M. Nishida et al., GAS DISPERSION IN A MODEL PULMONARY BIFURCATION DURING OSCILLATORY FLOW, Journal of biomechanical engineering, 119(3), 1997, pp. 309-316
In order to clarify the gas transport process in high-frequency oscill
ation, we measured the axial velocity profile and the axial effective
diffusivity in a single asymmetric bifurcating tube, based on the Hors
field airway model, with sinusoidally oscillatory pow. The axial veloc
ity profiles were measured using a laser-Doppler velocimeter, and the
effective diffusivities were evaluated using a simple bolus injection
method. The axial velocity profile was found to be nonuniform, promoti
ng axial gas dispersion by the spread of the concentration profile and
lateral mixing. The geometric asymmetry of the bifurcation was respon
sible for the difference in gas transport between the main bronchi. Th
e axial gas transport in the left main bronchus was 2.3 times as large
as that of the straight tube, whereas the gas transport in the right
main bronchus was slightly larger than that of the straight tube. Thus
localized variation in gas transport characterized the heterogeneous
respiratory function of the lung.