Investigation of combustion instability in ramjet combustors

Thesis/Dissertation · Fri Jan 01 00:00:00 EST 1988

OSTI ID:7075380

Reuter, D M

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.

• Research Organization: Georgia Inst. of Tech., Atlanta, GA (USA)
• OSTI ID: 7075380
• Resource Relation: Other Information: Thesis (Ph. D.)
• Country of Publication: United States
• Language: English

Related Subjects

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