Flame structure of lean premixed and diffusion combined flames near extinction limit

Takayuki Kawanami, Yuji Yahagi

研究成果: Article

抄録

Extinction and flame structure of lean premixed and diffusion combined flames formed in a counter flow are investigated experimentally and numerically. The extinction limits can be divided into two regions. One is a diffusion flame dominant extinction region (DF-DE) in which equivalence ratio of LPF side (φ L) at extinction limit is decreasing linearly with increasing fuel concentration of DF side (χ U). The other is a lean premixed flame dominant extinction region (LPF-DE) in which effect of χ U on extinction φ L is increasing with increasing χ U. In these two regions, the flame structures and its φ L dependence are different greatly. In the DF-DE, the temperature has symmetrical profile regardless of φ L and the temperature peak is located near DF. Since DF has higher temperature than LPF, LPF is thermally supported than DF. Temperature gradients between two reaction zones are decreasing with increasing φ L, while laminar burning velocity (S L) and burnt gas width (W B) are constant regardless of φ L. On the other hand, in the LPF-DE, the temperature has asymmetrical profile and the temperature peak leans to the LPF side. That is, the temperature gradient of LPF side is very steep compared with the DF side. Since LPF has higher temperature than DF, DF is thermally supported than LPF. Temperature gradients between two reaction zones are constant regardless of φ L, while S L and W B are increasing with increasing φ L.

元の言語English
ページ(範囲)1118-1126
ページ数9
ジャーナルNihon Kikai Gakkai Ronbunshu, B Hen/Transactions of the Japan Society of Mechanical Engineers, Part B
78
発行部数789
DOI
出版物ステータスPublished - 2012

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deuterium fluorides
flames
extinction
Thermal gradients
temperature gradients
Temperature
premixed flames
diffusion flames
temperature
counterflow
profiles
equivalence
Gases
gases

ASJC Scopus subject areas

  • Mechanical Engineering
  • Condensed Matter Physics

これを引用

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title = "Flame structure of lean premixed and diffusion combined flames near extinction limit",
abstract = "Extinction and flame structure of lean premixed and diffusion combined flames formed in a counter flow are investigated experimentally and numerically. The extinction limits can be divided into two regions. One is a diffusion flame dominant extinction region (DF-DE) in which equivalence ratio of LPF side (φ L) at extinction limit is decreasing linearly with increasing fuel concentration of DF side (χ U). The other is a lean premixed flame dominant extinction region (LPF-DE) in which effect of χ U on extinction φ L is increasing with increasing χ U. In these two regions, the flame structures and its φ L dependence are different greatly. In the DF-DE, the temperature has symmetrical profile regardless of φ L and the temperature peak is located near DF. Since DF has higher temperature than LPF, LPF is thermally supported than DF. Temperature gradients between two reaction zones are decreasing with increasing φ L, while laminar burning velocity (S L) and burnt gas width (W B) are constant regardless of φ L. On the other hand, in the LPF-DE, the temperature has asymmetrical profile and the temperature peak leans to the LPF side. That is, the temperature gradient of LPF side is very steep compared with the DF side. Since LPF has higher temperature than DF, DF is thermally supported than LPF. Temperature gradients between two reaction zones are constant regardless of φ L, while S L and W B are increasing with increasing φ L.",
keywords = "Combustion phenomena, Counterflow, Diffusion combustion, Extinction, Flame structure, Flame to flame interaction, Premixed combustion",
author = "Takayuki Kawanami and Yuji Yahagi",
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TY - JOUR

T1 - Flame structure of lean premixed and diffusion combined flames near extinction limit

AU - Kawanami, Takayuki

AU - Yahagi, Yuji

PY - 2012

Y1 - 2012

N2 - Extinction and flame structure of lean premixed and diffusion combined flames formed in a counter flow are investigated experimentally and numerically. The extinction limits can be divided into two regions. One is a diffusion flame dominant extinction region (DF-DE) in which equivalence ratio of LPF side (φ L) at extinction limit is decreasing linearly with increasing fuel concentration of DF side (χ U). The other is a lean premixed flame dominant extinction region (LPF-DE) in which effect of χ U on extinction φ L is increasing with increasing χ U. In these two regions, the flame structures and its φ L dependence are different greatly. In the DF-DE, the temperature has symmetrical profile regardless of φ L and the temperature peak is located near DF. Since DF has higher temperature than LPF, LPF is thermally supported than DF. Temperature gradients between two reaction zones are decreasing with increasing φ L, while laminar burning velocity (S L) and burnt gas width (W B) are constant regardless of φ L. On the other hand, in the LPF-DE, the temperature has asymmetrical profile and the temperature peak leans to the LPF side. That is, the temperature gradient of LPF side is very steep compared with the DF side. Since LPF has higher temperature than DF, DF is thermally supported than LPF. Temperature gradients between two reaction zones are constant regardless of φ L, while S L and W B are increasing with increasing φ L.

AB - Extinction and flame structure of lean premixed and diffusion combined flames formed in a counter flow are investigated experimentally and numerically. The extinction limits can be divided into two regions. One is a diffusion flame dominant extinction region (DF-DE) in which equivalence ratio of LPF side (φ L) at extinction limit is decreasing linearly with increasing fuel concentration of DF side (χ U). The other is a lean premixed flame dominant extinction region (LPF-DE) in which effect of χ U on extinction φ L is increasing with increasing χ U. In these two regions, the flame structures and its φ L dependence are different greatly. In the DF-DE, the temperature has symmetrical profile regardless of φ L and the temperature peak is located near DF. Since DF has higher temperature than LPF, LPF is thermally supported than DF. Temperature gradients between two reaction zones are decreasing with increasing φ L, while laminar burning velocity (S L) and burnt gas width (W B) are constant regardless of φ L. On the other hand, in the LPF-DE, the temperature has asymmetrical profile and the temperature peak leans to the LPF side. That is, the temperature gradient of LPF side is very steep compared with the DF side. Since LPF has higher temperature than DF, DF is thermally supported than LPF. Temperature gradients between two reaction zones are constant regardless of φ L, while S L and W B are increasing with increasing φ L.

KW - Combustion phenomena

KW - Counterflow

KW - Diffusion combustion

KW - Extinction

KW - Flame structure

KW - Flame to flame interaction

KW - Premixed combustion

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