The effect of mixing models in PDF calculations of piloted jet flames

Cao, Renfeng Richard; Wang, Haifeng; Pope, Stephen B.

doi:10.1016/j.proci.2006.08.052

Cited by 100 publications

(69 citation statements)

References 33 publications

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“…To circumvent the modeling of var(c), we propose a simpler and more straightforward approach than the beta-pdf. Equality (25) indicates that when the beta-pdf is evaluated, the flamelet is filtered in c-space. However, it is more straightforward to filter the flamelet directly in physical space.…”

Section: Four Sgs Modeling Approaches For Chemical Variables When Permentioning

confidence: 99%

See 1 more Smart Citation

Subgrid Scale Modeling in Large-Eddy Simulation of Turbulent Combustion Using Premixed Flamelet Chemistry

Vreman

Oijen

Goey

et al. 2008

Flow Turbulence Combust

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Large-eddy simulation (LES) of turbulent combustion with premixed flamelets is investigated in this paper. The approach solves the filtered NavierStokes equations supplemented with two transport equations, one for the mixture fraction and another for a progress variable. The LES premixed flamelet approach is tested for two flows: a premixed preheated Bunsen flame and a partially premixed diffusion flame (Sandia Flame D). In the first case, we compare the LES with a direct numerical simulation (DNS). Four non-trivial models for the chemical source term are considered for the Bunsen flame: the standard presumed beta-pdf model, and three new propositions (simpler than the beta-pdf model): the filtered flamelet model, the shift-filter model and the shift-inversion model. A priori and a posteriori tests are performed for these subgrid reaction models. In the present preheated Bunsen flame, the filtered flamelet model gives the best results in a priori tests. The LES tests for the Bunsen flame are limited to a case in which the filter width is only slightly larger than the flame thickness. According to the a posteriori tests the three models (beta-pdf, filtered flamelet and shift-inversion) show more or less the same results as the trivial model, in which subgrid reaction effects are ignored, while the shift-filter model leads to worse results. Since LES needs to resolve the large turbulent eddies, the LES filter width is bounded by a maximum. For the present Bunsen flame this means that the filter width should be of the order of the flame thickness or smaller. In this regime, the effects of subgrid reaction and subgrid flame wrinkling turn out to be quite modest. The LES-results of the second case (Sandia Flame D) are compared to experimental data. Satisfactory agreement is obtained for the main species. Comparison is made between different eddy-viscosity models for the subgrid turbulence, and the Smagorinsky eddy-viscosity is found to give worse results than eddy-viscosities that are not dominated by the mean shear.

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Section: Four Sgs Modeling Approaches For Chemical Variables When Permentioning

confidence: 99%

“…For this purpose we select the partially premixed diffusion flame, Sandia Flame D. For this flame a large amount of experimental information is available [12,13]. The flame has also been simulated many times, both LES [14][15][16][17][18][19][20][21] and RANS [22][23][24][25][26][27].…”

Section: Introductionmentioning

confidence: 99%

Subgrid Scale Modeling in Large-Eddy Simulation of Turbulent Combustion Using Premixed Flamelet Chemistry

Vreman

Oijen

Goey

et al. 2008

Flow Turbulence Combust

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“…The simulations presented in this figure are performed with 20 particles/cell, 293 the quality of predictions for test cases 1 to 3 (see Table 1) is comparable for all models and 294 none of them shows a significant dependence on the particle number. As it has been shown 295 in previous studies [4,36] the predictions for the mixture fraction depend mostly on the 296 choice of the mixing time scale that for the current work is the same for all four models.…”

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confidence: 68%

“…51 PDF methods have been extensively applied to the modelling of turbulent reacting flows and 52 a relatively recent comprehensive review is given by Haworth [14]. Of particular relevance 53 are the studies by Pope and co-workers [3,4,36] where sensitivities of the PDF modelling 54 approach towards parameters such as the mixing model [4], the mixing time scale [4] and 55 the chemical mechanism [3] were investigated. Raman and Pitsch [30] binomial Langevin-MMC model for the modelling of the velocity-scalar interactions [35] or 65 using a sparse particle method as sub-grid model for LES of the turbulent flow and mixing 66 fields [12,13].…”

mentioning

confidence: 99%

Mixing Modelling Framework Based on Multiple Mapping Conditioning for the Prediction of Turbulent Flame Extinction

Vogiatzaki

Navarro‐Martinez

et al. 2015

Flow Turbulence Combust

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This is the accepted version of the paper.This version of the publication may differ from the final published version. Abstract A stochastic implementation of the Multiple Mapping Conditioning (MMC) 8 approach has been applied to a turbulent piloted jet diffusion flame (Sandia flame F) that 9 is close to extinction. Two classic mixing models (Curl's and IEM) are introduced in the 10 MMC context to model the turbulent mixing. The suggested model involves the use of a 11 reference space (that is mapped to mixture fraction space) in order to define particle prox-12 imity. The addition of the MMC ideas to the IEM and Curl's models, that is suggested in 13 the current work, aspires to combine the simplicity of these two models with the enforced 14 compositional locality without violating the linearity and independence principles. The for-15 mulation of the approach is discussed in detail and results are presented for the mixing field 16 and reactive species. The predictions are compared with joint-scalar PDF simulations using 17 the same mixing models and experimental data. Moreover, the sensitivity of the model to 18 the particle number is examined. It is shown that MMC is less sensitive to the number of 19 particles and can generally produce improved predictions of major and minor chemically 20 reacting species with a lower number of particles. Permanent repository link 21K. Vogiatzaki

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“…Gordon et al [13] studied the auto-ignition of methane flame to understand the mechanism and showed the dominant species that controlled auto-ignition. Several authors [14][15][16] have used this method by applying different mixing models (MC, EMI and EMST) to study the effect of the model and to make a comparative analysis.…”

Section: Introductionmentioning

confidence: 99%

Untitled

2018

IJHT

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Transported probability density function (PDF) approach have been applied broadly and effectively for modelling turbulent reacting flows. The discretization of this approach is done with two methods, Multi-Environment Eulerian (MEPDF) and Lagrangian MonteCarlo (LPDF) which each method has advantages and disadvantages. The aim of this work is to investigate the capabilities of each method in predicting hydrogen combustion in a turbulent flame. A comparative study has been adopted between the two methodsby equivalent physical models and numerical parameters. The study was applied in the diffusion turbulent flame of hydrogen into a vitiated of hot coflow with modified K-epsilon model of turbulence. The chosen mixture model is the IEM (Interaction by Exchange with the Mean) with mixing constant (2.1). The number of environment in the first approach is (2.0). The model was solved in this work by the commercial CFD code, ANSYS fluent and the chemical reaction mechanism injected is GRI mech 2.1. The numerical results for temperature and species mass fractions are presented and compared with the experimental data. The comparison shows that the eulerian method gives better predictions than the lagrangian method. The advantages and disadvantages of both models are discussed in detail in relationship to the results.

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The effect of mixing models in PDF calculations of piloted jet flames

Cited by 100 publications

References 33 publications

Subgrid Scale Modeling in Large-Eddy Simulation of Turbulent Combustion Using Premixed Flamelet Chemistry

Subgrid Scale Modeling in Large-Eddy Simulation of Turbulent Combustion Using Premixed Flamelet Chemistry

Mixing Modelling Framework Based on Multiple Mapping Conditioning for the Prediction of Turbulent Flame Extinction

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