Influence of the Region Outside a Vent on the Explosion of an Indoor Gas

The overpressure and flame generated in the explosion of a gas in different regions of a room outside a vent in it were investigated using computational fluid dynamics. The calculation data obtained were compared with the corresponding results of earlier large-scale experiments on this subject, and they show that the smaller the distance from the vent, the larger the oscillations of the indoor overpressure and that the outside region of the vent substantially influences the indoor explosion flow field. It was established that, as the outside-region length increases, the peak indoor overpressure approaches the experimental one, but the amplitude of the overpressure oscillations caused by the Helmholtz and Taylor effects increases substantially in this case. The numerical simulation of the explosion hazard of a ventilated gas in a room seems reasonable in the case where the outside region of a vent is not shorter than the room.