Influence of Stacking Powder Kegs on Safe Warehouse Temperatures (De Invloed vande Stapeling van Vaten Kruit op de Veilige Opslagtemperatuur)

摘要

A commonly used safety criterion for the storage of gunpowder is the criticaldiameter. This diameter must not be exceeded by a stored package of gunpowder to ensure that the heat production caused by slow decomposition reactions can be compensated by loss of heat to the surroundings. This safety criterion is normally applied to the size of a single package. However, the cooling effect can be decreased by the close stacking of packages in a storage area, which could render the system unstable. A stack of two layers of twenty-five closely packed drums of powder was modelled using a finite element method and the results were compared with the behaviour of a single drum. The heat flow in the space between the drums was modelled using an effective conductivity of 1 W/mK. The stack had a 10 to 15 deg C lower critical ambient temperature as compared to the single drum. Critical ambient temperatures as low as approximately 50 deg C were encountered. The (effective) conductivity of the powder and the air between the drums are the most important factors that determine the thermal stability of the stack.