Numerical Study on the Deposition Characteristics of Particles in a Human Upper Respiratory Tract Model

The flow field of a simplified human upper respiratory tract was simulated by using the RNG k-e turbulence model.A stochastic eddy interaction model was applied to solve the local movement and deposition characteristics of particles.The results showed that for micrometer-sized particles,the inertial impaction is the main deposition mechanism and the inertial parameter is a good indicator for measuring the deposition of particles.The airflow in oral was smooth and the particles were slightly disturbed.In pharynx region,due to inertial impaction the particles moved close to the rearward of pharynx and were more liable to deposit on the posterior wall of pharynx.The maximum local deposition fraction in pharynx can reach 89%.The region with higher axial velocity was near the anterior wall at cross sections in trachea.In these regions,particles were concentrated.The particles with diameter larger than 10μm can deposit more in oral and pharynx.Furthermore,more fnutions of the particles released from middle and bottom oral can reach the deep lung zones through the trachea.