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Mathematical Modeling of Mathematical Modeling of Community Community-
scale Fires
Ronald Ronald Rehm Rehm
Howard Baum, Kevin Howard Baum, Kevin McGrattan McGrattan Glenn Forney, Ruddy Glenn Forney, Ruddy Mell Mell David Evans, Anthony David Evans, Anthony Hamins Hamins Charles Charles Bouldin Bouldin, , Simo Simo Hostikka Hostikka
Building & Fire Research Laboratory Building & Fire Research Laboratory
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SLIDE 2 T
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Wildland Fires 2000
- 80,000 fires
- 7 million acres
- $10 Billion loss
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Wildland-Urban Interface (WUI)
- WUI increasing rapidly
- Wildland fires also increasing rapidly
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B94"4 "<""4"
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- Hydrodynamics: (rectangular grid only)
Hydrodynamics: (rectangular grid only)
Low-
Mach-
Number Approx.
Large-
Eddy Simulations (LES)
Combustion: Flame-
sheet Approx.
Radiative transport: Finite volume method transport: Finite volume method
- Vegetation model (Thermally thin)
Vegetation model (Thermally thin)
Smoke: ALOFT -
Taylor Approx. also
Model Approximations Model Approximations
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MEASUREMENTS
- Full-scale fires – outdoors
- Laboratory fires
NIST Large Fire Laboratory Fires up to10 MW
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1 2 3 4 5 6 4000 5000 6000 7000 8000 9000
Garage burned in Odenton, Maryland 8-11-2002
Total heat flux KW /m2 Time seconds Measured 17 m from burning structure
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Simulation of Structure to Structure Fire Propagation
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The NIST Large Fire Facility (LFF) - 10 MW
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LFL Structure to Structure Fire Spread
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House to House Spread
Front Front Back Back Ignition Ignition right house right house
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House to House Spread
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Simulation of Burning Wildland Fuels
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NIST’s LFL Tree Burns
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Calculated Tree Heat-release rate [Tree 2]
1000 2000 3000 4000 5000 6000 7000 8000 9000 10000 20 40 60 80 100 120
Time [s] HRR [kW]
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1000 2000 3000 4000 5000 10 20 30 40 50 60 delta t (s) HRR (kW) 12-3 12-2 8-3 8-2 8-1 4-3 4-2 4-1
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Fuel Treatment
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Wildland Fire Simulation Australian Grassland Experiments
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Wildland & Structure Fires
Wildland-Urban-Interface (WUI) Fires
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Fire line invading a community
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Effects of Burning Structures on Fire-spread
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Closing 1 Closing 1
3D, transient physics 3D, transient physics-
based models needed for for wildland wildland & WUI fires & WUI fires data and computational data and computational-
resource intensive FDS simulates FDS simulates wildland wildland, structure and WUI fires , structure and WUI fires Efficiently Efficiently -
with visualization tool Smokeview Smokeview LFL & full LFL & full-
scale data needed for wildland wildland & WUI & WUI models models
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Thank you
Questions
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Simulations for Fire Effects
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Wind Tunnel Simulation
