TY - JOUR
T1 - An Engineering CFD Model for Fire Spread on Wood Cribs for Travelling Fires
AU - Dai, Xu
AU - Gamba, Antonio
AU - Liu, Chang
AU - Anderson, Johan
AU - Charlier, Marion
AU - Rush, David
AU - Welch, Stephen
N1 - Funding Information:
This work was carried out in the frame of the TRAFIR project with funding from the Research Fund for Coal and Steel (grant N°754198). Partners are ArcelorMittal Belval & Differdange, Liège Univ. the Univ. of Edinburgh, RISE Research Inst. of Sweden and the Univ. of Ulster. This work used the ARCHER UK National Supercomputing Service (http://www.archer.ac.uk), and the resources provided by the Edinburgh Compute and Data Facility (ECDF) (http://www.ecdf.ed.ac.uk/) and assistance of relevant administrators is acknowledged. The authors are grateful to EPSRC (grant number: EP/R029369/1) and ARCHER for financial and computational support as a part of their funding to the UK Consortium on Turbulent Reacting Flows (www.ukctrf.com). The UKCTRF Consortium benefits from the support of CoSeC, the Computational Science Centre for Research Community. The authors would like to thank IMFSE students Pei Ying Yang and Hongbo Zhen for pioneering development of the fire spread model, and SAFE MSc student Siqi Du for his assistance on collecting the cone calorimetry data for the “European spruce” (Picea abies) wood samples. Eric Mueller, Benjamin Ralph, Johan Sjöström, and Jean-Marc Franssen are gratefully acknowledged for their precious suggestions and discussions during the development of this work. For the purpose of open access, the author has applied a Creative Commons Attribution (CC BY) licence to any Author Accepted Manuscript version arising from this submission. The authors greatly appreciate the funding from the University of Edinburgh to make this paper available in gold open access.
Funding Information:
This work was carried out in the frame of the TRAFIR project with funding from the Research Fund for Coal and Steel (grant N°754198 ). Partners are ArcelorMittal Belval & Differdange, Liège Univ., the Univ. of Edinburgh, RISE Research Inst. of Sweden and the Univ. of Ulster. This work used the ARCHER UK National Supercomputing Service ( http://www.archer.ac.uk ), and the resources provided by the Edinburgh Compute and Data Facility (ECDF) ( http://www.ecdf.ed.ac.uk/ ) and assistance of relevant administrators is acknowledged. The authors are grateful to EPSRC (grant number: EP/R029369/1) and ARCHER for financial and computational support as a part of their funding to the UK Consortium on Turbulent Reacting Flows ( www.ukctrf.com ). The UKCTRF Consortium benefits from the support of CoSeC, the Computational Science Centre for Research Community. The authors would like to thank IMFSE students Pei Ying Yang and Hongbo Zhen for pioneering development of the fire spread model, and SAFE MSc student Siqi Du for his assistance on collecting the cone calorimetry data for the “European spruce” (Picea abies) wood samples. Eric Mueller, Benjamin Ralph, Johan Sjöström, and Jean-Marc Franssen are gratefully acknowledged for their precious suggestions and discussions during the development of this work. For the purpose of open access, the author has applied a Creative Commons Attribution (CC BY) licence to any Author Accepted Manuscript version arising from this submission. The authors greatly appreciate the funding from the University of Edinburgh to make this paper available in gold open access.
Publisher Copyright:
© 2022 The Author(s)
PY - 2022/11
Y1 - 2022/11
N2 - The temperature heterogeneity due to fire in large open-plan office compartments is closely associated with fire spread behaviour and has been historically limited to experimental investigations using timber cribs. This study explores the ability of Computational Fluid Dynamics (CFD) models, specifically the Fire Dynamics Simulator (FDS), to reproduce the results of full-scale tests involving fire spread over timber cribs for continuous fuel-beds. Mesh schemes are studied, with a fine mesh over the crib and 2 × 2 cells in the wood stick cross-section by default, this being relaxed in the surrounding regions to enhance computational efficiency. The simple pyrolysis model considers the charring phase and moisture. In application to the TRAFIR-Liège LB7 test, this calibrated “stick-by-stick” representation shows a good agreement for interrelated parameters of heat release rate, fire spread, gas phase temperature, and burn-away, a set of agreements which has not been demonstrated in previous studies. Fire spread shows relatively high sensitivities to: heat of combustion, ignition temperature, thermal inertia, radiation fraction, heat release rate per unit area, and the fuel load density. An approximately linear regression was found between the different fire modes and the thermal exposures, with “travelling” (and decaying) fires characterised by heat fluxes associated with the fire plume, while the growing fires were associated with proportionally higher heat fluxes on the horizontal surfaces of the sticks, in conditions where these receive more pre-heating. The trends in the overall HRR are more dependent on the fire spread rates than variations in the stick burning rates.
AB - The temperature heterogeneity due to fire in large open-plan office compartments is closely associated with fire spread behaviour and has been historically limited to experimental investigations using timber cribs. This study explores the ability of Computational Fluid Dynamics (CFD) models, specifically the Fire Dynamics Simulator (FDS), to reproduce the results of full-scale tests involving fire spread over timber cribs for continuous fuel-beds. Mesh schemes are studied, with a fine mesh over the crib and 2 × 2 cells in the wood stick cross-section by default, this being relaxed in the surrounding regions to enhance computational efficiency. The simple pyrolysis model considers the charring phase and moisture. In application to the TRAFIR-Liège LB7 test, this calibrated “stick-by-stick” representation shows a good agreement for interrelated parameters of heat release rate, fire spread, gas phase temperature, and burn-away, a set of agreements which has not been demonstrated in previous studies. Fire spread shows relatively high sensitivities to: heat of combustion, ignition temperature, thermal inertia, radiation fraction, heat release rate per unit area, and the fuel load density. An approximately linear regression was found between the different fire modes and the thermal exposures, with “travelling” (and decaying) fires characterised by heat fluxes associated with the fire plume, while the growing fires were associated with proportionally higher heat fluxes on the horizontal surfaces of the sticks, in conditions where these receive more pre-heating. The trends in the overall HRR are more dependent on the fire spread rates than variations in the stick burning rates.
KW - Fire spread
KW - CFD modeling
KW - FDS
KW - Wood crib fire experiments
KW - Travelling fires
KW - CFD modelling
U2 - 10.1016/j.advengsoft.2022.103213
DO - 10.1016/j.advengsoft.2022.103213
M3 - Article
SN - 0965-9978
VL - 173
JO - Advances in Engineering Software
JF - Advances in Engineering Software
M1 - 103213
ER -