Results 211 to 220 of about 34,611 (247)

Control of combustion oscillations

Combustion Science and Technology, 2003
Combinations of small quantities of fuel and imposed oscillations are shown to ameliorate combustion oscillations in ducted flows of premixed methane and air with equivalence ratios from the lean limit to stoichiometry. A sudden expansion from 51 to 80 mm stabilized the flames and the control arrangements were evaluated with an unconstricted exit and ...
I. Emiris, J. H. Whitelaw
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Thermokinetic Oscillations in Acetaldehyde CSTR Combustion

Combustion Science and Technology, 1993
Abstract Acetaldehyde combustion process in CSTR has been simulated by means of a model capable of describing the complex dynamic behavior experimentally observed, including periodic cool flames, single and complex waveform periodic ignitions and jumps.
DI MAIO, Francesco Paolo, Lignola P. G., Talarico P.   +2 more
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Feedback control of combustion oscillations in combustion chambers

Communications in Nonlinear Science and Numerical Simulation, 2010
Abstract Model-based algorithms are generally employed in active control of combustion oscillations. Since practical combustion processes consist of complex thermal and acoustic couplings, their accurate models and parameters may not be obtained in advance economically, a model free controller is necessary for the control of thermoacoustic ...
Wei Wei, Jing Wang, Dong-hai Li, Min Zhu, Ya-li Xue   +4 more
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Oscillations and chaos in CO+O2 combustion

Chaos: An Interdisciplinary Journal of Nonlinear Science, 1991
The gas-phase reaction between carbon monoxide and oxygen (in the presence of small amounts of hydrogen) shows bistability and oscillatory behavior. Typically, the oscillatory ignition has a period-1 relaxation waveform. The limit cycle is born at a saddle-node loop and terminates via a supercritical Hopf bifurcation.
Johnson, B. R., Griffiths, J. F., Scott, S. K.   +2 more
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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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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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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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Combustion oscillations in industrial combustion chambers

Symposium (International) on Combustion, 1969
Combustion roar is a “white” noise radiated from small regions in the flame which suddenly burn. Single frequency oscillations of the simple acoustic type in the combustion chamber (“screaming”) have a frequency 500 cps upwards; Helmholtz resonator oscillations have a frequency of the order of 10 times lower and occur fairly frequently in oil- and gas ...
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Combustion Oscillations in Ducts

1989
A series of measurements has been carried out with ducted flames and has quantified the relative importance of longitudinal-acoustic, Helmholtz and aerodynamic-shedding oscillations. The paper reviews the results and discusses their implications for ramjets and thrust augmentors.
S. Sivasegaram, J. H. Whitelaw
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