On the consumption of fuel pockets via inwardly propagating flames

Sun, Can; Law, Chung K.

doi:10.1016/s0082-0784(98)80495-5

Cited by 24 publications

(15 citation statements)

References 7 publications

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“…Similarly, figure 7(b) shows that the flame starts to accelerate prior to annihilation. Significant variations in the propagation velocity V f during flame annihilation have also been observed by others (see, for example, Chen & Sohrab 1995; Echekki et al 1996; Wichman & Vance 1997;Petrov & Ghoniem 1998;Sun & Law 1998;Lu & Ghosal 2003).…”

Section: Discussion Of the Theoretical Resultssupporting

confidence: 66%

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Sound generation by laminar premixed flame annihilation

2011

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This paper presents a numerical and theoretical investigation of the sound generated by premixed flame annihilation. Planar, axisymmetric and spherically symmetric flame annihilation events are considered. The compressible Navier-Stokes, energy and progress variable equations are first solved using simple chemistry simulations, resolving both the flame dynamics and the acoustics. These simulations show that the amplitude of the far-field sound produced by the annihilation events depends on the flame thickness, particularly for the axisymmetric and spherically symmetric flame annihilation events. The flame propagation velocity is also always observed to increase significantly prior to flame annihilation, which is in keeping with other reported experimental and numerical studies. A theory is then presented that relates the far-field sound to the flame annihilation event by using a previously reported and extended form of Lighthill's acoustic analogy. A comparison with the numerical results shows that this theory accurately represents the far-field sound produced by considering only the temporal heat release source term in Lighthill's acoustic analogy, as reported by others. Additional assumptions of an infinitely thin flame and constant flame speed are then invoked in an attempt to simplify the problem. In the planar annihilation, this theory results in good predictions of the overall pressure change. However, these assumptions lead to significant under-prediction of the amplitude of far-field sound produced for the axisymmetric and spherically symmetric annihilation events. Finally, dimensional reasoning supported by the simulations and theory is used to develop scalings of the far-field sound in terms of the flame parameters.

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Section: Discussion Of the Theoretical Resultssupporting

confidence: 66%

“…Chen & Sohrab 1995;Echekki, Chen & Gran 1996;Wichman & Vance 1997;Petrov & Ghoniem 1998;Sun & Law 1998;Lu & Ghosal 2003). The dynamics of converging spherical and cylindrical flames have also been investigated both experimentally and numerically (e.g.…”

Section: Introductionmentioning

confidence: 99%

Sound generation by laminar premixed flame annihilation

2011

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“…Then, the combustion wave can acquire the shape of a rotating spiral or other rotating structures observed in experiments [10,11]. Apparently, the effect of the splitting flames can also be related to formation of "pockets" or "islands," which are regions filled by the fresh mixture and surrounded by combustion products [13]. Let the vortex flow entrain the fresh mixture into the region of combustion products at a certain time, as is shown in Fig.…”

Section: Formation Of Two Chemical Reaction Fronts In the Frei Processmentioning

confidence: 92%

Splitting flames in a narrow channel with a temperature gradient in the walls

Minaev

Sereshchenko

Fursenko

et al. 2009

Combust Explos Shock Waves

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A possibility of simultaneous formation of two chemical reaction fronts during nonstationary combustion of a gas in a microchannel with a temperature gradient in the walls is demonstrated. Combustion in a straight tube and in a gap between two disks with radial fuel injection is considered. In both cases, the characteristic transverse size of the channel is smaller than the critical diameter determined for the ambient temperature, and gas combustion occurs in the region where the wall temperature is higher than the ambient temperature. A numerical study of flame repetitive extinction/ignition (FREI) demonstrated a possibility of simultaneous formation of two chemical reaction fronts in the hot region of the channel. One front corresponds to conventional flame propagating upstream from the hot to the cold part of the channel, and the other front moves in the downstream direction and decays as the fuel burns out. Based on this study, a new mechanism of ignition and incomplete combustion of the combustible mixture in microsystems is proposed.

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“…Chen et al [15] showed a four-fold increase in density-weighted displacement speed during pocket burnout due to preferential diffusion effects that occur locally during flame interaction. Sun and Law [17] also calculated increases in flame propagation speed during pocket burnout. Consumption speed increases have also been reported by Ranganath and Echekki [18], Chen and Sohrab [19], and Ranganath and Echekki [20].…”

Section: Introductionmentioning

confidence: 99%

Structure of Flames in Flame Interaction Zones

Tyagi

Boxx

Peluso

et al. 2018

2018 AIAA Aerospace Sciences Meeting

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Two identical burners with variable burner separations are used to investigate the dynamics of interacting flames. The presence of adjacent flames in large scale combustion devices influences the structure and dynamics of the flames, and understanding the sensitivity of flames to these interactions is vital for local and global flame characterization. The behavior of the flame in the interaction zone is dependent on a number of operating parameters, including burner separations, inlet bulk flow velocities, and flame stabilization or flame shape. High-repetion-rate CH* chemiluminescence and OH-planar laser-induced flourescence measurements are performed to obtain the flame structure and flame-front locations. These measurement techniques allow for the determination of how varying fluid-dynamic and geometric parameters change the behavior of these flames in the flame interaction zones. We also quantify global metrics like flame surface density, global consumption speed, and flame curvature PDFs to understand the impact of flame interaction.

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On the consumption of fuel pockets via inwardly propagating flames

Cited by 24 publications

References 7 publications

Sound generation by laminar premixed flame annihilation

Sound generation by laminar premixed flame annihilation

Splitting flames in a narrow channel with a temperature gradient in the walls

Structure of Flames in Flame Interaction Zones

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