Study On Flame Structure And Propagation Characteristic Of Methane And Coal Dust

The frequent gas and coal dust explosion accidents in coal mine is a big threat to the life and property. To ensure the safe production in coal mine, it is necessary to understand the process of explosion, and to disclose the intrinsic mechanism of the explosion accidents detailedly and fully.In the study, the flame structure experimental system was set up. The system can be used to study the flame structure and propagation mechanism of gas flame, dust flame and hybrid flame.The ignition of the coal dust in air with the system was firstly studied in open tube, and then, the premixed flames of methane and air in the close tube were studied. At process of the premixed flames propagation, the initial spherical flame fronts were transformed into tulip flame under the certain condition. The creation of tulip flame has a relationship with the volume percent of methane in the tube. The tulip flame can be formed only when the equivalence ratio is in a certain range. The decrease of the flame area due to touching the side wall is one of the reasons that form the tulip flame.Minimum explosive concentration (MEC) of the coal dust in the mixture of coal dust and methane was determined under different conditions. The propagation characteristics of the hybrid flame were analyzed through high speed camera, fine thermocouple, ion probe, diode and et al. The results show that the MEC of the coal dust is reduced at the presence of methane. The diameter of coal dust has lower influence on...