Fire Safety Science Digital Archive

Development of large-scale fireballs is a typical result of explosions associated with accidental fuel releases. One of the possible mechanisms, which can lead to fireball formation, is a vapour cloud explosion. Such events occur in the chemical and process industries and often result in huge property damage and human casualties. The present paper consists of two parts. In the first part, a simple model is proposed to estimate a rate of surrounding air entrainment into a rising fireball. The model is applied to estimation of the mass of fuel involved in the explosion. The results are compared to CFD modeling of the problem. In the second part, estimation is made of possible use of the entrainment effect for mitigation of fireballs. It is shown that the typical rates of air entrainment are sufficient to deliver significant amounts of fire suppressant, such as aerosols, into the core of a fireball.