Local extinction and reignition mechanism in a turbulent lifted flame

a direct numerical simulation study

Shahram Karami, Mohsen Talei, Evatt R. Hawkes, Jacqueline H. Chen

Research output: Contribution to journalArticleResearchpeer-review

4 Citations (Scopus)

Abstract

Local extinction and reignition was explored in a direct numerical simulation (DNS) dataset of a turbulent lifted flame. A lifted flame is relevant to practical combustion systems. Thirty individual extinction holes were identified as regions on the stoichiometric surface which have a product mass fraction less than a critical value. Large outwardly pushing structures caused compressive strain rates normal to the mixture-fraction iso-surface resulting to the initial creation of holes. Hole growth occurred in two phases. The edge-propagation velocity is initially negative and the fluid dynamic tangential strain rate on the hole surface is positive leading to rapid hole growth. Subsequently local compressive strain rates at the flame edge relax and the edge-flame propagation velocity switches to positive. When reignition starts the edge-propagation velocity is mainly influenced by the product-mass fraction displacement speed and exhibited a dependency on curvature and scalar dissipation rate.

Original languageEnglish
Pages (from-to)1685-1692
Number of pages8
JournalProceedings of the Combustion Institute
Volume36
Issue number2
DOIs
Publication statusPublished - 2017
Externally publishedYes

Keywords

  • Lifted flame
  • Local extinction
  • Reignition
  • Edge flame
  • DNS

Cite this

@article{2bf1482799eb4952bdb1b79556f01892,
title = "Local extinction and reignition mechanism in a turbulent lifted flame: a direct numerical simulation study",
abstract = "Local extinction and reignition was explored in a direct numerical simulation (DNS) dataset of a turbulent lifted flame. A lifted flame is relevant to practical combustion systems. Thirty individual extinction holes were identified as regions on the stoichiometric surface which have a product mass fraction less than a critical value. Large outwardly pushing structures caused compressive strain rates normal to the mixture-fraction iso-surface resulting to the initial creation of holes. Hole growth occurred in two phases. The edge-propagation velocity is initially negative and the fluid dynamic tangential strain rate on the hole surface is positive leading to rapid hole growth. Subsequently local compressive strain rates at the flame edge relax and the edge-flame propagation velocity switches to positive. When reignition starts the edge-propagation velocity is mainly influenced by the product-mass fraction displacement speed and exhibited a dependency on curvature and scalar dissipation rate.",
keywords = "Lifted flame, Local extinction, Reignition, Edge flame, DNS",
author = "Shahram Karami and Mohsen Talei and Hawkes, {Evatt R.} and Chen, {Jacqueline H.}",
year = "2017",
doi = "10.1016/j.proci.2016.07.121",
language = "English",
volume = "36",
pages = "1685--1692",
journal = "Proceedings of the Combustion Institute",
issn = "1540-7489",
publisher = "Elsevier",
number = "2",

}

Local extinction and reignition mechanism in a turbulent lifted flame : a direct numerical simulation study. / Karami, Shahram; Talei, Mohsen; Hawkes, Evatt R.; Chen, Jacqueline H.

In: Proceedings of the Combustion Institute, Vol. 36, No. 2, 2017, p. 1685-1692.

Research output: Contribution to journalArticleResearchpeer-review

TY - JOUR

T1 - Local extinction and reignition mechanism in a turbulent lifted flame

T2 - a direct numerical simulation study

AU - Karami, Shahram

AU - Talei, Mohsen

AU - Hawkes, Evatt R.

AU - Chen, Jacqueline H.

PY - 2017

Y1 - 2017

N2 - Local extinction and reignition was explored in a direct numerical simulation (DNS) dataset of a turbulent lifted flame. A lifted flame is relevant to practical combustion systems. Thirty individual extinction holes were identified as regions on the stoichiometric surface which have a product mass fraction less than a critical value. Large outwardly pushing structures caused compressive strain rates normal to the mixture-fraction iso-surface resulting to the initial creation of holes. Hole growth occurred in two phases. The edge-propagation velocity is initially negative and the fluid dynamic tangential strain rate on the hole surface is positive leading to rapid hole growth. Subsequently local compressive strain rates at the flame edge relax and the edge-flame propagation velocity switches to positive. When reignition starts the edge-propagation velocity is mainly influenced by the product-mass fraction displacement speed and exhibited a dependency on curvature and scalar dissipation rate.

AB - Local extinction and reignition was explored in a direct numerical simulation (DNS) dataset of a turbulent lifted flame. A lifted flame is relevant to practical combustion systems. Thirty individual extinction holes were identified as regions on the stoichiometric surface which have a product mass fraction less than a critical value. Large outwardly pushing structures caused compressive strain rates normal to the mixture-fraction iso-surface resulting to the initial creation of holes. Hole growth occurred in two phases. The edge-propagation velocity is initially negative and the fluid dynamic tangential strain rate on the hole surface is positive leading to rapid hole growth. Subsequently local compressive strain rates at the flame edge relax and the edge-flame propagation velocity switches to positive. When reignition starts the edge-propagation velocity is mainly influenced by the product-mass fraction displacement speed and exhibited a dependency on curvature and scalar dissipation rate.

KW - Lifted flame

KW - Local extinction

KW - Reignition

KW - Edge flame

KW - DNS

UR - http://www.scopus.com/inward/record.url?scp=85006041908&partnerID=8YFLogxK

U2 - 10.1016/j.proci.2016.07.121

DO - 10.1016/j.proci.2016.07.121

M3 - Article

VL - 36

SP - 1685

EP - 1692

JO - Proceedings of the Combustion Institute

JF - Proceedings of the Combustion Institute

SN - 1540-7489

IS - 2

ER -