Post-Detonation Afterburning of High Explosives
Post-Detonation Afterburning of High Explosives
Author
Summary, in English
This thesis presents modelling, simulation and experimental efforts in studying this two-phase post-detonation combustion event at different HoB of 1 kg trinitrotoluene (TNT) and TNT/aluminium charges. The main objectives of this work is to demonstrate the use of LES with finite rate chemistry for these types of applications, to elucidate the physical processes involved in near-ground air blasts, to demonstrate what effects the HoB has on the afterburning, and how aluminium particles affect the combustion.
Simulation results, supported by experimental data, show that the main mechanism responsible for the mixing, and therefore afterburning, is the rise of hydrodynamic instabilities, which trigger the build up of a mixing layer. Shock-mixing layer interactions further create more instabilities. Thus, in order to achieve maximum effect of the afterburning during an explosive blast, the existence of a turbulent mixing layer has to be combined with repeated shock propagation through it, by which the duration of the afterburning is maintained. The presence of reacting particles increases the vorticity generated by instabilities since the particles create perturbations in the detonation product cloud, hence disrupting the alignment of the pressure and density gradients. Burning particles intensify mixing even further through volumetric expansion induced by increased heat-release from particle combustion. The mixing intensity in its turn varies with HoB, as the shock propagation pattern is different for all HoB, which means that in order to achieve maximum effect from aluminium inclusion to an explosive, HoB must be considered as a parameter.
Department/s
Publishing year
2017-06-08
Language
English
Full text
- Available as PDF - 95 MB
- Download statistics
Document type
Dissertation
Publisher
Department of Energy Sciences, Lund University
Topic
- Engineering and Technology
Keywords
- Explosives
- Combustion
- LES
- Finite rate chemistry
- Explosives
- Combustion
- LES
- Finite rate chemistry
- Height of Burst
Status
Published
Supervisor
- Xue-Song Bai
- Christer Fureby
ISBN/ISSN/Other
- ISBN: 978-91-629-0222-3
- ISBN: 978-91-629-0221-6
Defence date
25 August 2017
Defence time
10:00
Defence place
lecture hall M:B, M-building, Ole Römers väg 1, Lund University, Faculty of Engineering LTH, Lund
Opponent
- Elaine Oran (Professor)