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Effects of high activation energies on acoustic timescale detonation initiation

Regele, J. D. and Kassoy, D. R. and Vasilyev, O. V. (2012) Effects of high activation energies on acoustic timescale detonation initiation. Combustion Theory and Modelling, 16 (4). pp. 650-678. ISSN 1364-7830. doi:10.1080/13647830.2011.647090. https://resolver.caltech.edu/CaltechAUTHORS:20121005-100444325

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Abstract

Acoustic timescale Deflagration-to-Detonation Transition (DDT) has been shown to occur through the generation of compression waves emitted by a hot spot or reaction centre where the pressure and temperature increase with little diminution of density. In order to compensate for the multi-scale nature of the physico-chemical processes, previous numerical simulations in this area have been limited to relatively small activation energies. In this work, a computational study investigates the effect of increased activation energy on the time required to form a detonation wave and the change in behaviour of each hot spot as the activation energy is increased. The simulations use a localised spatially distributed thermal power deposition of limited duration into a finite volume of reactive gas to facilitate DDT. The Adaptive Wavelet-Collocation Method is used to solve efficiently the 1-D reactive Euler equations with one-step Arrhenius kinetics. The DDT process as described in previous work is characterised by the formation of hot spots during an initial transient period, explosion of the hot spots and creation of an accelerating reaction front that reaches the lead shock and forms an overdriven detonation wave. Current results indicate that as the activation energy is raised the chemical heat release becomes more temporally distributed. Hot spots that produce an accelerating reaction front with low activation energies change behaviour with increased activation energy so that no accelerating reaction front is created. An acoustic timescale ratio is defined that characterises the change in behaviour of each hot spot.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1080/13647830.2011.647090 DOIUNSPECIFIED
http://www.tandfonline.com/doi/abs/10.1080/13647830.2011.647090PublisherUNSPECIFIED
Additional Information:© 2012 Taylor & Francis. Received 31 March 2011; final version received 7 October 2011. Version of record first published: 13 Jan 2012. JDR appreciates the guidance and support of OVV and DRK during his PhD thesis research project. Support for this work was provided by the National Science Foundation (NSF) under grants No. ACI-0242457 and No. CBET-0756046. DRK acknowledges support from Air Force STTR contact FA955010C0088 for the thermomechanical aspects of the current work.
Funders:
Funding AgencyGrant Number
NSFACI-0242457
NSFCBET-0756046
Air Force STTR ContactFA955010C0088
Subject Keywords:detonation initiation; deflagration-to-detonation transition; acoustic timescale; inertial confinement; wavelets
Issue or Number:4
DOI:10.1080/13647830.2011.647090
Record Number:CaltechAUTHORS:20121005-100444325
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20121005-100444325
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:34704
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:05 Oct 2012 20:56
Last Modified:09 Nov 2021 23:10

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