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Title: Uncertainty quantification in LES of a turbulent bluff-body stabilized flame

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Publication Date:
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
Resource Type:
Journal Article: Publisher's Accepted Manuscript
Journal Name:
Proceedings of the Combustion Institute
Additional Journal Information:
Journal Volume: 35; Journal Issue: 2; Related Information: CHORUS Timestamp: 2017-05-17 09:35:04; Journal ID: ISSN 1540-7489
Country of Publication:
United States

Citation Formats

Khalil, Mohammad, Lacaze, Guilhem, Oefelein, Joseph C., and Najm, Habib N. Uncertainty quantification in LES of a turbulent bluff-body stabilized flame. United States: N. p., 2015. Web. doi:10.1016/j.proci.2014.05.030.
Khalil, Mohammad, Lacaze, Guilhem, Oefelein, Joseph C., & Najm, Habib N. Uncertainty quantification in LES of a turbulent bluff-body stabilized flame. United States. doi:10.1016/j.proci.2014.05.030.
Khalil, Mohammad, Lacaze, Guilhem, Oefelein, Joseph C., and Najm, Habib N. 2015. "Uncertainty quantification in LES of a turbulent bluff-body stabilized flame". United States. doi:10.1016/j.proci.2014.05.030.
title = {Uncertainty quantification in LES of a turbulent bluff-body stabilized flame},
author = {Khalil, Mohammad and Lacaze, Guilhem and Oefelein, Joseph C. and Najm, Habib N.},
abstractNote = {},
doi = {10.1016/j.proci.2014.05.030},
journal = {Proceedings of the Combustion Institute},
number = 2,
volume = 35,
place = {United States},
year = 2015,
month = 1

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record at 10.1016/j.proci.2014.05.030

Citation Metrics:
Cited by: 4works
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  • This paper reports on an axisymmetric bluff body stabilized nonpremixed turbulent flame of 27.5% CO/32.3% H{sub 2}/40.2% N{sub 2}-in-air. The recirculation zone stabilized the flame and provided greater strain rates than possible in jet or even piloted-jet flames. Major species, density, and temperature were measured using a laser Raman scattering system, which was modified to operate in a chemiluminescent environment. The computational model was based on partial equilibrium in the radical pool, an assumed shape pdf over the two thermochemical variables required, and the k-{epsilon} turbulence model for closure of the density-weighted averaged Navier Stokes equations. The equations were solvedmore » in the elliptic form appropriate to recirculating flow. Enough grid was added to reduce the transverse cell Reynolds numbers to below two, ensuring second-order accurate and stable discretization of convection operators and so eliminating artificial diffusion. Mean properties such as density were obtained at each node by convolution with the joint pdf over the two thermochemical scalars. The k-{epsilon} turbulence model gave too rapid an initial decay. agreement was encouraging on mixture fraction mean and variance, temperature, and species concentration fields.« less
  • A large-eddy simulation (LES) of a bluff-body-stabilized flame has been carried out using a new strategy for LES grid generation. The recursive filter-refinement procedure (RFRP) has been used to generate optimized clustering for variable density combustion simulations. A methane-hydrogen fuel-based bluff-body-stabilized experimental configuration has been simulated using state-of-the-art LES algorithms and subfilter models. The combustion chemistry is described using a precomputed, laminar flamelet model-based look-up table. The GRI-2.11 mechanism is used to build the look-up table parameterized by mixture fraction and scalar dissipation rate. A beta function is used for the subfilter mixture fraction filtered density function (FDF). The simulationsmore » show good agreement with experimental data for the velocity field. Time-averaged profiles of major species and temperature are very well reproduced by the simulation. The mixture fraction profiles show excellent agreement at all locations, which helps in understanding the validity of flamelet assumption for this flame. The results indicate that LES computations are able to quantitatively predict the flame structure quite accurately using the laminar flamelet model. Simulations tend to corroborate experimental evidence that local extinction is not significant for this flame.« less
  • Large-eddy simulations have been performed for a turbulent nonpremixed bluff-body stabilized CH{sub 4}:H{sub 2} (50:50 vol.) flame at a Reynolds number of 15,800. The corresponding isothermal flow has also been computed. The Sydney bluff-body burner under consideration has been investigated experimentally by Masri and co-workers, who obtained velocity and scalar statistics. The focus of the current work is on flow and mixing effects with the thermochemistry evaluated using a steady-state laminar flamelet approach. The incompressible (low-Mach-number) governing equations for mass, momentum, and mixture-fraction have been solved on a structured cylindrical grid and resolution effects investigated using up to 3.643x10{sup 6}more » nodes. The corresponding nonreactive case was resolved by 5.76x10{sup 5} nodes, resulting in a resolution of more than 80% of the turbulence kinetic energy. The reacting case yields a resolution in excess of 75% on the finest grid--arguably sufficient to permit conclusions regarding the accuracy of submodels. Comparisons with experimental data show that for high resolutions comparatively good agreement is obtained for the flow field and for species other than nitric oxide. However, resolution effects are important and results obtained with 4.51x10{sup 5} nodes show that a resolution of less than 70% of the turbulent kinetic energy is insufficient in the context of the Smagorinsky subgrid model combined with the dynamic procedure of Germano. The latter result is consistent with the analysis of Pope.« less
  • Abstract not provided.