Influence of polyurethane foam on flame front propagation of hydrogen-air and acetylene-air mixtures in an open channel

Abstract

The motivation for this work is to ensure explosion safety when working with flammable gases. One of the passive methods for suppressing combustion of gases, consisting of the use of porous materials, is considered in this work. The propagation of a flame front of hydrogen-air and acetylene-air mixtures when passing through polyurethane foam was experimentally studied. To reduce the velocity of the unburned mixture ahead of the flame front, the initiation was carried out at the open end of the channel. In this event, the foam skeleton has a general effect on the propagation of the flame and not on the flow of the unburned mixture. The flame front velocity was determined with a high-speed camera using the shadow method. It was shown that the flame front does not pass through polyurethane foam containing 45 and 80 pores per inch (ppi). However, the use of foam with 10 and 30 ppi resulted in an acceleration of the flame front, up to 200 m/s for acetylene-air and 550 m/s for hydrogen-air mixtures. It was shown that the relative increase in the velocity of the flame front varied exponentially depending on the length of the foam. The exponent was determined for both mixtures.