Diagnostic possibilities on the basis of premixed flame noise levels

Petela, G.; Petela, Ryszard

doi:10.1016/0010-2180(83)90128-1

Cited by 12 publications

(3 citation statements)

References 11 publications

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“…All of the reported works appear to recognize the acoustic output and the acoustic interactions with combusting fields. The interesting possibility of scientific "listening" to combustion zones with the specific intention of diagnostics has been reported by Ramohalli (1978Ramohalli ( , 1979Ramohalli ( , 1981, Ramachandra and Strahle (1983), and Petela and Petela (1983). It was confirmed that small changes in the air/fuel ratio of simple (gaseous fuel) jet flames could be seen reflected in the acoustic spectra.…”

Section: Introductionsupporting

confidence: 50%

Reynolds Number Effects in Combustion Noise

Seshan

1986

Combustion Science and Technology

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Section: Introductionsupporting

confidence: 50%

Reynolds Number Effects in Combustion Noise

Seshan

1986

Combustion Science and Technology

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“…The absolute magnitude of these spectral components scales with the total acoustic emissions from the flame. For example, Petela & Petela (1983) observed changes in the magnitude, but not the shape of the spectra with changes in overall heat release rate. Similar conclusions were drawn by Kotake & Takamoto (1987 who measured the influence of burner diameter and shape, flow velocity and turbulence intensity on the combustion noise spectrum.…”

Section: Introductionmentioning

confidence: 95%

Acoustic radiation from turbulent premixed flames

2009

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Turbulent combustion processes are inherently unsteady and, thus, a source of acoustic radiation. While prior studies have extensively characterized their total sound power, their spectral characteristics are not well understood. This work investigates these acoustic spectral features, including the flame's low- and high-frequency characteristics and the scaling of the frequency of peak acoustic emissions. The spatiotemporal characteristics of the flame's chemiluminescence emissions, used as a marker of heat release fluctuations, were measured and used to determine the heat release spectrum, spatial distribution and spatial coherence characteristics. These heat release characteristics were then used as inputs to an integral solution of the wave equation and compared to measured acoustic spectra obtained over a range of conditions and burners and at several spatial locations. The spectral characteristics of the flame's acoustic emissions are controlled by two processes: the underlying spectrum of heat release fluctuations that are ultimately the combustion noise source, and the transfer function relating these heat release and acoustic fluctuations. An important result from this work is the clarification of the relative roles of these two processes in controlling the shape of the acoustic spectrum. This transfer function is primarily controlled by the spatiotemporal coherence characteristics of the heat release fluctuations which are, in turn, strongly influenced by burner configuration/geometry and operating conditions. Low-frequency acoustic emissions are controlled by the heat release spectrum essentially independent of flame geometry. Both the heat release spectrum and heat release-acoustic transfer function are important at intermediate and high frequencies. An important feature of the investigated geometry that controls the heat release phase dynamics is the high-velocity flow relative to the flame speed and anchored character of the flame. This leads to convection of flame sheet disturbances (i.e. heat release fluctuations) along the front that dominates the high frequency and peak frequency scaling of the flame's acoustic emissions.

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“…It is, therefore, only affected by the fuel type used. Putnam 14 , Kilham and Kirmani 15 and Petala and Petala 16 independently found through their own experiments that the total sound emission from flames scaled with heat release rate.…”

Section: Introductionmentioning

confidence: 99%

Combustion Noise of Auxiliary Power Units

Pastouchenko¹,

Mendoza

Brown

2005

11th AIAA/CEAS Aeroacoustics Conference

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Noise from auxiliary power units (APU) is an important contributor to the overall level of ramp noise. Currently, ramp noise is regulated by international governing bodies as well as by individual airport. A significant component of APU noise is combustion noise. In this study, the unique spectral shape of APU combustion noise is identified. It is found that the spectral shape is the same regardless of engine size, power setting and directivity. Also, it is practically the same as that of open flame combustion noise. The frequency at the peak of the combustion noise spectrum is found to lie in the narrow range between 250 to 350 Hz. The peak sound pressure level of a given APU varies as the square of the fuel consumption rate. In the literature, suggestions have been made concerning a second combustion noise mechanism arising from the passage of hot entropy spots through the exhaust nozzle or constriction. In this investigation, no evidence has been found to indicate the existence of a second APU combustion noise component.

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Diagnostic possibilities on the basis of premixed flame noise levels

Cited by 12 publications

References 11 publications

Reynolds Number Effects in Combustion Noise

Reynolds Number Effects in Combustion Noise

Acoustic radiation from turbulent premixed flames

Combustion Noise of Auxiliary Power Units

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