Modeling laser ignition of explosives and pyrotechnics: Effects and characterization of radiative transfer

The ignition of explosives and pyrotechnics using commercial diode lasers has been demonstrated and is of interest as a potential replacement for hot-wire ignition. Initial laser diode ignitor (LDI) test results using the detonation-to-deflagration transition(DDT) explosive CP (2-(5-cyanotetrazolato) pentaamminecobalt (III) perchlorate, C{sub 2}H{sub 15}N{sub 10}Co--Cl{sub 2}O{sub 8}) doped with carbon black and graphite have reinforced the need for a better understanding of the interaction of the radiant energy transfer within the pressed material. The present work is directed toward developing a model to predict the transfer of laser energy in the pressed particulate charges. It is shown here that scattering can have a major effect on the volumetric absorption of laser energy, significantly affecting the thermal response of the granular energetic material. This paper describes an effort to characterize the radiative properties of compacted granular beds of CP and CP doped with carbon black or graphite that were prepared using normal pressing techniques. Current estimates of the radiative properties are presented and indicate dramatic in absorption for CP when even a minute amount of carbon black or graphite is added. Initial data indicate pressed, undoped CP scatters radiative energy significantly. The radiative properties are dependent upon both wavelength and packingmore » density; the less-densely packed samples exhibit more scattering. Doped samples exhibit essentially wavelength-independent characteristics. 14 refs., 7 figs., 1 tab.« less