Modeling Small Scale Detonation Experiments with Pressed TATB

摘要

A unique small-scale characterization experiment has been proposed to measure the instantaneous shock or detonation velocity in small diameter explosive charges using microwave interferometry (MI). The experimental configuration allows for the investigation of steady state, failure, and shock-to-detonation phenomena. In this work, the well-studied explosive triaminotrinitrobenzene (TATB) is used to evaluate five pre-existing models based on Arrhenius, history variable, and ignition and growth reactive burn models at densities of 40-96% of TMD. Pressed TATB samples are in contact with an explosive booster, or separated by a polymethylmethacrylate (PMMA) attenuator to determine a critical thickness for initiation failure. One- and two- dimensional simulations using the hydrocode CTH show that Arrhenius and history variable models matched experimental reaction wave velocity data well above 60% TMD; however, the reaction zone thickness was anomalously thin (10-100 μm) and the critical attenuator thickness was under-predicted by a few millimeters. In contrast, the ignition and growth model did not match the measured velocities, but showed a realistic reaction zone thickness (0.5-2 mm), instabilities in shock pressure, detonation failure below 60% TMD, and longer critical attenuator thickness estimates. Future work will consider the small-scale experiment as an improved tool for the validation, and possibly calibration, of other explosives models.