A computational model of pulmonary gas transport incorporating effective diffusion.

A computational model of gas transport in the lung is described which remedies many of the deficiencies of previous models, as listed by Chang and Farhi (1973), in that it allows for fluctuating lung dimensions, gas exchange, simultaneous convection and diffusion, and the enhanced effective diffusion that occurs when convective flow is also present. The results of calculations using the model are presented, showing the maximum effect of Taylor diffusion. The actual magnitude of Taylor diffusion, suitably modified to allow for the disturbed conditions within the lung, is considered in the light of recent experiments.