Experimental investigation of shear coaxial cryogenic jet flames

This paper reports results from experiments carried out on the jet name for med from a single coaxial injector. This device was fed with Liquid oxygen and gaseous hydrogen and placed in a chamber equipped with quartz windows. The flame is observed with a set of optical methods: light emission from OH radicals, laser-induced fluorescence of OH and O-2, elastic, and Raman sca ttering from the liquid-oxygen jet. These techniques are used to obtain ima ges of the name zone. It is then possible to deduce the name location with respect to the liquid jet from simultaneous elastic scattering and laser-in duced fluorescence of OH measurements. Average emission images treated with Abel's transform provide the local volumetric light emission from OH radic als, This yields the mean flame structure and constitutes a different metho d for locating the flame. The images obtained by exciting the fluorescence of O-2 provide complementary information on the flame shape and they may be used to estimate the local reaction rate. Quantitative temperature measure ments based on coherent anti-Stokes Raman scattering from H-2 give addition al dues on the combustion zone. These data may be used to develop a unified picture of the name in the vicinity of the injection plane.