Study on airflow and inhaled particle deposition within realistic human upper respiratory tract

Based on the CT (Computerized Tomography) scanned images of a 19-years-old healthy boy, a realistic geometric model of URT from nasal cavity to the upper six-generation bronchial is rebuilt. To investigate airflow and particle deposition in the obtained realistic human upper respiratory tract, RNG k-ε turbulence model was used to describe the primary flow and particle deposition under three breathing intensity such as 15 L/min, 30 L/min and 60 L/min. The particle is tracked and analyzed in the Lagrangian frame. The velocity fields of airflow under different airflow rates were computed and discussed. The trapping of particles with diameter 1μm on the wall surfaces was monitored, and the locations of trapping in different region were visualized. In order to study the characteristics of particles movement and the effect of particles diameter on the deposition pattern, eleven kinds of sphere particles with different diameters are selected as research object. The diameters of selected particles as follows: 0.1μm, 0.5μm, 1μm, 2.5μm, 3μm, 3.5μm, 4μm, 4.5μm, 5μm, 6.5μm and 8μm. The variation of inhalable particles deposition in realistic human upper respiratory tract with respiratory intensity and particle size was researched and compared.