Effect of pressure on the transfer functions of premixed methane and propane swirl flames

Sabatino, Francesco Di; Guiberti, Thibault F.; Boyette, Wesley R.; Roberts, William L.; Moeck, Jonas P.; Lacoste, Déanna A.

doi:10.1016/j.combustflame.2018.03.011

Cited by 44 publications

(23 citation statements)

References 34 publications

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“…Figure 10 shows that the magnitude of the FTF gain at 176 Hz is proportional to FVR max . This result is in agreement with that of [32]…”

Section: A Relation Between Fvr and Ftf Gainsupporting

confidence: 93%

“…It is used to highlight the flame boundaries in order to help in visualizing the flame dynamics and the flame vortex roll-up mechanism. As shown in a previous study [32], choosing a different value for the iso-contour has no influence on the analysis and conclusions. The acoustically generated vortex (AGV) and the outer recirculation zone (ORZ) are also highlighted in these figures.…”

Section: A Flame Transfer Functionsmentioning

confidence: 61%

“…At low frequency, the gain approaches one and the phase approaches zero [47]. Focusing on the gain, a local minimum is found at 112 Hz followed by a local maximum at 176 Hz [15,17,32,48,49]. The competition between the fluctuations of the bottom region of the flame, generated by the oscillations of the flame base angle driven by the fluctuations of the swirl number [15,18], and the oscillations of the top region due to flame vortex roll-up [6,13,15,19,[21][22][23], generates this distinctive trend of the gain.…”

Section: A Flame Transfer Functionsmentioning

confidence: 99%

“…1. A detailed description can be found in Lacoste et al [31] and Di Sabatino et al [32]. The gaseous fuel and air are premixed 2 meters before being injected into a plenum of 120 mm length.…”

Section: A Premixed Swirl-stabilized Burner and Experimental Conditionsmentioning

confidence: 99%

See 3 more Smart Citations

Fuel and Equivalence Ratio Effects on Transfer Functions of Premixed Swirl Flames

Sabatino¹,

Guiberti²,

Moeck

et al. 2020

Journal of Propulsion and Power

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This paper reports on the effects of fuel and equivalence ratio on the response of lean premixed swirl flames to acoustic perturbations of the flow, at atmospheric pressure. The response is analyzed using flame transfer functions, which relate the relative heat release rate fluctuations from the flame to the relative velocity fluctuations of the incoming flow. Two fuels, propane and methane, and five equivalence ratios are considered. The ten flames investigated are selected to exhibit the local maximum of the transfer function gain around the same frequency, 176 Hz. The results show that changing fuel and equivalence ratio influences both

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“…Figure 10 shows that the magnitude of the FTF gain at 176 Hz is proportional to FVR max . This result is in agreement with that of [32]…”

Section: A Relation Between Fvr and Ftf Gainsupporting

confidence: 93%

Section: A Flame Transfer Functionsmentioning

confidence: 61%

Section: A Flame Transfer Functionsmentioning

confidence: 99%

Section: A Premixed Swirl-stabilized Burner and Experimental Conditionsmentioning

confidence: 99%

See 2 more Smart Citations

Fuel and Equivalence Ratio Effects on Transfer Functions of Premixed Swirl Flames

Sabatino¹,

Guiberti²,

Moeck

et al. 2020

Journal of Propulsion and Power

Self Cite

View full text Add to dashboard Cite

show abstract

“…The authors conjectured, that this observation could be attributed to the effects on the phase between heat release and dynamic pressure oscillations introduced upon adjusting the elevated pressure. In [27], the authors studied the effects of elevated pressure (up to five bar), on the flame shape and transfer function of a swirl stabilized fully premixed gas turbine burner. The flame shape was mostly unaltered by elevated pressures and it was thereby concluded that the mechanisms dictating the thermoacoustically induced flame motion were mostly independent from mean pressure.…”

Section: Introductionmentioning

confidence: 99%

Thermoacoustic phenomena in an industrial gas turbine combustor at two different mean pressures

Karlis

Hardalupas

Taylor

et al. 2019

AIAA Scitech 2019 Forum

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The current paper studies the thermoacoustically unstable combustion, under elevated mean pressure, of a commercial swirl stabilized gas turbine burner fitted with optically accessible windows. We study natural gas flames at mean pressures of 3, 4 and 6 bar which delivered thermal loads equal to 335 kW, 474kW and 685 kW respectively, at constant equivalence ratios and bulk velocities. In the 3 bar case, dynamic pressure bursts were observed amidst a quiescent acoustic background. The flame anchored on the shear layers of the recirculation zone and it periodically expanded in the outer recirculation zone (ORZ). In the 4 and 6 bar cases, the flame was thermoacoustically unstable with seldom requiescent events, with suppressed expansion to the ORZ. Dynamic Mode Decomposition on high speed images from the 3 bar case, showed that said expansion introduced an additional time scale, further to the fundamental acoustic timescale. A physical mechanism is suggested to link dynamics and flame shape differences on adjusting mean pressure. The premixture is characterized by a Lewis number lower than unity, the laminar flame speed increases on decreasing mean pressure and the flow imposed on the flame strain rate oscillated over a period of thermoacoustic instability. This combination resulted in local oscillations of the heat release rate, in the region of the outer shear layers. The phenomenon was pronounced in the 3 bar case, due to higher flow dilatation imposed strain rates than the 4 and 6 bar cases.

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A novel method for the identification of flame front’s position on thermoacoustic coupling combustion oscillations

Gao

Peng

Huang

et al. 2021

Energy Science & Engineering

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The flame front area is an important parameter to quantify the heat release rate. However, the limitations imposed by the measuring instruments and the measurement methodologies make it difficult to determine the flame front position in an image. This work introduces a method to detect and optimize the flame front boundary. A high‐speed camera was employed to continuously capture the flame images. By setting appropriate intensity thresholds, the impact noise can be eliminated from the image and the flame front boundary can be determined. The binary diagram of the image was morphologically processed to obtain the normalized area fluctuations of the flame front in a temporally resolved manner. Two flame types and combustion regimes were studied. A LABVIEW‐based program was used for the synchronous triggering of the camera, the photomultiplier, and the microphones. The normalized area and photomultiplier output signals of a multiple flame burner obtained within the same period were compared and combined with the spectrum information from the microphone in the cavity. The trend charts were investigated in terms of the Pearson correlation coefficient. The results showed a strong correlation, thereby verifying the feasibility of this method.

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Effect of pressure on the transfer functions of premixed methane and propane swirl flames

Cited by 44 publications

References 34 publications

Fuel and Equivalence Ratio Effects on Transfer Functions of Premixed Swirl Flames

Fuel and Equivalence Ratio Effects on Transfer Functions of Premixed Swirl Flames

Thermoacoustic phenomena in an industrial gas turbine combustor at two different mean pressures

A novel method for the identification of flame front’s position on thermoacoustic coupling combustion oscillations

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