Effects of the Coherent Vortex on Combustion in Jet Diffusion Flames

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1. The combination of the schlieren and the Mach-Zehnder method was applied to make clear an effect of the coherent vortex on combustion in jet diffusion flames. Application of this method to jet diffusion flames have shown that an effect of the center vortices is restricted just near the flame base and an effect of the boundary vortices extends over a wider region through the mixing with the surrounding air. Moreover, whereas the correlation between the temperature and the OH emission intensity is small at the position where the center vortices exist, the center vortices on the schlieren photographs are identified as the boundary between hot and cool gases which is occupied mainly by the fuel. However, the center vortices work for the stabilization of both the attached and lifted flames.2. The flame structure on the early stage of flame formation has been discussed in two-dimensional reacting mixing layr by a numerical analysis. The effects of velocity difference and of dilution fuel on its structure has been specifically. Flames are formed in the low-speed oxidizer side of the mixing layr, which is formed by a high-speed fuel flow and a low-speed oxidizer flow behind the split plate. The heat release reaction takes place mainly at the leading edge. The increase in velocity difference enlarges the scale of the vortices, to act as a quenching of flame, and to blow flame off.