Linear and non-linear forced response of a conical, ducted, laminar premixed flame

Karimi, Nader; Brear, Michael J.; Jin, Seong-Ho; Monty, Jason

doi:10.1016/j.combustflame.2009.06.027

Cited by 81 publications

(75 citation statements)

References 29 publications

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“…This model was later verified experimentally by Karimi et al [17]. In their experiment a ducted flame was subjected to harmonic downstream travelling acoustic disturbances with varying amplitude and frequency [17]. Karimi et al found that Schuller's linear theory matched their experimental results generally well [17].…”

Section: Introductionmentioning

confidence: 86%

“…(1) and experiment at higher frequencies. This model was later verified experimentally by Karimi et al [17]. In their experiment a ducted flame was subjected to harmonic downstream travelling acoustic disturbances with varying amplitude and frequency [17].…”

Section: Introductionmentioning

confidence: 89%

“…Laminar flames are often investigated experimentally [17], theoretically [18] and numerically [19,20] to obtain fundamental understanding on the essential physics of flame and sound wave interactions. The resultant physical insight is mostly transferable to more complex cases which include turbulent flames [21].…”

Section: Introductionmentioning

confidence: 99%

“…[17,22,23]. Response of the flame is characterised by the velocity modulations just upstream of the flame and the perturbations in the instantaneous flame heat release [17].…”

Section: Introductionmentioning

confidence: 99%

“…[17,22,23]. Response of the flame is characterised by the velocity modulations just upstream of the flame and the perturbations in the instantaneous flame heat release [17]. In the linear limit, a transfer function is then defined as the ratio of the disturbances in heat release and upstream mixture velocity, respectively normalised by the mean heat release and mixture velocity [5].…”

Section: Introductionmentioning

confidence: 99%

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Response of a conical, laminar premixed flame to low amplitude acoustic forcing – A comparison between experiment and kinematic theories

Karimi

2014

Energy

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This paper presents an experimental study on the dynamics of a ducted, conical, laminar premixed flame subjected to low amplitude acoustic excitation from upstream. The heat release response of the flame to velocity disturbances is investigated through measurement of the so called 'flame transfer function' for a wide range of forcing frequencies. The results are compared with those predicted by the existing linear kinematic theories. It is observed that these theories are in general agreement with the experiment, although there exist some disparities. A detailed comparison of the experimental data with the kinematic theories shows that the phase speed of flame disturbances has an essential influence upon the level of agreement between the theory and experiment. The data set presented in this work complements that reported in an earlier study. In keeping with others, visualisation of the excited flames clearly shows that the flame response includes waves on the flame front which are formed at the base and then convect along the flame.

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Section: Introductionmentioning

confidence: 86%

Section: Introductionmentioning

confidence: 89%

Section: Introductionmentioning

confidence: 99%

“…[17,22,23]. Response of the flame is characterised by the velocity modulations just upstream of the flame and the perturbations in the instantaneous flame heat release [17].…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Response of a conical, laminar premixed flame to low amplitude acoustic forcing – A comparison between experiment and kinematic theories

Karimi

2014

Energy

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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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Analysis of the sound sources of lean premixed methane–air flames

et al. 2021

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Two investigations on the sound generation mechanisms of lean methane–air flames are reviewed and linked. A two‐step approach is used for the analysis. First, the compressible conservation equations are solved in a large‐eddy simulation formulation to compute the acoustic source terms of the reacting fluid. Second, the acoustic source terms are used in computational aeroacoustics simulations to determine the acoustic field by solving the acoustic perturbation equations. To identify the contributions of the different source terms to the overall sound emission of the flames different source term formulations are considered in the computational aeroacoustics simulations. The results of various flames of increasing complexity are shown: harmonically excited laminar flames, a turbulent jet flame, and an unconfined and a confined swirl flame. The results show that in general the heat release source alone does not determine the acoustic emission of the flame. Only the acoustic emission of the unconfined swirl flame could be computed by the heat release source. To accurately predict the phase and the amplitude of the sound emission of the other flames the acceleration of density gradients occurring at the flame front must be included in the considered set of source terms.

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Linear and non-linear forced response of a conical, ducted, laminar premixed flame

Cited by 81 publications

References 29 publications

Response of a conical, laminar premixed flame to low amplitude acoustic forcing – A comparison between experiment and kinematic theories

Response of a conical, laminar premixed flame to low amplitude acoustic forcing – A comparison between experiment and kinematic theories

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

Analysis of the sound sources of lean premixed methane–air flames

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