Deflagration-to-detonation transition (DDT) in a granular high explosive in two dimensions
There are sound reasons to question whether historical 1-dimensional DDT tube tests have captured all of the physics required to precisely describe the complex process of the deflagration-to-detonation transition, especially as it evolves in three dimensions. Foremost is the fact that a burning colu...
Gespeichert in:
Hauptverfasser: | , , , |
---|---|
Format: | Tagungsbericht |
Sprache: | eng |
Schlagworte: | |
Online-Zugang: | Volltext |
Tags: |
Tag hinzufügen
Keine Tags, Fügen Sie den ersten Tag hinzu!
|
Zusammenfassung: | There are sound reasons to question whether historical 1-dimensional DDT tube tests have captured all of the physics required to precisely describe the complex process of the deflagration-to-detonation transition, especially as it evolves in three dimensions. Foremost is the fact that a burning column of explosive, mechanically constrained inside a tube, is prohibited from experiencing divergence in the stress forces and flows. As a result, these tests miss the effects of tensile fracture and flame intrusion into the deflagrating explosive likely precluding, or underrepresenting, phenomena associated with crack burning and its effects on deflagration propagation and mass-burn-rate enhancement. To investigate how channeling and flow divergence affect the DDT process in >1 dimension, we designed a strongly confined 2-dimensional DDT test containing thin (2 mm) HE slabs, where ignition location and slab shape (e.g., circle, ellipse and circular sector) were varied. The reaction vessels had transparent windows enclosing the explosive’s top surface and high-speed cameras were used to observe luminous flames, channeling, compaction, detonation transition and propagation within the explosive bed. In all but one case, DDT was the result of Mach stem formation, either by reflection at the confinement interface or at the intersection of colliding waves, to produce an amplified shock of sufficient strength to initiate detonation. This detail offers a significant refinement to the final steps of the widely accepted mechanism for DDT. We present novel image data and analysis describing the important differences in the mechanism for DDT in multiple dimensions. |
---|---|
ISSN: | 0094-243X 1551-7616 |
DOI: | 10.1063/12.0020440 |