Experimental investigation of Darrieus-Landau instability effects on turbulent premixed flames

G. Troiani, F. Creta, Moshe Matalon

Research output: Contribution to journalConference article

Abstract

The turbulent propagation speed of a premixed flame can be significantly enhanced by the onset of Darrieus-Landau (DL) instability within the wrinkled and corrugated flamelet regimes of turbulent combustion. Previous studies have revealed the existence of clearly distinct regimes of turbulent propagation, depending on the presence of DL instabilities or lack thereof, named here as super- and subcritical respectively, characterized by different scaling laws for the turbulent flame speed. In this study we present experimental turbulent flame speed measurements for propane/air mixtures at atmospheric pressure, variable equivalence ratio at Lewis numbers greater than one obtained within a Bunsen geometry with particle image velocimetry diagnostics. By varying the equivalence ratio we act on the cut-off wavelength and can thus control DL instability. A classification of observed flames into sub/supercritical regimes is achieved through the characterization of their morphology in terms of flame curvature statistics. Numerical low-Mach number simulations of weakly turbulent two-dimensional methane/air slot burner flames are also performed both in the presence or absence of DL instability and are observed to exhibit similar morphological properties. We show that experimental normalized turbulent propane flame speeds ST/SL are subject to two distinct scaling laws, as a function of the normalized turbulence intensity Urms/SL, depending on the sub/supercritical nature of the propagation regime. We also conjecture, based on the experimental results, that at higher values of turbulence intensity a transition occurs whereby the effects of DL instability become shadowed by the dominant effect of turbulence.

Original languageEnglish (US)
Pages (from-to)1451-1459
Number of pages9
JournalProceedings of the Combustion Institute
Volume35
Issue number2
DOIs
StatePublished - Jan 1 2015
Event30th International Symposium on Combustion - Chicago, IL, United States
Duration: Jul 25 2004Jul 30 2004

Fingerprint

turbulent flames
premixed flames
flames
Propane
Turbulence
Scaling laws
turbulence
propane
scaling laws
propagation
equivalence
turbulent combustion
Lewis numbers
air
Methane
burners
particle image velocimetry
Air
Fuel burners
Mach number

Keywords

  • Bunsen flames
  • Darrieus-Landau instability
  • Flame curvature
  • Premixed turbulent flames
  • Turbulent propagation speed

ASJC Scopus subject areas

  • Chemical Engineering(all)
  • Mechanical Engineering
  • Physical and Theoretical Chemistry

Cite this

Experimental investigation of Darrieus-Landau instability effects on turbulent premixed flames. / Troiani, G.; Creta, F.; Matalon, Moshe.

In: Proceedings of the Combustion Institute, Vol. 35, No. 2, 01.01.2015, p. 1451-1459.

Research output: Contribution to journalConference article

@article{58da1e3cdc164596a92464f4ae48ae6d,
title = "Experimental investigation of Darrieus-Landau instability effects on turbulent premixed flames",
abstract = "The turbulent propagation speed of a premixed flame can be significantly enhanced by the onset of Darrieus-Landau (DL) instability within the wrinkled and corrugated flamelet regimes of turbulent combustion. Previous studies have revealed the existence of clearly distinct regimes of turbulent propagation, depending on the presence of DL instabilities or lack thereof, named here as super- and subcritical respectively, characterized by different scaling laws for the turbulent flame speed. In this study we present experimental turbulent flame speed measurements for propane/air mixtures at atmospheric pressure, variable equivalence ratio at Lewis numbers greater than one obtained within a Bunsen geometry with particle image velocimetry diagnostics. By varying the equivalence ratio we act on the cut-off wavelength and can thus control DL instability. A classification of observed flames into sub/supercritical regimes is achieved through the characterization of their morphology in terms of flame curvature statistics. Numerical low-Mach number simulations of weakly turbulent two-dimensional methane/air slot burner flames are also performed both in the presence or absence of DL instability and are observed to exhibit similar morphological properties. We show that experimental normalized turbulent propane flame speeds ST/SL are subject to two distinct scaling laws, as a function of the normalized turbulence intensity Urms/SL, depending on the sub/supercritical nature of the propagation regime. We also conjecture, based on the experimental results, that at higher values of turbulence intensity a transition occurs whereby the effects of DL instability become shadowed by the dominant effect of turbulence.",
keywords = "Bunsen flames, Darrieus-Landau instability, Flame curvature, Premixed turbulent flames, Turbulent propagation speed",
author = "G. Troiani and F. Creta and Moshe Matalon",
year = "2015",
month = "1",
day = "1",
doi = "10.1016/j.proci.2014.07.060",
language = "English (US)",
volume = "35",
pages = "1451--1459",
journal = "Proceedings of the Combustion Institute",
issn = "1540-7489",
publisher = "Elsevier Limited",
number = "2",

}

TY - JOUR

T1 - Experimental investigation of Darrieus-Landau instability effects on turbulent premixed flames

AU - Troiani, G.

AU - Creta, F.

AU - Matalon, Moshe

PY - 2015/1/1

Y1 - 2015/1/1

N2 - The turbulent propagation speed of a premixed flame can be significantly enhanced by the onset of Darrieus-Landau (DL) instability within the wrinkled and corrugated flamelet regimes of turbulent combustion. Previous studies have revealed the existence of clearly distinct regimes of turbulent propagation, depending on the presence of DL instabilities or lack thereof, named here as super- and subcritical respectively, characterized by different scaling laws for the turbulent flame speed. In this study we present experimental turbulent flame speed measurements for propane/air mixtures at atmospheric pressure, variable equivalence ratio at Lewis numbers greater than one obtained within a Bunsen geometry with particle image velocimetry diagnostics. By varying the equivalence ratio we act on the cut-off wavelength and can thus control DL instability. A classification of observed flames into sub/supercritical regimes is achieved through the characterization of their morphology in terms of flame curvature statistics. Numerical low-Mach number simulations of weakly turbulent two-dimensional methane/air slot burner flames are also performed both in the presence or absence of DL instability and are observed to exhibit similar morphological properties. We show that experimental normalized turbulent propane flame speeds ST/SL are subject to two distinct scaling laws, as a function of the normalized turbulence intensity Urms/SL, depending on the sub/supercritical nature of the propagation regime. We also conjecture, based on the experimental results, that at higher values of turbulence intensity a transition occurs whereby the effects of DL instability become shadowed by the dominant effect of turbulence.

AB - The turbulent propagation speed of a premixed flame can be significantly enhanced by the onset of Darrieus-Landau (DL) instability within the wrinkled and corrugated flamelet regimes of turbulent combustion. Previous studies have revealed the existence of clearly distinct regimes of turbulent propagation, depending on the presence of DL instabilities or lack thereof, named here as super- and subcritical respectively, characterized by different scaling laws for the turbulent flame speed. In this study we present experimental turbulent flame speed measurements for propane/air mixtures at atmospheric pressure, variable equivalence ratio at Lewis numbers greater than one obtained within a Bunsen geometry with particle image velocimetry diagnostics. By varying the equivalence ratio we act on the cut-off wavelength and can thus control DL instability. A classification of observed flames into sub/supercritical regimes is achieved through the characterization of their morphology in terms of flame curvature statistics. Numerical low-Mach number simulations of weakly turbulent two-dimensional methane/air slot burner flames are also performed both in the presence or absence of DL instability and are observed to exhibit similar morphological properties. We show that experimental normalized turbulent propane flame speeds ST/SL are subject to two distinct scaling laws, as a function of the normalized turbulence intensity Urms/SL, depending on the sub/supercritical nature of the propagation regime. We also conjecture, based on the experimental results, that at higher values of turbulence intensity a transition occurs whereby the effects of DL instability become shadowed by the dominant effect of turbulence.

KW - Bunsen flames

KW - Darrieus-Landau instability

KW - Flame curvature

KW - Premixed turbulent flames

KW - Turbulent propagation speed

UR - http://www.scopus.com/inward/record.url?scp=84964253460&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84964253460&partnerID=8YFLogxK

U2 - 10.1016/j.proci.2014.07.060

DO - 10.1016/j.proci.2014.07.060

M3 - Conference article

AN - SCOPUS:84964253460

VL - 35

SP - 1451

EP - 1459

JO - Proceedings of the Combustion Institute

JF - Proceedings of the Combustion Institute

SN - 1540-7489

IS - 2

ER -