Results 121 to 130 of about 2,170 (163)

Combustion Stabilization by Forced Oscillations in a Duct

SIAM Journal on Applied Mathematics, 2005
The author develops a model and mathematical technique in order to simulate an active control input-output mechanism. The developed model describes the interaction of an existing oscillation in the combustor with a control input and with a flame. Such a model and mathematical technique significantly differ from that used by previous authors for single ...
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Combustion driven oscillations

Journal of Sound and Vibration, 1980
Abstract Combustion driven oscillations can occur when a turbulent flame is enclosed in a tube or cavity. Interaction between heat fluctuations and the internal standing wave field at one of the natural frequencies of the air column produces strong organ pipe tones. The sound power emitted by this thermal-acoustic interaction depends on the impedance
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Adaptive control of combustion oscillations

4th AIAA/CEAS Aeroacoustics Conference, 1998
© 1997 by S. Evesque and A.P. Dowling. Self-excited oscillations of a ducted flame, burning in the wake of a bluff-body flame-holder, are considered. The non-linear kinematic model used here to describe these oscillations calculates the influence of the velocity fluctuations on the shape of the flame surface, and hence on the heat release rate.
S. Evesque, A. Dowling
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Nonlinear Pressure Oscillations in a Combustion Field

ARS Journal, 1960
M practical importance has been attached to the problem of high frequency combustion instability, in particular, the unstable pressure oscillations which may affect the performance of a rocket motor. A thorough mathematical treatment of the linearized aspects of this problem has been given by Crocco and Cheng (1-3). Basing their theory on the sensitive
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FEEDBACK CONTROL OF COMBUSTION OSCILLATIONS

Annual Review of Fluid Mechanics, 2005
▪ Abstract  Early work and recent advances in feedback control of combustion oscillations are described. The physics of combustion oscillations, most commonly caused by a coupling between acoustic waves and unsteady heat release, are discussed, and the concept of using feedback control to interrupt these interactions is introduced.
Ann P. Dowling, Aimee S. Morgans
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Active control of combustion oscillations

30th Fluid Dynamics Conference, 1999
© 1999 A P Dawling. Published by the American Institute of Aeronautics and Astronautics, Inc. Early work on active control of combustion oscillations is reviewed. It is over ten years since the first full-scale demonstration of the feasibility of feedback control to eliminate combustion instability.
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Complex oscillations in the combustion of acetaldehyde

The Journal of Chemical Physics, 1988
Aperiodic dynamics are observed experimentally in the cool flame combustion region of acetaldehyde (ACH) in a continuous stirred tank reactor (CSTR). A gradual transition is seen, with variation of exit orifice size, from limit cycle oscillation to aperiodic variations in light emission, and then back to near periodic oscillations.
Robert H. Harding, Hana Sevčikova, John Ross   +2 more
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FEEDBACK CONTROL OF COMBUSTION OSCILLATIONS

Journal of Fluids and Structures, 1998
Abstract Combustion oscillations are excited by a feedback mechanism which results from the coupling between the flame instability and an acoustic resonance mode of the combustion chamber. The most important event of this mechanism is believed to be the upstream feedback from the acoustic resonance to the initial region of the flame, where new ...
S. ZIADA, H. GRAF
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The relaxation oscillation in ramjet combustion

Symposium (International) on Combustion, 1981
A mechanism of low frequency relaxation oscillation in ram jet combustion is proposed. Initial pressure disturbances induce combustion instability which results in periodic heat release. Acting as feedback, the periodic heat release boosts the pressure pulsations.
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Robust control of combustion oscillations

Proceedings of the 1998 IEEE International Conference on Control Applications (Cat. No.98CH36104), 2002
The physics involved in combustion oscillations is complex, and the controller design has frequently been hampered by the lack of reliable models. We make use of a new theory, based on the constant flame speed model of Fleifil et al. (1996), for the nonlinear oscillations of a ducted flame burning in the wake of a bluff-body flame-holder to provide a ...
null Yun-Chung Chu, A.P. Dowling, K. Glover   +2 more
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