Explosion propagation in inert porous media

Area of Science:

• Combustion Science
• Fluid Dynamics
• Materials Science

Background:

• Porous media are utilized in flame arresters for their high surface area, crucial for flame quenching.
• Obstructions in porous media can lead to explosion escalation, similar to phenomena in obstacle-laden channels.
• The role of obstructions in explosion propagation is dual: enhancing turbulence and shock-flame interactions while also causing energy losses.

Purpose of the Study:

• To investigate the parallels and distinctions in explosion propagation between porous media and obstacle-laden channels.
• To elucidate the blended influence of heat loss, turbulence, and compressibility on flame propagation in porous media.

Main Methods:

• Comparative analysis of explosion propagation mechanisms in porous media and obstacle-laden channels.
• Examination of the influence of obstructions on turbulence production, shock-flame interactions, momentum, and heat losses.
• Characterization of propagation regimes based on velocity changes and the interplay of physical phenomena.

Main Results:

• Obstructions in both media enhance propagation via turbulence and shock-flame interactions but can suppress it through energy losses.
• Porous media exhibit smoothly blended propagation regimes, unlike the distinct regimes observed in obstacle-laden channels.
• Heat loss dominates at low subsonic speeds, while turbulence and compressibility become significant at higher supersonic speeds in porous media.

Conclusions:

• The blended nature of phenomena in porous media prevents clear transitions in propagation mechanisms, unlike the abrupt velocity changes in channels.
• Above the speed of sound, experiments show a smooth increase in propagation velocity with mixture reactivity in fuel-air mixtures.
• Understanding these blended effects is crucial for designing effective flame arresters and predicting explosion behavior in porous materials.