The role of extinction on the re-ignition potential of wood-based embers in bushfires

Author

Behdad Moghtaderi A B , Tri Poespowati A , Eric M. Kennedy A and Bogdan Z. Dlugogorski A

A Industrial Safety and Environment Protection Group, Discipline of Chemical Engineering, School of Engineering, Faculty of Engineering and Built Environment, The University of Newcastle, Callaghan, NSW 2308, Australia. 

B Corresponding author. Email: behdad.moghtaderi@newcastle.edu.au

International Journal of Wildland Fire 16(5) 547-555 http://dx.doi.org/10.1071/WF06029
Submitted: 6 March 2006  Accepted: 24 March 2007   Published: 26 October 2007 

Abstract

The re-ignition potential of partially burnt wood-based embers was investigated theoretically by studying their extinction characteristics. An adaptation of Semenov’s thermal explosion theory was used in conjunction with a linear stability analysis to determine the critical particle size at which extinction occurs. Particles of various shapes were studied and the analysis was carried out for both thermally thin and thermally thick particles. The results of our analysis indicate that thermally thick embers are less susceptible to extinction than thermally thin ones and, as such, are more prone to re-ignition. The results also show that the extinction of wood embers is strongly affected by the particle temperature, particle shape, and reaction kinetics. The effects of ambient conditions were found to be less pronounced than particle properties.

Additional keywords: flame spread, mathematical modelling.

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