Open Access Open Access  Restricted Access Subscription or Fee Access

Modeling of Thermal Reactions and Associated Events



Thermal stimuli through slow cook-off heating are particularly interesting, since underlying phenomena are very complex, responses depend upon various parameters and they may have a significant impact on warhead system design. A standardized test device with cast-cured or pressed plastic-bonded high explosive charges is used at TDW for investigating such slow thermal stimuli that allows evaluating reaction levels and decomposition temperatures of high explosives. It provides a confined environment and also permits temperature measurements inside the high explosive charge. Experimental tests results of KS57, KS22, and P31 charges varied between burn and deflagration reactions depending on high explosive charges and charge confinements. Such experimental data provide a profound basis for thermal modeling of slow cook-off responses. Multi-physics coupling of transient heat conduction with Arrhenius reaction kinetics form a system of coupled partial differential equations. AKTS-Thermokinetics software deliver corresponding input functions that were determined through differential scanning calorimetry tests of small explosive samples. The recently enhanced model implemented in MATLAB considers additional boundary conditions such as heat conduction through the casing, convection of the turbulent oven heat flow into the casing, and end cap venting effects. Predicted self-heating times, rates, and peak temperatures approach well experimental data. Using this proposed multi-physics model in finite element simulations like COMSOL provides spatial temperature distributions over time and allows future application to full-scale warheads.


Full Text: