Large-Eddy Simulation and Experimental Observation of Combustion-Induced Vortex Breakdown

Tangermann, Eike; Pfitzner, Michael; Konle, Marco; Sattelmayer, Thomas

doi:10.1080/00102200903463126

Cited by 19 publications

(21 citation statements)

References 8 publications

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“…The primary difference arises due to the burner configuration between the earlier studies [18,19] and the present study. In that burner [18,19], fuel and air has been premixed at a section which is far away from dump plane while in the present case we have a jet in cross flow injection close to the dump plane and that has lot of impact. That's why the flow dynamics has been presented first and then followed by the discussion on upstream flame movement.…”

Section: Upstream Flame Propagationmentioning

confidence: 64%

“…The primary difference arises due to the burner configuration between the earlier studies [18][19] and the present study. In that burner [18][19],…”

Section: Upstream Flame Propagationmentioning

confidence: 66%

“…However, it is noteworthy to mention that the previous studies [12][13][14][15][16][18][19] on different swirl stabilized burner reported CIVB driven flashback where the time scale for flashback was in the order of milliseconds for a laboratory scale burners fired with CH4. In contrast, flame…”

Section: Upstream Flame Propagationmentioning

confidence: 93%

“…Flashback via flame propagation [5,11], (ii) Flashback due to combustion instabilities, (iii) Combustion-induced vortex breakdown [8,[10][11][12][13][14][15][16][17][18][19].…”

Section: Recent Interest In Clean Coal Technology and The Associated mentioning

confidence: 99%

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Dynamics of upstream flame propagation in a hydrogen-enriched premixed flame

Acharya

2012

International Journal of Hydrogen Energy

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a b s t r a c tAn unconfined strongly swirled flow is investigated to study the effect of hydrogen addition on upstream flame propagation in a methane-air premixed flame using Large Eddy Simulation (LES) with a Thickened Flame (TF) model. A laboratory-scale swirled premixed combustor operated under atmospheric conditions for which experimental data for validation is available has been chosen for the numerical study. In the LES-TF approach, the flame front is resolved on the computational grid through artificial thickening and the individual species transport equations are directly solved with the reaction rates specified using Arrhenius chemistry. Good agreement is found when comparing predictions with the published experimental data including the predicted RMS fluctuations. Also, the results show that the initiation of upstream flame propagation is associated with balanced maintained between hydrodynamics and reaction. This process is associated with the upstream propagation of the center recirculation bubble, which pushes the flame front in the upstream mixing tube. Once the upstream movement of the flame front is initiated, the hydrogen-enriched mixture exhibits more unstable behavior; while in contrast, the CH 4 flame shows stable behavior.

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Section: Upstream Flame Propagationmentioning

confidence: 64%

“…The primary difference arises due to the burner configuration between the earlier studies [18][19] and the present study. In that burner [18][19],…”

Section: Upstream Flame Propagationmentioning

confidence: 66%

Section: Upstream Flame Propagationmentioning

confidence: 93%

“…Flashback via flame propagation [5,11], (ii) Flashback due to combustion instabilities, (iii) Combustion-induced vortex breakdown [8,[10][11][12][13][14][15][16][17][18][19].…”

Section: Recent Interest In Clean Coal Technology and The Associated mentioning

confidence: 99%

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Dynamics of upstream flame propagation in a hydrogen-enriched premixed flame

Acharya

2012

International Journal of Hydrogen Energy

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“…Upstream flame propagation may occur in the core of a swirling flow, e.g. in combustors without a central fuel tube [23][24][25][26][27][28][29][30]. Flashback in such configurations is related to flame propagation along a vortex axis, and this mode of flame propagation has been studied extensively in laminar flows as summarized by Ishizuka [31].…”

Section: Introductionmentioning

confidence: 99%

Experimental investigation of upstream flame propagation during boundary layer flashback of swirl flames

Ebi

Clemens

2016

Combustion and Flame

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Boundary layer flashback of swirling turbulent lean-premixed methane-hydrogen-air flames is investigated in a model combustor featuring a mixing tube with center body. The focus of our work is on improving the understanding of the flow-flame interaction during flashback. We combine high-speed chemiluminescence imaging, stereoscopic and tomographic particle image velocimetry, and a three-dimensional flame front reconstruction technique to reveal the time-resolved, volumetric velocity field in the vicinity of the flame front during flashback. We find two different ways in which a flame front propagates upstream along the center body wall. The first mode concerns small-scale bulges counter-propagating into the approach flow, similar to channelflow flashback, but is found not to be a dominant propagation mechanism. Instead, flashback occurs primarily in the form of large-scale flame tongues swirling in the bulk flow direction as they propagate upstream. The approach flow is modified significantly in both cases, but the scale and nature of the resulting velocity fields differ fundamentally. A key characteristic of the approach flow found previously, both in channel and swirl flame flashback, is regions of negative axial velocity upstream of the flame front. We reveal, however, that in the case of swirl flames the region of negative axial velocity is the result of a primarily swirling motion ahead of the leading flame tongue in contrast to the reverse flow pockets ahead of small-scale bulges. The boundary layer neither separates nor does fluid recirculate in the negative axial velocity region upstream of the flame tongues.Instead, flame tongues impose a local blockage effect causing significant deflection of the approach flow, which results in a constant region of negative axial velocity for the leading side of the flame tongue to propagate into.

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