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Direct observations of reaction zone structure in propagating detonations

Pintgen, F. and Eckett, C. A. and Austin, J. M. and Shepherd, J. E. (2003) Direct observations of reaction zone structure in propagating detonations. Combustion and Flame, 133 (3). pp. 211-229. ISSN 0010-2180. http://resolver.caltech.edu/CaltechAUTHORS:20140908-132245693

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Abstract

We report experimental observations of the reaction zone structure of self-sustaining, cellular detonations propagating near the Chapman-Jouguet state in hydrogen-oxygen-argon/nitrogen mixtures. Two-dimensional cross sections perpendicular to the propagation direction were imaged using the technique of planar laser induced fluorescence (PLIF) and, in some cases, compared to simultaneously acquired schlieren images. Images are obtained which clearly show the nature of the disturbances in an intermediate chemical species (OH) created by the variations in the strength of the leading shock front associated with the transverse wave instability of a propagating detonation. The images are compared to 2-D, unsteady simulations with a reduced model of the chemical reaction processes in the hydrogen-oxygen-argon system. We interpret the experimental and numerical images using simple models of the detonation front structure based on the “weak” version of the flow near the triple point or intersection of three shock waves, two of which make up the shock front and the third corresponding to the wave propagating transversely to the front. Both the unsteady simulations and the triple point calculations are consistent with the creation of keystone-shaped regions of low reactivity behind the incident shock near the end of the oscillation cycle within the “cell.”


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1016/S0010-2180(02)00458-3DOIArticle
http://www.sciencedirect.com/science/article/pii/S0010218002004583PublisherArticle
ORCID:
AuthorORCID
Shepherd, J. E.0000-0003-3181-9310
Additional Information:Copyright © 2003 The Combustion Institute. Published by Elsevier. Received 4 February 2002; received in revised form 16 July 2002; accepted 6 August 2002. The development of the detonation facility and imaging experiments has occupied several generations of students and technicians who have worked in the Explosion Dynamics Laboratory at Caltech over the last decade. The authors thank R. Akbar, M. J. Kaneshige, E. Schultz, and P. Svitek for their invaluable contributions. The simulations were carried out with J. J. Quirk’s Amrita computational system. Portions of this work were supported by the ONR and the DOE.
Group:GALCIT
Funders:
Funding AgencyGrant Number
Office of Naval Research (ONR)UNSPECIFIED
Department of Energy (DOE)UNSPECIFIED
Subject Keywords:Detonation; Transverse waves; Laser-induced fluorescence; Cellular structure; Reaction zone
Record Number:CaltechAUTHORS:20140908-132245693
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:20140908-132245693
Official Citation:F. Pintgen, C.A. Eckett, J.M. Austin, J.E. Shepherd, Direct observations of reaction zone structure in propagating detonations, Combustion and Flame, Volume 133, Issue 3, May 2003, Pages 211-229, ISSN 0010-2180, http://dx.doi.org/10.1016/S0010-2180(02)00458-3. (http://www.sciencedirect.com/science/article/pii/S0010218002004583)
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:49350
Collection:CaltechAUTHORS
Deposited By: George Porter
Deposited On:08 Sep 2014 21:16
Last Modified:22 Sep 2016 23:28

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