Combustion (eBook)

Front Cover 1
Combustion 4
Copyright Page 5
Contents 10
Prologue 18
Preface 20
CHAPTER 1. CHEMICAL THERMODYNAMICS AND FLAME TEMPERATURES 22
A. Introduction 22
B. Heats of reaction and formation 22
C. Free energy and the equilibrium constants 29
D. Flame temperature calculations 37
1. Analysis 37
2. Practical considerations 43
E. Sub- and super sonic combustion thermodynamics 53
1. Comparisons 53
2. Stagnation pressure considerations 54
Problems 57
CHAPTER 2. CHEMICAL KINETICS 64
A. Introduction 64
B. Rates of reactions and their temperature dependence 64
1. The Arrhenius rate expression 66
2. Transition state and recombination rate theories 68
C. Simultaneous interdependent reactions 73
D. Chain reactions 74
E. Pseudo-first-order reactions and the "fall-off" range 78
F. The partial equilibrium assumption 81
G. Pressure effect in fractional conversion 82
H. Chemical kinetics of large reaction mechanisms 83
1. Sensitivity analysis 84
2. Rate of production analysis 86
3. Coupled thermal and chemical reacting systems 87
4. Mechanism simplification 89
Problems 90
CHAPTER 3. EXPLOSIVE AND GENERAL OXIDATIVE CHARACTERISTICS OF FUELS 96
A. Introduction 96
B. Chain branching reactions and criteria for explosion 96
C. Explosion limits and oxidation characteristics of hydrogen 104
D. Explosion limits and oxidation characteristics of carbon monoxide 112
E. Explosion limits and oxidation characteristics of hydrocarbons 119
1. Organic nomenclature 120
2. Explosion limits 124
3. "Low-temperature" hydrocarbon oxidation mechanisms 127
F. The oxidation of aldehydes 131
G. The oxidation of methane 133
1. Low-temperature mechanism 133
2. High-temperature mechanism 134
H. The oxidation of higher-order hydrocarbons 138
1. Aliphatic hydrocarbons 138
2. Alcohols 148
3. Aromatic hydrocarbons 150
4. Supercritical effects 160
Problems 162
CHAPTER 4. FLAME PHENOMENA IN PREMIXED COMBUSTIBLE GASES 168
A. Introduction 168
B. Laminar flame structure 172
C. The laminar flame speed 174
1. The theory of Mallard and Le Chatelier 177
2. The theory of Zeldovich, Frank-Kamenetskii, and Semenov 182
3. Comprehensive theory and laminar flame structure analysis 189
4. The laminar flame and the energy equation 197
5. Flame speed measurements 197
6. Experimental results: physical and chemical effects 206
D. Stability limits of laminar flames 212
1. Flammability limits 213
2. Quenching distance 221
3. Flame stabilization (low velocity) 222
4. Stability limits and design 228
E. Flame propagation through stratified combustible mixtures 232
F. Turbulent reacting flows and turbulent flames 234
1. The rate of reaction in a turbulent field 237
2. Regimes of turbulent reacting flows 239
3. The turbulent flame speed 252
G. Stirred reactor theory 256
H. Flame stabilization in high-velocity streams 261
I. Combustion in small volumes 271
Problems 275
CHAPTER 5. DETONATION 282
A. Introduction 282
1. Premixed and diffusion flames 282
2. Explosion, deflagration, and detonation 282
3. The onset of detonation 283
B. Detonation phenomena 285
C. Hugoniot relations and the hydrodynamic theory of detonations 286
1. Characterization of the Hugoniot curve and the uniqueness of the C–J point 287
2. Determination of the speed of sound in the burned gases for conditions above the C–J point 297
3. Calculation of the detonation velocity 303
D. Comparison of detonation velocity calculations with experimental results 307
E. The ZND structure of detonation waves 314
F. The structure of the cellular detonation front and other detonation phenomena parameters 318
1. The cellular detonation front 318
2. The dynamic detonation parameters 322
3. Detonation limits 323
G. Detonations in nongaseous media 327
Problems 328
CHAPTER 6. DIFFUSION FLAMES 332
A. Introduction 332
B. Gaseous fuel jets 332
1. Appearance 333
2. Structure 337
3. Theoretical considerations 339
4. The Burke–Schumann development 343
5. Turbulent fuel jets 350
C. Burning of condensed phases 352
1. General mass burning considerations and the evaporation coefficient 353
2. Single fuel droplets in quiescent atmospheres 358
D. Burning of droplet clouds 385
E. Burning in convective atmospheres 386
1. The stagnant film case 386
2. The longitudinally burning surface 388
3. The flowing droplet case 390
4. Burning rates of plastics: The small B assumption and radiation effects 393
Problems 395
CHAPTER 7. IGNITION 400
A. Concepts 400
B. Chain spontaneous ignition 403
C. Thermal spontaneous ignition 405
1. Semenov approach of thermal ignition 405
2. Frank-Kamenetskii theory of thermal ignition 410
D. Forced ignition 416
1. Spark ignition and minimum ignition energy 417
2. Ignition by adiabatic compression and shock waves 422
E. Other ignition concepts 423
1. Hypergolicity and pyrophoricity 424
2. Catalytic ignition 427
Problems 428
CHAPTER 8. ENVIRONMENTAL COMBUSTION CONSIDERATIONS 430
A. Introduction 430
B. The nature of photochemical smog 431
1. Primary and secondary pollutants 432
2. The effect of NO[sub(x)] 432
3. The effect of SO[sub(x)] 436
C. Formation and reduction of nitrogen oxides 438
1. The structure of the nitrogen oxides 439
2. The effect of flame structure 440
3. Reaction mechanisms of oxides of nitrogen 441
4. The reduction of NO[sub(x)] 457
D. SO[sub(x)] emissions 462
1. The product composition and structure of sulfur compounds 463
2. Oxidative mechanisms of sulfur fuels 465
E. Particulate formation 478
1. Characteristics of soot 479
2. Soot formation processes 480
3. Experimental systems and soot formation 481
4. Sooting tendencies 483
5. Detailed structure of sooting flames 495
6. Chemical mechanisms of soot formation 499
7. The influence of physical and chemical parameters on soot formation 503
F. Stratospheric ozone 506
1. The HO[sub(x)] catalytic cycle 507
2. The NO[sub(x)] catalytic cycle 508
3. The ClO[sub(x)] catalytic cycle 510
Problems 512
CHAPTER 9. COMBUSTION OF NONVOLATILE FUELS 516
A. Carbon char, soot, and metal combustion 516
B. Metal combustion thermodynamics 517
1. The criterion for vapor-phase combustion 517
2. Thermodynamics of metal–oxygen systems 517
3. Thermodynamics of metal–air systems 530
4. Combustion synthesis 534
C. Diffusional kinetics 541
D. Diffusion-controlled burning rate 543
1. Burning of metals in nearly pure oxygen 545
2. Burning of small particles – diffusion versus kinetic limits 548
3. The burning of boron particles 551
4. Carbon particle combustion (C. R. Shaddix) 552
E. Practical carbonaceous fuels (C. R. Shaddix) 555
1. Devolatilization 555
2. Char combustion 560
3. Pulverized coal char oxidation 561
4. Gasification and oxy-combustion 563
F. Soot oxidation (C. R. Shaddix) 566
Problems 569
APPENDIXES 572
APPENDIX A. THERMOCHEMICAL DATA AND CONVERSION FACTORS 576
Table A1. Conversion factors and physical constants 577
Table A2. Thermochemical data for selected chemical compounds 578
Table A3. Thermochemical data for species included in reaction list of Appendix C 667
APPENDIX B. ADIABATIC FLAME TEMPERATURES OF HYDROCARBONS 674
Table B1. Adiabatic flame temperatures 674
APPENDIX C. SPECIFIC REACTION RATE CONSTANTS 680
Table C1. H[sub(2)]/O[sub(2)] mechanism 680
Table C2. CO/H[sub(2)]/O[sub(2)] mechanism 682
Table C3. CH[sub(2)]O/CO/H[sub(2)]/O[sub(2)] mechanism 683
Table C4. CH[sub(3)]OH/CH[sub(2)]O/CO/H[sub(2)]/O[sub(2)] mechanism 684
Table C5. CH[sub(4)]/CH[sub(3)]OH/CH[sub(2)]O/CO/H[sub(2)]/O[sub(2)] mechanism 686
Table C6. C[sub(2)]H[sub(6)]/CH[sub(4)]/CH[sub(3)]OH/CH[sub(2)]O/CO/H[sub(2)]/O[sub(2)] mechanism 689
Table C7. Selected reactions of a C[sub(3)]H[sub(8)] oxidation mechanism 694
Table C8. N[sub(x)]O[sub(y)]/CO/H[sub(2)]/O[sub(2)] mechanism 698
Table C9. HCl/N[sub(x)]O[sub(y)]/CO/H[sub(2)]/O[sub(2)] mechanism 704
Table C10. O[sub(3)]/N[sub(x)]O[sub(y)]/CO/H[sub(2)]/O[sub(2)] mechanism 705
Table C11. SO[sub(x)]/N[sub(x)]O[sub(y)]/CO/H[sub(2)]/O[sub(2)] mechanism 706
APPENDIX D. BOND DISSOCIATION ENERGIES OF HYDROCARBONS 714
Table D1. Bond dissociation energies of alkanes 715
Table D2. Bond dissociation energies of alkenes, alkynes, and aromatics 716
Table D3. Bond dissociation energies of C/H/O compounds 719
Table D4. Bond dissociation energies of sulfur-containing compounds 720
Table D5. Bond dissociation energies of nitrogen-containing compounds 721
Table D6. Bond dissociation energies of halocarbons 723
APPENDIX E. FLAMMABILITY LIMITS IN AIR 724
Table E1. Flammability limits of fuel gases and vapors in air at 25°C and 1 atm 725
APPENDIX F. LAMINAR FLAME SPEEDS 734
Table F1. Burning velocities of various fuels at 25°C air-fuel temperature (0.31 mol% H[sub(2)]O in air). Burning velocity S as a function of equivalence ratio ø in cm/s 735
Table F2. Burning velocities of various fuels at 100°C air-fuel temperature (0.31 mol% H[sub(2)]O in air). Burning velocity S as a function of equivalence ratio ø in cm/s 740
Table F3. Burning velocities of various fuels in air as a function of pressure for an equivalence ratio of 1 in cm/s 741
APPENDIX G. SPONTANEOUS IGNITION TEMPERATURE DATA 742
Table G1. Spontaneous ignition temperature data 743
APPENDIX H. MINIMUM SPARK IGNITION ENERGIES AND QUENCHING DISTANCES 764
Table H1. Minimum spark ignition energy data for fuels in air at 1 atm pressure 765
APPENDIX I. PROGRAMS FOR COMBUSTION KINETICS 768
A. Thermochemical parameters 768
B. Kinetic parameters 768
C. Transport parameters 769
D. Reaction mechanisms 769
E. Thermodynamic equilibrium 771
F. Temporal kinetics (Static and flow reactors) 773
G. Stirred reactors 774
H. Shock tubes 775
I. Premixed flames 775
J. Diffusion flames 777
K. Boundary layer flow 777
L. Detonations 777
M. Model analysis and mechanism reduction 777
Author Index 780
A 780
B 780
C 781
D 781
E 782
F 782
G 782
H 783
I 783
J 783
K 784
L 784
M 785
N 785
O 786
P 786
Q 786
R 786
S 786
T 787
U 787
V 787
W 788
X 788
Y 788
Z 788
Subject Index 790
A 790
B 790
C 790
D 791
E 791
F 791
G 792
H 792
I 792
K 792
L 792
M 792
N 793
O 793
P 793
Q 793
R 793
S 793
T 794
U 794
V 794
W 794