Temperature dynamics of aluminized cyclotrimethylenetrinitramine fireballs for event classification

Abstract

The remote sensing and classification of battlespace explosions might be improved by developing optical signatures for the heat released during secondary combustion. To explore this possibility, mid-wave infrared spectra (1800 to 10,000 cm −1 ) from the detonation of aluminized cyclotrimethylenetrinitramine (RDX) have been observed and analyzed. The field detonations of 12 high-explosive compositions of RDX with varying aluminum and liner volumes were remotely observed with a suite of imagers, spectrometers, and radiometers. The evolution of spatially averaged fireball temperatures has been estimated from the infrared spectra. The effective temperatures decay from initial values of 1290 to 1850 K to less than 1000 K during a 1-s interval. Secondary maxima are observed in the temperature profiles, indicating delayed combustion resulting from the mixing of atmospheric oxygen with the detonation products. The heat released in the secondary combustion is well correlated with the high explosive and liner theoretical heats of secondary combustion and exhibits an average efficiency of about 50%. Fireball lofting rates increase by more than 50% for events where the combustion heat release increases by a factor of 2.