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Experimental study on bluff-body stabilized premixed flame with a central air/fuel jet

Tong, Yiheng LU ; Chen, Shuang LU ; Li, Mao LU ; Li, Zhongshan LU and Klingmann, Jens LU (2017) In Energies 10(12).
Abstract

Bluff-body flame holders are commonly employed in many industrial applications. A bluff-body is usually adopted to enhance the downstream mixing of the combustion products and the fresh fuel-air mixtures, thus to improve the flame stability and to control the combustion process. In the present paper, flames stabilized by a conical-shape bluff-body flame holder with a central air/fuel jet were studied. Effects of both a central air jet and a central fuel jet on the structures and lean blowout limits of the premixed annular flames, and on the temperature on the upper surface of the bluff-body were investigated and presented. It was revealed that a central jet led to a considerable reduction of the temperature on the upper surface of the... (More)

Bluff-body flame holders are commonly employed in many industrial applications. A bluff-body is usually adopted to enhance the downstream mixing of the combustion products and the fresh fuel-air mixtures, thus to improve the flame stability and to control the combustion process. In the present paper, flames stabilized by a conical-shape bluff-body flame holder with a central air/fuel jet were studied. Effects of both a central air jet and a central fuel jet on the structures and lean blowout limits of the premixed annular flames, and on the temperature on the upper surface of the bluff-body were investigated and presented. It was revealed that a central jet led to a considerable reduction of the temperature on the upper surface of the bluff-body. It was proposed to be caused by the alternation of flow structures (in the case with a central air jet) altogether with the flame lifting from the burner (in the case with a central fuel jet). Thus, it might be used to solve the problem of the bluff-body with high heat loads in practical applications. The flame stability characteristics, for example the unstable flame dynamics and the lean blowout limits, varied with the injection of an air or fuel jet through the central pipe. Different blowout behaviors, being with or without the occurrence of flame split and flashing, caused by a central air jet were presented in the paper. In addition, when a small amount of central fuel jet (i.e., Uf/Ua = 0.045) was injected into the flow fields, an unsteady circular motion of the flame tip along the outer edge of the bluff-body was observed as well. Whereas, with an increase in the amount of the central fuel jet, the flame detached from the outer edge of the bluff-body and then became much more unstable. With a central air or fuel jet injecting into the flow field, premixed flames stabilized by the bluff-body became more unstable and easier to blowout.

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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Bluff-body, Flame instabilities, Flame structures, Lean blowout, Premixed flame
in
Energies
volume
10
issue
12
publisher
MDPI AG
external identifiers
  • scopus:85044499237
ISSN
1996-1073
DOI
10.3390/en10122011
language
English
LU publication?
yes
id
d2fb2ebf-68f6-4490-a920-4109f950bd34
date added to LUP
2018-04-12 16:08:00
date last changed
2019-02-20 11:14:02
@article{d2fb2ebf-68f6-4490-a920-4109f950bd34,
  abstract     = {<p>Bluff-body flame holders are commonly employed in many industrial applications. A bluff-body is usually adopted to enhance the downstream mixing of the combustion products and the fresh fuel-air mixtures, thus to improve the flame stability and to control the combustion process. In the present paper, flames stabilized by a conical-shape bluff-body flame holder with a central air/fuel jet were studied. Effects of both a central air jet and a central fuel jet on the structures and lean blowout limits of the premixed annular flames, and on the temperature on the upper surface of the bluff-body were investigated and presented. It was revealed that a central jet led to a considerable reduction of the temperature on the upper surface of the bluff-body. It was proposed to be caused by the alternation of flow structures (in the case with a central air jet) altogether with the flame lifting from the burner (in the case with a central fuel jet). Thus, it might be used to solve the problem of the bluff-body with high heat loads in practical applications. The flame stability characteristics, for example the unstable flame dynamics and the lean blowout limits, varied with the injection of an air or fuel jet through the central pipe. Different blowout behaviors, being with or without the occurrence of flame split and flashing, caused by a central air jet were presented in the paper. In addition, when a small amount of central fuel jet (i.e., U<sub>f</sub>/U<sub>a</sub> = 0.045) was injected into the flow fields, an unsteady circular motion of the flame tip along the outer edge of the bluff-body was observed as well. Whereas, with an increase in the amount of the central fuel jet, the flame detached from the outer edge of the bluff-body and then became much more unstable. With a central air or fuel jet injecting into the flow field, premixed flames stabilized by the bluff-body became more unstable and easier to blowout.</p>},
  articleno    = {2011},
  author       = {Tong, Yiheng and Chen, Shuang and Li, Mao and Li, Zhongshan and Klingmann, Jens},
  issn         = {1996-1073},
  keyword      = {Bluff-body,Flame instabilities,Flame structures,Lean blowout,Premixed flame},
  language     = {eng},
  month        = {12},
  number       = {12},
  publisher    = {MDPI AG},
  series       = {Energies},
  title        = {Experimental study on bluff-body stabilized premixed flame with a central air/fuel jet},
  url          = {http://dx.doi.org/10.3390/en10122011},
  volume       = {10},
  year         = {2017},
}