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Laminar premixed flat non-stretched lean flames of hydrogen in air

Alekseev, Vladimir LU ; Christensen, Moah LU ; Berrocal, Edouard LU ; Heimdal Nilsson, Elna LU and Konnov, Alexander LU (2015) In Combustion and Flame 162(10). p.4063-4074
Abstract
Laminar burning velocity of lean hydrogen + air flames at standard conditions is still a debated topic in combustion. The existing burning velocity measurements possess a large spread due to the use of different measurement techniques and data processing approaches. The biggest uncertainty factor in these measurements comes from the necessity to perform extrapolation to the flat flame conditions, since all of the previously obtained data were recorded in stretched flames. In the present study, laminar burning velocity of lean hydrogen + air flames and its temperature dependence were for the first time studied in stretch-free flat flames on a heat flux burner. The equivalence ratio was varied from 0.375 to 0.5 and the range of the unburned... (More)
Laminar burning velocity of lean hydrogen + air flames at standard conditions is still a debated topic in combustion. The existing burning velocity measurements possess a large spread due to the use of different measurement techniques and data processing approaches. The biggest uncertainty factor in these measurements comes from the necessity to perform extrapolation to the flat flame conditions, since all of the previously obtained data were recorded in stretched flames. In the present study, laminar burning velocity of lean hydrogen + air flames and its temperature dependence were for the first time studied in stretch-free flat flames on a heat flux burner. The equivalence ratio was varied from 0.375 to 0.5 and the range of the unburned gas temperatures was 278-358 K. The flat flames tended to form cells at adiabatic conditions, therefore special attention was paid to the issue of their appearance. The shape of the flames was monitored by taking OH* images with an EM-CCD camera. In most cases, the burning velocity had to be extrapolated from flat subadiabatic conditions, and the impact of this procedure was quantified by performing measurements in H-2 + air mixtures diluted by N-2. The effect of extrapolation was estimated to be of negligible importance for the flames at standard conditions. The measured burning velocities at 298 K showed an important difference to the previously obtained literature values. The temperature dependence of the burning velocity was extracted from the measured results. It was found to be in agreement with the trends predicted by the detailed kinetic modeling, as opposed to a vast majority of the available literature data. (C) 2015 The Combustion Institute. Published by Elsevier Inc. All rights reserved. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Hydrogen, Burning velocity, Heat flux method, Temperature dependence, Instability
in
Combustion and Flame
volume
162
issue
10
pages
4063 - 4074
publisher
Elsevier
external identifiers
  • wos:000361925600051
  • scopus:84946485461
ISSN
0010-2180
DOI
10.1016/j.combustflame.2015.07.045
language
English
LU publication?
yes
id
f419f2bf-4c56-487e-ba14-85553d5fa1cc (old id 8221408)
date added to LUP
2015-11-30 14:05:42
date last changed
2017-09-24 03:54:57
@article{f419f2bf-4c56-487e-ba14-85553d5fa1cc,
  abstract     = {Laminar burning velocity of lean hydrogen + air flames at standard conditions is still a debated topic in combustion. The existing burning velocity measurements possess a large spread due to the use of different measurement techniques and data processing approaches. The biggest uncertainty factor in these measurements comes from the necessity to perform extrapolation to the flat flame conditions, since all of the previously obtained data were recorded in stretched flames. In the present study, laminar burning velocity of lean hydrogen + air flames and its temperature dependence were for the first time studied in stretch-free flat flames on a heat flux burner. The equivalence ratio was varied from 0.375 to 0.5 and the range of the unburned gas temperatures was 278-358 K. The flat flames tended to form cells at adiabatic conditions, therefore special attention was paid to the issue of their appearance. The shape of the flames was monitored by taking OH* images with an EM-CCD camera. In most cases, the burning velocity had to be extrapolated from flat subadiabatic conditions, and the impact of this procedure was quantified by performing measurements in H-2 + air mixtures diluted by N-2. The effect of extrapolation was estimated to be of negligible importance for the flames at standard conditions. The measured burning velocities at 298 K showed an important difference to the previously obtained literature values. The temperature dependence of the burning velocity was extracted from the measured results. It was found to be in agreement with the trends predicted by the detailed kinetic modeling, as opposed to a vast majority of the available literature data. (C) 2015 The Combustion Institute. Published by Elsevier Inc. All rights reserved.},
  author       = {Alekseev, Vladimir and Christensen, Moah and Berrocal, Edouard and Heimdal Nilsson, Elna and Konnov, Alexander},
  issn         = {0010-2180},
  keyword      = {Hydrogen,Burning velocity,Heat flux method,Temperature dependence,Instability},
  language     = {eng},
  number       = {10},
  pages        = {4063--4074},
  publisher    = {Elsevier},
  series       = {Combustion and Flame},
  title        = {Laminar premixed flat non-stretched lean flames of hydrogen in air},
  url          = {http://dx.doi.org/10.1016/j.combustflame.2015.07.045},
  volume       = {162},
  year         = {2015},
}