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Framework for submodel improvement in wildfire modeling

Author(s): M. El Houssami, A. Lamorlette, D. Morvan, Rory Hadden, Albert Simeoni
Year Published: 2018

An experimental and numerical study was carried out to assess the performance of the different submodels and parameters used to describe the burning dynamics of wildfires. A multiphase formulation was used and compared to static fires of dried pitch pine needles of different bulk densities. The samples were exposed to an external heat flux of 50 kW/m2 in the FM Global Fire Propagation Apparatus and subjected to different airflows, providing a controlled environment and repeatable conditions. Submodels for convective heat transfer, drag forces, and char combustion were investigated to provide mass loss rate, flaming duration, and gas emissions. Good agreement of predicted mass loss rates and heat release rates was achieved, where all these submodels were selected to suit the tested conditions. Simulated flaming times for different flow conditions and different fuel bulk densities compared favorably against experimental measurements. The calculation of the drag forces and the heat transfer coefficient was demonstrated to influence greatly the heating/cooling rate, the degradation rate, and the flaming time. The simulated CO and CO2 values compared well with experimental data, especially for reproducing the transition between flaming and smoldering. This study complements a previous study made with no flow to propose a systematic approach that can be used to assess the performance of the submodels and to better understand how specific physical phenomena contribute to the wildfire dynamics. Furthermore, this study underlined the importance of selecting relevant submodels and the necessity of introducing relevant subgrid-scale modelling for larger scale simulations.

Citation: El Houssami, Mohamad; Lamorlette, Aymeric; Morvan, Dominique; Hadden, Rory M.; Simeoni, Albert. 2018. Framework for submodel improvement in wildfire modeling. Combustion and Flame 190:12-24. https://doi.org/10.1016/j.combustflame.2017.09.038
Topic(s): Fire Behavior, Simulation Modeling
Ecosystem(s): None
Document Type: Book or Chapter or Journal Article
NRFSN number: 17259
FRAMES RCS number: 25307
Record updated: May 16, 2018