Gaseous Contaminant Diffusion Under Stratum Ventilation

Numerical methods are utilized to study the diffusion of gaseous contaminants under stratum ventilation, and experimental validation is conducted. The findings indicate that the concentration of gaseous contaminants along the supply air jet is lower compared to other areas of the room. When compared with displacement ventilation, lower formaldehyde concentrations are observed in the breathing zone when the contaminant source is situated near the occupant, while similar concentrations are found when the source is upstream of the occupant. Furthermore, concentrations in the occupied zone (within 1.9 m from the floor) are lower when the contaminant source is located on the floor. However, when the supply air temperatures are optimized for displacement ventilation, the toluene concentration in the breathing zone is higher under stratum ventilation than under displacement ventilation when the area source is positioned on the four surrounding walls of the room.