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Title: Investigation of combustion instability in ramjet combustors

Abstract

This research is concerned with investigation of the mechanisms responsible for the driving of longitudinal instabilities in dump-type ramjet combustors. In particular, the coupling between the core flame which is stabilized at the entrance of the combustor and the longitudinal acoustic field was studied. The time-dependent structure of premixed V-shaped flames was experimentally examined using pressure measurements, space- and time-resolved C-H radical radiation measurements, high-speed shadow cine photography, and laser-Doppler velocimetry. The investigation revealed that the acoustic energy to sustain the instability is mainly supplied by the oscillatory heat release from the flame. Based on this finding, a model was developed that is capable of predicting the acoustic pressure spectrum from measured heat-release rates. Furthermore, it was shown that the periodic heat-release rates largely result from periodic changes in the flame surface area caused by acoustically triggered symmetric vortex shedding in the wake of the flame holders. Lastly, experiments were conducted that used this mechanism to show the suppression of instabilities at the fundamental acoustic mode by staggering multiple flames so that the unsteady heat release fields destructively interfere with one another.

Authors:
Publication Date:
Research Org.:
Georgia Inst. of Tech., Atlanta, GA (USA)
OSTI Identifier:
7075380
Resource Type:
Thesis/Dissertation
Resource Relation:
Other Information: Thesis (Ph. D.)
Country of Publication:
United States
Language:
English
Subject:
33 ADVANCED PROPULSION SYSTEMS; 37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; COMBUSTION INSTABILITY; MEASURING METHODS; COMBUSTORS; RAMJET ENGINES; HEAT TRANSFER; MATHEMATICAL MODELS; ENERGY TRANSFER; ENGINES; HEAT ENGINES; INSTABILITY; INTERNAL COMBUSTION ENGINES; 330100* - Internal Combustion Engines; 400800 - Combustion, Pyrolysis, & High-Temperature Chemistry

Citation Formats

Reuter, D M. Investigation of combustion instability in ramjet combustors. United States: N. p., 1988. Web.
Reuter, D M. Investigation of combustion instability in ramjet combustors. United States.
Reuter, D M. 1988. "Investigation of combustion instability in ramjet combustors". United States.
@article{osti_7075380,
title = {Investigation of combustion instability in ramjet combustors},
author = {Reuter, D M},
abstractNote = {This research is concerned with investigation of the mechanisms responsible for the driving of longitudinal instabilities in dump-type ramjet combustors. In particular, the coupling between the core flame which is stabilized at the entrance of the combustor and the longitudinal acoustic field was studied. The time-dependent structure of premixed V-shaped flames was experimentally examined using pressure measurements, space- and time-resolved C-H radical radiation measurements, high-speed shadow cine photography, and laser-Doppler velocimetry. The investigation revealed that the acoustic energy to sustain the instability is mainly supplied by the oscillatory heat release from the flame. Based on this finding, a model was developed that is capable of predicting the acoustic pressure spectrum from measured heat-release rates. Furthermore, it was shown that the periodic heat-release rates largely result from periodic changes in the flame surface area caused by acoustically triggered symmetric vortex shedding in the wake of the flame holders. Lastly, experiments were conducted that used this mechanism to show the suppression of instabilities at the fundamental acoustic mode by staggering multiple flames so that the unsteady heat release fields destructively interfere with one another.},
doi = {},
url = {https://www.osti.gov/biblio/7075380}, journal = {},
number = ,
volume = ,
place = {United States},
year = {Fri Jan 01 00:00:00 EST 1988},
month = {Fri Jan 01 00:00:00 EST 1988}
}

Thesis/Dissertation:
Other availability
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