Temperature measurement and intermediate emitting species identification in deflagrating PBX 9502 reaction zones using visible emission

The reaction kinetic pathways for the decomposition of 1,3,5,-triamino-2,4,6-trinitrobenzene (TATB) in detonating conditions are not fully understood. Current models use only a 1- or 2-step reaction mechanism, which may not encompass relevant kinetic effects on detonative performance. There is a need for data on transient species that can be used to develop, validate, and improve multi-step reaction models. Spectroscopic interrogation of the reaction zone in detonating conditions is challenging due to high optical capacity, spatially and temporally short scales ( <100 ns and < 500 microns). Deflagrations are temporally and spatially stretched (mm/s) by comparison and with lower optical opacities. This readily enables optical diagnostics to generate data to develop mechanisms that can be extrapolated to detonating conditions. Here, we study the decomposition of TATB in its PBX 9502 formulation (95% wt TATB and 5% wt Kel-F-800) when deflagrating at 100 bar in an argon atmosphere. The burn rates for five separate tests were measured and are found to be consistent with prior measurement. Emission spectroscopy is used to infer temperature and validated using a non-optical technique. A MatLab script automated the identification and analysis of transient species across the hundreds of spectra that were collected over five separate tests. The analysis incorporated correlation functions to find related peaks and trends across all tests. Highly correlated peaks were found to match known species. These species and their spectra will be discussed in detail.