A simplified analytical model for radiation dominated ignition of solid fuels exposed to multiple non-steady heat fluxes
Parot
R
author
Rivera
J
I
author
Reszka
P
author
Torero
J
L
author
Fuentes
A
author
2022
Heat fluxes from fires are strongly time-dependent. Historically, the thermal ignition theory in its classical form has neglected this time dependency until recent years, where theories have been developed to include time-varying incident heat fluxes. This article proposes a simplified general model formulation for the heating of solid fuels exposed to four different heat flux behaviors, considering the penetration of radiation into the medium. The incident heat flux cases developed where: Constant, Linear, Exponential and Polynomial, which represent different situations related to structural and wildland fires. The analytical models consider a spatially averaged medium temperature and exact and approximate solutions are presented, based on the critical ignition temperature criterion, which are valid for solids of any optical thickness. The results were validated by comparison with various models presented in the literature, where the model granted in this work was capable to adjust to all of them, especially when high heat fluxes are involved. Therefore, the proposed model acquires a significant engineering utility since it provides a single model to be used as a general and versatile tool to predict the ignition delay time in a manageable way for solid fuels exposed to different fire conditions.
Ignition delay time
Fire safety
Integral heat equation
Solid ignition
Translucent solids
In-depth absorption of radiation
WOS:000735880500007
exported from refbase (show.php?record=1521), last updated on Thu, 27 Jan 2022 12:31:17 -0300
text
10.1016/j.combustflame.2021.111866
Parot_etal2022
Combustion and Flame
Combust. Flame
2022
continuing
periodical
academic journal
237
111866
0010-2180