Numerical simulation for airflow movement in the human upper respiratory tract

The CFD(Computational Fluid Dynamic)technology was used to investigate the air movement within the human upper respiratory tract.The simulation results were validated by the experimental results based on the PIV(Particle Image Velocimetry)experiment.The results show that the phenomenon of airflow separation appears near the outer wall of the pharynx and the trachea.The high velocity zone is created near the inner wall of the trachea.The airflow splits at the divider and high velocity zone is generated near the inner wall of the trachea.The maximum velocity appears at the exterior of the boundary layer.The secondary swirls and axial velocity distribution result in the high shearing stress acting on the inner wall of the trachea and bifurcation,finally lead to injury on the inner wall.