Influence to Combustion Characteristic with Time-dependent Mixing Process of Microscopic Structure in Turbulent Diffusion Fiames

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Space- and time-resolved information, as well as macro- and microscopic visualizations, is essential for detailed study of mixing, reaction and heat transfer mechanisms in a turbulent diffusion flame. However, turbulent diffusion flame structures have been studied almost solely by time-resolved single-point measurement due to the restriction of diagnostics. In this study, time-dependent spatial mixing processes in turbulent diffusion flame are visualized by instantaneous flame luminosity and plane Mie scattering images by an ultrahigh-speed video system (Fastcam). It is found that the auto-similarity of the instantaneous turbulent diffusion flame structure has a fractal dimension defined by fractal analysis which appears corresponding to the fractal analysis of the combustion region. Macroscopic movements of the flame region are classified in terms of the instantaneous variations of flame shape. The texture analysis resulted the relationships in flame structures in different areas. Information entropy analysis was used to get its existing probability and gave the information on the existence of wrinkling flame structures.