동축 수소 확산화염에서의 NOx 생성 분석

Analysis of NOx Emissions in Thrbulent Nonpremixed Hydrogen-Air Jet Flames with Coaxial Air

  • 박양호 (서울대학교 항공우주공학과) ;
  • 김성룡 (서울대학교 항공우주공학과) ;
  • 문희장 (한국항공대학교 항공우주 및 기계공학부) ;
  • 윤영빈 (서울대학교 항공우주공학과) ;
  • 정인석 (서울대학교 항공우주공학과)
  • 발행 : 2000.06.30

초록

The characteristics of NOx emissions in pure hydrogen nonpremixed flames with coaxial air are analyzed numerically for the three model cases of coaxial air flames classified by varying coaxial air velocity and/or fuel velocity. In coaxial air flames, the flame length is reduced by coaxial air and can be represented as a function of the ratio of coaxial air to fuel velocity. Coaxial air decreases flame reaction zone, resulting in reducing flame residence time significantly. Finally, the large reduction of EINOx is achieved by the decrease of the flame residence time. It is found that because coaxial air can break down the flame self-similarity law, appropriate scaling parameters, which are different from those in the simple jet flames, are recommended. In coaxial air flames, the flame residence time based on the flame volume produces better results than that based on a cube of the flame length. And some portion of deviations from the 1/2 scaling law by coaxial air may be due to the violation of the linear relationship between the flame volume and the flame reaction zone.

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