Active Control of Combustion Instability in a Ramjet Using Large-Eddy Simulations

Menon, Suresh

doi:10.21236/ada255226

Cited by 5 publications

(4 citation statements)

References 11 publications

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“…For the studies described, the AF scheme was used and applied with sub-iterations to remove the splitting error. For subgrid modeling, the code includes a compressible version of the algebraic Smagorinsky model 11 as well as a one-equation model of Menon 12 . The one equation model solves a transport equation for subgrid turbulent kinetic energy, k sgs .…”

Section: High Altitude Modelingmentioning

confidence: 99%

Scramjet Propulsive Flowpath Prediction Improvements Using Recent Modeling Upgrades

Ott

Kannepalli

Brinckman

et al. 2005

43rd AIAA Aerospace Sciences Meeting and Exhibit

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Reynolds Averaged Navier Stokes simulations have been performed to examine modeling upgrades for scramjet flowpath predictions. A flush, non-reacting hydrogen fuel injector flowfield was used as the model problem, and an LES simulation of the problem was used for comparison purposes. Calculations were first performed examining the effect of Schmidt number with a constant Prandtl number. Next the effect of the compressibility correction used was examined. These findings indicated that for this injector configuration, the effect of the compressibility had a major impact on the solution, and that the average Schmidt number of about 0.45 compared closely to the LES simulation results. Next, a new scalar fluctuation model was used to obtain local values of Prandtl and Schmidt number whose values were found to vary significantly across the fuel jet mixing layer. The turbulent Prandtl number was found to vary between 0.4 to 0.9, and the turbulent Schmidt number varied from 0.6 to 1.2. Finally, a comparison was performed using an unstructured flow solver with grid adaptation. This technique is now being used to obtain grid resolved solutions in a systematic and straightforward manner in our design studies. Public reporting burden for the 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 this burden, to Washington Headquarters Services, Directorate for Information Operations and Reports, 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 a penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number.

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Section: High Altitude Modelingmentioning

confidence: 99%

Scramjet Propulsive Flowpath Prediction Improvements Using Recent Modeling Upgrades

Ott

Kannepalli

Brinckman

et al. 2005

43rd AIAA Aerospace Sciences Meeting and Exhibit

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“…In this case ft/ should be a heavy side function of G, however, this produces a numerical instability when the flame front is steeply varying. Menon (1991) has pointed out that the linear dependence on G results in a distributed heat release that tracks the flame and does not cause significant error as long as the front is not a broad front.…”

Section: G-equation Flamelet Modelmentioning

confidence: 99%

Subgrid combustion modeling for premixed turbulent reacting flows

Smith

Menon

1998

36th AIAA Aerospace Sciences Meeting and Exhibit

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Two combustion models for turbulent premixed combustion in the flamelet regime are developed for unsteady simulations. The first model is a convensional G equation flamelet model and the main issues discussed are the subgrid closure. The second model is based on the Linear-Eddy Model. Both models are used in simulation of turbulent stagnation point flames. The heat release and turbulence intensity are varied. Time averaged statistics from convensional simulations show good qualitative agreement with experiments and the normalized turbulent flame speed agrees well with the experimental data. Counter-gradient scalar diffusion is observed in high heat release, low turbulence intensity flames. This raises the question about how important the gradient diffusion approximation is to these results. Preliminary results from LES-LEM simulations involving moderate heat release and high turbulence intensities are reported. The key role of the front tracking algorithm is demonstrated. Qualitative trends in the burning rates with varying turbulence intensity is also demonstrated.

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“…In this case hj should be a heavy side function of G, however, this produces a numerical instability when the flame front is steeply varying. Menon (1991) has pointed out that the linear dependence on G results in a distributed heat release that tracks the flame and does not cause significant error as long as the front is not a broad front.…”

Section: Thin Flame Propagation Modelmentioning

confidence: 99%

Large-eddy simulations of turbulent reacting stagnation point flows

Smith

Menon

1997

35th Aerospace Sciences Meeting and Exhibit

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A methodology for solving unsteady premixed turbulent flame propagation problems in high Reynolds number (Re), high Damkoehler number spatially evolving flows is developed. The method is based on Large-Eddy Simulation (LES) with a subgrid combustion model based on the Linear-Eddy Model (Kerstein, 1991). An inter-LES cell burning mechanism has been added to the present formulation to account for molecular diffusion (burning) across LES cells which was been neglected in earlier studies. Two-dimensional simulations of passive isotropic flame propagation using the LES-LEM for Re from 100 to 1000 are conducted to validate the subgrid and supergrid propagation mechanisms. Two models are used to simulate turbulent premixed stagnation point flames. The first model is a conventional approach which uses a thin flame model (Kerstein et al., 1988) , 1991). An inter-LES cell burning mechanism has been added to the present formulation to account for molecular diffusion (burning) across LES cells which was been neglected in earlier studies. Two-dimensional simulations of passive isotropic flame propagation using the LES-LEM for Re from 100 to 1000 are conducted to validate the subgrid and supergrid propagation mechanisms. Two models are used to simulate turbulent premixed stagnation point flames. The first model is a conventional approach which uses a thin flame model (Kerstein ti al, 1988) with and without significant heat release. The second model uses the LES-LEM approach without heat release. Qualitative comparisons between simulations and experimental data are made.

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Active Control of Combustion Instability in a Ramjet Using Large-Eddy Simulations

Cited by 5 publications

References 11 publications

Scramjet Propulsive Flowpath Prediction Improvements Using Recent Modeling Upgrades

Scramjet Propulsive Flowpath Prediction Improvements Using Recent Modeling Upgrades

Subgrid combustion modeling for premixed turbulent reacting flows

Large-eddy simulations of turbulent reacting stagnation point flows

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