Use of recirculated air curtains inside ventilated rooms for the isolation of transient contaminant

Abstract

An air curtain is an aerodynamic barrier for regional isolation and protection; however, research on its application in ventilated rooms is insufficient. This study investigated the effect of a recirculated air curtain on transient contaminant transport when used inside a room with diluted ventilation. The effects of the discharge air velocity, air intake position, and air curtain position were studied using a numerical method. The results were compared with those of diluted ventilation only. The results showed that even when the air curtain recirculated the polluted indoor air, adding a recirculated air curtain based on traditional ventilation significantly reduced the pollution in the protected zone. The containment effect on pollution initially increased and then decreased as the discharge air velocity of the air curtain increased from 0.5 to 4 m/s. A moderate velocity of 1 m/s for a jet width of 0.06 m acted as an effective aerodynamic barrier, with the average concentration in the protected zone reduced by up to 66 % at 600 s. The air intake of the air curtain strengthened the deflection of the air supply jet and vortex in the region. The air curtain exhibited better performance when the air was recirculated from the floor below it. Reducing the protected area did not significantly improve the regional protection capacity. This study guides the joint design of air curtains and air distribution patterns in healthy indoor environments.