Covid-19 is transmitted through droplets containing the virus and very small particles exhaled by infected people. These droplets and particles may be inhaled by others, or fall into their eyes, mouth and nose. In some cases, they may contaminate the contact surface. It is most likely to be infected if they are less than 1m away from the infected person. To evaluate the effects of different air conditioning systems on the spread of human exhaled pollutants, computational uid dynamics (CFD) was used to study the movement and diffusion of exhaled air from two rows of 12 sitting adults in a hospital's closed transfusion room. In this paper, a closed transfusion room with 12 human models was established rstly, and the mathematical model veri ed by experimental test results was used to study the propagation of viral aerosol particles in the enclosed space under different air conditioning systems. The result showed that when the transverse strong air ow is generated in the room, the concentration distribution of virus particles will show a roll like distribution, and the personnel inside the roll will cause new infection. The air ow generated by the air conditioning system will affect the dispersion of droplets in the air. Evaluating and guiding the air ow to avoid blowing air from one person to another may reduce the risk.
Article Highlights1. The air conditioning system inside the enclosed space can reduce the risk of virus cross infection.2. New infections can be triggered by strong lateral air ow generated by indoor air conditioning systems.3. Setting the air ow reasonably to avoid blowing air from one person to another may reduce the risk.