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Title: Experimental study of premixed flames in intense isotropic turbulence

Abstract

A methodology for investigating premixed turbulent flames propagating in intense isotropic turbulence has been developed. The burner uses a turbulence generator developed by Videto and Santavicca and the flame is stabilized by weak-swirl generated by air injectors. This setup produces stable premixed turbulent flames under a wide range of mixture conditions and turbulence intensities. The experiments are designed to investigate systematically the changes in flame structures for conditions which can be classified as wrinkled laminar flames, corrugated flames, and flames with distributed reaction zones. Laser Doppler anemometry and Rayleigh scattering techniques are used to determine the turbulence and scalar statistics. In the intense turbulence, the flames are found to produce very little changes in the mean and rms velocities. Their flame speed increase linearly with turbulence intensity as for wrinkled laminar flames. The Rayleigh scattering probability density functions (pdfs) for flames within the distributed reaction zone regime are distinctly bimodal. The probabilities of the reacting states (i.e. contributions from within the reaction zone) is not higher than those of wrinkled laminar flame. These results show that there is no drastic changes in flame structures at Karlovitz number close to unity. This suggests that the Klimov-Williams criterion underpredicts the resilience ofmore » wrinkled flamelets to intense turbulence.« less

Authors:
;  [1]
  1. Lawrence Berkeley Lab., CA (United States). Combustion Group
Publication Date:
OSTI Identifier:
28066
Report Number(s):
CONF-940711-
Journal ID: CBFMAO; ISSN 0010-2180; TRN: IM9516%%192
Resource Type:
Journal Article
Journal Name:
Combustion and Flame
Additional Journal Information:
Journal Volume: 100; Journal Issue: 3; Conference: 25. international symposium on combustion, Irvine, CA (United States), 31 Jul - 5 Aug 1994; Other Information: PBD: Feb 1995
Country of Publication:
United States
Language:
English
Subject:
40 CHEMISTRY; FLAMES; MORPHOLOGY; TURBULENT FLOW; BURNERS; FLAME PROPAGATION; LAMINAR FLOW; LASER DOPPLER ANEMOMETERS; COMBUSTION KINETICS; MATHEMATICAL MODELS

Citation Formats

Bedat, B, and Cheng, R K. Experimental study of premixed flames in intense isotropic turbulence. United States: N. p., 1995. Web. doi:10.1016/0010-2180(94)00138-I.
Bedat, B, & Cheng, R K. Experimental study of premixed flames in intense isotropic turbulence. United States. doi:10.1016/0010-2180(94)00138-I.
Bedat, B, and Cheng, R K. Wed . "Experimental study of premixed flames in intense isotropic turbulence". United States. doi:10.1016/0010-2180(94)00138-I.
@article{osti_28066,
title = {Experimental study of premixed flames in intense isotropic turbulence},
author = {Bedat, B and Cheng, R K},
abstractNote = {A methodology for investigating premixed turbulent flames propagating in intense isotropic turbulence has been developed. The burner uses a turbulence generator developed by Videto and Santavicca and the flame is stabilized by weak-swirl generated by air injectors. This setup produces stable premixed turbulent flames under a wide range of mixture conditions and turbulence intensities. The experiments are designed to investigate systematically the changes in flame structures for conditions which can be classified as wrinkled laminar flames, corrugated flames, and flames with distributed reaction zones. Laser Doppler anemometry and Rayleigh scattering techniques are used to determine the turbulence and scalar statistics. In the intense turbulence, the flames are found to produce very little changes in the mean and rms velocities. Their flame speed increase linearly with turbulence intensity as for wrinkled laminar flames. The Rayleigh scattering probability density functions (pdfs) for flames within the distributed reaction zone regime are distinctly bimodal. The probabilities of the reacting states (i.e. contributions from within the reaction zone) is not higher than those of wrinkled laminar flame. These results show that there is no drastic changes in flame structures at Karlovitz number close to unity. This suggests that the Klimov-Williams criterion underpredicts the resilience of wrinkled flamelets to intense turbulence.},
doi = {10.1016/0010-2180(94)00138-I},
journal = {Combustion and Flame},
number = 3,
volume = 100,
place = {United States},
year = {1995},
month = {2}
}