Research On Deposition Characteristics Of Haze-fog Particles In Realistic Human Upper Respiratory Tract

Haze-fog particles seriously jeopardize the human health and life.The human upper respiratory tract is the main passageway for inhaled haze-fog particles damage human health.Understanding the flow properties and deposition patterns of inhalable particles in the human upper respiratory tract can not only help us study the pathogeny of respiratory disease and find the treatments for those diseases,but also propel the development of some respiratory aerosol drugs and instruments.In this paper,the airflow properties and particles deposition characteristics in a realistic human upper respiratory tract were numerically studied.The contents mainly focus on the following aspects:1.Using the realistic human medical CT scanning data,the three-dimensional upper respiratory tract from nose to epiglottis sites has been exactly reconstructed.2.Using the large eddy simulation method,the airflow dynamics in the human upper respiratory tract were studied under three typical respiratory intensities,namely Q = 15 L/min(slight breathing),30 L/min(moderate breathing),60 L/min(severe breathing).Finally,the airflow properties in the realistic human upper respiratory tract are obtained.3.Based on the Lagrangian method,the motion and deposition of haze-fog particles with diameters of d = 0.5 μm,1 μm,2.5 μm,5 μm,10 μm under three respiratory intensities were investigated.The local deposition rate,total deposition rate,and escape rate of the inhalable particles have been statistically analyzed.The particles deposition characteristics in the human upper respiratory are achieved.4.For the large size of inhaled haze-fog particles,the two-ways couplings between fluid and particle phases have been conducted.Moreover,the discrepancies of deposition rates in the human upper respiratory have been analyzed.