Effects of diluents on cellular instabilities in outwardly propagating spherical syngas-air premixed flames

Tran Manh Vu, Jeong Park, Oh Boong Kwon, Dae Seok Bae, Jin Han Yun, Sang In Keel

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86 Citations (Scopus)

Abstract

Experiments were conducted in a constant pressure combustion chamber using schlieren system to investigate the effects of carbon dioxide-nitrogen-helium diluents on cellular instabilities of syngas-air premixed flames at room temperature and elevated pressures. The cellular instabilities for the diluted syngas-air flames were interpreted and evaluated in the viewpoint of the hydrodynamic and diffusional-thermal instabilities. Laminar burning velocities and Markstein lengths were calculated by analyzing high-speed schlieren images at various diluent concentrations and equivalence ratios. The measured unstretched laminar burning velocities were compared with the predicted results computed using the PREMIX code with the kinetic mechanism developed by Sun et al. Also, experimentally measured Peclet numbers were compared with the predicted results for fuel-lean flames. Experimental results showed substantial reduction of the laminar burning velocities and of the Markstein lengths with the diluent additions in the fuel blends. Effective Lewis numbers of helium-diluted syngas-air flames increased but those of carbon dioxide- and nitrogen-diluted syngas-air flames decreased in increase of diluents in the reactant mixtures. With helium diluent, the propensity for cells formation was significantly diminished, whereas the cellular instabilities for carbon dioxide- and nitrogen-diluted syngas-air flames were not suppressed.

Original languageEnglish
Pages (from-to)3868-3880
Number of pages13
JournalInternational Journal of Hydrogen Energy
Volume35
Issue number8
DOIs
Publication statusPublished - Apr 2010
Externally publishedYes

Keywords

  • Cellular instabilities
  • Diffusive-thermal effect
  • Effective Lewis number
  • Hydrodynamic effect
  • Markstein length
  • Premixed combustion
  • Syngas-air flame

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