Effect of Precompression on Detonation Performance and Products of Energetic Materials: Application to CL-20

Abstract

The initial pressure plays an important role in the energy behavior of energetic materials (EMs) during combustion or detonation, but difficulties in experimental monitoring and the lack of equation-of-state data in numerical models make the effects of high initial pressure hard to estimate. To investigate the effects of preloading on the thermodynamic properties of CL-20, quantum mechanics (QM) calculations were performed under external pressures ranging from 1 atm to 50 GPa. As the pressure rises, the density increases from 2.04 g/cm 3 to 3.38 g/cm 3, and the enthalpy of formation increases to 1842 kcal/mol. To understand the effects of preloading on detonation properties, a combined simulation method of reactive molecular dynamics (RMD) and quantum mechanics molecular dynamics (QM-MD) was performed at two precompression pressures of 6.4 and 21.2 GPa. The calculated Chapman–Jouguet (CJ) properties indicated that compared to the uncompressed system, a 44.5% increase in density at precompression of 21.2 GPa leads to a doubling of the CJ pressure, an over 8% increase in detonation velocity, and an approximate 1000 K decrease in CJ temperature. Thus, introducing precompression is a promising way to increase the external energy delivery capability of EMs.