Mesoscale modeling of explosive mixtures containing TNT and HMX

Different energetic constituents can be combined to achieve desired explosive mixture properties. One example of an explosive mixture is Octol which is comprised of a less ideal constituent, TNT, and a more ideal constituent, HMX. Changes to HMX content in this mixture can alter its shock sensitivity and performance. However, the microscale reaction mechanisms underlying such changes are not well understood. In this study we perform mesoscale simulations to investigate different TNT-HMX mixtures. Simulations are performed with the multi-physics code, ALE3D. A coupled thermochemical code provides equation-of-state and chemical kinetic properties. Simulations are performed for TNT-HMX weight ratios of 25-75, 40-60, and 70-30 with 2 and 5% porosity. A range of shock pressures are considered. Non-reactive studies examining changes to the p-v response and temperature distribution will be discussed with comparisons to common mixture rules. Trends for the mixture reaction rate with varying HMX content and porosity will also be discussed. These studies are important for developing mixture reactive flow models when the constituents are mixed at length-scales below the reaction zone size.