CFD analysis on characteristics of contaminated indoor air ventilation and its application in the evaluation of the effects of contaminant inhalation by a human occupant

CFD analysis was performed to examine the characteristics of contaminated indoor air ventilation in a simplified two-dimensional room model. To evaluate the effectiveness of exhaust openings, we introduced a new index, IECV, showing the effectiveness of contaminant ventilation, using the product of the concentration of the contaminant in the air and the portion of the air vented from an exhaust opening. We then applied these concepts to the more realistic case of inhalation by a human occupant in a room with three-dimensional CFD, assuming the human mouth at inhalation to be an exhaust opening. It was found that the region of inhalation was greatly influenced by the rising stream of air resulting from the heat generated by metabolic activity. Corresponding to the index IECV, we defined another new index, IECI, showing the effects of contaminant inhalation. Using IECI and other factors, the characteristics of contaminant inhalation by an occupant in the room were examined in detail for some common human postures.