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Title: Local extinction Karlovitz number for premixed flames

Abstract

The extinction of laminar premixed flames under the influence of stretch is studied experimentally and numerically. Experiment involves measuring the velocity field of methane/air and propane/air flames in an opposed jet with a laser Doppler velocimeter and computations are made using several chemical kinetic mechanisms. The major result is that, in contrast to the various previous claims of extinction Karlovitz number being anywhere between 0.03 and 20, it is found to be constant around unity for the mixtures tested. That is, premixed flames are extinguished when the physical flow time approximately equals the chemical reaction time. Here the relevant chemical reaction time is not the one computed using the one-dimensional flame properties as originally suggested in the formulation of Karlovitz number, but rather it is the one obtained using the stretched flame properties which fully reflect the effect of straining on the flame structure.

Authors:
;  [1]; ;  [2]
  1. Seoul National Univ. (Korea, Republic of)
  2. Michigan Technological Univ., Houghton, MI (United States). Dept. of Mechanical Engineering and Engineering Mechanics
Publication Date:
OSTI Identifier:
413468
Resource Type:
Journal Article
Journal Name:
Combustion and Flame
Additional Journal Information:
Journal Volume: 106; Journal Issue: 4; Other Information: PBD: Sep 1996
Country of Publication:
United States
Language:
English
Subject:
03 NATURAL GAS; FLAMES; INHIBITION; METHANE; COMBUSTION KINETICS; PROPANE; MORPHOLOGY; QUENCHING

Citation Formats

Chung, S H, Chung, D H, Fu, C, and Cho, P. Local extinction Karlovitz number for premixed flames. United States: N. p., 1996. Web. doi:10.1016/0010-2180(96)00109-5.
Chung, S H, Chung, D H, Fu, C, & Cho, P. Local extinction Karlovitz number for premixed flames. United States. doi:10.1016/0010-2180(96)00109-5.
Chung, S H, Chung, D H, Fu, C, and Cho, P. Sun . "Local extinction Karlovitz number for premixed flames". United States. doi:10.1016/0010-2180(96)00109-5.
@article{osti_413468,
title = {Local extinction Karlovitz number for premixed flames},
author = {Chung, S H and Chung, D H and Fu, C and Cho, P},
abstractNote = {The extinction of laminar premixed flames under the influence of stretch is studied experimentally and numerically. Experiment involves measuring the velocity field of methane/air and propane/air flames in an opposed jet with a laser Doppler velocimeter and computations are made using several chemical kinetic mechanisms. The major result is that, in contrast to the various previous claims of extinction Karlovitz number being anywhere between 0.03 and 20, it is found to be constant around unity for the mixtures tested. That is, premixed flames are extinguished when the physical flow time approximately equals the chemical reaction time. Here the relevant chemical reaction time is not the one computed using the one-dimensional flame properties as originally suggested in the formulation of Karlovitz number, but rather it is the one obtained using the stretched flame properties which fully reflect the effect of straining on the flame structure.},
doi = {10.1016/0010-2180(96)00109-5},
journal = {Combustion and Flame},
number = 4,
volume = 106,
place = {United States},
year = {1996},
month = {9}
}