2024-10-31 ロスアラモス国立研究所(LANL)
ロスアラモス国立研究所のチームは、爆発物の安全性をより正確に評価する新しい試験法「高爆発物開始時間（HEIT）実験」を開発しました。この方法では、高電圧で加熱した小さな試料を使用し、温度と爆発までの時間を計測します。従来の「ドロップウェイト衝撃試験」では限界がありましたが、この新技術により、爆発の反応速度や温度変化が詳しくわかり、爆発事故を分子レベルで理解する画期的な手法とされています。
＜関連情報＞
- https://discover.lanl.gov/news/1030-explosives-testing/
- https://pubs.acs.org/doi/10.1021/jacs.4c08424
火薬類の高温分解速度論評価のための実験とモデリングの統合アプローチ An Integrated Experimental and Modeling Approach for Assessing High-Temperature Decomposition Kinetics of Explosives
Virginia W. Manner,Marc J. Cawkwell,Kyle D. Spielvogel,Douglas G. Tasker,John W. Rose,Michael Aloi,Robert Tucker,Jeremiah D. Moore,Maria C. Campbell,Tariq D. Aslam
Journal of the American Chemical Society Published: September 11, 2024
DOI:https://doi.org/10.1021/jacs.4c08424
Abstract
We present a new integrated experimental and modeling effort that assesses the intrinsic sensitivity of energetic materials based on their reaction rates. The High Explosive Initiation Time (HEIT) experiment has been developed to provide a rapid assessment of the high-temperature reaction kinetics for the chemical decomposition of explosive materials. This effort is supported theoretically by quantum molecular dynamics (QMD) simulations that depict how different explosives can have vastly different adiabatic induction times at the same temperature. In this work, the ranking of explosive initiation properties between the HEIT experiment and QMD simulations is identical for six different energetic materials, even though they contain a variety of functional groups. We have also determined that the Arrhenius kinetics obtained by QMD simulations for homogeneous explosions connect remarkably well with those obtained from much longer duration one-dimensional time-to-explosion (ODTX) measurements. Kinetic Monte Carlo simulations have been developed to model the coupled heat transport and chemistry of the HEIT experiment to explicitly connect the experimental results with the Arrhenius rates for homogeneous explosions. These results confirm that ignition in the HEIT experiment is heterogeneous, where reactions start at the needle wall and propagate inward at a rate controlled by the thermal diffusivity and energy release. Overall, this work provides the first cohesive experimental and first-principles modeling effort to assess reaction kinetics of explosive chemical decomposition in the subshock regime and will be useful in predictive models needed for safety assessments.
