Numerical study of the superadiabatic flame temperature phenomenon in hydrocarbon premixed flames

Download
  1. (PDF, 972 KB)
  2. Get@NRC: Numerical study of the superadiabatic flame temperature phenomenon in hydrocarbon premixed flames (Opens in a new window)
AuthorSearch for: ; Search for: ; Search for: ; Search for:
TypeArticle
Journal titleProceedings of the Combustion Institute
Volume29
Pages15431550; # of pages: 8
AbstractThe phenomenon of superadiabatic flame temperature that was numerically predicted and experimentally observed in rich acetylene/oxygen flames used in chemical vapor deposition of diamond layers is of fundamental interest to combustion science. The chemical mechanism of this phenomenon has not been systematically studied. In this paper, the structure of planar freely propagating premixed flames of mixtures of CH4/air, CH4/O2, C2H2/H2/O2, C2H4/O2, C3H8/O2 and H2/O2 was computed using detailed chemistry and complex thermal and transport properties to gain an insight into the common chemical mechanism responsible for this phenomenon in these flames. It was found that superadiabatic temperatures occur only in hydrocarbon flames when the equivalence ratio of the mixture is greater than a critical value, but not in hydrogen flames. The superadiabatic temperature in these hydrocarbon flames is associated with superequilibrium concentrations of some hydrocarbon species and H2O, and with negative heat production rates at the end of main heat release reactions. The net negative heat production is caused by the endothermic dissociation reactions of these superequilibrium larger hydrocarbon molecules into smaller ones and of H2O into H2 and OH. In hydrogen flames, neither the concentration of H2O nor the flame temperature exceeds their superequilibrium level. Radiation heat loss has negligible effect on the peak flame temperature and therefore does not affect the occurrence or the degree of superadiabatic temperatures.
Publication date
LanguageEnglish
AffiliationNRC Institute for Chemical Process and Environmental Technology; National Research Council Canada (NRC-CNRC)
Peer reviewedNo
NRC number51498
NPARC number12327429
Export citationExport as RIS
Report a correctionReport a correction
Record identifier84055070-ea52-4b05-b458-fe969f8ac31e
Record created2009-09-10
Record modified2016-05-09
Bookmark and share
  • Share this page with Facebook (Opens in a new window)
  • Share this page with Twitter (Opens in a new window)
  • Share this page with Google+ (Opens in a new window)
  • Share this page with Delicious (Opens in a new window)