Experimental Investigation of Shear Coaxial Cryogenic Jet Flames

This paper reports results from experiments carried out on the jet  ame formed 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  ame is observed with a set of optical methods: light emission from OH radicals, laser-induced  uorescence of OH and O2, elastic, and Raman scattering from the liquid-oxygen jet. These techniques are used to obtain images of the  ame zone. It is then possible to deduce the  ame location with respect to the liquid jet from simultaneous elastic scattering and laser-induced  uorescence of OH measurements. Average emission images treated with Abel’s transform provide the local volumetric light emission from OH radicals. This yields the mean  ame structure and constitutes a different method for locating the  ame. The images obtained by exciting the  uorescence of O2 provide complementary information on the  ame shape and they may be used to estimate the local reaction rate. Quantitative temperature measurements based on coherent anti-Stokes Raman scattering from H2 give additional clues on the combustion zone. These data may be used to develop a uniŽ ed picture of the  ame in the vicinity of the injection plane.