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One-dimensional model describing eigenmode frequency shift during transverse excitation

Webster, Samuel and Hardi, Justin and Oschwald, Michael (2019) One-dimensional model describing eigenmode frequency shift during transverse excitation. In: Progress in Propulsion Physics Torus Press. pp. 273-294. doi: 10.1051/eucass/201911273. ISBN 978-5-94588-228-7.

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Official URL: https://www.eucass-proceedings.eu/articles/eucass/abs/2019/01/eucass2019_273/eucass2019_273.html


A shift in transverse eigenmode frequency was observed in an experimental combustion chamber when exposed to large amplitude acoustic oscillations during oxygen–hydrogen combustion tests. A shift in eigenmode frequency under acoustic conditions representative of combustion conditions is of critical importance when tuning acoustic absorbers or investigating injection coupled combustion instabilities. The experimentally observed frequency shift was observed both in the frequency domain and as an asymmetric amplitude response to a linear frequency ramp of an external excitation system in the time domain. The frequency shift was found to be dependent on amplitude and operating condition. A hypothesis is presented for the frequency shift based on change in speed-of-sound distributions due to flame contraction when exposed to high amplitude pressure oscillations. A one-dimensional (1D) model was created to test the hypothesis. Model parameters were based on relationships observed in experimental data. The model was found to accurately recreate the frequency shifting asymmetric response observed in test data as well as its amplitude dependence. Further development is required to investigate the influence of operating conditions and chamber design on the quantitative modeling of the frequency shift.

Item URL in elib:https://elib.dlr.de/132325/
Document Type:Book Section
Title:One-dimensional model describing eigenmode frequency shift during transverse excitation
AuthorsInstitution or Email of AuthorsAuthor's ORCID iDORCID Put Code
Webster, SamuelGerman Aeorspace Center (DLR), Lampoldshausen, DUNSPECIFIEDUNSPECIFIED
Hardi, JustinUNSPECIFIEDhttps://orcid.org/0000-0003-3258-5261UNSPECIFIED
Oschwald, MichaelUNSPECIFIEDhttps://orcid.org/0000-0002-9579-9825UNSPECIFIED
Date:8 February 2019
Journal or Publication Title:Progress in Propulsion Physics
Refereed publication:Yes
Open Access:Yes
Gold Open Access:No
In ISI Web of Science:No
Page Range:pp. 273-294
Publisher:Torus Press
Keywords:combustion, instability
HGF - Research field:Aeronautics, Space and Transport
HGF - Program:Space
HGF - Program Themes:Space Transportation
DLR - Research area:Raumfahrt
DLR - Program:R RP - Space Transportation
DLR - Research theme (Project):R - Antriebsystemtechnik - Schubkammertechnologie (old)
Location: Lampoldshausen
Institutes and Institutions:Institute of Space Propulsion > Rocket Propulsion
Deposited By: Hanke, Michaela
Deposited On:09 Dec 2019 08:19
Last Modified:09 Dec 2019 08:19

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