The University of Southampton
University of Southampton Institutional Repository

Adaptive simulations of viscous detonations initiated by a hot jet using a high-order hybrid WENO–CD scheme

Adaptive simulations of viscous detonations initiated by a hot jet using a high-order hybrid WENO–CD scheme
Adaptive simulations of viscous detonations initiated by a hot jet using a high-order hybrid WENO–CD scheme
In the present work a sixth-order hybrid WENO–Centered Difference (CD) scheme with an adaptive mesh refinement method is employed to investigate gaseous detonation by injecting a hot jet into a hydrogen–oxygen combustible mixture flowing at supersonic speed. Two-dimensional reactive Navier–Stokes (NS) equations with one-step two-species chemistry model are solved numerically. The comparison between viscous and inviscid detonation structures shows that due to the absence of both the physical viscosity in Euler equations and minimization of numerical dissipation in the hybrid WENO–CD scheme, very small-scale vortices can be observed behind the detonation front. The diffusion effect in the NS equations suppresses the small-scale vortices, but it has negligible influence on the large-scale vortices generated by Richtmyer–Meshkov (RM) instability and those along the highly unstable shear layers induced by Kelvin–Helmholtz (KH) instability. When studying the same setup in an expanding channel and beyond the point of detonation initiation, it is found that because of the diffusion effect of detached shear layers, any unburned jet flow is consumed quickly and then additional energy is released periodically. Because of the formation of multiple secondary triple points and subsequent shear layers after the shutdown of the hot jet, a highly turbulent flow is produced behind the detonation front. Rather than the commonly known RM instability, the large-scale vortices involved in the highly unstable shear layers dominate the formation of the turbulent flow and the rapid turbulent mixing between the unburned jet flow and burned product. It is found that the size of unburned jets and vortices due to KH instability is growing for larger expansion angles. The further generated turbulent flow resulting from larger sized vortices, significantly enhances the mixing rate behind the Mach stem, leading to rapid consumption of the unburned reactants. Therefore, detonations propagate faster in channels with larger expansion angle and higher expansion ratio.
1540-7489
2725-2733
Cai, Xiaodong
293bf621-f0e1-48ba-abaa-b41da81ea244
Deiterding, Ralf
ce02244b-6651-47e3-8325-2c0a0c9c6314
Liang, Jiahan
3bd9af6d-929a-4b54-a17d-302a63f9aa44
Mahmoudi, Yasser
5c336547-605b-4f01-afea-2fc24a922798
Cai, Xiaodong
293bf621-f0e1-48ba-abaa-b41da81ea244
Deiterding, Ralf
ce02244b-6651-47e3-8325-2c0a0c9c6314
Liang, Jiahan
3bd9af6d-929a-4b54-a17d-302a63f9aa44
Mahmoudi, Yasser
5c336547-605b-4f01-afea-2fc24a922798

Cai, Xiaodong, Deiterding, Ralf, Liang, Jiahan and Mahmoudi, Yasser (2017) Adaptive simulations of viscous detonations initiated by a hot jet using a high-order hybrid WENO–CD scheme. Proceedings of the Combustion Institute, 36 (2), 2725-2733. (doi:10.1016/j.proci.2016.06.161).

Record type: Article

Abstract

In the present work a sixth-order hybrid WENO–Centered Difference (CD) scheme with an adaptive mesh refinement method is employed to investigate gaseous detonation by injecting a hot jet into a hydrogen–oxygen combustible mixture flowing at supersonic speed. Two-dimensional reactive Navier–Stokes (NS) equations with one-step two-species chemistry model are solved numerically. The comparison between viscous and inviscid detonation structures shows that due to the absence of both the physical viscosity in Euler equations and minimization of numerical dissipation in the hybrid WENO–CD scheme, very small-scale vortices can be observed behind the detonation front. The diffusion effect in the NS equations suppresses the small-scale vortices, but it has negligible influence on the large-scale vortices generated by Richtmyer–Meshkov (RM) instability and those along the highly unstable shear layers induced by Kelvin–Helmholtz (KH) instability. When studying the same setup in an expanding channel and beyond the point of detonation initiation, it is found that because of the diffusion effect of detached shear layers, any unburned jet flow is consumed quickly and then additional energy is released periodically. Because of the formation of multiple secondary triple points and subsequent shear layers after the shutdown of the hot jet, a highly turbulent flow is produced behind the detonation front. Rather than the commonly known RM instability, the large-scale vortices involved in the highly unstable shear layers dominate the formation of the turbulent flow and the rapid turbulent mixing between the unburned jet flow and burned product. It is found that the size of unburned jets and vortices due to KH instability is growing for larger expansion angles. The further generated turbulent flow resulting from larger sized vortices, significantly enhances the mixing rate behind the Mach stem, leading to rapid consumption of the unburned reactants. Therefore, detonations propagate faster in channels with larger expansion angle and higher expansion ratio.

Text
Adaptive simulations of viscous detonations initiated by a hot jet using a high-order hybrid WENO-CD scheme.pdf - Accepted Manuscript
Download (700kB)

More information

Accepted/In Press date: 24 June 2016
e-pub ahead of print date: 9 July 2016
Published date: 2 April 2017
Organisations: Aerodynamics & Flight Mechanics Group

Identifiers

Local EPrints ID: 399593
URI: https://eprints.soton.ac.uk/id/eprint/399593
ISSN: 1540-7489
PURE UUID: 314323fe-68cc-4a86-bce5-f9eaa69bf918
ORCID for Ralf Deiterding: ORCID iD orcid.org/0000-0003-4776-8183

Catalogue record

Date deposited: 19 Aug 2016 14:19
Last modified: 06 Jun 2018 12:20

Export record

Altmetrics

Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton: eprints@soton.ac.uk

ePrints Soton supports OAI 2.0 with a base URL of https://eprints.soton.ac.uk/cgi/oai2

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.

×