Identification and preliminary design of dyes and extraction techniques for diffusion modeling in a prototype freon atomospheric boundary layer simulation tunnel

Diffusion modeling in a water tunnel is a frequently used technique to predict the path and relative concentration of a spilled contaminant in the atmosphere. This technique involves injection of a dye into the tunnel and measurment of its position and concentration along the dispersion path. One illustration of this technique is the prediction of the dispersion path of the space shuttle's plume at Kennedy Space Center, Florida, and Vandenburg Air Force Base, California. Due to the temperature constraints imposed on diffusion modeling in a water tunnel, development of a prototype Freon tunnel is being considered. The types of dye best suited for diffusion modeling in Freon are discussed in this thesis. Combinations of dye and Freon to simulate lighter-than- and heavier- than-air spills are also briefly described. Due to the relative cost of the Freon, various techniques are discussed on how the dye can be extracted such that the Freon is reusable.

Criteria were first established to define those characteristics of dyes best suited for diffusion modeling in a Freon tunnel. Hundreds of dyes were researched for suitability but only those dyes with characteristics meeting the established criteria were recommended for use. Guidelines and illustrations were identified for mixing dyes with various Freons to simulate the range of atmospheric diffusion processes which are of interest for simulation. Several separation and filtration techniques were researched to identify the best and most practical procedure for extracting the dye from the Freon.