Large eddy simulation of reacting flows applied to bluff body stabilized flames

Fureby, Christer; Möller, Sven-Inge

doi:10.2514/3.12989

Cited by 107 publications

(49 citation statements)

References 27 publications

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“…This new velocity field is obtained by convolution of the LES filtered velocity with the test filter. The subgrid stress corresponding to the scales in between the grid filter width and the test filter width can be written as [11]: (8) and the corresponding dissipation is defined as Assuming stress similarity and the present model to be valid for length scales between A and 2A (which imposes a further restriction that the test filter width is also in the inertia! range of length scales), <; ; -and e can be written as follows.…”

Section: Les Modelmentioning

confidence: 99%

Large eddy simulation of premixed flames in Couette flow

Menon

Chakravarthy

1996

32nd Joint Propulsion Conference and Exhibit

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Section: Les Modelmentioning

confidence: 99%

Large eddy simulation of premixed flames in Couette flow

Menon

Chakravarthy

1996

32nd Joint Propulsion Conference and Exhibit

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“…All simulations in this study are non-reactive, and the impact of these diffusion terms is expected to be small. Also,T" 9 " and E^9 8 are usually found to be very small (Fureby and Moller [1995], Veynante and Poinsot [1996]), and will be neglected in the present study as well. The determination of the local value of the subgrid kinetic energy k sgs is needed for the evaluation of the eddy viscosity, and is described next.…”

Section: )mentioning

confidence: 90%

Hybrid LES of Detonations in Reacting Multi-Phase Mixtures

Menon¹,

Génin²

2009

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REPORT DOCUMENTATION PAGEThe public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing the burden, to Department of Defense, Washington Headquarters Services, Directorate for Information Operations and Reports (0704-0188), 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to any penalty for failing to comply with a collection of information if it does not display a currently valid 0MB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. REPORT DATE (DD-MM-YYYY) 28-02-2009 2. REPORT TYPE Final Report DATES COVERED {From -To)December 1 PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES)School of Aerospace Engineering Georgia Institute of Technology Atlanta, GA 30332 PERFORMING ORGANIZATION REPORT NUMBERCCL-TR-2009-02-1 SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES)AFOSR/NL 4015 Wilson Blvd ? Arlington, VA 22203 Dr. Fariba Fahroo SPONSOR/MONITORS ACRONYM(S)AFOSR/NM SPONSOR/MONITORS REPORT NUMBER(S) DISTRIBUTION/AVAILABILITY STATEMENTUnlimited, Unclassified SUPPLEMENTARY NOTES ABSTRACTA Large-Eddy Simulation (LES) methodology adapted to the resolution of high Reynolds number turbulent flows in supersonic conditions was proposed and developed. A novel numerical scheme was designed, that switches from a low-dissipation central scheme for turbulence resolution to a flux difference splitting scheme in regions of discontinuities. A state-of-the-art closure model was extended in order to take compressibility effects and the action of shock / turbulence interaction into account. The proposed method was validated and employed for the study of shock / turbulent shear layer interaction as a mixing-augmentation technique, and highlighted the efficiency in mixing improvement after the interaction, but also the limited spatial extent of this turbulent enhancement. A second study focused on the injection of a sonic jet normally to a supersonic crossflow. The validity of the simulation was assessed by comparison with experimental data, and the dynamics of the interaction was examined. The sources of vortical structures were identified, with a particular emphasis on the impact of the flow speed onto the vortical evolution. It is shown that the developed hybrid methodology permits a capture of shock / turbulence interactions in direct simulations that agrees well with other reference simulations, and that the LES methodology effectively reproduces the turbulence evolution and physical phenomena involved in the interaction. This numerical approach is then employed to study a problem of practical importance in high-speed mixing. The inter...

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“…Although specific literature on the effects of syngas compositions on flashback due to turbulent flame propagation is limited, the topic of turbulence-kinetics interactions is well studied and can be found in the following references [10][11][12]. Other authors such as Candel [13] have also addressed various issues of turbulent flame propagation flashback in premixed combustion conditions.…”

Section: B Turbulent Flame Propagation In the Core Flowmentioning

confidence: 99%

Effects of Combustion-Induced Vortex Breakdown on Flashback Limits of Syngas-Fueled Gas Turbine Combustors

Choudhuri¹

2011

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Turbine combustors of advanced power systems have goals to achieve very low pollutants emissions, fuel variability, and fuel flexibility. Future generation gas turbine combustors should tolerate fuel compositions ranging from natural gas to a broad range of syngas without sacrificing operational advantages and low emission characteristics. Additionally, current designs of advanced turbine combustors use various degrees of swirl and lean premixing for stabilizing flames and controlling high temperature NO x formation zones. However, issues of fuel variability and NO x control through premixing also bring a number of concerns, especially combustor flashback and flame blowout.Flashback is a combustion condition at which the flame propagates upstream against the gas stream into the burner tube. Flashback is a critical issue for premixed combustor designs, because it not only causes serious hardware damages but also increases pollutant emissions. In swirl stabilized lean premixed turbine combustors onset of flashback may occur due to (i) boundary layer flame propagation (critical velocity gradient), (ii) turbulent flame propagation in core flow, (iii) combustion instabilities, and (iv) upstream flame propagation induced by combustion induced vortex breakdown (CIVB).Flashback due to first two foregoing mechanisms is a topic of classical interest and has been studied extensively. Generally, analytical theories and experimental determinations of laminar and turbulent burning velocities model these mechanisms with sufficient precision for design usages. However, the swirling flow complicates the flashback processes in premixed combustions and the first two mechanisms inadequately describe the flashback propensity of most practical combustor designs.The presence of hydrogen in syngas significantly increases the potential for flashback. Due to high laminar burning velocity and low lean flammability limit, hydrogen tends to shift the combustor operating conditions towards flashback regime. Even a small amount of hydrogen in a fuel blend triggers the onset of flashback by altering the kinetics and thermophysical characteristics of the mixture. Additionally, the presence of hydrogen in the fuel mixture modifies the response of the flame to the global effects of stretch and preferential diffusion.Despite its immense importance in fuel flexible combustor design, little is known about the magnitude of fuel effects on CIVB induced flashback mechanism. Hence, this project investigates the effects of syngas compositions on flashback resulting from combustion induced vortex breakdown. The project uses controlled experiments and parametric modeling to understand the velocity field and flame interaction leading to CIVB driven flashback.

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Large eddy simulation of reacting flows applied to bluff body stabilized flames

Cited by 107 publications

References 27 publications

Large eddy simulation of premixed flames in Couette flow

Large eddy simulation of premixed flames in Couette flow

Hybrid LES of Detonations in Reacting Multi-Phase Mixtures

Effects of Combustion-Induced Vortex Breakdown on Flashback Limits of Syngas-Fueled Gas Turbine Combustors

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