Large deformation and gas retention during cookoff of a plastic bonded explosive (PBX 9407)
| Autor: | Michael L. Hobbs, Cole Yarrington, Michael J. Kaneshige |
|---|---|
| Rok vydání: | 2018 |
| Předmět: |
Materials science
Explosive material 020209 energy General Chemical Engineering General Physics and Astronomy Energy Engineering and Power Technology 02 engineering and technology General Chemistry Vinyl chloride law.invention Ignition system chemistry.chemical_compound Fuel Technology Pressure measurement 020401 chemical engineering chemistry law Thermocouple Desorption 0202 electrical engineering electronic engineering information engineering 0204 chemical engineering Composite material Hydrogen chloride Chlorotrifluoroethylene |
| Zdroj: | Combustion and Flame. 198:278-289 |
| ISSN: | 0010-2180 |
| DOI: | 10.1016/j.combustflame.2018.09.020 |
| Popis: | We have used several configurations of the Sandia Instrumented Thermal Ignition (SITI) experiment to develop a pressure-dependent, four-step ignition model for a plastic bonded explosive (PBX 9407) consisting of 94 wt.% RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine), and a 6 wt.% VCTFE binder (vinyl chloride/chlorotrifluoroethylene copolymer). The four steps include desorption of water, decomposition of RDX to form equilibrium products, pressure-dependent decomposition of RDX forming equilibrium products, and decomposition of the binder to form hydrogen chloride and a nonvolatile residue (NVR). We address drying, binder decomposition, and decomposition of the RDX component from the pristine state through the melt and into ignition. We used Latin Hypercube Sampling (LHS) of the parameters to determine the sensitivity of the model to variation in the parameters. We also successfully validated the model using one-dimensional time-to-explosion (ODTX and P-ODTX) data from a different laboratory. Our SITI test matrix included 1) different densities ranging from 0.7 to 1.63 g/cm3, 2) free gas volumes ranging from 1.2 to 38 cm3, and 3) boundary temperatures ranging from 170 to 190 °C. We measured internal temperatures using embedded thermocouples at various radial locations as well as pressure using tubing that was connected from the free gas volume (ullage) to a pressure gauge. We also measured gas flow from our vented experiments. A borescope was included to obtain in situ video during some SITI experiments. We observed significant changes in the explosive volume prior to ignition. Our model, in conjunction with data observations, imply that internal accumulation of decomposition gases in high density PBX 9407 (90% of the theoretical maximum density) can contribute to significant strain whether or not the experiment is vented or sealed. |
| Databáze: | OpenAIRE |
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