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CFD Modeling of Large Scale Fires based on OpenFOAM
Yi WangFM Global, Research DivisionNorwood, MA, USA
OpenFOAM Summer School, Sep 1st - Sep 15th, 2010, Zagreb, Croatia
Fire growth and suppression
Buoyancy-driven wall-bounded turbulent flow
Diffusion combustion & soot formation
Radiative & convective heat transfer
Pyrolysis
Droplet atomization
Droplet transport
Pre-wetting
Surface suppression
Fire growth Fire suppression
FireFoam solver• Buoyancy driven reacting flow
– Density – velocity coupling– Choice of equations
• Total enthalpy and mixture fraction– HRR calculation?– Multiple streams? – Conservation of enthalpy?
• Sensible enthalpy and species– Efficiency and stability
• Coupling with other physical models
Energy conservation• 1 vs 3 outer loops• Better when use sensible enthalpy equation
Buoyancy driven flow• Density – velocity coupling
– grad(p) + rho*g– P = p0 + pd + rho * gh– grad(pd) + gh*grad(rho)– fvc:reconstruct()
Stability and efficiency• Co number: increase form 0.5 to 5
– Under-relaxation (0.9) • U, Yi, hs
– Euler of Yi, Hs– Backward for U
Topological change• Proof of concept for box burn-though
• Step one– Add stitchPatch functionality into top solver
• Step two – attachDetachFvMesh: topoChangerFvMesh– FireDyMFoam (with pyrolysis)
• Stability issues
Animation
CFD Modeling of Large Scale Fires based on OpenFOAMFire growth and suppressionFireFoam solverEnergy conservationBuoyancy driven flowStability and efficiencyTopological changeAnimation
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