Detonations Supported by Physical Explosions of Liquefied Gases

The possibility of detonation of gas/droplets mixtures due to phase change (without chemical reaction) is examined by using one-dimensional analysis. The Chapman-Jouguet point is shown to be reached through volume gain by vaporization of liquid droplets. The existence of a lower liquid temperature limit below which such detonation cannot occur is demonstrated. This temperature, which provides a measure for safety in the transportation or storage of cryogenic liquids, defines a material constant to be compared with the boiling temperature. For most liquids, the temperature is higher than the boiling temperature; they are not hazardous except under superheated conditions. For some liquids, such as benzene, ethylether or freon, it is lower than the boiling temperature, which demonstrates the existence of a detonable temperature range without superheating. The propagation velocity of the ChapmanJouguet detonation under an idealized condition of sufficiently small droplet size and instant vaporization through leading shock wave is calculated. Factors causing failure in the onset of detonation are discussed.