Acoustical Extinction of Flame on Moving Firebrand for the Fire Protection in Wildland–Urban Interface

Xiong, Caiyi; Liu, Yanhui; Xu, Cangsu; Huang, Xinyan

doi:10.1007/s10694-020-01059-w

Cited by 14 publications

(10 citation statements)

References 32 publications

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“…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. 1 b–c.…”

Section: Experimental Methodssupporting

confidence: 77%

“…Table 2 summarized the measured the critical local sound pressure ( in Pa) for flame extinction as a function of sound frequency from the literature 6 – 9 , 14 , 15 . The flame-related parameters like the flame type, height, heat release rate (HRR), and Froude number were also listed.…”

Section: Resultsmentioning

confidence: 99%

“…Thus, all tested diffusion flames are unlifted and laminar, driven by the buoyancy.

Figure 1 ( a ) The schematic of gas burner and sound source, ( b ) sound pressure distribution on the plane 100-mm away from the speaker 15 , ( c ) the decay of sound pressure with the distance to the speaker membrane, and ( d ) the corresponding flame characteristics. …”

Section: Experimental Methodsmentioning

confidence: 99%

“…The response of flame to the external sound field is affected by the sound frequency 6 – 15 . When using a high sound frequency (> 200 Hz), it is difficult to extinguish a flame 16 – 18 but can only cause flame tilting or fluctuation 13 .…”

Section: Introductionmentioning

confidence: 99%

“…Our recent works used a loudspeaker and low-frequency acoustic waves (without tube between speaker and flame) to extinguish the stationary candle flame 14 , the moving flames in plastic drips 14 , 24 , and the flaming firebrand 15 . By converting the sound pressure into a velocity component, a characteristic Damköhler (Da) number was introduced as an indicator for the acoustic extinction limit.…”

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: Experimental Methodssupporting

confidence: 77%