Abstract
A series of field explosion experiments of hydrogen-air mixtures were carried out. The mixtures were accumulated in plastic greenhouses and ignited by electric spark or by high explosive detonation. The sound generated by these explosions were measured over a wide range. The sound pressure waveform and frequency spectrum were compared among the cases of spark ignition and high explosive ignition of hydrogen-air mixtures, together with the cases of high explosive explosion in free air, and the relationship between the peak sound pressure/frequency and scaled distance was revealed. It was found that the cases of high explosive ignition of hydrogen-air mixtures and the cases of high explosive explosion in free air showed almost the same sound pressure characteristics, but the cases of spark ignition showed significantly different sound pressure characteristics.
