Transactions of the Korean Society of Mechanical Engineers B (대한기계학회논문집B)

The Korean Society of Mechanical Engineers (대한기계학회)
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Combustion Characteristics of CH4 Nonpremixed Flame with Recession Distance

메탄 비예혼합 화염의 후퇴거리에 따른 연소특성

  • Kim, Jun-Hee (Dept. of Mechanical Engineering, Kyungpook Nat'l Univ.) ;
  • Ku, Kun-Woo (Dept. of Mechanical Engineering, Kyungpook Nat'l Univ.) ;
  • Hong, Jung-Goo (Dept. of Mechanical Engineering, Kyungpook Nat'l Univ.) ;
  • Lee, Choong-Won (Dept. of Mechanical Engineering, Kyungpook Nat'l Univ.) ;
  • Kim, In-Su (Technical Research Center Energy Technology Team, Hyundai Steel) ;
  • Cheong, In-Mo (Technical Research Center Energy Technology Team, Hyundai Steel)
  • Received : 2011.09.05
  • Accepted : 2012.01.16
  • Published : 2012.03.01
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Abstract

A lot of research on the stability of nonpremixed flames has focused on the fuel-nozzle and quarl geometries. Of the work carried out, only a small amount has focused on the stability of the nonpremixed flame according to the recession distance and air-nozzle geometry. Therefore, in this study, a coaxial-diffusion-type gas burner with a swirler is designed for the systematic investigation of the combustion characteristics of a $CH_4$ flame depending on the recession distance and secondary air-nozzle geometry. 1st air is flowed through the swirler, and 2nd air is flowed through each nozzle. It is shown that the secondary air velocity greatly influences the flame length and shape. There is an optimum recession distance for each nozzle for the best combustion efficiency. In this study, it is shown that the optimized recession distance is nearly half the outer diameter of the air-supply nozzle.

비예혼합 화염의 안정성에 관한 종래의 연구는 연료노즐이나 퀄의 형상에 초점을 많은 맞추어 왔으나 화염안정화에 중요한 연료의 후퇴거리 및 공기노즐의 홀 형상에 대한 연구는 상대적으로 부족하여 이에 관한 연구가 절실한 실정이다. 따라서, 본 연구에서는 메탄 분류 후퇴거리 및 2 차 공기의 홀 형상에 따른 연소특성을 관찰하기 위해 동축 삼중관 형태의 버너를 설계하였다. 1 차 공기는 스월러를 통하여 분류하였고, 2 차 공기는 홀 형상 및 슬릿 형상의 각 노즐로부터 분류되었다. 본 연구에 사용된 실험실 스케일 버너로부터 2 차 공기의 유속은 화염의 형태에 영향을 끼치는 것을 알 수 있었다. 후퇴거리의 경우 공급관외경의 절반에 해당하는 거리로 설정했을 때 화염이 안정적으로 존재하고, 휘도는 더욱 높아짐을 알 수 있었다.

Keywords

References

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