UNIVERSAL BIFURCATION MODEL AND ITS APPLICATION TO STUDY LOCAL PARTICLE-TRANSPORT PHENOMENA IN UPPER AIRWAYS

A universal bifurcation model developed to study a variety of transpor t phenomena in the human lung is described. This paper focuses on tech nical specifications of the model and on local particle concentration patterns within post-bend and post-bifurcation zones. Results are pres ented for uniformly sized solid microspheres, 1.4 mum in diameter, ove r a range of steady air velocity conditions. It is shown that local pa rticle concentration can be significantly higher than the initial conc entration, which demonstrates that the particle phase component of the aerosol is not incompressible (de la Mora, 1985, Aerosol Sci. Technol . 4, 339-349; Konstandopoulos, 1990, J. Aerosol Sci. 21, 983-987), and that a significant boundary layer particle concentration enhancement in the post-bend/bifurcation zone can be produced by the vortices orig inated in bends and bifurcations.