Blowoff characteristics of edge flames in the stagnant region of an axisymmetric impinging jet

Hiroyuki Torikai, Akiko Matsuo, Toshihisa Ueda, Masahiko Mizomoto

研究成果: Article

抄録

Blowoff characteristics of methane-air and propane-air edge flames are experimentally investigated by using the newly proposed burner that utilizes the stagnation region of an axisymmetric impinging jet. In the burner, "edge flame without premixed flame" can be formed as a hole in the diffusion flame, and, by changing the hole diameter as a parameter, the diffusion flame can be gradually turned from a pure diffusion flame to the diffusion flame with a hole. In the present study, the observation of flame shapes and the blowoff processes, and the measurements of the blowoff and separation limits have been performed. As a results, it is found that the blowoff and separation limits of the diffusion flames with a hole show qualitatively same tendencies with a pure diffusion flame, that is, the flames with a hole have critical stagnation velocity gradients for blowoff and separation phenomena, beyond which the flame can never be stabilized or existed. Especially, the critical stagnation velocity gradient for blowoff of "edge flame without premixed flame" decreases as the hole diameter is increased, and always shows lower value than that of a pure diffusion flame. Finally, it is clarified that Peclet number which is a ratio of the characteristic diffusion time to the characteristic convection time, is an important parameter for edge flame's blowoff process, and the transition of the blowoff process from blowoff without separation to blowoff with separation occurs at a constant I'eclet number.

元の言語English
ページ(範囲)2848-2855
ページ数8
ジャーナルNihon Kikai Gakkai Ronbunshu, B Hen/Transactions of the Japan Society of Mechanical Engineers, Part B
67
発行部数663
出版物ステータスPublished - 2001 11
外部発表Yes

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flameout
flames
diffusion flames
Fuel burners
premixed flames
burners
Peclet number
Air
gradients
Propane
stagnation point
air
Methane
propane
tendencies
convection
methane

ASJC Scopus subject areas

  • Mechanical Engineering
  • Condensed Matter Physics

これを引用

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title = "Blowoff characteristics of edge flames in the stagnant region of an axisymmetric impinging jet",
abstract = "Blowoff characteristics of methane-air and propane-air edge flames are experimentally investigated by using the newly proposed burner that utilizes the stagnation region of an axisymmetric impinging jet. In the burner, {"}edge flame without premixed flame{"} can be formed as a hole in the diffusion flame, and, by changing the hole diameter as a parameter, the diffusion flame can be gradually turned from a pure diffusion flame to the diffusion flame with a hole. In the present study, the observation of flame shapes and the blowoff processes, and the measurements of the blowoff and separation limits have been performed. As a results, it is found that the blowoff and separation limits of the diffusion flames with a hole show qualitatively same tendencies with a pure diffusion flame, that is, the flames with a hole have critical stagnation velocity gradients for blowoff and separation phenomena, beyond which the flame can never be stabilized or existed. Especially, the critical stagnation velocity gradient for blowoff of {"}edge flame without premixed flame{"} decreases as the hole diameter is increased, and always shows lower value than that of a pure diffusion flame. Finally, it is clarified that Peclet number which is a ratio of the characteristic diffusion time to the characteristic convection time, is an important parameter for edge flame's blowoff process, and the transition of the blowoff process from blowoff without separation to blowoff with separation occurs at a constant I'eclet number.",
keywords = "Axisynimetric impinging jet, Combustion phenomena, Diffusion combustion, Edge flame, Partially premixed flame, Stagnation flow",
author = "Hiroyuki Torikai and Akiko Matsuo and Toshihisa Ueda and Masahiko Mizomoto",
year = "2001",
month = "11",
language = "English",
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journal = "Nihon Kikai Gakkai Ronbunshu, B Hen/Transactions of the Japan Society of Mechanical Engineers, Part B",
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publisher = "Japan Society of Mechanical Engineers",
number = "663",

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TY - JOUR

T1 - Blowoff characteristics of edge flames in the stagnant region of an axisymmetric impinging jet

AU - Torikai, Hiroyuki

AU - Matsuo, Akiko

AU - Ueda, Toshihisa

AU - Mizomoto, Masahiko

PY - 2001/11

Y1 - 2001/11

N2 - Blowoff characteristics of methane-air and propane-air edge flames are experimentally investigated by using the newly proposed burner that utilizes the stagnation region of an axisymmetric impinging jet. In the burner, "edge flame without premixed flame" can be formed as a hole in the diffusion flame, and, by changing the hole diameter as a parameter, the diffusion flame can be gradually turned from a pure diffusion flame to the diffusion flame with a hole. In the present study, the observation of flame shapes and the blowoff processes, and the measurements of the blowoff and separation limits have been performed. As a results, it is found that the blowoff and separation limits of the diffusion flames with a hole show qualitatively same tendencies with a pure diffusion flame, that is, the flames with a hole have critical stagnation velocity gradients for blowoff and separation phenomena, beyond which the flame can never be stabilized or existed. Especially, the critical stagnation velocity gradient for blowoff of "edge flame without premixed flame" decreases as the hole diameter is increased, and always shows lower value than that of a pure diffusion flame. Finally, it is clarified that Peclet number which is a ratio of the characteristic diffusion time to the characteristic convection time, is an important parameter for edge flame's blowoff process, and the transition of the blowoff process from blowoff without separation to blowoff with separation occurs at a constant I'eclet number.

AB - Blowoff characteristics of methane-air and propane-air edge flames are experimentally investigated by using the newly proposed burner that utilizes the stagnation region of an axisymmetric impinging jet. In the burner, "edge flame without premixed flame" can be formed as a hole in the diffusion flame, and, by changing the hole diameter as a parameter, the diffusion flame can be gradually turned from a pure diffusion flame to the diffusion flame with a hole. In the present study, the observation of flame shapes and the blowoff processes, and the measurements of the blowoff and separation limits have been performed. As a results, it is found that the blowoff and separation limits of the diffusion flames with a hole show qualitatively same tendencies with a pure diffusion flame, that is, the flames with a hole have critical stagnation velocity gradients for blowoff and separation phenomena, beyond which the flame can never be stabilized or existed. Especially, the critical stagnation velocity gradient for blowoff of "edge flame without premixed flame" decreases as the hole diameter is increased, and always shows lower value than that of a pure diffusion flame. Finally, it is clarified that Peclet number which is a ratio of the characteristic diffusion time to the characteristic convection time, is an important parameter for edge flame's blowoff process, and the transition of the blowoff process from blowoff without separation to blowoff with separation occurs at a constant I'eclet number.

KW - Axisynimetric impinging jet

KW - Combustion phenomena

KW - Diffusion combustion

KW - Edge flame

KW - Partially premixed flame

KW - Stagnation flow

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