Modeling the Evaporation and Dispersion of Cough Droplets in an Office Room under Different Ventilation Methods

The transmission of respiratory droplets, especially in confined indoor spaces like offices, has gained heightened attention in the context of public health. Reasonable ventilation is one of the effective ways to improve indoor air quality and ensure the comfort of indoor environment. In this study, the effects of three different ventilation systems on indoor air flow organization and thermal comfort were simulated using the experimentally verified RNG model. Considering the thermal effect of human microenvironment and its interaction with the surrounding environment, the diffusion laws of indoor aerosol particles were compared and analyzed. The results of the study showed that although natural ventilation in the transitional season could enhance the air feeling of indoor people, it had a significant effect on the removal of aerosol particles exhaled by indoor infected patients, and almost all of them could be discharged after 20 seconds of ventilation. DV and UFAD had obvious temperature stratification, and DR less than 10% in summer and less than 15% in winter. In summer, a small air supply temperature difference or a large air supply speed in both DV and UFAD modes is conducive to the rapid discharge of aerosol particles, and the removal effect of DV is better. In winter, the removal effect of aerosol is decreased under both ventilation systems. Comparing the two mechanical ventilation systems, it is found that the DV system can discharge 89% of indoor aerosol particles in a short time (100 seconds). The findings is help to deeply understand of the indoor airflow structure and aerosol pollutant diffusion characteristics under different ventilation modes, and provide scientific reference and methodological guidance for reasonable selection of indoor ventilation modes to optimize indoor air quality.