EFFECT OF VENTILATION RATE ON DUST SPATIAL DISTRIBUTION IN A MECHANICALLY VENTILATED AIRSPACE

Dust spatial distribution is an important variable to understand the nature of dust transportation and toimplement appropriate control strategies. There is a lack of data on dust spatial distribution in mechanically ventilatedairspaces because of lack of adequate sampling techniques. In this project, a multi-point sampler was used to measure thedust spatial distribution at different ventilation rates in a mechanically ventilated airspace, which was an isothermal andtwo-dimensional flow empty room. Dust mass concentration varied as much as 30-fold between the lowest and the highestwithin the mechanically ventilated airspace. Ventilation rate had a large effect on the dust spatial distribution. Increasingthe ventilation rate reduced the overall mean dust concentration when ventilation rates were lower than 56 air changes/h(ACH). When ventilation rates were higher than 56 ACH in this study, the overall mean dust concentration did not changemuch (<4%) as the ventilation rate increased by 18%. The spatial gradients of dust concentration become relativelylower as the ventilation rate increases. There is a high dust concentration zone in the ventilated airspace, which isimportant for selecting proper locations for air cleaning devices.