Flame stabilization by baffles in a high velocity gas stream

Longwell, John P.; Chenevey, J.E.; Clark, W.W.; Frost, Edward E.

doi:10.1016/s1062-2896(49)80007-9

Cited by 43 publications

(14 citation statements)

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“…These results were due to the difference in the size of the recirculation zone, which increased when the bluff body had a larger diameter and more internal space. These results are consistent with observations reported by Longwell et al [9]. They demonstrate that the recirculation zone developed in the inner space of the bluff body has a significant effect on the stabilization of the flame.…”

Section: B Experimental Conditionssupporting

confidence: 93%

Effect of the Acoustic Excitation on Lean Blowoff in Turbulent Premixed Bluff Body Flames

Jeong¹,

Shin²,

Yoon³

2014

50th AIAA/ASME/SAE/ASEE Joint Propulsion Conference

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The characteristics of premixed flame closed to lean blowoff were investigated in a ducted combustor with the bluff body. The combustor has a long duct and a rectangular cross-section. The bluff body is in the shape of an equilateral triangle. Methane was used as fuel, which was injected transversely into the cross-flow.The blowoff equivalence ratio increased with the Reynolds number, and the blowoff equivalence ratio changed depending on the extent of the recirculation zone. Shortly before the blowoff, the unburned gas strongly penetrated into the recirculation zone, resulting in a dramatic change in the heat release in the vicinity of the bluff body. This change can be used as a precursor to predict blowoff. The blowoff occurred in a similar process regardless of the excitation. The blowoff equivalence ratio was increased by the intensity of the excitation and rapidly increased at particular frequencies of excitation. The POD analysis revealed that the frequencies with a high blowoff equivalence ratio corresponded to the peak frequencies of the shear generated vortex of the bluff body. This result suggests that the resonance phenomenon of the excitation and the shear generated vortex is the cause of increase in the blowoff equivalence ratio. Nomenclature d = width of the bluff body f ex = frequency of the acoustic excitation f sh = frequency of the shear generated vortex ̇a = inlet air mass flow rate R 2 = correlation coefficient Re d,lip = Reynolds number based on d and U lip t bo = time to blowoff U lip = tip velocity of the bluff body Φ bo = blowoff equivalence ratio

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Section: B Experimental Conditionssupporting

confidence: 93%

Effect of the Acoustic Excitation on Lean Blowoff in Turbulent Premixed Bluff Body Flames

Jeong¹,

Shin²,

Yoon³

2014

50th AIAA/ASME/SAE/ASEE Joint Propulsion Conference

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“…concern since the concept is to react with a fuel rich mixture in the initial combustion zone. From a stability point of view, operational difficulties [9][10][11][12] are generally associated with low pressure conditions such as encountered in very high altitude aircraft operation and thus no significant limitations were obvious for the operating range typical of the Allison Model 570-K industrial gas turbine engine. Based on current experience with the can annular combustion system in Allison Model 501K industrial engine the pressure drop goal of 6% provides adequate mixing and air management and is not detrimental to engine performance.…”

Section: Figure 1 Effect Of Temperature On Fuel Viscositymentioning

confidence: 99%

Design and Preliminary Results of a Fuel Flexible Industrial Gas Turbine Combustor

Novick¹,

Troth²,

Yacobucci

1981

Volume 2: Coal, Biomass and Alternative Fuels; Combustion and Fuels; Oil and Gas Applications; Cycle Innovations

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The work described in this paper is a part of the DOE/ LeRc “Advanced Conversion Technology Project” (ACT). The program is a multiple contract effort with funding provided by the Department of Energy and Technical Program Management provided by NASA LeRc. It is anticipated that future industrial gas turbine engines will require fuel flexibility. The emphasis in this paper is the fuel flexible combustor technology developed under the “Low NOx Heavy Fuel Combustor Concept Program” for application to the Detroit Diesel Allison (DDA) Model 570-K industrial gas turbine engine. The technology, to achieve emission goals, emphasizes dry NO, reduction methods. Due to the high levels of fuel bound nitrogen (FBN) control of NOx can be effected through a staged combustor with a rich initial combustion zone. A RICH/QUENCH/LEAN (RQL) variable geometry combustor is the technology that will be presented to achieve low NO, from alternate fuels containing FBN. The results will focus on emissions and durability for fuel flexible operation.

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“…There were two basic theoretical models for flames stabilized by bluff-bodies: Longwell's [6] Well Stirred Reactor (WSR) model and Zukoski's [7] recirculation zone ignition (RZI) model. Based on the WSR model, Ballal and Lefebvre [8] showed that blowout occurs when the heat release rate in the wake region becomes insufficient to heat the incoming unburned mixture.…”

Section: Introductionmentioning

confidence: 99%