bronchi generations are obtained using high-resolution computed tomography (HRCT) of a rubber cast of an adult human tracheobronchial tree. A computer model of this data is used as a bounding surface for a hybrid unstructured CFD mesh. The differential model employed in the analyses is the ensemble averaged n-fluid system, wherein continuity, momentum, and turbulence quantity conservation equations are solved for an arbitrary number of constituents, here one carrier phase (air) and multiple particulate fields representing different characteristic sizes. Models for non-equilibrium interfacial transfer are incorporated to account for particle drag, dispersion, and deposition. In the present work, steady state simulations were performed corresponding to a nominal adult human inhalation rate 770 of cm3/s. It is found that the detailed geometric and physical modeling employed gives rise to qualitatively and quantitatively correct deposition rate predictions for particle size ranges of pharmaceutical interest.