Preliminary Study for a New Dust Wind Tunnel: Small Scale Testing

Abstract

Wind tunnel testing is important for aerosol sampling studies. The goal of this study was todesign a wind tunnel that meets the USEPA requirements: the maximum deviation of both theaerosol concentration and the velocity from the mean should be less than 10% at the cross sectionalworking area. Several challenges are associated with the wind tunnel design. First, the design of theair mixer is difficult since there is few scientific relationship between the mixing efficiency and the mixing distance. Second, if a big wind tunnel is built using a poor design, it will be expensive andtime consuming to modify or rebuild it. Therefore, a 1:5 scale tunnel was built to predict the behaviorof the full-scale module. From the experiments carried out in the small wind tunnel, a Generic TeePlenum System (GTPS) was found to be a good mixer with a coefficient of variance (COV) of 2.5%in the testing area. When employing a modified shape inlet to the GTPS or adding a double airblender downwind of the GTPS, the deviation of the velocity from the mean was found to be lessthan 10%. Based on the result of the small scale test, a full-scale wind tunnel has been built. It isexpected that the full-scale wind tunnel will meet the USEPAs requirements with few modifications.