Influence of venting coefficient on disastrous effects of aluminium powder explosions

Abstract

Aluminium powder has a very high risk of explosion. To clarify the disastrous effects of the overpressure and high temperatures during an aluminium powder explosion in a constrained space and the distribution of the outdoor safe distance, the explosion and venting processes of aluminium dust in a large-scale building were investigated under different venting coefficients, Kv (Kv = Av/Ap), using computational fluid dynamics (CFD). The results show that although an increase in the venting coefficient can reduce the indoor overpressure and explosion temperature, it can also increase the distance up to which the outdoor overpressure and high temperature can cause damage. Moreover, the distance up to which explosion overpressures can be harmful to personnel and buildings increases with an increase in the venting coefficient. Hence, the safe outdoor distance may be more than 1.5–2 times the fire safe distance listed in the Chinese Code for fire protection design of buildings. The high-temperature damage caused by the explosion also increases with an increase in the venting coefficient. Therefore, the current explosion safety protection distances for aluminium powder production sites need to be revised.