Wind Tunnel for Odour Sampling from Area Sources
The wind tunnel used for odour sampling from area sources, is a portable emission hood with open bottomed enclosures which are placed over the emitting surface.
The up-to-date version of UNSW wind tunnel is as shown in Figure 1.
Figure 1 Up-to-date UNSW wind tunnel
When sampling, filtered ambient air is blown or drawn (the blown option is better) through the tunnel to mix with the emissions from the source surface. Concentrations in the exhaust stream and the air velocity at the sampling point are used to estimate the emission rate.
It is recommended that the portable wind tunnel be made with stainless steel, which makes it easy to be clean. The chance of air leakage around the base of the tunnel can be eliminated by submerging the edges of the tunnel base into the source surface. For sampling on a solid surface, some sealing material like sand can be used to seal the outsides of the tunnel base.
To collect odour samples from a liquid surface, supporting floats constructed from PVC pipe are needed to make the tunnel seating just on the liquid surface.
If you want to know more about the wind tunnel design, please go to UNSW Wind Tunnel Dimensions page.
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