Framework for submodel improvement in wildfire modeling

Mohamad El Houssami, Aymeric Lamorlette, Dominique Morvan, Rory M. Hadden, Albert Simeoni

Research output: Contribution to journalArticlepeer-review

Abstract

An experimental and numerical study was carried out to assess the performance of the different sub models 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/m(2) in the FM Global Fire Propagation Apparatus and subjected to different airflows, providing a controlled environment and repeatable conditions. Sub models 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. (C) 2017 Published by Elsevier Inc. on behalf of The Combustion Institute.

Original languageEnglish
Pages (from-to)12-24
Number of pages13
JournalCombustion and Flame
Volume190
Early online date24 Nov 2017
DOIs
Publication statusPublished - Apr 2018

Keywords

  • Multiphase
  • Forced flow
  • Porous
  • LES
  • LARGE-EDDY SIMULATION
  • FIRE SPREAD
  • NUMERICAL-SIMULATION
  • WILDLAND FUELS
  • MULTIPHASE FORMULATION
  • HEAT-TRANSFER
  • PINE NEEDLES
  • COMBUSTION
  • FOREST
  • FLOW

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