Experimental Study of the Effect of Ambient Pressure on Oscillating Behavior of Pool Fires

Published

December 4, 2020

Author(s)

Jian Chen, Andy Tam, Wei Tang, Chao Zhang, Changhai Li, Shouxiang Lu

Abstract

Pool fires are known to exhibit self-sustained oscillatory behavior, which plays an important role in the understanding of flame and fire spreading. To investigate the effect of ambient pressure on oscillating behavior of pool fires, the ethanol pool fires with diameters from 2 to 10 cm were conducted under a wide range of pressure from 0.6 to 2.5 atm, where different pressure environments were achieved and maintained using a closed high pressure chamber. The dimensional analysis, including flame structure and oscillation frequency, was performed. Grashof number was introduced to explain the flame structure changing from laminar to turbulent, and the flame structure could be divided into four regions. The oscillation intensity of pool fire, which was redefined using the probability contour of the flame, was found related to Grashof number. Furthermore, it was noticed that the influence of ambient pressure and gravity on oscillation frequency depends on the scale of a pool fire and the flame structure. Based on the one dimensional movement of vortex along the axis, a theoretical model was proposed to explain the effect of ambient pressure and gravity on frequency, and then the obtained relationship between Strouhal and Grashof was verified by the experimental results.

Citation

Energy

Pub Type

Journals

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Keywords

Pool fire, Ambient pressure effect, Flame structure, Oscillation frequency

Citation

Chen, J. , Tam, A. , Tang, W. , Zhang, C. , Li, C. and Lu, S. (2020), Experimental Study of the Effect of Ambient Pressure on Oscillating Behavior of Pool Fires, Energy, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=929347 (Accessed April 25, 2024)