Computational Analysis of Inspiratory and Expiratory Flow in the Lung Airway

TL;DR

This study numerically analyzed airflow in pig lung airways, revealing complex flow patterns and differences from human airways, emphasizing species-specific considerations in respiratory research.

Contribution

It provides detailed flow maps and compares airflow dynamics between pig and human airways, highlighting the importance of anatomical differences.

Findings

Complex secondary flow structures observed at bifurcations

Flow morphology differs significantly from human airways

Viscous pressure drops are comparable to human airway studies

Abstract

Inspiratory and expiratory flow in a multi-generation pig lung airway was numerically studied at a peak tracheal flow rate corresponding to a Reynolds number of 1150. The model was validated by comparing velocity distributions with previous measurements for a simple airway bifurcation. Simulation results at different cross sections of the airway tree provided detailed maps of the axial and secondary flow patterns. Flow at the main bifurcation and in many other bifurcations showed complex secondary flow structures. The flow morphology in the pig airways differed from that of simplified bifurcation airway models and that of humans, which is likely due to the large differences in the airway geometry of the different species. The inspiratory pressure drop was calculated, and simulation results suggested that the viscous pressure drop values were comparable to earlier studies in human airway geometries. The reported differences between pig and human airways need to be taken into consideration when generalizing results of animal experiments to humans.