Experimental study of premixed methane-air flame propagation in a closed duct with porous obstacle

The propagation and shape of methane-air premix flame in an enclosure with dimensions of 50 × 11 × 8 cm and the effect of porous obstacle with a porosity percentage of 95 with 20 cavities per square inch in the flow path has been studied in a laboratory. The study of flame behavior has been done with high speed camera photography. One side of the enclosure is made of transparent plexiglas with dimensions of 8 x 50 cm for photographing. The pressure variations inside the enclosure are recorded with the help of a pressure sensor and converter located on top of the enclosure. The results for the unobstructed enclosure correctly represent the process of forming the classical tulip flame inside the enclosure. The range of pressure variations has been adapted to the reference samples and has been validated. The location of the porous obstacle has been tested for four different spacings of 5 cm, 10 cm, 15 cm and 20 cm from the spark location. In the chamber without obstacle, the tulip flame at a location of 25 cm from the spark and 50 ms from the time of sparking was created. The results for the four porous obstacle states indicate that the turbulence created in the flow field can change the location of formation of the tulip flame, as well as its formation time. For a distance of 20 cm the porous obstacle from the spark location, the turbulence of the flow field is at its maximum.