High Speed Schlieren Visualization on Explosion Flame Microstructure and Propagation Behavior

To discern flame microstructure dynamic behavior of gas explosion under restricted condition, the premixed methane-air explosion was performed in a semi-vented tube. In the experiment, the schlieren photography system was built to record the explosion flame microstructure and propagation behavior, and the relationship between flame speed and flame structure was discussed in detail. The results show that the regular flame front was stretched inward and separated into several flame fronts during the flame structure change. The phenomenon indicates the original laminar-turbulent transition was accomplished in the period of flame structure change. The inverted flame structure ("tulip flame") appeared in the case of the existence of the flow among the combustion cores when the minimum flame speed was obtained, and the flame speed oscillation was mainly caused by the strong turbulent combustion.