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Sirak Ghebreamlak: Initiation of energetic materials caused by hot fragments -- Study of current hot fragment thermal initiation models

Tid: Fr 2022-09-23 kl 14.45

Plats: 3721, Lindstedtsvägen 25

Respondent: Sirak Ghebreamlak

Opponent: Antoni Plonczak

Handledare: Olof Runborg, Rasmus Wedberg

Abstract:

The cause of unintentional initiations of energetic materials is an important area of study due to the dangers that comes with storing energetic materials such as explosives. The current models used to simulate the process of heating energetic materials by a hot metal fragment do not give reliable predictions. The objective of this thesis is to study the current models in order to get a better understanding of how to improve the accuracy of the simulations. The heat transfer in the fragment and energetic material is modeled using the heat equation and the reaction rates in the chemical decomposition of the energetic material are modeled using Arrhenius equations. This study shows the importance of accurately implementing the contact area and heat transfer coefficient between the fragment and the energetic material. The thermal conductivity has a significantly smaller affect on the initiation time compared to the heat transfer coefficient. Furthermore, the dimensions of the fragment affect the resulting simulations greatly, while the dimensions of the energetic material only does so for sufficiently small dimensions.