Comparison of simplified and actual model of trachea and main bronchi in airflow simulation

Understanding of airflow in human airways is beneficial to medical field. Through the understanding, assessment on severity of airway disease and efficiency of medical inhalation drugs delivery can be assessed. For this purpose, an accurate and realistic human lung model is needed. With the variability in the outcomes based on both models notified, the reliability of the simplified models is questionable. It is the aim of this paper to determine the accuracy of the simplified models against actual human airways. Two models of trachea and main bronchi with different conditions; actual model and simplified were developed for comparison purpose. Different conditions of inspiratory breathing, 5 l/min, 9 l/min, 12 l/min and 15 l/min were imposed at the outlet with different ratio, 55% for right bronchus and another 45% for left. The results showed that the simplified model is reliable to provide accurate result on airflow in the airways. However, the level of accuracy diminished in regions with complex geometry i.e. highly irregular cross-sectional shape, rapid change in cross-sectional area, and around small radius curvature.