Experimental Study of Turbulent Diffusion Flame Structure and Its Similarity

Abstract

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 such 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 measured by laser Rayleigh scattering. It also discusses the factors affecting the similarity in flame structure and the turbulent diffusion flame 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 which shows that both turbulent and molecular thermal diffusions become important. The constancy of the turbulent diffusion flame length at a high Reynolds number is discussed with respects to the characteristics of flame structure.