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Author (up) Alvarez, C.; Moreno, G.; Valenzuela, F.; Rivera, J.I.; Ebensperger, F.; Reszka, P.; Fuentes, A.
Title Use of an electric heater as an idealized firebrand to determine ignition delay time of Eucalyptus globulus leaves Type
Year 2023 Publication Fire Safety Journal Abbreviated Journal Fire Saf. J.
Volume 141 Issue Pages 103923
Keywords Wildfires; Spotting fires; Thermal model
Abstract The Idealized-Firebrand Ignition Test (I-FIT) protocol was used to evaluate the piloted ignition delay times of fuel beds composed of leaves of Eucalyptus globulus (Labill.). The amount of fuel layer used for evaluation ranged between the fraction volume (������) of 0.03 to 0.07 which are values expected to be found in forest bed fuels. A theoretical model was developed to describe the heating and ignition of the fuel beds, based on the thermal ignition theory. The model, which was originally developed for pine needle beds, considers the penetration of radiation to the porous matrix. The model is able to accurately predict the ignition delay time for different values of ������, but shows a poorer accuracy for the temperature evolution. This is explained by the large variability observed for the Eucalyptus leaves.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0379-7112 ISBN Medium
Area Expedition Conference
Notes WOS:001072435400001 Approved
Call Number UAI @ alexi.delcanto @ Serial 1889
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Author (up) Valenzuela, F.; Rivera, J.I.; Ebensperger, F.; Alvarez, C.; Reszka, P.; Auat Cheein, F.; Fuentes, A.
Title Ignition of Wildland Fuels Exposed to a Time-Decreasing Incident Heat Flux Type
Year 2023 Publication Combustion Science and Technology Abbreviated Journal Combust. Sci. Technol.
Volume 195 Issue 14 Pages 3596-3611
Keywords Wildfires; Spotting fires; Thermal model; Firebrand
Abstract The effect of decreasing incident heat fluxes on the ignition delay time of dry pine needles is addressed in the present study. A customized modular instrument (I-FIT) that uses radiant heaters to simulate idealized firebrands ensures experimental repeatability for combustion experiments. Linear incident heat flux ramps are obtained by controlling the power of the heating element, thus simulating idealized firebrands. An analytical model based on the thermal ignition theory was developed and solved analytically using an integral approach. This model includes convective losses and in-depth penetration of radiation. Radiation was modeled using the P1 approximation. The theoretical model is complemented and validated by experimental data, showing increments of the ignition delay times when the negative slope steepness over time increases for the same heat flux. For given values of the initial incident heat flux on the sample, a critical slope beta(cri) is observed. For slopes steeper than this critical value, ignition is not attained.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0010-2202 ISBN Medium
Area Expedition Conference
Notes WOS:001044563300001 Approved
Call Number UAI @ alexi.delcanto @ Serial 1865
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