EXPERIMENTAL-STUDY OF TURBULENT-DIFFUSION FLAME STRUCTURE AND ITS SIMILARITY

The interaction between reaction and turbulent mixing strongly affects the structures of a turbulent diffusion flame, the characteristics of which are greatly affected by the combination of working conditions s uch as burner exit configurations, burner size, fuel and oxidant. This study discusses in detail the turbulent diffusion flame structure and its similarity using a laboratory-scale turbulent diffusion flame mea sured by laser Rayleigh scattering. It also discusses the factors affe cting the similarity in flame structure and the turbulent diffusion fl ame length determined using its turbulent power spectral density. The -5/3 power law holds in the fuel jet and combustion regions but in the air entrainment regions, the -5/3 and -1 power laws coexist, and whic h shows that both turbulent and molecular thermal diffusions become im portant. The constancy of the turbulent diffusion flame length at a hi gh Reynolds number is discussed with respects to the characteristics o f flame structure.