Porous media quenching behaviors of gas deflagration in the presence of obstacles

•Ten cases have been examined.•Obstacles may cause a failure in the operation of porous media quenching.•Porous media quenching performance is dependent on the number of the obstacles.•Porous media material has a significant effect on the quenching characteristics.•Mechanisms for the observed phenomena are detailedly discussed. To understand the mechanism for the porous media quenching of gas deflagration in the presence of obstacles, an experimental study has been conducted, and ten cases in a laboratory scale obstructed chamber varying in terms of the number of obstacles, porous media pore size, thickness, and material have been examined. The results show that if the premixed flame propagating away from an ignition source encounters obstacles before the flame front arrives to the porous media, the interaction between flame and obstacles will result in higher flame speed and overpressure, which may cause a failure in the operation of porous media quenching. The porous media quenching behavior is dependent on the number of the obstacles in the flame path. Moreover, the smaller the pore size or the thicker the porous media plate, the better the flame quenching performance, but the larger the drop of the overpressure for flow-through the porous media. The material of the porous media is also found to have a significant effect on the quenching characteristics of gas deflagration. Compared to Al2O3 and SiC, the Al porous media shows superior flame quenching and overpressure attenuating performances. Mechanisms for the observed phenomena are discussed in detail.