Acetone laser induced fluorescence for low pressure/low temperature flow visualization

Acetone fluorescence provides a useful way to visualize the fluid mixing pr ocess within supersonic wind tunnels, some of which operate in the low temp erature (240-300 K) and low pressure range (0.1-1 atm). Measurements are pr esented to quantify the dependence of the acetone laser induced fluorescenc e (LIF) signal on temperature and pressure in this range. The temperature a nd pressure sensitivity of the acetone LIF signal resulted in less than an 8% variation over the experimental conditions for a laser excitation wavele ngth of 266 nm. Condensation of the acetone vapor was identified as a poten tial problem for this diagnostic technique. Methods to prevent and check fo r condensation are discussed.