In silico analysis of airflow in a single path configuration of the pulmonary tree

This paper presents a lung model that allows the simulation of the airflow down to level 23 (alveoli). The flow trajectory along only one of every two airways at each bronchiole is calculated. The non-calculated airways are simulated by a User-Defined Function that prescribes the velocity profile at a surface located inside the calculated airway to the exit boundary of the truncated airway. The model is validated with experimental data of a real spirometry and it is used to predict the performance of a lung with bronchitis. The results show a decrease of the volume of air of about 13% with typical values of FEV1/FVC around 70.8% for the healthy lung and about 67% for the lung with bronchitis. This methodology can be adopted to simulate a full model of a human lung under healthy and bronchitis conditions while providing a practical description of the flow field within the lung.