Comparison Studies of Hydrogen Flame in Cocurrent Supersonic Air Flow during Registration of Radiation in Different Spectral Ranges

Results of the experiments are given in which optical methods are used to investigate the pattern of hydrogen burnout in the case of burning in a cocurrent supersonic off-design (overexpanded) air jet. The images of flames are compared during the registration of hydrogen–air flame radiation in the ultraviolet, visible, and infrared wavelength ranges. Analysis of the obtained data reveals that the radiation of OH radical in the ultraviolet range allows the most accurate determination of the structure of heat release zones, the flame boundaries, and the completeness of combustion in the given conditions. Conclusions are drawn about the possibilities of obtaining quality information about the combustion zones by registering the flame radiation in the visible spectrum and excited H₂O molecules in the infrared region.