Mitigation of premixed flame-sustained thermoacoustic oscillations using an electrical heater

Zhao, Dan; Ji, Chenzhen; Li, X.; Li, S.

doi:10.1016/j.ijheatmasstransfer.2015.03.012

Cited by 79 publications

(26 citation statements)

References 43 publications

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“…Several methods for damping combustion instability in Rijke tubes have been tested. Some recent works include the use of injected air [6], use of an adaptive system with an external loudspeaker to uncouple acoustic pressure oscillations and unsteady heat release [7], Helmholtz resonators [8,9], and the addition of a secondary heater [10]. A recent overview of passive acoustic dampers and potential challenges associated with implementation of the dampers to real-world engines is given by Zhao and Li [11].…”

Section: Nomenclaturementioning

confidence: 99%

Electric Field Damping of Rijke Tube Combustion Instabilities

Henderson

2018

Journal of Propulsion and Power

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A direct-current electric field was investigated as a damping method for thermoacoustic instabilities generated in a horizontal Rijke tube driven by a premixed propane torch. Electrode lengths of 2.54, 5.08, and 15.24 cm were used with electrode locations relative to the burner tip of −4.60, −2.06, and 0.458 cm and voltages up to 4.68 kV being tested. Electrodes downstream of the burner tip, rather than surrounding the burner, and longer electrodes were most effective at damping instabilities. Damping also increased with applied voltage. These findings held true for both laminar and turbulent flames and were in agreement with theoretical predictions made based on two-dimensional static electric field models. Sound pressure level reductions up to 21 dB for the laminar flame, which completely damped the instability, and 4.4 dB for the turbulent flame were seen using the 15.24 cm electrode at 4.68 kV. When the entire Rijke tube acted as the electrode, a reduction of 19 dB was seen for the turbulent flame at 9 kV, which suppressed the instability. The damping effect was attributed to stabilization of the oscillating flame and its unsteady heat release, driven by the combustion instability pressure fluctuations, via the ionic wind.

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Section: Nomenclaturementioning

confidence: 99%

Electric Field Damping of Rijke Tube Combustion Instabilities

Henderson

2018

Journal of Propulsion and Power

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“…The open loop transfer function (OLTF) from the microphone reading to the loudspeaker voltage is measured, since it provides insights on the system to be controlled, and is critical for control purpose [43][44][45]. We use a phase-shifter i.e.…”

Section: Measurement Of the Transfer Function Of A Standing-wave Thermentioning

confidence: 99%

Theoretical and experimental investigation of thermoacoustics transfer function

et al. 2015

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“…Such instability is characterized by periodic acoustic pressure perturbations; its amplitude may be up to 5-15% of the engine mean pressure. To mitigate these acoustic fluctuations, [9][10][11][12] Helmholtz resonators are designed and implemented. With these resonators implemented, acoustic pulsations may be attenuated somehow and small-amplitude acoustic perturbations are acceptable in engines to increase the fuel-air mixing.…”

Section: Introductionmentioning

confidence: 99%

Numerical studies of transmission loss performances of asymmetric Helmholtz resonators in the presence of a grazing flow

Pan

Guan

2018

Journal of Low Frequency Noise, Vibration and Active Control

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As a typical noise-attenuating device, Helmholtz resonators are widely implemented in aero-engines and gas turbines to decrease the transmission of acoustic noise. However, an asymmetric Helmholtz resonator could be designed and implemented due to the limited space available in the engines. To examine and optimize the noise-attenuating performances of the asymmetric resonator, comparison studies are performed. For this, a two-dimensional frequency-domain model of a cylindrical duct with a grazing flow is developed. An asymmetric Helmholtz resonator is attached as a side branch. The model containing the linearized Navier-Stokes equations is validated first by comparing the predicted results with the experimental ones available in the literature. Further validation is conducted by comparing the results of an asymmetric resonator with the analytical ones available in the literature. The effects of (1) neck offset distance from the center of the resonator cavity denoted by e c =a s and (2) the grazing flow Mach number M u are evaluated. It is shown that as the grazing flow Mach number is increased, the resonant frequencies and the maximum transmission losses are dramatically varied for a given e c =a s. As e c =a s is increased from 0 to 0.5 and M u ! 0:1, the resonant frequencies and the maximum transmission losses are increased. However, when M u is lower than 0.07, i.e. M u 0:07, the transmission loss performances are almost unchanged with e c =a s increased. The optimum design of the asymmetric resonator is shown to give rise to the resonant frequency being shifted by 10% and 2-5 dB more transmission loss at higher Mach number. Finally, visualization of vortex shedding formed at the neck of the asymmetric resonator confirms that acoustical energy is transformed into kinetic energy and absorbed by the surrounding air. This study opens up a numerical design approach to optimize an asymmetric resonator.

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Mitigation of premixed flame-sustained thermoacoustic oscillations using an electrical heater

Cited by 79 publications

References 43 publications

Electric Field Damping of Rijke Tube Combustion Instabilities

Electric Field Damping of Rijke Tube Combustion Instabilities

Theoretical and experimental investigation of thermoacoustics transfer function

Numerical studies of transmission loss performances of asymmetric Helmholtz resonators in the presence of a grazing flow

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