Quantifying Energy Transfer From a Reacting Thermite to a Target Using Infrared Diagnostics

A study was conducted to examine the energy transfer from a reacted thermite placed on a steel target substrate. A high speed infrared camera captured a temporally evolving thermal distribution on the substrate, while the thermite, which was placed in a v-notch, self propagated. The thermite investigated for this experiment was Aluminum with Iron (III) Oxide (Al-Fe₂O₃). An energy balance model was developed to predict temperatures near the v-notch in order to quantify the amount of energy transferred into the steel. Results quantified the percent of energy available from the reaction that was conducted through the substrate and energy losses were estimated. The thermite reaction transferred 10% of the heat of reaction to the steel. The Al-Fe2O3 exhibited greater heat losses to convection and radiation upon propagation through the powder mixture. The Al-Fe₂O₃ reaction produced more gas by chemistry, 10% by mass, which contributed to transporting energy away from the v-notch. Much work had been performed that examined the combustion behaviors from a reacting thermite, but there are very few studies that quantify the energy transfer from a reacting thermite to a target. This diagnostic approach and numerical analysis were the first steps toward understanding energy transferred from a thermite into a target, and lost to the environment.