Phase-resolved no planar laser-induced fluorescence of a jet flame in an acoustic chamber with excitation at frequencies &lt;60 Hz

Ratner, Albert; Pun, Winston; Palm, Steven L.; Culick, F. E. C.

doi:10.1016/s1540-7489(02)80015-3

Cited by 5 publications

(8 citation statements)

References 9 publications

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“…The Rayleigh plots in figures 10 (left) and 11 (left) indicate that the flame being central contributes most to the driving mechanism of this pulsation. Note that this plot could not have been produced with the conventional technique [15,17] as shown in figure 9.…”

Section: Resultsmentioning

confidence: 99%

“…For the high frequency mode (Sr = 1.8) however the mode shape of the acoustic mode has several nodal planes with varying sign and intensities. Note that such a presentation is closely related to the Rayleigh criterion for combustion instability [18,19] because it visualizes where heat release and pressure are in phase, and hence drives the instability. The interpretation of the heat release-pressure correlation plot as the Rayleigh plot for the high frequency mode is however not straightforward.…”

Section: Visualization Of Acoustic Sourcesmentioning

confidence: 99%

“…The heat release-pressure correlation plot can be obtained in several ways. In the standard procedure [17], each heat release measurement (∼pixel intensity) is multiplied with each unfiltered pressure signal including all frequencies and noise sources. However, the filtered microphone signal can also be used to obtain the phase relation referring to a selected frequency band allowing one plot to be obtained for each frequency band.…”

Section: Visualization Of Acoustic Sourcesmentioning

confidence: 99%

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Phase-locking in post-processing for pulsating flames

Güthe

Schuermans

2007

Meas. Sci. Technol.

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A new approach to studying thermo-acoustically driven heat release fluctuations has been developed. By performing a phase correlation of the pulsation signal for each instant in time in post-processing, a number of advantages over the usual online processing technique are obtained: many frequencies can be analysed from the same data set allowing faster recording and introducing fewer errors than performing the phase correlation online. The method does not require complicated trigger and delay line setups and is most flexible. As an example of this technique, two different pulsation modes of a swirl combustor are resolved from only 300 chemiluminescence images. Further use of this method for a wide variety of applications is indicated.

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Section: Resultsmentioning

confidence: 99%

Section: Visualization Of Acoustic Sourcesmentioning

confidence: 99%

Section: Visualization Of Acoustic Sourcesmentioning

confidence: 99%

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Phase-locking in post-processing for pulsating flames

Güthe

Schuermans

2007

Meas. Sci. Technol.

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“…Even though the online monitoring of equivalence ratio has been carried out in a variety of practical cases one also deduces from the results reported that well-controlled cases are still lacking. Ratner et al (2002) are able to induce equivalence ratio fluctuations but the space time structure of these perturbations is not fully characterized. The recent experiments of Ax et al (2009) concern mixture fraction oscillations in a low pressure environment (69 mbar), conditions rarely met in industrial applications.…”

Section: Introductionmentioning

confidence: 99%

Detailed measurements of equivalence ratio modulations in premixed flames using laser Rayleigh scattering and absorption spectroscopy

et al. 2010

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Sébastien Candel. Detailed measurements of equivalence ratio modulations in premixed flames using laser Rayleigh scattering and absorption spectroscopy. AbstractEquivalence ratio non-uniformities may give rise to some of the instabilities observed in modern lean premixed combustion systems. The present work intends to investigate the influence of equivalence ratio perturbations on the dynamics of premixed flames. A burner equipped with a secondary injection system is used to generate equivalence ratio perturbations which are convected by the flow and impinge on a conical flame. Two laser-diagnostics, based on Rayleigh scattering and hydrocarbon infrared absorption respectively, are employed to give insight into the spatial and temporal evolution of the mixture composition field. Rayleigh scattering images also reveal the flame front dynamics providing an indication on the response of a weakly turbulent flame subject to mixture composition inhomogeneities. Laser light absorption provides a time resolved signal which is used to estimate the equivalence ration perturbation level. A theoretical model based on the G-equation is used to interpret the experimental data and compare the relative effects of velocity and equivalence ratio perturbations.

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“…This revealed that in the flame region the response of the combustion process under acoustic excitation is strongly phase-dependent, and this dependence was quantified. The flame base behavior and NO production rates were also studied [14,15]. Work by Kang et al [16] focused on the measurement of swirl combustor dynamics, employing modern laser-based experimental techniques, and fuel-air ratio…”

Section: Introductionmentioning

confidence: 99%