Sun Dong

Creation of standardized geometric model of the human upper respiratory airway

A novel, standardized geometric model of the human upper respiratory tract was created by aligning and processing the computed tomography (CT) scans of upper respiratory airway of healthy subjects. Digital three-dimensional (3-D) geometric model of 3 single human upper respiratory airway were generated from the CT scans and a methodology was developed to scale, orient, and align the models, after which 2-D digital coronal cross-section slices were generated. With the use of an image processing algorithm, median cross-sectional geometries were created to match median physical parameters which retaining the unique geometric feature of human upper respiratory airway. From these idealized 2-D images and the original image-fusion model was created. Then, the statistical data of human upper respiratory airway was used to scale the model and to get the standardized model. Compared to the simplified model, the standardized model is more similar to the real human upper respiratory tract in the completeness of structural characteristics and the reality of geometry, the deviation degree of key dimension is only 0.16, and it possesses more application value in scientific research.

Influence of Vortex Evolution in Human Mouth and Throat to the Diffusion of Virus Aerosol

Revealing the influential action of vortex evolution in human upper respiratory tract on diffusion of virus aerosol has great significance for the prevention and treatment of respiratory tract diseases. Large eddy simulation was used to simulate the vortex structure and the diffusion of virus aerosol in human mouth-throat model in cyclic respiratory pattern, and the vortex evolution in mouth-throat model with the trajectories of aerosol particles was discussed in this paper. The results show that the trajectories of virus aerosol particles congregate in regions with higher airflow vorticity affected by the vortex evolution in mouth-throat model. Due to the joint influence of transverse and longitudinal vortex, the helicoidal trajectories combined annular and wavy trajectories of aerosol particles appear in the model. This study disclosed the relationship between the vortex evolution and the diffusion of aerosol in human mouth and throat from the microcosmic angle, which provides a new way for deepening understanding of the propagating characteristics of virus aerosol in human upper respiratory tract.