Initiation of Homogeneous Combustion in a High-Velocity Jet of a Fuel-Air Mixture by an Optical Discharge
V. N. Zudov, P. K. Tretyakov
Khristianovich Institute of Theoretical and Applied Mechanics, Siberian Branch, Russian Academy of Sciences, Novosibirsk, 630090 Russia
Keywords: оптический разряд, гомогенное горение, сверхзвуковая нерасчетная струя, спектрозональная регистрация, теневая регистрация, спектроскопия, optical discharge, homogeneous combustion, supersonic off-design jet, spectrozonal detection, schlieren visualization, spectroscopy
Abstract
The effect of a focused pulsed-periodic beam of a CO2 laser on initiation and evolution of combustion in subsonic and supersonic flows of homogeneous fuel-air mixtures (H2 + air and CH4 + air) is experimentally studied. The beam generated by the CO2 laser propagates across the flow and is focused by a lens at the jet axis. The flow structure is determined by a schlieren device with a slot and a plane sheet aligned in the streamwise direction. The image is recorded by a high-speed camera with an exposure time of 1.5 s and a frame frequency of 1000 s-1. The structure of the combustion region is studied by an example of inherent luminescence of the flame at the wavelengths of OH and CH radicals. The distribution of the emission intensity of the mixture components in the optical discharge region is investigated in the present experiments by methods of emission spectroscopy.
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