Scaled experiments for improving diagnosis of pathological lower airway obstruction

Many lung diseases, such as asthma and chronic obstructive pulmonary disease, are characterized by obstructed airflow, particularly, in the lower airway branches in the lung. Our current work aims to provide a better understanding of the connection between lower-airway obstruction and modifications to the velocity profiles within the trachea as a potential means of pathology diagnosis. To investigate this matter, a transparent patient-specific lung model, resolved down to the 5^th daughter branches and scaled up to 1.8 times the human size, was constructed. 5 independently controlled piston pumps are used to prescribe the flowrate to the different lung lobes, simulating constant inhalation and exhalation processes with both healthy and diseased/obstructed lobar flow fractions. Quantification of the complex 3D flow in the lower trachea is achieved by conducting stereo PIV measurements performed in the coronal midplane and several transverse planes at different elevations. Results obtained under two different Reynolds numbers (1461 and 3506 respective, based upon the bulk flowrate and the tracheal diameter) will be presented, documenting the system performance and examining the detectability of under-performing lobes within the tracheal flow profile.