Visualization of Flame Propagation and Quenching of Methane/Air Mixture in a cubic enclosure with Perforated Plates: Experimental Study

Flame Propagation in closed chambers is one of the most important process in the industry which may lead to a severe damage in the systems. The purpose of this study is to observe the flame propagation process of methane/air mixture and to investigate the flame velocity using perforated plates in a cubic enclosure. The experiments are performed at atmospheric pressure. The flame front of the methane/air mixture is visualized by using a high speed camera. In this study, perforated plates are used with hole sizes of 5 mm, 4 mm, 3 mm and 2 mm. by increasing the hole size of the perforated plates, the velocity of the flame increases after hitting the perforated plates. Therefore, in the case of a hole diameter of 5 mm in the perforated plate, the maximum flame tip speed (i.e. 12 m/s) is recorded. By increasing the hole diameter (between 2 mm to 5 mm), the absolute pressure generated by combustioninside the chamber is augmented up to 2.97 (bara). In addition to considering the effect of the hole diameter of perforated plates, the effects of the position of perforated barriers (quenching distance) on flame progress, flame velocity, combustion chamber pressure and flame quenchingare investigated. Also, flame quenching patterns (head on and sidewall) arevisualized and the effects of the position of obstacles from the spark plug on changing the flame quenching patterns are analyzed. By visualization of the quenching process of premixed flame in the presence of perforated plates, both head-on quenching, and sidewall quenching are analyzed by using nondimensional groups. According to the results, by increasing distance of the perforated obstacle from spark, the flame quenching pattern changes from head-on mode to side-wall mode. The quenching mode, in this condition, is related to the flame Reynolds number.