Droplet combustion in standing sound waves

Tanabe, Mitsuaki; Kuwahara, Taishi; Satoh, Kimiyoshi; Fujimori, Takahiro; Sato, Junichi; Kono, Michikata

doi:10.1016/j.proci.2004.07.019

Cited by 33 publications

(34 citation statements)

References 9 publications

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“…That is to say, the inclination of the jet flow occurred with a density difference between the center jet and surrounding gas, with the direction determined by the magnitude. This effect was the same as the heat acoustic-flow effect based on density difference indicated by Tanabe et al (17) …”

Section: Details Of the Flow-field Inclinationsupporting

confidence: 75%

Improvement of Laminar Lifted Flame Stability Excited by High-Frequency Acoustic Oscillation

Hirota

Hashimoto

Oso

et al. 2009

JTST

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A high-frequency (20kHz) standing wave was applied to the unburned mixture upstream of a methane-air lifted jet flame using a bolt-clamped Langevin transducer (BLT) to improve stability. The flow field near the flame was visualized using acetone planar-laser-induced fluorescence (PLIF). The standing wave decreased the lifted flame height and increased the blow-off limit. The upstream flow field of the center jet then bent. This phenomenon appeared when there was a density difference between the center jet and the surrounding secondary flow. When the density of the center jet was less than that of the co-flow, the center jet was redirected to the pressure anti-node side. Conversely, when the density of the center jet was greater than that of the co-flow, the center jet was redirected to the pressure node side. This redirection tended to stabilize the laminar lifted flame.

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Section: Details Of the Flow-field Inclinationsupporting

confidence: 75%

Improvement of Laminar Lifted Flame Stability Excited by High-Frequency Acoustic Oscillation

Hirota

Hashimoto

Oso

et al. 2009

JTST

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“…Increase in the burning rate constant by the acoustic oscillation was explained through the view point of enhanced turbulent transport since the velocity oscillation by sound is supposed to play a similar role with turbulence. Along with the effect of diffusion enhancement by the acoustic oscillation, the acoustically induced thermal convection, that is generated when the density difference exists in a standing acoustic field, has been reported recently (Tanabe et al 2005). Acoustic radiation force in the standing acoustic field drives this thermal convection.…”

Section: Introductionmentioning

confidence: 93%

“…Acoustic radiation force in the standing acoustic field drives this thermal convection. It plays an important role on the burning enhancement of the droplet in the standing acoustic fields under microgravity (Tanabe et al 2005). However, Dattarajan et al suggest that the significant increases in the burning rate resulting from the acoustic excitation are not completely explained by the convective effect alone (Dattarajan et al 2006).…”

Section: Introductionmentioning

confidence: 99%

Influence of Acoustic Perturbation and Acoustically Induced Thermal Convection on Premixed Flame Propagation

Yano

Takahashi

Kuwahara

et al. 2009

Microgravity Sci. Technol.

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Interference between an acoustic field and premixed flame is investigated. Two kinds of transport processes are considered to cause combustion promotion in the acoustic field. One is diffusive transport. It has long been considered that the acoustic oscillation promotes diffusion, like turbulence does. The other is convective transport. Acoustically induced thermal convection that is driven by a kind of acoustic radiation force in a standing acoustic field has been previously found (Tanabe et al., Proc Combust Inst 28:1007-1013, 2000. The burning rate of an isolated single droplet is promoted by this thermal convection. In this report, the influence of the acoustic oscillation on the premixed flame propagation was examined through experiment and numerical simulation. The gravitational force was not taken into account since it complicates the combustion phenomena. The experiment and numerical simulation were done in microgravity condition. Each influence of turbulent diffusion and thermal convection were evaluated from the burning velocity, flame shape and flame speed, since the diffusive effect has been considered to have an influence on the burning velocity, while the convective effect has an influence on the flame speed and flame shape. As a result, it was clarified that the diffusive effect has a minor influence on the

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“…The effect of forced flow/convection on hydrocarbon droplet combustion has been studied quite extensively under laminar flow conditions and therefore there is a wealth of knowledge (see, e.g., recent references [1][2][3][4][5][6][7][8][9][10], and references cited therein, M. Birouk ( ) · S. L. Toth Department of Mechanical Engineering, University of Manitoba, Winnipeg, MB R3T 5V6, Canada e-mail: madjid.birouk@umanitoba.ca to cite only a few). However, studies reporting on the effect of a turbulent or an acoustic field are quite limited (e.g., [11][12][13][14][15][16][17]). Birouk et al [11] investigated experimentally the combustion of a suspended hydrocarbon droplet under turbulent flow environment at atmospheric/room conditions.…”

Section: Introductionmentioning

confidence: 99%

“…They also reported an increase in the burning rate with ambient pressure. Tanabe et al [14] studied droplet burning in a standing sound wave at elevated ambient pressure under normal and microgravity conditions. They observed that the burning rate increases with the acoustic Grashof number (defined as the ratio of acoustic radiation force to viscosity) regardless of the ambient pressure and acoustic frequency.…”

Section: Introductionmentioning

confidence: 99%

Hydrocarbon Droplet Turbulent Combustion in an Elevated Pressure Environment

Birouk

Toth

2015

Flow Turbulence Combust

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New experimental data on the effect of turbulence on the combustion of nheptane and n-decane droplet at elevated pressure are reported. Turbulent flow field in the central volume of a spherical vessel was generated by a set of eight axial fans. Flow characterization demonstrated that turbulence is isotropic and homogeneous within the 40 mm central volume of the vessel. The combustion of n-heptane and n-decane droplet was examined by varying turbulence intensity via the fans rotational speed and ambient pressure and temperature inside the vessel/chamber. Results showed that droplet burning rate becomes sensitive to turbulence only at elevated ambient pressure. Droplet flame extinction was found to depend on the heat loss from the droplet envelop flame, which increases with turbulence intensity.

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Droplet combustion in standing sound waves

Cited by 33 publications

References 9 publications

Improvement of Laminar Lifted Flame Stability Excited by High-Frequency Acoustic Oscillation

Improvement of Laminar Lifted Flame Stability Excited by High-Frequency Acoustic Oscillation

Influence of Acoustic Perturbation and Acoustically Induced Thermal Convection on Premixed Flame Propagation

Hydrocarbon Droplet Turbulent Combustion in an Elevated Pressure Environment

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