Abstract
The effect of the diameter of dead twigs of Cistus monspeliensis on their ignition was studied experimentally and theoretically. Autoignition experiments were carried out in a cone calorimeter. The ignition time, surface temperature before ignition, flame residence time, smoldering time and mass loss were measured. The particles were classified into two groups based on their ignitability. The first group contained the most flammable twigs, which had diameters smaller than or equal to 4 mm, along with leaves. The second one included twigs with diameters equal to or larger than 5 mm. For a radiant heat flux of 50 kW/m2, the 4-mm value appeared to be the upper limit for the size of the particles potentially involved in the spread dynamics of wildfires. However, bark detachment was observed on the thickest twigs, which greatly decreased their ignition time. Two ignition criteria were investigated: the ignition temperature and critical mass flux. The ignition temperature increased with the twig diameter, showing that this quantity should be carefully considered in ignition models. A thermal ignition model was proposed to determine the ignition time of twigs according to their diameter. The critical mass flux appeared to be fairly constant for any fuel diameter and could also be convenient for modeling the ignition of shrub fuels.
Similar content being viewed by others
Abbreviations
- a:
-
Thermal diffusivity (m2/s)
- cp :
-
Specific heat [J/(kg K)]
- d:
-
Diameter of the flame base (m)
- D:
-
Diameter (mm)
- f:
-
Ratio of the cross sectional area occupied by twigs to the total cross sectional area of the sample (–)
- F fl-med :
-
View factor between the flame and the top of the medium
- g:
-
Acceleration of gravity (m/s2)
- h:
-
Heat transfer coefficient [W/(m2 K)]
- H:
-
Flame height (m)
- HRR:
-
Heat release rate (W)
- L:
-
Length (m)
- \( {\dot{\text{m}}} \) :
-
Mass loss rate (kg/s)
- n:
-
Number of twigs
- N(βm):
-
Norm of the eigenfunctions
- Nu:
-
Nusselt number (−)
- \( \dot{q}^{\prime\prime} \) :
-
Density of radiant heat flux (W/m2)
- Ra:
-
Rayleigh number (–)
- t:
-
Time (s)
- T:
-
Temperature (°C)
- X(βm,z):
-
Eigenfunctions
- z:
-
Vertical coordinate (m)
- α:
-
Absorptivity (–)
- β:
-
Volumetric thermal expansion coefficient (K−1)
- βm :
-
Eigenvalues
- \( {\Delta }H_{{{\text{c}},{\text{net}}}} \) :
-
Net heat of combustion (J/kg)
- ε:
-
Emissivity (–)
- λ:
-
Thermal conductivity [W/(m K)]
- ν:
-
Kinematic viscosity (m2/s)
- ρ:
-
Density (kg/m2)
- θ:
-
Variable change \( \theta = T - T_{\infty } \) (°C)
- \( \chi \) :
-
Combustion efficiency (–)
- τ:
-
Reflectivity (−)
- ∞:
-
Ambient
- 0:
-
Steady state problem
- 1:
-
Homogenous problem
- air:
-
Air
- b:
-
Bottom size
- bot:
-
Burn out time
- c:
-
Characteristic
- cone:
-
Cone calorimeter
- conv:
-
Convective
- crit:
-
Critical
- ign:
-
Ignition
- f:
-
Film
- fl:
-
Flame
- frt:
-
Flame residence time
- med:
-
Medium equivalent to the twigs
- rad:
-
Radiant
- smt:
-
Smoldering time
- tw:
-
Twig
- u:
-
Upper side
- T:
-
Total
References
Sullivan AL (2007) A review of wildland fire spread modelling, 1990–2007, 1: Physical and quasi-physical models. Int J Wildland Fire 18:349–368
Sullivan AL (2007) A review of wildland fire spread modelling, 1990–2007, 2: Empiricaland quasi-empirical models. Int J Wildland Fire 18:369–386
Porterie B, Consalvi JL, Loraud JC, Giroud F, Picard C (2007) Dynamics of wildland fires and their impact on structures. Combust Flame 149:314–328.
Mell W, Jenkins MA, Gould J, Cheney P (2007) A physics-based approach to modelling grassland fires. Int J Wildland Fire 16:1–22.
Morvan S, Méradji S, Accary G (2009) Physical modeling of fire spread in Grasslands. Fire Safety J 44:50–61.
Rothermel RC (1972) A mathematical model for predicting fire spread in wildland fuels, Res. Pap. INT-115. Ogden, UT: U.S. Department of Agriculture, Intermountain Forest and Range Experiment Station.
Porterie B, Zekri N, Clerc JP, Loraud JC (2007) Modeling forest fire spread and spotting process with small world networks. Combust Flame 149:63–78.
Santoni PA, Filippi JB, Balbi JH, Bosseur F (2011) Wildland fire behaviour case studies and fuel models for landscape-scale fire modeling. J Combust. doi:10.1155/2011/613424.
Fons WL (1946) Analysis of fire spread in light forest fuels. J Agric Res 72:93–121.
Koo E, Pagni P, Stephens S, Huff J, Woycheese J, Weise DR (2005) A simple physical model for forest fire spread rate. In: Fire Safety Science Proceedings of the Eighth International Symposium, pp 851–862.
Babrauskas V (2001) Ignition of wood: a review of the state of the art. In: Interflam 2001, Interscience Communications Ltd., London, pp 71–88.
Finney MA, Cohen JD, McAllister SS, Jolly WM (2013) On the need for a theory of wildland fire spread. Int J Wildland Fire 22:25–36.
Rasbash DJ, Drysdale DD, Deepak D (1986) Critical heat and mass transfer at pilot ignition and extinction of material. Fire Safety J 10:1–10.
Melinek SJ (1969) Ignition behaviour of heated wood surfaces. Fire Research Station, Borehamwood.
Delichatsios MA (2005) Piloted ignition times, critical heat fluxes and mass loss rates at reduced oxygen atmospheres. Fire Safety J 40:197–212
Lyon RE, Quintere JG (2007) Criteria for piloted ignition of combustible solids. Combust Flame 151:551–559
McAllister S (2013) Critical mass flux for flaming ignition of wet wood. Fire Safety J 61:200–206
Fateh T, Rogaume T, Luche J, Richard F, Jabouille F (2014) Characterization of the thermal decomposition of two kinds ofplywood with a cone calorimeter—FTIR apparatus. J Anal Appl Pyrol 107:87–100.
Torero JL, Simeoni A (2010) Heat and mass transfer in fires: scaling laws, ignition of solid fuels and application to forest fires. Open Thermodyn J 4:145–155
Simeoni A, Thomas JC, Bartoli P, Borowieck P, Reszka P, Colella F, Santoni PA, Torero JL (2012) Flammability studies for wildland and wildland–urban interface fires applied to pine needles and solid polymers. Fire Safety J 54:203–217
McArthur AG (1962) Control burning in eucalypt forests. In: Commonwealth of Australia Forest and Timber Bureau, Leaflet Number 80. Canberra, ACT
Peet GB (1965) A fire danger rating and controlled burning guide for the Northern Jarrah (Euc Marginata sm) forest of Western Australia. Forests Dept, Perth
Burrows ND (2001) Flame residence times and rates of weight loss of eucalypt forest fuel particles. Int J Wildland Fire 10:137–143
DeBano LF, Neary DG, Fflolliott PF (1998) Fire Effects on Ecosystems. Wiley, New York
Cohen JD, Deeming JE (1985) The National Fire-Danger Rating System: basic equations, General Technical Report PSW-82, United States Department of Agriculture Forest Service.
Simms DL (1960) Ignition of cellulosic materials by radiation. Combust Flame 4:293–300
Simms DL, Law M (1967) The ignition of wet and dry wood by radiation. Combust Flame 11:377–388
Shi L, Yit M, Chew L (2013) Experimental study of woods under external heat flux by autoignition, ignition time and mass loss rate. J Therm Anal Calorim 111:1399–1407
Poespowati T (2009) An experimental study on autoignition of wood. In: Recent advances in technologies, Maurizio A Strangio, InTech, pp 577–586
Atreya A, Carpentier C, Harkleroad M (1986) Effect of sample orientation on piloted ignition and flame spread. Fire Safety Sci 1:97–109
Dietenberg MA (1995) Protocol for ignitability, lateral flame spread and heat release rate using lift apparatus, chapter 29. Fire Polym II, pp 435–449
Harada T (2001) Time to ignition, heat release rate and fire endurance time of wood in cone calorimeter test. Fire Mater 25:161–167
Spearpoint MJ, Quintiere JG (2001) Predicting the piloted ignition of wood in the cone calorimeter using an integral model—effect of species, grain orientation and heat flux. Fire Safety J 36:391–415
Delichatsios MA (2005) Piloted ignition times, critical heat fluxes and mass loss rates at reduced oxygen atmospheres. Fire Safety J 40:197–212
[35] Bilbao R, Mastral JF, Aldea ME, Ceamanos J, Betran M (2001) Experimental and theoretical study of the ignition and smoldering of wood including convective effects. Combust Flame 126:1363–1372
[36] Koohyar AN, Welker JR, Sliepcevich CM (1968) The irradiation and ignition of wood by flame. Fire Technol 4:284–291
Anderson HE (1970) Forest fire ignitibility. Fire Technol 6:312–319
[38] Dimitrakopoulos AP (2001) A statistical classification of Mediterranean species based on their flammability components. Int J Wildland Fire 10:113–118
Mindykowski P, Fuentes A, Consalvi JL, Porterie B (2011) Piloted ignition of wildland fuels. Fire Safety J 46:34–40
Tihay V, Santoni PA, Barboni T, Leonelli L (2014) Experimental and theoretical study of diameter effect on the ignition of cistus twigs. In: Viegas DX (ed) VII International Conference on Forest Fire Research
Cruz G, Butler BW, Viegas DX, Palheiro P (2011) Characterization of flame radiosity in shrubland fires. Combust Flame 158:1970–1976
Boulet P, Parent G, Acem Z, Collin A, Séro-Guillaume O (2011) On the emission of radiation by flames and corresponding absorption by vegetation in forest fires. Fire Safety J 46:21–26
[43] Tihay V, Santoni PA, Simeoni A, Garo JP, Vantelon JP (2009) Skeletal and global mechanisms for the combustion of gases released by crushed forest fuels. Combust Flame 156:1565–1575.
Quintiere JG (2006) Fundamentals of fire phenomena. Wiley, The Atrium, Southern Gate, Chichester
Wilkie CA, Morgan AB (2009) Fire retardancy of polymeric materials. CRC Press, Boca Raton
Andrews PL (1986) BEHAVE: Fire behavior prediction and fuel modeling system—Burn Subsystem Part 1, General Technical Report INT-1 94, United States Department of Agriculture Forest Service.
Finney MA (1998) FARSITE: fire area simulator—Model Development and Evaluation, Research Paper RMRS-RP-4 Revised, United States Department of Agriculture Forest Service
Dupuy JL, Larini M (1999) Fire spread through a porous forest fuel bed: a radiative and convective model including fire-induced flow effects. Int J Wildland Fire 9:155–172
Cruz MG, Butler BW, Alexander ME, Forthofer JM, Wakimoto RH (2006) Predicting the ignition of crown fuels above a spreading surface fire. Part I: model idealization. Int J Wildland Fire 15:47–60
Cruz MG, Butler BW, Alexander ME (2006) Predicting the ignition of crown fuels above a spreading surface fire. Part 2: model evaluation. Int J Wildland Fire 15:61–67
Staggs JE (2001) Ignition of char-forming polymers at a critical mass flux. Polym Degrad Stabil 74:433–439.
Özisik MN (1993) Heat conduction. Wiley, New York
Nield DA, Bejan A (2006) Convection in porous media. Springer, Berlin
Moro C (2006) Détermination des caractéristiques physiques de particules de quelques espèces forestières méditerranéennes, INRA PIF2006-06.
Liodakis S, Bakirtzis D, Dimitrakopoulos AP (2003) Autoignition and thermogravimetric analysis of forest species treated with fire retardants. Thermochim Acta 399:31-42.
Leroy V, Cancellieri D, Leoni E (2006) Thermal degradation of logno-cellulosic fuels: DSC and TGA studies. Thermochim Acta 451:131–138
Incropera FP, DeWitt DP, Bergman TL, Lavine AS (2007) Fundamentals of heat and mass transfer. Wiley, New York.
Morandini F, Perez-Ramirez Y, Tihay V, Santoni PA, Barboni T (2013) Radiant, convective and heat release characterization of vegetation fire. Int J Therm Sci 70:83–91
Heskestad G (1983) Luminous height of turbulent diffusion flames. Fire Safety J 5:103–108
Howell JR, Siegel R, Pinar Menguc M (2010) Thermal radiation heat transfer, 5th edn. Taylor and Francis/CRC, New York.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Tihay-Felicelli, V., Santoni, PA., Barboni, T. et al. Autoignition of Dead Shrub Twigs: Influence of Diameter on Ignition. Fire Technol 52, 897–929 (2016). https://doi.org/10.1007/s10694-015-0514-x
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10694-015-0514-x