Large eddy simulation of vortex breakdown/flame interaction

Duwig, Christophe; Fuchs, László

doi:10.1063/1.2749812

Cited by 61 publications

(56 citation statements)

References 35 publications

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“…The temporal phase shift ensures orthogonality of the time terms and is common for POD modes that appear in pairs. 36,37 In Fig. 19, frequency analysis in Fourier space is carried out.…”

Section: G Proper Orthogonal Decompositionmentioning

confidence: 99%

Large-eddy simulation of highly underexpanded transient gas jets

Vuorinen¹,

Yu²,

Tirunagari³

et al. 2013

Physics of Fluids

157

142

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Large-eddy simulations (LES) based on scale-selective implicit filtering are carried out in order to study the effect of nozzle pressure ratios on the characteristics of highly underexpanded jets. Pressure ratios ranging from 4.5 to 8.5 with Reynolds numbers of the order 75 000-140 000 are considered. The studied configuration agrees well with the classical picture of the structure of highly underexpanded jets. Similarities and differences between simulation and experiments are discussed by comparing the concentration field structures from LES and planar laser induced fluorescence data. The transient stages, leading eventually to the highly underexpanded state, are visualized and investigated in terms of a phase diagram revealing the shock speeds and duration of the transient stages. For the studied nozzle pressure ratio range, the Mach disk dimensions are found to be in good agreement with literature data and experimental observations. It is observed how the nozzle pressure ratio influences the Mach disk width, and thereby the slip line separation, which leads to co-annular jets with inner and outer shear layers at higher pressure ratios. The improved mixing with increasing pressure ratio is demonstrated by the probability density functions of the concentration. The coherent structures downstream of the Mach disk are identified using proper orthogonal decomposition (POD). The structures indicate a helical mode originating from the shear layers of the jet. Despite the relatively low energy content of the dominant POD modes, the frequencies of the POD time coefficients explain the dominant frequencies in the pressure fluctuation spectra. C

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“…The temporal phase shift ensures orthogonality of the time terms and is common for POD modes that appear in pairs. 36,37 In Fig. 19, frequency analysis in Fourier space is carried out.…”

Section: G Proper Orthogonal Decompositionmentioning

confidence: 99%

Large-eddy simulation of highly underexpanded transient gas jets

Vuorinen¹,

Yu²,

Tirunagari³

et al. 2013

Physics of Fluids

157

142

View full text Add to dashboard Cite

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“…In particular, a spectacular large scale structure connected with vortex breakdown stabilisation is the Precessing Vortex Core (PVC) [13]. It has been reported [14,15] that the PVC induces very large flame fluctuations and we focus on this phenomenon. In the literature, several works focus on the response of the precessing vortex core to axial fluctuations, although they mostly deal with cold jets.…”

Section: Introductionmentioning

confidence: 99%

Large Eddy Simulation of the Sensitivity of Vortex Breakdown and Flame Stabilisation to Axial Forcing

Iudiciani

Duwig

2011

Flow Turbulence Combust

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The effect of axial forcing on the flame/vortex breakdown interaction is studied, with particular focus on the Precessing Vortex Core (PVC). Large Eddy Simulation (LES), together with a filtered flamelet model describing the subgrid combustion, is performed to study a lean premixed flame undergoing mass flow fluctuations in a wide range of frequencies and amplitude. In average, forcing at frequencies lower than the PVC characteristic frequency moves the recirculation zone upstream the combustor in the premixing tube, while higher frequencies do not relevantly affect the flow/flame. With the help of Proper Orthogonal Decomposition (POD) a detailed analysis of the dynamics of the central recirculation zone (CRZ) is performed showing how the excitation at lower frequencies weakens the PVC and allows the flame to propagate upstream. Extended POD is also applied to illustrate the flow/flame interactions during the excitation cycle.

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“…However, the use of a structured mesh with a suitable spatial resolution is a prerequisite of LES [18,19]. Uniform hexahedral mesh was built and the criterion was enough spatial and time resolution to predict correctly the energy spectrum.…”

Section: Resultsmentioning

confidence: 99%

Aerodynamic characterization of isothermal swirling flows in combustors

Parra-Santos

Vuorinen

Perez-Dominguez

et al. 2014

Int J Energy Environ Eng

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Swirl flame stabilization is widespread among burners' manufacturers, but the complex flow patterns are not yet fully understood. The interaction of two confined swirling jets leads to the formation of two recirculation zones being the flame located on the shear layer between the both zones. In such conditions, the lean mixtures can be burned producing low emissions. In the present study, flow structure and turbulent mixing of two isothermal coaxial jets are investigated using Large Eddy Simulation (LES). This is a challenging tool to achieve accuracy but it requests demanding spatial resolution and special treatment of results. By contrasting time-averaged radial profiles with experimental data of a classical benchmark, the model is validated. Results show that LES is able to reproduce the basic features of the flow pattern. Besides, the spectra analysis of instantaneous flow fields provides not only the energy decay but also the most energetic flow structures.

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Large eddy simulation of vortex breakdown/flame interaction

Cited by 61 publications

References 35 publications

Large-eddy simulation of highly underexpanded transient gas jets

Large-eddy simulation of highly underexpanded transient gas jets

Large Eddy Simulation of the Sensitivity of Vortex Breakdown and Flame Stabilisation to Axial Forcing

Aerodynamic characterization of isothermal swirling flows in combustors

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