Digital imaging of reaction zones in hydrocarbon–air flames using planar laser-induced fluorescence of CH and C_2

Abstract
A method for instantaneously imaging the position of the reaction zone in hydrocarbon–air flames is described. The technique is based on planar laser-induced fluorescence of the combustion radicals CH and C2. Using a Nd:YAG-pumped dye-laser illumination source, fluorescence images were recorded with an image-intensified 100 × 100 photodiode array camera. Results are presented for acetylene–air and ethylene–air gaseous flames as well as for a heptane–air spray flame. Details of excitation–detection strategies and fluorescence yields are discussed.