Formation and combustion of gas clouds in accidental discharge to the atmosphere

The formation and combustion of a fire-hazardous cloud arising in accidental discharge of a flammable gas is analyzed. A criterion is obtained which makes it possible to identify instantaneous, continuous, and intermediate types of discharge from the known physicochemical properties of the material, vessel and hole configurations, and storage conditions. Relations for the critical hole dimensions corresponding to the boundaries between the different discharge regimes are given. Ranges of parameters for which ignition of the outflowing gas can give rise to a flame or a fireball are established. The most probable limits for the coefficient of fuel participation in the burning fireball for various ignition delays are determined. The results are compared with the available experimental data.