Scalar mixing in direct numerical simulations of temporally evolving plane jet flames with skeletal CO/H2 kinetics

Evatt R. Hawkes; Ramanan Sankaran; James C. Sutherland; Jacqueline H. Chen

doi:10.1016/j.proci.2006.08.079

Scalar mixing in direct numerical simulations of temporally evolving plane jet flames with skeletal CO/H₂ kinetics

Evatt R. Hawkes, Ramanan Sankaran, James C. Sutherland, Jacqueline H. Chen

Research output: Contribution to journal › Conference article › peer-review

229 Scopus citations

Abstract

Direct numerical simulations of three-dimensional turbulent temporally evolving plane CO/H₂ jet flames are performed with detailed chemistry at Reynolds numbers of up to 9000 and with up to 500 million grid points. The effect of Reynolds number on turbulent mixing properties and flame structure is quantified for low Damköhler number flames. These flames exhibit strong flame-turbulence interactions resulting in local extinction followed by re-ignition. The probability density of the stoichiometric scalar dissipation rate is found to be nearly log-normal with some negative skewness. Conditional statistics of the hydroxyl radical reveal increasing levels of extinction and longer re-ignition times with increasing Reynolds number. The mechanical-to-scalar mixing time scale ratio, a key quantity in transported probability density function (pdf) modeling, is investigated for both conserved and reacting scalars. The conserved scalar timescale ratio is found to be consistent with prior studies. For reacting scalars, the effects of molecular diffusivity and chemical reaction on the timescale ratio are quantified.

Original language	English
Pages (from-to)	1633-1640
Number of pages	8
Journal	Proceedings of the Combustion Institute
Volume	31 I
Issue number	1
DOIs	https://doi.org/10.1016/j.proci.2006.08.079
State	Published - 2007
Externally published	Yes
Event	31st International Symposium on Combustion - Heidelberg, Germany Duration: Aug 5 2006 → Aug 11 2006

Funding

This work was supported by the Division of Chemical Sciences, Geosciences and Biosciences, the Office of Basic Energy Sciences, the US Department of Energy (DOE). This research used resources of the National Energy Research Computing Center (NERSC), of the National Center for Computational Sciences at Oak Ridge National Laboratory (NCCS/ORNL) which are supported by the Office of Science of the US DOE under contract nos. DE-AC03-76SF00098 and DE-AC05-00OR22725, respectively. This research was performed in part using the MSCF in EMSL, a national scientific user facility sponsored by the US DOE, OBER and located at PNNL. We acknowledge the award from DOE’s Innovative and Novel Computational Impact on Theory and Experiments (INCITE) program and the excellent computing support provided by Mark Fahey of NCCS and David Skinner of NERSC.

Keywords

Direct numerical simulation
Jet flames
Mixing
Scalar dissipation rate
Turbulent nonpremixed combustion

Access to Document

10.1016/j.proci.2006.08.079

Cite this

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title = "Scalar mixing in direct numerical simulations of temporally evolving plane jet flames with skeletal CO/H2 kinetics",

abstract = "Direct numerical simulations of three-dimensional turbulent temporally evolving plane CO/H2 jet flames are performed with detailed chemistry at Reynolds numbers of up to 9000 and with up to 500 million grid points. The effect of Reynolds number on turbulent mixing properties and flame structure is quantified for low Damk{\"o}hler number flames. These flames exhibit strong flame-turbulence interactions resulting in local extinction followed by re-ignition. The probability density of the stoichiometric scalar dissipation rate is found to be nearly log-normal with some negative skewness. Conditional statistics of the hydroxyl radical reveal increasing levels of extinction and longer re-ignition times with increasing Reynolds number. The mechanical-to-scalar mixing time scale ratio, a key quantity in transported probability density function (pdf) modeling, is investigated for both conserved and reacting scalars. The conserved scalar timescale ratio is found to be consistent with prior studies. For reacting scalars, the effects of molecular diffusivity and chemical reaction on the timescale ratio are quantified.",

keywords = "Direct numerical simulation, Jet flames, Mixing, Scalar dissipation rate, Turbulent nonpremixed combustion",

author = "Hawkes, {Evatt R.} and Ramanan Sankaran and Sutherland, {James C.} and Chen, {Jacqueline H.}",

year = "2007",

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language = "English",

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journal = "Proceedings of the Combustion Institute",

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note = "31st International Symposium on Combustion ; Conference date: 05-08-2006 Through 11-08-2006",

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AU - Hawkes, Evatt R.

AU - Sankaran, Ramanan

AU - Sutherland, James C.

AU - Chen, Jacqueline H.

PY - 2007

Y1 - 2007

N2 - Direct numerical simulations of three-dimensional turbulent temporally evolving plane CO/H2 jet flames are performed with detailed chemistry at Reynolds numbers of up to 9000 and with up to 500 million grid points. The effect of Reynolds number on turbulent mixing properties and flame structure is quantified for low Damköhler number flames. These flames exhibit strong flame-turbulence interactions resulting in local extinction followed by re-ignition. The probability density of the stoichiometric scalar dissipation rate is found to be nearly log-normal with some negative skewness. Conditional statistics of the hydroxyl radical reveal increasing levels of extinction and longer re-ignition times with increasing Reynolds number. The mechanical-to-scalar mixing time scale ratio, a key quantity in transported probability density function (pdf) modeling, is investigated for both conserved and reacting scalars. The conserved scalar timescale ratio is found to be consistent with prior studies. For reacting scalars, the effects of molecular diffusivity and chemical reaction on the timescale ratio are quantified.

AB - Direct numerical simulations of three-dimensional turbulent temporally evolving plane CO/H2 jet flames are performed with detailed chemistry at Reynolds numbers of up to 9000 and with up to 500 million grid points. The effect of Reynolds number on turbulent mixing properties and flame structure is quantified for low Damköhler number flames. These flames exhibit strong flame-turbulence interactions resulting in local extinction followed by re-ignition. The probability density of the stoichiometric scalar dissipation rate is found to be nearly log-normal with some negative skewness. Conditional statistics of the hydroxyl radical reveal increasing levels of extinction and longer re-ignition times with increasing Reynolds number. The mechanical-to-scalar mixing time scale ratio, a key quantity in transported probability density function (pdf) modeling, is investigated for both conserved and reacting scalars. The conserved scalar timescale ratio is found to be consistent with prior studies. For reacting scalars, the effects of molecular diffusivity and chemical reaction on the timescale ratio are quantified.

KW - Direct numerical simulation

KW - Jet flames

KW - Mixing

KW - Scalar dissipation rate

KW - Turbulent nonpremixed combustion

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