Register      Login
International Journal of Wildland Fire International Journal of Wildland Fire Society
Journal of the International Association of Wildland Fire
Shopping Cart: ( empty )
You are here: Home > Journals > WF > WF06029
RESEARCH ARTICLE
Contents Vol 16(5)

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

Behdad Moghtaderi A B , Tri Poespowati A , Eric M. Kennedy A and Bogdan Z. Dlugogorski A
+ Author Affiliations
- Author Affiliations

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 https://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.


Acknowledgements

The authors wish to acknowledge the financial support provided to them by the Australian Research Council under the ARC-Discovery scheme and the University of Newcastle, Australia.


References


Albini FA (1979) Spot fire distance from burning trees – a predictive model. USDA Forest Services, General Technical Report INT-56. (Washington, DC)

Albini FA (1983) Transport of firebrands by line thermals. Combustion Science and Technology  32, 277–288.
| Crossref | GoogleScholarGoogle Scholar | Australian Bureau of Statistics (2005) http://www.ABS.gov.au [Verified 5 February 2005].

Aziz A, Na TY (1984) ‘Perturbation Methods in Heat Transfer.’ (Hemisphere Publishing Corporation: New York)

Babrauskas V (2003) ‘Ignition Handbook. Fire Sciences Publishers.’ USA. (Fire Science Publishers: Issaquah, WA, USA)

Beer T (1990) The Australian National Bushfire model project. Mathematical and Computer Modelling  13((12)), 49–56.
| Crossref | GoogleScholarGoogle Scholar | Clements HB (1977) Lift-off of forest firebrands. USDA Forest Services, Southeast Forest Experiment Station, Research Paper SE-159. (Asheville, NC)

Cottrell A (2005) Communities and bushfire hazard in Australia: more questions than answers. Environmental Hazards  6, 109–114.
Ellis PF (2000) The aerodynamic and combustion characteristics of eucalypt bark – a firebrand study. PhD Thesis, Australian National University, Canberra.

Finney MA (1998) FARSITE: Fire Area Simulator – model development and evaluation. USDA Forest Service, Rocky Mountain Research Station Paper RMRS-RP-4. (Ogden, UT)

Gill AM (2004) Landscape fires as social disasters: an overview of the bushfire problem. Environmental Hazards  6, 65–80.
Goodman TR (1964) Application of integral methods to transient non-linear heat transfer. In ‘Advances in Heat Transfer. VI’. (Eds TF Irvine, JP Hartnelt) pp. 51–122. (Academic Press: New York)

Green DG, Tridgell A , Gill AM (1990) Interactive simulation of bushfires in heterogeneous fuels. Mathematical and Computer Modelling  13((12)), 57–66.
| Crossref | GoogleScholarGoogle Scholar | Griffith JF, Barnard JA (1995) ‘Flame and Combustion.’ 3rd edn. (Blackie Academic & Professional: Glasgow, Scotland)

Hamada M (1951) Experiments on the ignition due to firebrands. Property and Casualty Insurance Rating Organisation of Japan, Fire Research Report. (Tokyo, Japan)

Handmer J , Tibbits A (2005) Is staying at home the safest option during bushfires? Historical evidence for an Australian approach. Environmental Hazards  6, 81–91.
Moghtaderi B, Novozhilov V, Fletcher DF, Kent JH (1995) An integral model for the pyrolysis of non-charring materials. In ‘Fire Science and Technology – Proceedings of the Second Asia–Oceania Symposium’. 13–17 September 1995, Khabarovsk, Russia. (Eds VK Bulgakov, AI Karpov) pp. 308–319. (Khabarovsk State University of Technology: Khabarovsk, Russia)

Moghtaderi B, Novozhilov V, Fletcher DF , Kent JH (1997) An integral model for the transient pyrolysis of solid materials. Fire and Materials  21, 7–16.
| Crossref | GoogleScholarGoogle Scholar | Ozisik MN (1992) ‘Heat Conduction.’ 2nd edn. (Wiley: New York)

Peters B (2002) Extinction of burning particles due to unstable combustion modes. Fuel  81, 391–396.
| Crossref | GoogleScholarGoogle Scholar | Ramsey GC, McArthur NA (1995) Building in the urban interface: lessons from the January 1994 Sydney bushfires. In ‘Bushfire’ 95 Conference’. 27–30 September 1995, Hobart, TAS. (Forestry Tasmania, Parks and Wildlife Service and Tasmania Fire Service: Hobart)

Ranz W , Marshall W (1952) Evaporation from drops. Chemical Engineering Progress  48, 141–146.
Semenov NN (1935) ‘Chemical Kinetics and Chain Reactions.’ (Oxford University Press: London)

Spearpoint MJ , Quintiere JG (2000) Predicting the burning of wood using an integral model. Combustion and Flame  123, 308–325.
| Crossref | GoogleScholarGoogle Scholar | van der Wel PGJ (1993) Ignition and propagation of dust explosions. PhD Thesis, Delft University, the Netherlands.

Wang H, Dlugogorski BZ , Kennedy EM (1999) Theoretical analysis of reaction regimes in low-temperature oxidation of coal. Fuel  78, 1073–1081.
| Crossref | GoogleScholarGoogle Scholar |




1 Typically tens of metres and occasionally hundreds of metres ahead of the main front.

2 Bi ≡ Biot number ≡ hL/k where h is the convective heat transfer coefficient and L and k are the characteristic length and thermal conductivity of the particle, respectively.

3 In the absence of flame, oxygen can penetrate into the particle causing a char oxidation reaction on the internal surfaces of the particle. This process, however, is diffusion-limited.