Decreasing liftoff height behavior in diluted laminar lifted methane jet flames

Kyuho Van, Ki Sung Jung, Chun Sang Yoo, Soohyun Oh, Byeong Jun Lee, Min Suk Cha*, Jeong Park, Suk Ho Chung

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

24 Scopus citations

Abstract

Stabilization of laminar lifted coflow jet flames of nitrogen-diluted methane was investigated experimentally and numerically. As the fuel jet velocity was increased, two distinct behaviors in liftoff height were observed depending on the initial fuel mole fraction; a monotonically increasing trend and a decreasing and then increasing trend (U-shaped behavior). The former was observed in the jet-developing region and the latter in the jet-developed region. Because the decreasing behavior of liftoff height with jet velocity has not been observed at ambient temperature, the present study focuses on decreasing liftoff height behavior. To elucidate the physical mechanism underlying the U-shaped behavior, numerical simulations of reacting jets were conducted by adopting a skeletal mechanism. The U-shaped behavior was related to the buoyancy. At small jet velocities, the relative importance of the buoyancy over convection was strong and the flow field was accelerated in the downstream region to stabilize the lifted flame. As the jet velocity increased, the relative importance of buoyancy decreased and the liftoff height decreased. As the jet velocity further increased, the flame stabilization was controlled by jet momentum and the liftoff height increased.

Original languageEnglish (US)
Pages (from-to)2005-2012
Number of pages8
JournalProceedings of the Combustion Institute
Volume37
Issue number2
DOIs
StatePublished - 2019

Keywords

  • Buoyancy
  • Coflow jet
  • Edge flame
  • Laminar flame
  • Lifted flame

ASJC Scopus subject areas

  • General Chemical Engineering
  • Mechanical Engineering
  • Physical and Theoretical Chemistry

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