Results 161 to 170 of about 34,664 (208)

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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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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Nonlinear acoustically-coupled combustion oscillations

Aeroacoustics Conference, 1996
Self-excited oscillations of a confined flame, burning in the wake of a bluff body flame holder, are considered. These oscillations occur due to interaction between unsteady combustion and acoustic waves. According to linear theory, flow disturbances grow exponentially with time.
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Control of Combustion Oscillations Close to Stoichiometry

Flow, Turbulence and Combustion, 2000
The oscillations that occur in ducted plane and round sudden-expansions with combustion of premixed air and methane have been examined for flow conditions which gave rise to large amplitudes corresponding to half-waves. They were present above a minimum flow rate and in a range of equivalence ratios that increased slightly with flow rate and centred ...
de Zilwa, S. R. N., Sivasegaram, S., Whitelaw, J. H.   +2 more
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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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Active control of combustion oscillations for premixed combustion systems

Journal de Physique IV (Proceedings), 2002
Methane premixed flame is studied extensively using a swirl burner and a swirl combustion chamber. First the fundamental study for the flame properties is performed for the swirl burner. Flame configuration is analyzed by a high speed photography and Schlieren system. Then a control system is set up using MATLAB, Simulink, PPC Controller board, dSPACE,
A. K. Hayashi, Y. Yamazaki, T. Mizuno, S. Ogawa, T. Yamamoto, S. Kagiya, T. Motegi   +6 more
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Self-tuning regulators for combustion oscillations

Proceedings of the Royal Society of London. Series A: Mathematical, Physical and Engineering Sciences, 2003
Summary: Self-excited combustion oscillations arise from a coupling between unsteady combustion and acoustic waves, and can cause structural damage to many combustion systems. Active control provides a way of extending the systems' stable operating range by interrupting the damaging thermoacoustic interaction.
Evesque, Stéphanie, Dowling, Ann P., Annaswamy, Anuradha M.   +2 more
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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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Soot suppression by acoustic oscillated combustion

Fuel, 1998
The soot suppression of acetylene diffusion flames by applying acoustic oscillation was studied experimentally. The soot emission decreased by increasing the sound pressure level and lowering the frequency of the acoustic oscillation. The efficiency of soot suppression can be related with acoustic Reynolds number, Re∗.
Masahiro Saito, Masayuki Sato, Akira Nishimura   +2 more
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