Hot Spot Mechanism in Bubble Sensitized Commercial Explosives

摘要

Water-gels and emulsions exhibit two fundamental hot-spot mechanisms, namely shock heating of materials surrounding voids and adiabatic compression heating of bubble gases. By a comparison of the reaction kinetics derived from (a) VOD-diameter data using the recently developed computer code CPEX and (b) a reaction model proposed-previously, it is shown that at the detonation regime, the dominant hot-spot mechanism is shock heating and the remaining explosive outside of the hot-spots is consumed by burning as proposed in the model. At the lower compression rates, the dominant initiation sensitization mechanism is the adiabatic compression of the gas in entrained bubbles. This is proven by the results from an experimental impact test on chemically sensitized water-gel explosive. The same mechanism operates in the DDT regime of these explosives. The time to ignition is shown to be related to the time of pressurization in both the impact test and the DDT tests.