Formation and Characteristics of Tulip Flame Propagating Through the Premixed Methane/Air Mixture in a Duct

Abstract: In order to explore the formation process and characteristics of tulip flame propagating through methane/air premixed gases in a duct, the techniques of Schlieren, high-speed video camera and micro-thermocouples are used to study the propagating flame in the closed duct. Based on the experimental results, Combustion behaviors and characteristics of the premixed gases are analyzed. The results show that, the period of the tulip flame structure formation is about 20ms and the zone of that is about 6cm in width. The temperature of the tulip flame is higher than that of the laminar flame, which is mainly due to the turbulent combustion in the tulip flame. The turbulent intensity increases greatly after the rarefaction wave interferences the flame front, which make the combustion process in the duct more comprehensive.

Keywords: tulip flame; methane; laminar flame; turbulent combustion; rarefaction wave