LES of Delft Jet-in-Hot Coflow burner to investigate the effect of preferential diffusion on autoignition of CH4/H2 flames

Ebrahim Abtahizadeh, P. de Goey, J. van Oijen

Research output: Contribution to journalArticle

9 Citations (Scopus)
16 Downloads (Pure)

Abstract

This paper reports on numerical investigations of preferential diffusion effects in Large Eddy Simulation (LES) of turbulent lifted CH4/H2 flames. For this purpose, a combined LES and Flamelet Generated Manifolds (FGM) model is developed to simulate the Delft Jet-in-Hot Coflow (DJHC) burner. A novel type of flamelets, entitled “IML Flamelets”, has been used to tabulate the chemistry. IML flamelets are capable to incorporate preferential diffusion effects in autoigniting flames. The IML technique is coupled with LES to simulate the DJHC burner with CH4/H2 fuels where CH4 has been enriched with H2 ranging from 0% to 25% of the fuel volume. The significance of this study is to illustrate complex interactions of molecular diffusion, chemistry and turbulent transport. A good agreement has been found between LES and measurements for the velocity and OH fields. It turns out that preferential diffusion has a significant influence on the lift-off height and stabilization mechanism of the lifted H2-enriched turbulent flames. Predictions of the 0%H2 case indicate that inclusion of preferential diffusion in the combustion model modestly affects lift-off heights. However, for 5%H2, 10% H2 and 25%H2 cases, inclusion of preferential diffusion in the model affects strongly lift-off heights yielding much improved predictions compared to the unity Lewis number model. Predictions of lift-off heights and formation of ignition kernels agree very well with the measured instantaneous snapshots of OH chemiluminescence. It turns out that the combined FGM-IML approach can successfully capture main features of turbulent lifted flames such as formation of ignition kernels and stabilization mechanisms.

NOTICE: this is the author’s version of a work that was accepted for publication in Fuel. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Fuel, [191, March (2016)] DOI: 10.1016/j.fuel.2016.11.054

© 2016, Elsevier. Licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International http://creativecommons.org/licenses/by-nc-nd/4.0/
Original languageEnglish
Pages (from-to)36-45
JournalFuel
Volume191
Issue numberMarch 2017
DOIs
Publication statusPublished - 22 Nov 2016

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Large eddy simulation
Fuel burners
Ignition
Stabilization
Chemiluminescence
Quality control

Bibliographical note

Due to publisher policy, the full text is not available on the repository until the 22nd of November 2017.

Keywords

  • Turbulent combustion
  • Large Eddy Simulation
  • Flamelet Generated Manifolds
  • Autoignition
  • Preferential diffusion
  • Mild combustion

Cite this

LES of Delft Jet-in-Hot Coflow burner to investigate the effect of preferential diffusion on autoignition of CH4/H2 flames. / Abtahizadeh, Ebrahim; de Goey, P.; van Oijen, J.

In: Fuel, Vol. 191, No. March 2017, 22.11.2016, p. 36-45.

Research output: Contribution to journalArticle

Abtahizadeh, Ebrahim ; de Goey, P. ; van Oijen, J. / LES of Delft Jet-in-Hot Coflow burner to investigate the effect of preferential diffusion on autoignition of CH4/H2 flames. In: Fuel. 2016 ; Vol. 191, No. March 2017. pp. 36-45.
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AU - de Goey, P.

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N2 - This paper reports on numerical investigations of preferential diffusion effects in Large Eddy Simulation (LES) of turbulent lifted CH4/H2 flames. For this purpose, a combined LES and Flamelet Generated Manifolds (FGM) model is developed to simulate the Delft Jet-in-Hot Coflow (DJHC) burner. A novel type of flamelets, entitled “IML Flamelets”, has been used to tabulate the chemistry. IML flamelets are capable to incorporate preferential diffusion effects in autoigniting flames. The IML technique is coupled with LES to simulate the DJHC burner with CH4/H2 fuels where CH4 has been enriched with H2 ranging from 0% to 25% of the fuel volume. The significance of this study is to illustrate complex interactions of molecular diffusion, chemistry and turbulent transport. A good agreement has been found between LES and measurements for the velocity and OH fields. It turns out that preferential diffusion has a significant influence on the lift-off height and stabilization mechanism of the lifted H2-enriched turbulent flames. Predictions of the 0%H2 case indicate that inclusion of preferential diffusion in the combustion model modestly affects lift-off heights. However, for 5%H2, 10% H2 and 25%H2 cases, inclusion of preferential diffusion in the model affects strongly lift-off heights yielding much improved predictions compared to the unity Lewis number model. Predictions of lift-off heights and formation of ignition kernels agree very well with the measured instantaneous snapshots of OH chemiluminescence. It turns out that the combined FGM-IML approach can successfully capture main features of turbulent lifted flames such as formation of ignition kernels and stabilization mechanisms.NOTICE: this is the author’s version of a work that was accepted for publication in Fuel. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Fuel, [191, March (2016)] DOI: 10.1016/j.fuel.2016.11.054© 2016, Elsevier. Licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International http://creativecommons.org/licenses/by-nc-nd/4.0/

AB - This paper reports on numerical investigations of preferential diffusion effects in Large Eddy Simulation (LES) of turbulent lifted CH4/H2 flames. For this purpose, a combined LES and Flamelet Generated Manifolds (FGM) model is developed to simulate the Delft Jet-in-Hot Coflow (DJHC) burner. A novel type of flamelets, entitled “IML Flamelets”, has been used to tabulate the chemistry. IML flamelets are capable to incorporate preferential diffusion effects in autoigniting flames. The IML technique is coupled with LES to simulate the DJHC burner with CH4/H2 fuels where CH4 has been enriched with H2 ranging from 0% to 25% of the fuel volume. The significance of this study is to illustrate complex interactions of molecular diffusion, chemistry and turbulent transport. A good agreement has been found between LES and measurements for the velocity and OH fields. It turns out that preferential diffusion has a significant influence on the lift-off height and stabilization mechanism of the lifted H2-enriched turbulent flames. Predictions of the 0%H2 case indicate that inclusion of preferential diffusion in the combustion model modestly affects lift-off heights. However, for 5%H2, 10% H2 and 25%H2 cases, inclusion of preferential diffusion in the model affects strongly lift-off heights yielding much improved predictions compared to the unity Lewis number model. Predictions of lift-off heights and formation of ignition kernels agree very well with the measured instantaneous snapshots of OH chemiluminescence. It turns out that the combined FGM-IML approach can successfully capture main features of turbulent lifted flames such as formation of ignition kernels and stabilization mechanisms.NOTICE: this is the author’s version of a work that was accepted for publication in Fuel. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Fuel, [191, March (2016)] DOI: 10.1016/j.fuel.2016.11.054© 2016, Elsevier. Licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International http://creativecommons.org/licenses/by-nc-nd/4.0/

KW - Turbulent combustion

KW - Large Eddy Simulation

KW - Flamelet Generated Manifolds

KW - Autoignition

KW - Preferential diffusion

KW - Mild combustion

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DO - 10.1016/j.fuel.2016.11.054

M3 - Article

VL - 191

SP - 36

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JO - Fuel

JF - Fuel

SN - 0016-2361

IS - March 2017

ER -