Journal of the Korean Society of Combustion (한국연소학회지)

The Korean Society of Combustion (한국연소학회)
권호 표지

Helieum-dilution Effect of Coflow Air on Self-excitation in Laminar Coflow Jet Flames

층류 동축류 제트에서 공기측 헬륨 희석이 화염진동에 미치는 영향

  • 이원준 (부경대학교 기계공학과) ;
  • 박정 (부경대학교 기계공학과) ;
  • 권오붕 (부경대학교 기계공학과) ;
  • 백세현 (한국전력연구원 수화력발전팀) ;
  • 고성호 (충남대학교 기계공학과)
  • Received : 2012.12.07
  • Accepted : 2012.12.11
  • Published : 2012.12.30
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Abstract

Experimental study in coflow jet flames has been conducted to investigate the helium-dilution effect of coflow air on self-excitation. For various helium mole fractions and jet velocities, two types of self-excitation were observed: buoyancy-driven self-excitation and Lewis-number-induced self-excitation(here after called Le-ISE) coupled with buoyancy-driven one. The difference between buoyancy-driven and Le-ISE is clarified by using the Mie-scattering visualization as well as exploring the different features. The mechanism of Le-ISE is proposed. When the system Damk$\ddot{o}$hler number was lowered, Le-ISE is shown to be launched. Le-ISE is closely related to heat loss, in that it can be launched in even methane jet flame (Lewis number less than unity) with helium-diluted coflow air. Particularly, Le-ISE becomes significant as the Damk$\ddot{o}$hler number decreases and heat-loss becomes significant.

Keywords

References

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