Analytical study of TATB preheating methods

TATB (1,3,5 - triamino 2,4,6 - Trinitrobenzene) is a very stable explosive that is remarkably insensitive to severe impact and thermal environment. Experiments on its initiation and detonation characteristics have found it difficult to initiate under the energy transfer of thin flyer plates accelerated by electrically exploded metal foils. Figure 1 shows the propagation of a detonation front in such an experiment. Generally, the detonation waves are confined in the region directly in front of the flyer impact surface, leaving a substantial portion of the HE undetonated. It has been suggested by Lawrence Livermore personnel that a preheated TATB charge may improve its sensitivity and thus reduce or eliminate this deficiency. The above experiments were performed at the sample temperatures ranging from -54{degrees} to +74{degrees}C. As the temperature was lowered while the flyer impact velocity remained the same, a pronounced increase in the curvature of the detonation front was observed. This results in a significant decrease in the divergence of the detonation wave. Although an accurate relationship between the wave front divergence and the sample temperature is not available, it is generally believed that, due to an accelerated rate of chemical reaction, the detonation will significantly improve at higher temperatures. It is assumed that desired results may be obtained if we preheat the TATB to 100{degrees}C at a depth of 1 cm from the flyer impact surface. Many parameters influence the methods to be considered for carrying out this HE preheating. The most important among them are the time allowed and the amount of energy available. The task is made extremely difficult by the fact that TATB is a poor thermal conductor and that deflagration occurs at around 250{degrees}C. In this study, we investigate several heating arrangements and predict the temperature distributions under prescribed boundary conditions