Assessment of the performances of sub-grid scalar flux models for premixed flames with different global Lewis numbers: A Direct Numerical Simulation analysis

Gao, Yuan; Chakraborty, Nilanjan; Klein, Markus

doi:10.1016/j.ijheatfluidflow.2014.10.022

Cited by 30 publications

(34 citation statements)

References 52 publications

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“…Interested readers are referred to [11,12] for examples of LES implementations of FSD based reaction rate closures. A-priori analysis of both FRDI and SGSF terms individually was reported by the authors in the past [13][14][15]. Recent a-posteriori analyses [16,17] …”

Section: ∂ (ρC) /∂T+∇· (ρũC) = −∇ · (ρUc −ρũC) + ∇ · (ρD∇c) +ω Cmentioning

confidence: 97%

“…5 is responsible for gradient transport (GT), whereas the second term −ρ 0 S L M i (c −c) accounts for counter-gradient transport (CGT). Variants of this model have been discussed in Chakraborty and Klein [14,15] and only one representative model will be considered here for the sake of brevity. Nevertheless it is worth mentioning that Lecocq et al [8] suggested that replacingc on the right hand side of Eq.…”

Section: Closures For Sub-grid Scalar Flux (Sgsf)mentioning

confidence: 99%

“…Hence the CGM model inherently accounts for the possibility of CGT (GT) when (u i ) P >(u i ) R (u i ) P <(u i ) R and ∂c/∂x i > 0. It was demonstrated in [14,15] that the CM model performs very well in a-priori analysis despite the fact that it was originally proposed for momentum transport in the context of incompressible flows.…”

Section: Closures For Sub-grid Scalar Flux (Sgsf)mentioning

confidence: 99%

“…For flames with Le ≈ 1 turbulence effects become relatively strong and the amount of CGT is reduced for cases C, D, E with Le = 0.8, 1.0, 1.2. Details are presented in [14,15] and are not repeated here. In contrast to [14,15], the analysis of the SGSF models is done here in terms of the divergence of the scalar flux T SGSF i rather than the individual vector components.…”

Section: Analysis Of Sub-grid Scalar Flux Modelsmentioning

confidence: 99%

“…Details are presented in [14,15] and are not repeated here. In contrast to [14,15], the analysis of the SGSF models is done here in terms of the divergence of the scalar flux T SGSF i rather than the individual vector components. This is due to the fact that only the scalar expression ∂ T SGSF i /∂x i can be combined with T F RDI .…”

Section: Analysis Of Sub-grid Scalar Flux Modelsmentioning

confidence: 99%

See 4 more Smart Citations

Analysis of the Combined Modelling of Sub-grid Transport and Filtered Flame Propagation for Premixed Turbulent Combustion

Klein

Chakraborty

Pfitzner

2016

Flow Turbulence Combust

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Flame surface density (FSD) based reaction rate closure is an important methodology of turbulent premixed flame modelling in the context of Large Eddy Simulations (LES). The transport equation for the Favre-filtered reaction progress variable needs closure of the filtered reaction diffusion imbalance (FRDI) term (i.e. filtered value of combined reaction rate and molecular diffusion rate) and the sub-grid scalar flux (SGSF). A-priori analysis of the FRDI and SGSF terms has in the past revealed advantages and disadvantages of the specific modelling attempts. However, it is important to understand the interaction of the FRDI and SGSF closures for a successful implementation of the FSD based closure. Furthermore, it is not known a-priori if the combination of the best SGSF model with the best FRDI model results in the most suitable overall modelling strategy. In order to address this question, a variety of SGSF models is analysed in this work together with one well established and one recent FRDI closure based on a-priori analysis. It is found that the success of the combined FRDI and SGSF closures depends on subtle details like the co-variances of the FRDI and SGSF terms. It is demonstrated that the gradient hypothesis model is not very successful in representing the SGSF term. However the gradient hypothesis provides satisfactory performance in combination of a recently proposed FRDI closure, whereas unsatisfactory results are obtained when used in combination with another existing closure, which was shown to predict the FRDI term satisfactorily in several previous analyses.

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Section: ∂ (ρC) /∂T+∇· (ρũC) = −∇ · (ρUc −ρũC) + ∇ · (ρD∇c) +ω Cmentioning

confidence: 97%

Section: Closures For Sub-grid Scalar Flux (Sgsf)mentioning

confidence: 99%

Section: Closures For Sub-grid Scalar Flux (Sgsf)mentioning

confidence: 99%

Section: Analysis Of Sub-grid Scalar Flux Modelsmentioning

confidence: 99%

Section: Analysis Of Sub-grid Scalar Flux Modelsmentioning

confidence: 99%

See 3 more Smart Citations

Analysis of the Combined Modelling of Sub-grid Transport and Filtered Flame Propagation for Premixed Turbulent Combustion

Klein

Chakraborty

Pfitzner

2016

Flow Turbulence Combust

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Evaluations of SGS Combustion, Scalar Flux and Stress Models in a Turbulent Jet Premixed Flame

Hiraoka

Naka

Shimura

et al. 2016

Flow Turbulence Combust

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Statistics of Scalar Flux Transport of Major Species in Different Premixed Turbulent Combustion Regimes for H2-air Flames

Papapostolou

Chakraborty

Klein

et al. 2019

Flow Turbulence Combust

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The statistical behaviour of turbulent scalar flux and modelling of its transport have been analysed for both major reactants and products in the context of Reynolds Averaged Navier Stokes simulations using a detailed chemistry Direct Numerical Simulation (DNS) database of freely-propagating H 2 −air flames (with an equivalence ratio of 0.7) spanning the corrugated flamelets, thin reaction zones and broken reaction zones regimes of premixed turbulent combustion. The turbulent scalar flux in the cases representing the corrugated flamelets and thin reaction zones regimes of combustion exhibit predominantly countergradient transport, whilst a gradient transport has been observed for the broken reaction zones regime flame considered here. It has been found that the qualitative behaviour of the various terms of the turbulent scalar flux transport equation for the major species such as H 2 , O 2 and H 2 O in the cases representing the corrugated flamelets and thin reaction zones regimes of combustion are mostly similar, whilst the behaviour is markedly different for the case representing the broken reaction zone regime. However, the terms for the scalar flux transport equation for H 2 and O 2 show same signs whereas the corresponding terms for H 2 O show signs opposite to those for H 2 and O 2 . The performances of the well-established existing models for the unclosed terms of the turbulent scalar flux transport equation have been found to be similar for H 2 , O 2 and H 2 O Some of the existing models for turbulent flux, pressure gradient, molecular diffusion and reaction contributions have been found to yield reasonable performance for the cases representing the corrugated flamelets and thin reaction zones regimes but the existing closures for these terms have been found to be mostly inadequate for the broken reaction zones regime flames.

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Assessment of the performances of sub-grid scalar flux models for premixed flames with different global Lewis numbers: A Direct Numerical Simulation analysis

Cited by 30 publications

References 52 publications

Analysis of the Combined Modelling of Sub-grid Transport and Filtered Flame Propagation for Premixed Turbulent Combustion

Analysis of the Combined Modelling of Sub-grid Transport and Filtered Flame Propagation for Premixed Turbulent Combustion

Evaluations of SGS Combustion, Scalar Flux and Stress Models in a Turbulent Jet Premixed Flame

Statistics of Scalar Flux Transport of Major Species in Different Premixed Turbulent Combustion Regimes for H2-air Flames

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