High-speed schlieren photography of confined gaseous explosions

The tempo-spatial evolution of the combustion kernel in gas phase explosions was experimentally investigated using millisecond-resolution Schlieren photography. Methane and propane -air explosions were initiated in a cylindrical explosion vessel at a range of equivalence ratios ranging from 0.6 to 1.4. All explosions were initiated using a 25 mJ ignition energy source at ambient conditions. The explosion kernel growth rate and cellular flame structure are observed and analyzed. The growth of the primary flame kernel in propane-air explosions was found to be slower than that of the methane-air explosions, for lean mixtures. The opposite was found for stoichiometric and rich mixtures. The establishment of the cellular structure was found to occur after a certain period of time, which varies according to the fuel type and equivalence ratio. Keyword: Combustion; Explosion; Gas