A Fractal Dynamic SGS Combustion Model for Large Eddy Simulation of Turbulent Premixed Flames

Hiraoka, Katsuhiro; Minamoto, Yuki; Shimura, Masayasu; Naka, Yoshifumi; Fukushima, Naoya; Tanahashi, Mamoru

doi:10.1080/00102202.2016.1195820

Cited by 6 publications

(3 citation statements)

References 49 publications

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“…This implies that in a LES calculation resolving l + p or l + 10 would be sufficient to resolve the tangential strain rate term in the context of FSD transport equation. Furthermore, the inner cut-off scale l p has been found to be of the order of flame thickness δ th which is consistent with previous analysis in the context of FSD 12,20,27 and scalar dissipation rate 15 closures.…”

Section: B Multiscale Analysis Of Tangential Strain Ratesupporting

confidence: 89%

Multiscale analysis of head-on quenching premixed turbulent flames

et al. 2018

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Multiscale analysis of wall-bounded turbulent premixed flames is performed using three-dimensional direct numerical simulation (DNS) data of flame-wall interaction (FWI). The chosen configuration represents head-on quenching of a turbulent statistically planar stoichiometric methane-air flame by an isothermal inert wall. Different turbulence intensities and chemical mechanism have been analysed. A bandpass filtering technique is utilised to analyse the influence of turbulent eddies of varying size and the statistics of vorticity and strain rate fields associated with them. It is found that the presence of the flame does not alter the mechanism of vortex stretching in turbulent flows when the flame is away from the wall, but in the case of FWI, the mechanism of vortex stretching is altered due to a reduction in the contribution from non-local strain, and the small scales of turbulence start to contribute to flame straining process. The results indicate that small scale eddies do not contribute to the tangential strain rate when the flames are away from the walls, whereas the contribution from the small scales to the tangential strain rate increases when the flame is in the vicinity of the wall. It is also found that the choice of chemical mechanism does not influence the underlying fluid mechanical processes involved in flame-wall interaction.

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Section: B Multiscale Analysis Of Tangential Strain Ratesupporting

confidence: 89%

Multiscale analysis of head-on quenching premixed turbulent flames

et al. 2018

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“…Jiang et al extracted and analyzed the cell information in the cellular structure to explore the correlation between the cellular structure and dynamic pressure in the limited space, proving that, when the flame expands to a certain degree, the effect of the pressure to the cellular structure is reduced. The fractural dimension is of great significance in the flame structure research and is widely used in the combustion model. − Moreover, fast Fourier transform (FFT) is also applied to investigate the effect of the flame intrinsic instability on the disturbance evolution in the flame front in a microscope …”

Section: Introductionmentioning

confidence: 99%

Experimental Study on the Turbulent Premixed Flame Structural Characteristics Based on the Wavelet Transform

Jiang

et al. 2017

Energy Fuels

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To investigate the effect of the flame inherent instabilities and turbulence on the flame structural characteristics, premixed combustion experiments of 50% H2/50% CO at a equivalence ratio of 0.6 were conducted in a turbulent combustion bomb in atmospheric temperature and pressure. The correlation degree was defined to study the correlation relation between flame structural characteristics at different moments, and the wavelet transform was used to investigate the detail components at different scales. The results indicate that, with the development of the flame, the cellular structure was enhanced and the correlation degree gradually decreased. The fluctuations of the detail components at the larger scale were stronger and included more energy, which corresponded to the main factor causing the flame front complex. With the turbulence intensity increase, the root mean square amplitude and energy of the detail components increased, leading to the increase of the interaction of different disturbances, while the correlation degree of the flame decreased. The correlation degree of the detail components presented a staggered distribution of higher and lower values, which indicated the complex changes of the disturbances at different scales.

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“…The fractal dimension derived from fractal geometry is an important parameter to quantify the degree of folds of the flame profile [22,23] and is widely used in turbulent combustion models [24,25]. The quantified study on the cellular structure under the detonation condition were studied in [26,27], Moreover, Askari and Jiang also carried out quantitative studies on the cellular structure of the expanding flame [28,29].…”

Section: Introductionmentioning

confidence: 99%

Study on the Effect of Flame Instability on the Flame Structural Characteristics of Hydrogen/Air Mixtures Based on the Fast Fourier Transform

Jiang

et al. 2017

Energies

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Abstract:In this study, the effect of flame intrinsic instability on the flame structural characteristics of hydrogen/air mixtures premixed at various equivalence ratios were experimentally investigated from the macroscopic and microscopic perspectives, respectively. The correlation degree and the relative deformation degree were defined to quantitatively study the global flame structural characteristics. Peak detection was used to capture the characteristic length of the flame and fast Fourier transform was adopted to study the components of the fluctuation of the flame front. The results show that with the development of flames, the wrinkles in the flame front increase and the correlation degree of the flame decreases. The relative deformation degree of the flame first decreases and then increases. When the equivalence ratio is 0.6, the average characteristic length initially exhibits an increasing trend, followed by a decreasing trend. The average characteristic length scale gradually increases, and the growth rate gradually decreases when the equivalence ratio ranges from 0.70 to 0.99. With the increase in the wavenumber, the amplitude of the corresponding disturbance exhibited an increasing trend followed by a decreasing one. With the development of the flame, the maximum amplitude of the disturbance shows a reverse trend, i.e., first decreasing and then increasing. The disturbances with smaller wavelengths could be further developed.

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A Fractal Dynamic SGS Combustion Model for Large Eddy Simulation of Turbulent Premixed Flames

Cited by 6 publications

References 49 publications

Multiscale analysis of head-on quenching premixed turbulent flames

Multiscale analysis of head-on quenching premixed turbulent flames

Experimental Study on the Turbulent Premixed Flame Structural Characteristics Based on the Wavelet Transform

Study on the Effect of Flame Instability on the Flame Structural Characteristics of Hydrogen/Air Mixtures Based on the Fast Fourier Transform

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