Micro Wind Tunnel for Hazardous Chemical Fate Studies

A special micro wind tunnel has been designed specifically to measure the release and retention (i.e., Fate) of hazardous chemicals deposited on natural and man-made material substrates such as glass, sand and concrete. The data will be used to predict hazard levels associated with chemical warfare defense, terrorist attacks, pesticides, and other chemical related environmental issues. The tunnel’s 5-cm square test section allows the tunnel to operate within a standard chemical laboratory fume hood, enabling it to test actual hazardous chemicals. A key feature of the wind tunnel is its ability to provide a specified vertical velocity profile, temperature and relative humidity (simulating the natural environment) for a sustained time period ranging from hours to weeks. Associated instrumentation measures the time history of the vapor released during the evaporation of the chemical from the material substrate. The wind tunnel combines a full-scale, velocity profile produced by a wind-induced, atmospheric boundary layer; a full scale chemical drop and a full scale material substrate, differentiating it from environmental wind tunnels where scaling is required. The capability to test a single drop of chemical provides unique insights into the fundamental phenomena involved. The paper describes the design, operational use and resulting data for the 5-cm Wind Tunnel.