Investigation on the respiratory airflow in human airway by PIV

The creation of the accurate transparent flow passage is essential to analyze the flow inward a geometrically complex flow passage like human airway by PIV. We have established the procedure to create a transparent box containing a model of the human airway for PIV measurements. A flow passage includes the whole human upper airway, nasal cavities, larynx, trachea, and 2 generations of bronchi. The phase averaged mean and RMS velocity distributions in sagittal and coronal planes are obtained for 7 phases in a respiratory period by tomographic PIV. Some physiologic conjectures are obtained. The main stream went through the backside of larynx and trachea in inspiration and the frontal side in expiration.