Noise sources of an unconfined and a confined swirl burner

Pausch, Konrad; Herff, Sohel; Schröder, Wolfgang

doi:10.1016/j.jsv.2020.115293

Cited by 14 publications

(13 citation statements)

References 49 publications

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“…The SPL spectra of the unconfined swirl flame for all APE‐4 sources (solid black line) and the heat release source

q_{e, h}

alone (dotted red line) [37]…”

Section: Resultsmentioning

confidence: 99%

“…Visualization of the instantaneous flame front position by the

c_{s} = 0.5

iso‐contours colored by the flame front curvature of (A) the unconfined swirl flame and (B) the unconfined jet burner from Section 4.2 [37]…”

Section: Resultsmentioning

confidence: 99%

“…Schematics (not to scale) of the computational setups of the LES (A) and the CAA simulations (B) of the swirl flame configuration. The reference length

D_{SB} = 12

mm is the diameter of the injection tube located between the swirler and the combustion chamber [37]. The two monitoring positions in the CAA domain are indicated by the crosses.…”

Section: Numerical Configurationsmentioning

confidence: 99%

“…The bottom of figure (B) shows every fourth grid point of the CAA mesh of the combustion chamber. The source region is colored in red [37]…”

Section: Numerical Configurationsmentioning

confidence: 99%

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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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“…The SPL spectra of the unconfined swirl flame for all APE‐4 sources (solid black line) and the heat release source

q_{e, h}

alone (dotted red line) [37]…”

Section: Resultsmentioning

confidence: 99%

“…Visualization of the instantaneous flame front position by the

c_{s} = 0.5

iso‐contours colored by the flame front curvature of (A) the unconfined swirl flame and (B) the unconfined jet burner from Section 4.2 [37]…”

Section: Resultsmentioning

confidence: 99%

“…Schematics (not to scale) of the computational setups of the LES (A) and the CAA simulations (B) of the swirl flame configuration. The reference length

D_{SB} = 12

mm is the diameter of the injection tube located between the swirler and the combustion chamber [37]. The two monitoring positions in the CAA domain are indicated by the crosses.…”

Section: Numerical Configurationsmentioning

confidence: 99%

“…The bottom of figure (B) shows every fourth grid point of the CAA mesh of the combustion chamber. The source region is colored in red [37]…”

Section: Numerical Configurationsmentioning

confidence: 99%

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

et al. 2021

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“…In addition, the relationship between swirl flow and thermoacoustic instability has been studied numerically by means of computational fluid dynamics (CFD) simulations [19]. Huang et al [20] examined swirling intensity effects on the pressure and heat release fluctuations of swirling flames by conducting a large eddy simulation (LES).…”

Section: Introductionmentioning

confidence: 99%

Generation and Mitigation Mechanism Studies of Nonlinear Thermoacoustic Instability in a Modelled Swirling Combustor with a Heat Exchanger

2021

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In the present work, 3D Unsteady Reynolds-Averaged Navier-Stokes (URANS) simulations are performed to investigate the generation and mitigation mechanism of combustion-sustained thermoacoustic instabilities in a modelled swirl combustor. The effects of (1) swirling number SN, (2) inlet air flow rate Va and (3) inlet temperature Ti on the amplitudes and frequencies of swirling combustion-excited limit cycle oscillations are examined. It is found that the amplitude of acoustic fluctuations is increased with increasing SN and Va and decreased with the increase of Ti. The dominant frequency of oscillations is also found to increases with the increase of SN and Va. However, increasing Ti leads to the dominant frequency being decreased first and then increased. An alternative passive control method of installing an adjustable temperature heat exchanger on the combustion chamber wall is then proposed. Numerical results show that thermoacoustic oscillations could be excited and mitigated by setting the heat exchanger temperature to TH. Global and local Rayleigh indexes are applied to further reveal the excitation and attenuation effects on mechanisms. The present study is conducive to developing a simulation platform for thermoacoustic instabilities in swirling combustors. It also provides an alternative method to amplify or mitigate thermoacoustic oscillations.

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