A COMBINED OH ACETONE PLANAR LASER-INDUCED FLUORESCENCE IMAGING TECHNIQUE FOR VISUALIZING COMBUSTING FLOWS/

A combined OH/acetone planar laser-induced fluorescence (PLIF) imaging technique that provides simultaneous visualizations of regions of unb urned fuel and of combustion in a reacting flow is described. OH marks the location of chemical reaction and of combustion products, and ace tone vapor, which is seeded into the fuel stream, marks unburned fuel. A single pulse from an ultraviolet laser is used to simultaneously ex cite both the OH and acetone, and the fluorescence from each is detect ed on separate cameras. Acetone spectroscopy and chemistry are reviewe d to provide a basis for interpreting acetone fluorescence signals in high-temperature combusting environments. The imaging technique is app lied to two nonpremixed turbulent reacting flows to assess the utility of the technique for visualizing the instantaneous flow structure and to illustrate the dependence of the interpretation of the acetone PLI F images on the flow conditions.