Investigation of the Airflow inside Realistic and Semi-Realistic Replicas of Human Airways

Abstract

Measurement of velocity in human lungs during breathing cycle is a challenging task for researchers, since the measuring location is accessible only with significant difficulties. A special measuring rig consisting of optically transparent replica of human lungs, breathing simulator, particle generator and Laser-Doppler anemometer was developed and used for investigation of the velocity in specific locations of lungs during simulated breathing cycle. Experiments were performed on two different replicas of human lungs in corresponding measuring points to facilitate the analysis of the influence of the geometry and its simplification on the flow. The analysis of velocity course and turbulence intensity revealed that special attention should be devoted to the modelling of vocal cords position during breathing, as the position of laryngeal jet created by vocal cords significantly influences velocity profiles in trachea. The shapes of velocity courses during expiration proved to be consistent for both replicas; however magnitudes of peak expiratory velocity differ between the corresponding measuring points in both the replicas.