Acoustically Driven Extinction in a Droplet Stream Flame

McKINNEY, D.J.; Dunn‐Rankin, Derek

doi:10.1080/00102200008935810

Cited by 21 publications

(16 citation statements)

References 26 publications

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“…4 b, can indicate the flame extinction limit. On the other hand, the positive correlation between the critical strain rate and sound frequency was also reported previously 9 , where the acoustic extinction of tiny droplet flame was studied. It is possible that the diffusion velocity within the flame sheet should also be considered, which requires a more detailed analysis of the coupled flame-acoustic field in future study.…”

Section: Resultssupporting

confidence: 82%

“…More importantly, there was no tubular sound amplifier or sidewall nearby the speaker to concentrate the sound wave, different from past studies 6 – 9 . Thus, the sound field around flame was almost homogeneous, as quantified previously 14 , 15 and seen in Figs.…”

Section: Experimental Methodsmentioning

confidence: 68%

“…McKinney and Dunn-Rankin 9 first used the low-frequency acoustic waves (75–135 Hz) to extinguish a methanol droplet flame. They found that a higher sound pressure was required to extinguish the flame at a higher frequency and concluded that the extinction was caused by the acoustic-induced flame displacement from the fuel droplet.…”

Section: Introductionmentioning

confidence: 99%

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Fluctuation and extinction of laminar diffusion flame induced by external acoustic wave and source

Xiong

Liu

Fan

et al. 2021

Sci Rep

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Acoustic wave can destabilize the flame and has a potential in firefighting, but the influences of the sound source and its frequency are still poorly understood. This work applies a loudspeaker to extinguish a laminar diffusion propane flame of 5–25 mm high, where the local sound frequency is 50–70 Hz and sound pressure is 0.8–3.2 Pa (92.0–104.1 dB). Results reveal a constant flame pulsating displacement at the extinction limit, independent of the sound environment used. Such a flame pulsating displacement is found to be caused by the motion of the speaker membrane (or diaphragm) and its induced wind, which could be two orders of magnitude larger than the displacement of the air that transmits acoustic wave. Thus, under the influence of sound source, a critical flame strain rate, stretched by the pulsating airflow, can be formulated to characterize the blow-off limit better than the local sound pressure. The sound source with a lower frequency can produce larger pulsating displacements of both membrane and flame, and thus promoting extinction. This work improves the understanding of flame dynamics under the external sound field and source, and it helps establish a scientific framework for acoustic-based fire suppression technologies.

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Section: Resultssupporting

confidence: 82%

Section: Experimental Methodsmentioning

confidence: 68%

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Fluctuation and extinction of laminar diffusion flame induced by external acoustic wave and source

Xiong

Liu

Fan

et al. 2021

Sci Rep

View full text Add to dashboard Cite

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“…Okai et al [72] explore the influence of frequency and oscillation amplitude for n-octane single droplets and droplet pairs. Results show burning rates having a dependence on amplitude, with burning rates increasing with amplitude until flame extinction occurs, which is an event requiring more detailed inspection conducted by others [74,75]. Experiments by Tanabe et al [20,21] confirm the burning rate conclusions noted above for both micro-gravity and normal gravity with n-decane droplets.…”

Section: Effects Of Acoustics On Fuel Droplet Combustionmentioning

confidence: 54%

Multi-Phase Combustion and Transport Processes Under the Influence of Acoustic Excitation

Wegener¹

2014

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“…Flame quenching induced by acoustic excitation [18] is not considered in this study in which acoustic disturbances remain small and in the linear regime. Also, the acoustic radiation force [19] can be neglected in comparison with the drag force exerted by the flow.…”

Section: Introductionmentioning

confidence: 99%