Research of detonation products of RDX/Al from the perspective of composition

Abstract

Aluminized explosives exhibit excellent performance because the oxidation of aluminum (Al) powders enhances the pressure and temperature of detonation products. However, the equation of state (EOS) of detonation products has not been understood well. In the present study, we conducted long-time tests (approximately 1 ms) of a metal rod driven by detonation products of RDX, RDX/LiF, and RDX/Al. In addition, we used laser velocimetry (PDV) to measure the freesurface velocity of the rod. Thermochemical code DLCHEQ was successfully applied to the hydrodynamic program SSS to perform the rod-driven test, and a novel method was established to study the EOS of detonation products from the perspective of composition. The reliability of DLCEHQ was validated by a small deviation (<10%) between the experimental rod free-surface velocity of RDX and the calculated results; the deviation was considerably less than that from the results obtained using the JWL EOS and ideal-gas EOS. The endothermic process and the reaction of Al powders (Al+H2O+NO+CO2→CO+H2+N2+Al2O3) were analyzed by calculating the rod free-surface velocity of RDX/LiF and RDX/Al, respectively. The results of the present study demonstrated that the thermodynamic state of Al powders has notable influence on the EOS of aluminized detonation products, and the findings were compared with those of previous studies. First, the temperature equilibrium between Al powders and CHNO products is not always achieved, and the disequilibrium is more obvious when the reaction of Al powders is stronger. Second, the reaction rate of Al powders depends on pressure and Al content. Finally, the endothermic process of Al powders has a high contribution to the decrease in the work ability of RDX/Al instead of the gasconsumption mechanism of the Al reaction. More than half of the reaction heat of Al powders is used to heat itself, whereas the gas consumption during the reaction is negligible.