The Characteristics of Aerosol Diffusion in a Public Space

Numerical simulation was used to predict the spread of locally triggered virus aerosols in a public indoor environment. The common realizable k-ε turbulence model was used to study the transient diffusion characteristics of aerosols in a public space. Aerosol particles diffused forward and upward over time in a confined space and finally stayed in the air with the indoor circulation. After the particles were ejected, only a few large particles fall to the ground within 15 s, some particles adhered to the wall and the human body in 60 s, and 70.86%(particle number residual rate) of the particles were still in the indoor air. On this basis, a comparative study of three ventilation schemes was carried out, including opposite-side ventilation, upper-side ventilation, and single-side air ventilation of opposite- and upper-side return air. Ventilation conditions destroyed the original indoor circulation, and particles flew out of the exhaust vent along with the airflow. The results showed that the residual rate of indoor particles in the opposite ventilation scheme was 65.40%, that in the upper-side ventilation scheme was 63.22%, that in the single-side air ventilation scheme was 70.32%. Therefore, the upper-side ventilation scheme has a shorter particle transmission distance and a lower residual rate of indoor particles, which is an ideal ventilation scheme for reducing aerosols in a public spaces.