Assessment of dynamic closure for premixed combustion large eddy simulation

Langella, Ivan; Swaminathan, Nedunchezhian; Gao, Yuan; Chakraborty, Nilanjan

doi:10.1080/13647830.2015.1080387

Cited by 42 publications

(59 citation statements)

References 65 publications

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“…(1) on 4.2M grid having Δ + < 1. The DNS analysis discussed in Section 6.1 suggests that this reaction rate closure underestimates the reaction rate for Δ < δ th, which is also observed in LES (Langella et al, 2015). The results for the 1.5M grid discussed in Appendix B compares well with experimental data.…”

Section: Sensitivity Of Statisticssupporting

confidence: 75%

“…Although a reasonably robust value of β c ¼ 6:7 was established in past RANS calculations of various premixed flames (Ahmed and Swaminathan, 2013;Amzin and Swaminathan, 2013;Amzin et al, 2012;Kolla et al, 2009;Ruan et al, 2014;Swaminathan et al, 2012), this value cannot be used for LES because the processes influencing β c are effected by SGS turbulence. Thus, it can be evaluated dynamically as suggested by Langella et al (2015) and Gao et al (2014). However, a representative value guided by DNS analysis as discussed in Section 6.1 is used here to investigate the influences of u 0 Δ modeling on the reaction rate closure and LES statistics.…”

Section: Algebraic Closure For Filtered Reaction Ratementioning

confidence: 99%

“…The measurements of mean velocity and turbulent kinetic energy for a nonreacting jet are reported in Chen et al (1996) for the conditions of the F2 flame. The LES results are time averaged first over the sampling period and then averaged in azimuthal direction in order to get radial variation of mean quantities at various axial positions, as has been done by Langella et al (2015). This averaging procedure, which is also density weighted when required (Poinsot and Veynante, 2005), is denoted by using hÁ Á Ái in the following discussion.…”

Section: A Posteriori Analysismentioning

confidence: 99%

“…Three piloted stoichiometric methane-air Bunsen flames of Chen et al (1996) considered in many past RANS (Amzin et al, 2012;Herrmann, 2006;Kolla and Swaminathan, 2010b;Lindstedt and Vaos, 2006;Prasad and Gore, 1999;Salehi and Bushe, 2010;Salehi et al, 2012;Heinz, 2008, 2010) and LES (De and Acharya, 2009;Dodoulas and Navarro-Martinez, 2013;Langella et al, 2015;Pitsch and de Lagneste, 2002;Wang et al, 2011;Yilmaz et al, 2010) studies are chosen for this investigation. The reactant jet with a diameter of D = 12 mm issues into quiescent air and the flame is stabilized by laminar pilot flames of the same mixture.…”

Section: Experimental Casesmentioning

confidence: 99%

“…The geometrical category of flamelets includes thickened flame (Colin et al, 2000;De and Acharya, 2009), flame surface density or flame-wrinkling (see, for example, Boger et al 1998;Chakraborty and Cant 2007;Chakraborty and Klein 2008;Gubba et al, 2012;Hawkes and Cant 2001;Knikker et al, 2004;Wang et al, 2012), and level-set or G equation (Moureau et al, 2008;Pitsch, 2005). The statistical category of flamelets includes approaches, such as EBU (eddy-break-up model), algebraic closure involving scalar dissipation rate (Butz et al, 2015;Dunstan et al, 2013;Gao et al, 2014;Langella et al, 2015;Ma et al, 2014), and presumed probability density function (PDF) methodology with laminar flamelets. The nonflamelets category includes transported PDF and conditional moment closure (CMC) methodologies.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Large Eddy Simulation of Premixed Combustion: Sensitivity to Subgrid Scale Velocity Modeling

Langella

Swaminathan

Gao

et al. 2016

Combustion Science and Technology

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An algebraic reaction rate closure involving filtered scalar dissipation rate of reaction progress variable is studied. The filtered scalar dissipation rate closure requires a model for sub-grid scale velocity, u 0 Δ , which is estimated using four algebraic models and transported subgrid scale kinetic energy. A priori analyses using direct numerical simulation (DNS) data show that the filtered dissipation rate, and thus the reaction rate closure, has some sensitivity to the u 0 Δ model. The sensitivity of various statistics obtained from large eddy simulation (LES) of three piloted Bunsen flames of stoichiometric methaneair mixture to the modeling of u 0 Δ is observed to be weaker compared to that for the DNS analysis. Moreover, analysis using transported sub-grid scale kinetic energy does not indicate a necessity to include flame-generated turbulence in the modeling of u 0 Δ for the Bunsen flames in the thin reaction zones regime. The measured and computed flame brush structures are compared and studied and the algebraic closure for the filtered reaction rate is found to be quite good. ARTICLE HISTORY

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Section: Sensitivity Of Statisticssupporting

confidence: 75%

Section: Algebraic Closure For Filtered Reaction Ratementioning

confidence: 99%

Section: A Posteriori Analysismentioning

confidence: 99%

Section: Experimental Casesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Large Eddy Simulation of Premixed Combustion: Sensitivity to Subgrid Scale Velocity Modeling

Langella

Swaminathan

Gao

et al. 2016

Combustion Science and Technology

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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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A Posteriori Assessment of Algebraic Scalar Dissipation Models for RANS Simulation of Premixed Turbulent Combustion

Ahmed

Prosser

2017

Flow Turbulence Combust

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Citation for published version (APA):Ahmed, U., & Prosser, R. (2017). A posteriori assessment of algebraic scalar dissipation models for RANS simulation of premixed turbulent combustion. Flow, Turbulence and Combustion. https://doi.Abstract This paper examines the effects of scalar dissipation rate modelling on mean reaction rate predictions in turbulent premixed flames. The sensitivity of the mean reaction rate is explored by using different closures for scalar dissipation and the sensitivity of the scalar dissipation models themselves is also examined with respect to their defining constants. The influence of different scalar dissipation models on the flame location and mean velocities is reported and compared with experimental results. The predicted reaction rate is found to be sensitive to the choice of closure used for scalar dissipation and also to the respective constants used in the scalar dissipation models. It is also found that the scalar dissipation models involving chemical and turbulent time scales yield a more physically plausible reaction rate when compared with the scalar dissipation models relying only on the turbulent time scale.Keywords Algebraic scalar dissipation models · Flame turbulence interaction · RANS simulation of premixed turbulent combustion · Premixed turbulent combustion · Turbulence scalar interaction 1 Introduction Accurate prediction of the mean reaction rate using computational methods remains a challenge for premixed turbulent combustion, and usually requires the use of statistical methods. There is a strong coupling between turbulence and chemistry in premixed flames and several modelling strategies have been developed to account for their interaction. In many cases, the total aerothermochemistry of the flow can be described via a Probability Density Function (PDF) and a multidimensional PDF can in principal be obtained by a PDF transport equation [31,59]. This procedure circumvents a number of modelling assumptions and consequently produces quite general reaction rate models. However the method requires a closure for the molecular diffusion terms which remains a modelling challenge [31]. Conditional Moment Closure (CMC) is another method which provides an alternative strategy for closing the reaction rate [39]. This method was originally developed for non-premixed combustion [16,51] and recently has been extended to account for premixed combustion [5,4,49]. One of the major challenges encountered by the CMC approach in premixed combustion is the modelling of the conditional scalar dissipation rate [43].

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Assessment of dynamic closure for premixed combustion large eddy simulation

Cited by 42 publications

References 65 publications

Large Eddy Simulation of Premixed Combustion: Sensitivity to Subgrid Scale Velocity Modeling

Large Eddy Simulation of Premixed Combustion: Sensitivity to Subgrid Scale Velocity Modeling

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

A Posteriori Assessment of Algebraic Scalar Dissipation Models for RANS Simulation of Premixed Turbulent Combustion

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