Exploring the effects of reactive additives in explosives In search of higher efficiency with various energetic combinations

摘要

The energy available for useful work in C,H,N and O explosive materials has for the most part plateaued with the synthesis of dense nitramines such as hexanitrohexaazaisowurtz-itane (CL-20). In order to obtain higher overall energy, reactive additives can be formulated with various explosive materials, such that significant gains can be obtained. Powdered aluminum is a common additive to energetic materials, but little is understood regarding its reaction rate at very high temperatures as well as high pressures in specific oxidizing gases such as carbon dioxide or water. When looking at other materials, such as physical mixtures or alloys containing silicon or boron, even less is understood due to difficulties in the study of particulate oxidation at the high pressures and temperatures in detonation reaction zones. To study these reactions, small particle size reactive materials (Al, B, Si, AI/PTFE and MgB) or the inert surrogate, LiF, was added to various energetic material including HMX, CL-20, benzotrifuroxan (BTF) and hydrazinium ni-trate/hydrazlne eutectic and performance of the formulations were evaluated. High-fidelity detonation velocity diagnostics were utilized to determine reactive material contribution in the detonation reaction zone and PDV measurements allowed determination of the contribution from these additives in the expanding product gases via early wall velocity expansion measurements in 12.7 mm diameter copper cylinders. Both thermal equilibrium calculations and solutions of the JWL equation of state were used to determine temperature, pressure and energies at specific time periods, in addition to Gurney energies, which enables the elucidation of reactive material reaction extent. Comparison of this oxidation with the inert formulation data indicates that oxidation can occur on an extremely fast time scale, beginning and completing between one and 25 microseconds in some cases.