Explosion waves and shock waves. IV—Quasi-detonation in mixtures of methane and air

Abstract

The possibility of detonation in mixtures of methane and air, apart from its theoretical interest, is of practical importance in connexion with the study of explosions in coal mines. Many attempts have been made experimentally to increase the violence of explosion or the intensity of combustion of mixtures of methane and air to see if speeds of flame and effects of violence comparable with those of detonation could be obtained. Mason and Wheeler noted that restrictions in the path of an explosion accelerated the flame, and observed that as the flame of a methane-air mixture passed through the second of two restrictions placed in a 30·5-cm. tube “the development of the detonation wave appeared imminent”. The experiments were continued by Chapman and Wheeler, who obtained a maximum speed of 420 metres per second beyond the restricted section of a tube 5 cm. in diameter. The effect of the restrictions was in their opinion to induce rapid motion in the mixture through which the flame was travelling.