Energy and blast performance of beryllium in a model thermobaric composition in comparison with aluminum and magnesium

Abstract

A direct comparison is made between the effectiveness of Al, Mg, and Be powders as additional fuels in model thermobaric compositions containing 20% fuel, 20% ammonium perchlorate, and 60% RDX (1,3,5-Trinitro-1,3,5-triazacyclohexane) passivated with wax. Experimentally determined calorimetric measurements of the heat of detonation, along with the overpressure histories in an explosion chamber filled with nitrogen, were used to determine the quasi-static pressure (QSP) under anaerobic conditions. Overpressure measurements were also performed in a semi-closed bunker, and all blast wave parameters generated after the detonation of 500 g charges of the tested explosives were determined. Detonation calorimetry results, QSP values, and blast wave parameters (pressure amplitude, specific and total impulses) clearly indicate that Be is much more effective as an additional fuel than either Al or Mg in both anaerobic post-detonation reactions as well as the subsequent aerobic combustion. The heat of detonation of the RDXwax/AP/Be explosive mixture is over 40% and 50% higher than that of the mixture containing aluminum and magnesium instead of beryllium, respectively. Moreover, the TNT equivalent of the Be-containing composition due to the overpressure in the nitrogen-filled explosion chamber is 1.66, while the equivalent calculated using an air shock wave-specific impulse at a distance of 2.5 m is equal to 1.69. The high values of these parameters confirm the high reactivity of beryllium in both the anaerobic and aerobic stages of the thermobaric explosion.