Heat of Detonation of Aluminised Explosives

摘要

Aluminium is a highly energetic material that releases large quantities of heat during combustion. It is commonly added to explosives to enhance both air blast and underwater detonation performance. The aluminium reacts behind the reaction front, during the expansion of the detonation products and behaves largely as an inert material with little contribution to enhancing the detonation front. Nanometric aluminium grades such as Alex, however are known to react more rapidly than conventional aluminium grades in explosive compositions. The heat of detonation of an explosive is a measure of the chemical energy content of the explosive. To better understand the behaviour of aluminium in a non-ideal detonation process and the influence of Alex upon non-ideal detonation in the aluminised explosives, heat of detonation and Chapman-Jouget (CJ) parameters were calculated with different mass fractions of the aluminium frozen (thus limiting the amount of aluminium reacting in the detonation front) to provide a means of estimating the amount of reacting aluminium that supports the propagation of detonation. The Lawrence Livermore National Laboratory's (LLNL) thermochemical code CHEETAH 2.0 has been used for calculations. Two non-ideal explosive formulations, TNT/Al 70/30 and TNT/Al 80/20 were studied. The computed heats of detonation were also compared with available experimental data. It was found that approximately 66% of the Al reacted with detonation products in TNT/Al compositions. Better correlation with the experimental results was achieved when using the "NEWC1" library. Heat of detonation and CJ parameter calculations were also performed using CHEETAH for another non-ideal explosive H6 (RDX/TNT/Al/Paraffin 44.15/29.31/20/6.54).