Preface ........................................................ xv
Chapter 1 Mathematical modelling and numerical simulation
of fires ............................................. 1
E.E.A. Nilsson, B. Sunden, Z. Yan & M. Faghri
1 Introduction ................................................. 1
2 Turbulent combustion in fires ................................ 2
2.1 Governing equations for turbulent reacting flows ........ 2
2.2 Chemical kinetics ....................................... 4
2.3 Convection .............................................. 5
2.4 Radiation ............................................... 6
2.5 Burning of solids ....................................... 6
3 Simulation and modelling ..................................... 6
3.1 Turbulence modelling and simulation ..................... 6
3.2 Combustion modelling ................................... 10
3.3 Pyrolysis modelling .................................... 11
3.4 Consideration of soot formation ........................ 11
3.5 Radiation modelling .................................... 12
4 Numerical method ............................................ 12
4.1 Domain discretization .................................. 12
4.2 Equation discretization ................................ 13
4.3 Linear multi-step method ............................... 13
4.4 Multi-grid solver ...................................... 14
4.5 Parallel computing ..................................... 14
5 Boundary conditions and wall treatment ...................... 14
5.1 Boundary conditions .................................... 15
5.2 Wall functions ......................................... 15
6 Case study of upward flame spread over a PMMA board ......... 16
6.1 Problem description .................................... 18
6.2 Boundary and initial conditions ........................ 18
6.3 Results and discussion of the case study ............... 19
Chapter 2 Transport phenomena that affect heat transfer
in fully turbulent fires ............................. 25
S.R. Tieszen & L.A. Gritzo
1 Introduction ................................................ 25
2 Length and time scales within a fire ........................ 26
2.1 Overview ............................................... 26
2.2 Time and length scale range ............................ 28
2.3 Implication for numerical simulation ................... 31
2.4 Implications for modeling .............................. 33
3 Fluid dynamics within large fires ........................... 36
3.1 Quiescent conditions ................................... 37
3.2 Interaction with cross-winds ........................... 47
4 Scalar transport and radiative properties ................... 50
4.1 Mixing ................................................. 50
4.2 Combustion ............................................. 52
4.3 Absorption properties .................................. 55
4.4 Emission properties .................................... 58
5 Future of transport research in fires ....................... 63
Chapter 3 Heat transfer to objects in pool fires ............... 69
J.P. Spinti, J.N. Thornock, E.G. Eddings,
P.J. Smith & A.F. Sarofim
1 Introduction ................................................ 69
1.1 Chapter outline ........................................ 70
2 Historical modeling approaches .............................. 71
2.1 Homogeneous flame ...................................... 71
2.2 Homogeneous model and observable fire phenomena ........ 73
3 V&V as a foundation for predicting heat transfer to
embedded objects in pool fires .............................. 78
3.1 V&V hierarchy .......................................... 78
3.2 Validation metric ...................................... 79
4 Surrogate fuel formulation .................................. 81
4.1 Validation of surrogate formulation .................... 81
4.2 Burning rates and heat fluxes at steady state .......... 83
4.3 Burning rates and heat fluxes for transient burning .... 84
4.4 Effect on fuel composition changes on sooting
propensity ............................................. 85
4.5 Improved surrogate formulation ......................... 86
5 Chemical kinetics for soot production from JP-8 ............. 86
5.1 Utah Surrogate mechanism ............................... 87
5.2 Soot formation and oxidation ........................... 88
6 Use of LES methods for pool fires ........................... 90
6.1 LES equations .......................................... 91
6.2 Subgrid turbulence models .............................. 93
6.3 LES algorithm .......................................... 94
6.4 Large scale, parallel computing with LES ............... 96
6.5 V&V studies of LES code/turbulence model ............... 97
7 Combustion/reaction models .................................. 99
7.1 Parameterization of a reacting system ................. 101
7.2 Use of canonical reactors ............................. 101
7.3 Progress variable parameterization .................... 102
7.4 Heat loss parameterization ............................ 104
7.5 Soot models ........................................... 107
8 Turbulence/chemistry interactions .......................... 107
8.1 Validation of presumed PDF models in nonpremixed
flames ................................................ 109
8.2 Shape of presumed PDF ................................. 110
9 Radiative heat transfer model .............................. 111
9.1 Discrete ordinates method ............................. 1ll
9.2 Radiative properties .................................. 112
9.3 Algorithm verification ................................ 113
10 Heat transfer to an embedded object in a JP-8 pool fire .... 115
10.1 Modified LES algorithm ................................ 115
10.2 Coupling between LES fire phase and container
heat-up phase ......................................... 115
10.3 Subsystem cases: heat transfer in a large JP-8 pool
fire .................................................. 116
11 Prediction of heat flux to an explosive device in a JP-8
pool fire .................................................. 120
12 Predicting the potential hazard of an explosive device
immersed in a JP-8 pool fire ............................... 122
12.1 Three-dimensional heat transfer, PBX combustion
model ................................................. 122
12.2 One-dimensional heat transfer, fast cook-off HMX
model ................................................. 123
12.3 Prediction of time to ignition and explosion
violence .............................................. 123
13 Toward predictivity: error quantification and
propagation ................................................ 126
14 Summary .................................................... 127
Chapter 4 Heat and mass transfer effects to be considered
when modelling the effect of fire on structures ..... 137
A. Jowsey, S. Welch & J.L. Torero
1 Introduction ............................................... 137
2 Building fires ............................................. 138
3 Methods of thermal analysis ................................ 140
4 The boundary condition ..................................... 141
4.1 Gas-phase conditions .................................. 142
4.2 Application examples .................................. 143
5 The compartment fire ....................................... 144
5.1 Compartment fire models (CFMs) ........................ 147
6 Solid-phase phenomena ...................................... 153
6.1 Material integrity .................................... 153
6.2 Treatment of moisture and other chemical processes .... 154
7 Conclusions ................................................ 155
Chapter 5 Weakly buoyant turbulent fire plumes in uniform
still and crossflowing environments ................. 161
F.J. Diez, L.P. Bernal & G.M. Faeth
1 Introduction ............................................... 162
2 Structure of steady plumes in still environments ........... 162
2.1 Introduction .......................................... 162
2.2 Experimental methods .................................. 164
2.3 Theoretical methods ................................... 166
2.4 Results and discussion ................................ 168
2.5 Conclusions ........................................... 175
3 Penetration of starting plumes in still environments ....... 176
3.1 Introduction .......................................... 176
3.2 Experimental methods .................................. 176
3.3 Theoretical methods ................................... 178
3.4 Results and discussion ................................ 180
3.5 Conclusions ........................................... 182
4 Penetration and concentration properties of startingand
steady plumes in crossflows ................................ 182
4.1 Introduction .......................................... 182
4.2 Experimental methods .................................. 185
4.3 Theoretical methods ................................... 187
4.4 Results and discussion ................................ 191
4.5 Conclusions ........................................... 203
5 Concluding remarks ......................................... 203
Chapter 6 Pyrolysis modeling, thermal decomposition, and
transport processes in combustible solids ........... 209
C. Lautenberger & C. Fernandez-Pello
1 Introduction ............................................... 209
2 Pyrolysis modeling and fire modeling ....................... 209
2.1 Semi-empirical and fire property-based pyrolysis/
gasification models ................................... 211
2.2 Comprehensive pyrolysis models: thermoplastics ........ 213
2.3 Comprehensive pyrolysis models: charring materials .... 217
2.4 Comprehensive pyrolysis models: intumescent
materials and coatings ................................ 222
3 Decomposition kinetics and thermodynamics .................. 224
3.1 Thermal and thermooxidative stability ................. 224
3.2 Reaction enthalpies ................................... 229
4 Heat, mass, and momentum transfer .......................... 233
4.1 Solid phase heat conduction ........................... 233
4.2 Radiation ............................................. 237
4.3 Convection, advection, and diffusion .................. 243
4.4 Momentum .............................................. 244
4.5 Special topics: melting, bubbling, and related
phenomena ............................................. 244
5 Fire growth modeling ....................................... 245
6 Concluding remarks ......................................... 247
Chapter 7 Radiative heat transfer in fire modeling ........... 261
M.F. Modest
1 Introduction ................................................ 261
2 Radiative properties of combustion gases ................... 263
3 Radiative properties of soot ............................... 264
4 Band models ................................................ 264
4.1 Traditional narrow band models ........................ 265
4.2 Traditional wide band models .......................... 266
4.3 Narrow band k-distributions ........................... 266
5 Global models .............................................. 269
5.1 The WSGG method ....................................... 270
5.2 The SLW method ........................................ 271
5.3 Full-spectrum k-distributions ......................... 272
5.4 FSK assembly from a narrow band database .............. 275
6 Turbulence-radiation interactions .......................... 276
6.1 Turbulence-radiation coupling ......................... 277
6.2 Assumed-PDF investigations ............................ 279
6.3 Composition PDF methods ............................... 280
6.4 Direct numerical simulations of TRIs .................. 289
6.5 TRI effects in nonpremixed flames ..................... 289
7. Summary .................................................... 292
Chapter 8 Thermal radiation modeling in flames and fires ...... 301
S. Sen & I.K. Puri
1 Introduction ............................................... 301
2 Basic equations ............................................ 302
2.1 Energy conservation equation .......................... 302
2.2 Radiative transfer equation ........................... 302
3 Solution of the RTE ........................................ 303
3.1 Radiative property models ............................. 303
3.2 Radiative properties of entrained and generated
particles ............................................. 306
3.3 Solution methodologies ................................ 307
4 Radiation from flames ...................................... 308
5 Radiation from fires .................................... 315
6 Summary ................................................. 317
Chapter 9 Combustion subgrid scale modeling for large eddy
simulation of fires ................................. 327
P.E. DesJardin, H. Shihn & M.D. Carrara
1 Introduction ............................................... 327
2 LES mathematical formulation ............................... 328
3 Combustion SGS models ...................................... 331
3.1 Filtered density function ............................. 331
3.2 One-dimensional turbulence ............................ 344
4 Summary .................................................... 352
Chapter 10 CFD fire simulation and its recent development ..... 357
Z. Yan
1 Introduction ............................................... 357
2 CFD simulation of conventional fire ........................ 358
2.1 Gas phase simulation .................................. 358
2.2 Modeling of the response of solid materials ........... 382
2.3 Conventional fire simulation cases .................... 393
3 CFD simulation of spontaneous ignition in porous fuel
storage .................................................... 396
3.1 The comprehensive spontaneous ignition CFD model ...... 398
3.2 CFD simulation of spontaneous ignition experiment ..... 399
4 Conclusions ................................................ 400
Chapter 11 The implementation and application of a fire CFD
model .............................................. 407
J. Trelles & J.E. Floyd
1 Introduction ............................................... 407
2 Turbulence modelling ....................................... 409
3 Solution speed and stability ............................... 410
4 Accounting for energy ...................................... 411
4.1 Combustion modelling .................................. 411
4.2 Heat transfer ......................................... 415
5 Liquid sprays .............................................. 419
5.1 Drop size distribution ................................ 420
5.2 Spray pattern creation ................................ 422
5.3 Spray momentum ........................................ 422
5.4 Droplet heat transfer and evaporation ................. 424
5.5 Evaporation impact on divergence ...................... 425
6 Boundary and initial conditions ............................ 425
7 The practice of modelling .................................. 426
7.1 Preparation ........................................... 426
8 Assessing the model, assessing the results ................. 428
8.1 Verification .......................................... 429
8.2 Validation ............................................ 429
8.3 Uncertainty and sensitivity analyses .................. 430
8.4 Certification, accreditation, quality assurance ....... 432
8.5 Review ................................................ 433
9 Examples ................................................... 433
9.1 Grid density .......................................... 433
9.2 Turbulence model ...................................... 433
9.3 Symmetry .............................................. 435
9.4 Sprinklers ............................................ 435
9.5 Combustible material properties ....................... 435
9.6 Radiation solver settings ............................. 437
10 Conclusions ................................................ 437
Chapter 12 CFD-based modeling of combustion and suppression
in compartment fires ............................... 441
A. Trouve & A. Marshall
1 Introduction ............................................... 441
2 Transient ignition and early fire growth ................... 443
2.1 Modeling of PPC ....................................... 444
2.2 Simulation of the transient ignition and combustion
of a fuel vapor cloud ................................. 449
3 Smoke filling and pre-flashover fire spread ................ 454
3.1 Modeling of fire spread ............................... 455
3.2 Simulation of fire spread (without flashover) ......... 456
4 Flashover and transition to under-ventilated combustion .... 459
4.1 Modeling of under-ventilated combustion ............... 460
4.2 Simulation of fire spread (with flashover) ............ 461
5 Water-based fire suppression and fire control/extinction ... 464
5.1 Models for water-based fire suppression ............... 466
5.2 Simulation of water-based fire suppression ............ 472
6 Conclusion ................................................. 473
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