Evaluating Mixing Length Scale using Coaxial Explosive Composites

Blends of explosive formulations with different characteristics may provide the means for a formulator to balance safety and performance; however, the level of mixing necessary to treat the materials as a single, homogeneous material is not known. To evaluate the intimacy of mixing necessary to propagate a homogenous detonation front in mixtures of an HMX-based formulation and a TATB-based formulation, binary periodic composites of the two explosive formulations have been fabricated and tested. The composites consist of alternating cylindrical shells of the formulations, arranged coaxially and with the overall materials ratio set to 50/50 by volume. To evaluate the importance of mixing, five different periodicity wavelengths were tested, ranging from 12.7 mm to 2.54 mm. Initial results from detonation velocity and front curvature experiments on these articles will be presented, with conclusions drawn regarding their implications for a “critical mixing length” in the context of the estimated reaction zone sizes for these formulations. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. LLNL-ABS-768210