Simulations of Highly Concentrated Droplet Transport and Deposition in an Idealized Mouth-Throat Airway Model

Yu Liu, XIAOLE CHEN, Nanjing Normal University

     Abstract Number: 268
     Working Group: Health-Related Aerosols

Abstract
Previous experimental studies have found that the deposition fraction of high-concentfractionn droplets generated by a nebulizer in an idealized mouth-throat model decreases first and then increases with increasing inhalation flow rate. Theoretical analysis suggests that this phenomenon is due to the increased humidity of the inhaled air caused by the evapofractionn of high-concentfractionn droplets, which inhibits further evapofractionn of the droplets. This numerical simulation uses a small number of calculation particles of different diameters to replace actual droplets and calculates the amount of vapor exchanged between the droplets and the environment by multiplying the substitute fraction. Based on the earlier droplet/particle-vapor interaction model, the simulation of the transport and deposition of high-concentfractionn monodispersed droplets generated by a vibrating mesh nebulizer in an idealized mouth-throat airway model was achieved. The deposition fraction of droplets varies with the inhalation flow rate, consistent with experimental results, thus validating the theoretical analysis. The study also analyzed the influence of environmental temperature and humidity on droplet deposition. The results show that the higher the mass fraction of water vapor in the environment, the higher the deposition fraction of droplets in the mouth-throat model, and the larger the average droplet diameter at the outlet.