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Experimental study on dynamics of a confined low swirl partially premixed methane-hydrogen-air flame

Tong, Yiheng LU ; Yu, Senbin LU ; Liu, Xiao LU and Klingmann, Jens LU (2017) In International Journal of Hydrogen Energy
Abstract

The addition of hydrogen to swirl stabilized methane-air flame in gas turbine has gained more and more attentions in recent years. In the current study, flame structures, flame dynamics and lean blowout limits of partially premixed hydrogen-methane-air flames were investigated. The swirling flow, which was generated from the tangential flow injection, was utilized to stabilize the flame. The flow swirl number was kept low varying from S ≈ 0.28 to S ≈ 0.34 while the thermal power of the burner ranged from 10.8 kW to 13.8 kW. Two different fuel injection strategies were investigated and compared with each other. Long exposure CH* chemiluminescence from the flame was captured to visualize the time averaged flame shapes. In addition, an... (More)

The addition of hydrogen to swirl stabilized methane-air flame in gas turbine has gained more and more attentions in recent years. In the current study, flame structures, flame dynamics and lean blowout limits of partially premixed hydrogen-methane-air flames were investigated. The swirling flow, which was generated from the tangential flow injection, was utilized to stabilize the flame. The flow swirl number was kept low varying from S ≈ 0.28 to S ≈ 0.34 while the thermal power of the burner ranged from 10.8 kW to 13.8 kW. Two different fuel injection strategies were investigated and compared with each other. Long exposure CH* chemiluminescence from the flame was captured to visualize the time averaged flame shapes. In addition, an intensified high speed camera was adopted to study the flame dynamics. A high speed PIV system was utilized to investigate the interaction of flame dynamics and flow fields oscillations. Based on the experimental results, it can be concluded that: in the current experimental cases, fuel injection strategy plays an important role in determining the flame macro-structures and thus strongly affects the flame dynamics and lean blowout limits. Flame with fuel injected through the axial flow has lower lean blowout limits. The flashback and vortex breakdown were observed when fuel was injected in the tangential flow near lean blowout. High frequency flame oscillations (f ≈ 170 Hz) were observed when the global equivalence ratio Φ g > 0.72 while lower frequency oscillations (f ≈ 50 Hz and f ≈ 20 Hz) were found near lean blowout limits, Φ g < 0.55. Combustion dynamic and its interaction with the pressure oscillation, flow fields alternation and mass flow rate oscillation are proposed. The differences on fuel concentration at the burner exit are proposed as the main reason for different flame instabilities and flame structures.

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Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
epub
subject
keywords
Combustion dynamics, Flame structures, Flashback, Flow fields, Hydrogen combustion, Swirling flow
in
International Journal of Hydrogen Energy
publisher
Elsevier
external identifiers
  • scopus:85030776602
  • wos:000415768200039
ISSN
0360-3199
DOI
10.1016/j.ijhydene.2017.09.066
language
English
LU publication?
yes
id
08d8278d-3839-44e2-b9e4-be2cabb8fdd9
date added to LUP
2017-10-18 08:59:21
date last changed
2018-01-16 13:23:36
@article{08d8278d-3839-44e2-b9e4-be2cabb8fdd9,
  abstract     = {<p>The addition of hydrogen to swirl stabilized methane-air flame in gas turbine has gained more and more attentions in recent years. In the current study, flame structures, flame dynamics and lean blowout limits of partially premixed hydrogen-methane-air flames were investigated. The swirling flow, which was generated from the tangential flow injection, was utilized to stabilize the flame. The flow swirl number was kept low varying from S ≈ 0.28 to S ≈ 0.34 while the thermal power of the burner ranged from 10.8 kW to 13.8 kW. Two different fuel injection strategies were investigated and compared with each other. Long exposure CH* chemiluminescence from the flame was captured to visualize the time averaged flame shapes. In addition, an intensified high speed camera was adopted to study the flame dynamics. A high speed PIV system was utilized to investigate the interaction of flame dynamics and flow fields oscillations. Based on the experimental results, it can be concluded that: in the current experimental cases, fuel injection strategy plays an important role in determining the flame macro-structures and thus strongly affects the flame dynamics and lean blowout limits. Flame with fuel injected through the axial flow has lower lean blowout limits. The flashback and vortex breakdown were observed when fuel was injected in the tangential flow near lean blowout. High frequency flame oscillations (f ≈ 170 Hz) were observed when the global equivalence ratio Φ <sub> g </sub> &gt; 0.72 while lower frequency oscillations (f ≈ 50 Hz and f ≈ 20 Hz) were found near lean blowout limits, Φ <sub> g </sub> &lt; 0.55. Combustion dynamic and its interaction with the pressure oscillation, flow fields alternation and mass flow rate oscillation are proposed. The differences on fuel concentration at the burner exit are proposed as the main reason for different flame instabilities and flame structures.</p>},
  author       = {Tong, Yiheng and Yu, Senbin and Liu, Xiao and Klingmann, Jens},
  issn         = {0360-3199},
  keyword      = {Combustion dynamics,Flame structures,Flashback,Flow fields,Hydrogen combustion,Swirling flow},
  language     = {eng},
  month        = {10},
  publisher    = {Elsevier},
  series       = {International Journal of Hydrogen Energy},
  title        = {Experimental study on dynamics of a confined low swirl partially premixed methane-hydrogen-air flame},
  url          = {http://dx.doi.org/10.1016/j.ijhydene.2017.09.066},
  year         = {2017},
}