1 Fuels ........................................................ 1
1.1 Types of Fuel ........................................... 1
1.2 Fuel Usage .............................................. 5
1.3 Basic Considerations of the Choice of Fuels ............. 6
1.4 Classification of Fuels by Phase at Ambient Conditions .. 8
1.5 Identification of Fuel by Molecular Structure:
International Union of Pure and Applied Chemistry
(IUPAC) ................................................. 9
1.6 Some Related Properties of Liquid Fuels ................ 12
Exercises ................................................... 13
References .................................................. 13
2 Thermodynamics of Combustion ................................ 15
2.1 Properties of Mixtures ................................. 15
2.2 Combustion Stoichiometry ............................... 17
2.2.1 Methods of Quantifying Fuel and Air Content
of Combustible Mixtures ......................... 19
2.3 Heating Values ......................................... 23
2.3.1 Determination of HHV for Combustion Processes
at Constant Pressure ............................ 24
2.3.2 Determination of HHV for Combustion Processes
from a Constant-Volume Reactor .................. 27
2.3.3 Representative HHV Values ....................... 29
2.4 Adiabatic Flame Temperature ............................ 31
2.4.1 Constant-Pressure Combustion Processes .......... 31
2.4.2 Comparison of Adiabatic Flame Temperature
Calculation Methods ............................. 36
2.5 Chapter Summary ........................................ 40
Exercises ................................................... 44
3 Chemical Kinetics ........................................... 49
3.1 The Nature of Combustion Chemistry ..................... 50
3.1.1 Elementary Reactions: Chain Initiation .......... 51
3.1.2 Elementary Reactions: Chain Branching ........... 51
3.1.3 Elementary Reactions: Chain Terminating
or Recombination ................................ 52
3.1.4 Elementary Reactions: Chain Propagating ......... 52
3.2 Elementary Reaction Rate ............................... 52
3.2.1 Forward Reaction Rate and Rate Constants ........ 52
3.2.2 Equilibrium Constants ........................... 54
3.3 Simplified Model of Combustion Chemistry ............... 55
3.3.1 Global One-Step Reaction ........................ 55
3.3.2 Pressure Dependence of Rate of Progress ......... 61
3.3.3 Heat Release Rate (HRR) ......................... 61
3.3.4 Modeling of Chemical Kinetics with Detailed
Description ..................................... 61
3.3.5 Partial Equilibrium ............................. 65
3.3.6 Quasi-Steady State .............................. 65
Exercises ................................................... 69
References .................................................. 73
4 Review of Transport Equations and Properties ................ 75
4.1 Overview of Heat and Mass Transfer ..................... 75
4.2 Conservation of Mass and Species ....................... 78
4.3 Conservation of Momentum ............................... 80
4.4 Conservation of Energy ................................. 80
4.4.1 Terms in the Conservation of Energy Equation .... 80
4.4.2 Derivation of a 1-D Conservation of Energy
Equation ........................................ 82
4.5 Normalization of the Conservation Equations ............ 84
4.6 Viscosity, Conductivity and Diffusivity ................ 87
References ............................................. 88
5 Ignition Phenomena .......................................... 89
5.1 Autoignition (Self-ignition, Spontaneous Ignition)
Based on Thermal Theory ................................ 89
5.2 Effect of Pressure on the Autoignition Temperature ..... 93
5.3 Piloted Ignition ....................................... 95
5.4 Condensed Fuel Ignition ................................ 98
5.4.1 Fuel Vaporization ............................... 98
5.4.2 Important Physiochemical Properties ............. 99
5.4.3 Characteristic Times in Condensed Fuel
Ignition ....................................... 100
5.4.4 Critical Heat Flux for Ignition ................ 106
Exercises .................................................. 108
References ................................................. 109
6 premixed Flames ............................................ 111
6.1 Physical Processes in a Premixed Flame ................ 111
6.1.1 Derivation of Flame Speed and Thickness ........ 113
6.1.2 Measurements of the Flame Speed ................ 117
6.1.3 Structure of Premixed Flames ................... 119
6.1.4 Dependence of Flame Speed on Equivalence
Ratio, Temperature and Pressure ................ 121
6.1.5 Dependence of Flame Thickness on Equivalence
Ratio, Temperature and Pressure ................ 125
6.2 Flammability Limits ................................... 125
6.2.1 Effects of Temperature and Pressure on
Flammability Limits ............................ 127
6.3 Flame Quenching ....................................... 127
6.4 Minimum Energy for Sustained Ignition and Flame
Propagation ...........................................
6.5 Turbulent Premixed Flames ............................. 133
6.5.1 Eddy Diffusivity ............................... 133
6.5.2 Turbulent Flame Speed .......................... 134
6.6 Summary ............................................... 135
Exercises .................................................. 136
References ................................................. 137
7 Non-premixed Flames (Diffusion Flames) ..................... 139
7.1 Description of a Candle Flame ......................... 139
7.2 Structure of Non-premixed Laminar Free Jet Flames ..... 140
7.3 Laminar Jet Flame Height (Lf) ......................... 142
7.4 Empirical Correlations for Laminar Flame Height ....... 145
7.5 Burke-Schumann Jet Diffusion Flame .................... 147
7.6 Turbulent Jet Flames .................................. 149
7.6.1 Lift-Off Height (h) and Вlowout Limit .......... 151
7.7 Condensed Fuel Fires .................................. 152
Exercises .................................................. 153
References ................................................. 154
8 Droplet Evaporation and Combustion ......................... 155
8.1 Droplet Vaporization in Quiescent Air ................. 155
8.1.1 Droplet Vaporization in Convective Flow ........ 159
8.2 Droplet Combustion .................................... 162
8.3 Initial Heating of a Droplet .......................... 164
8.3.1 Effect of Air Temperature and Pressure ......... 166
8 4 Droplet Distribution .................................. 171
9 Emissions .................................................. 177
9.1 Negative Effects of Combustion Products ............... 177
9.2 Pollution Formation ................................... 178
9.2.1 Parameters Controlling Formation of
Pollutants ..................................... 179
9.2.2 CO Oxidation ................................... 182
9.2.3 Mechanisms for NO Formation .................... 183
9.2.4 Controlling NO Formation ....................... 189
9.2.5 Soot Formation ................................. 190
9.2.6 Relation Between NOx and Soot Formation ........ 191
9.2.7 Oxides of Sulfur (SOx) ......................... 191
9.3 Quantification of Emissions ........................... 193
Exercises .................................................. 196
References ................................................. 198
10 Premixed Piston 1С Engines ................................. 199
10.1 Principles of SI Engines .............................. 199
10.2 Thermodynamic Analysis ................................ 201
10.3 Relationship between Pressure Trace and Heat Release .. 206
10.4 Octane Number ......................................... 207
10.4.1 Definition of Octane Rating .................... 207
10.4.2 Measurement Methods ............................ 208
10.5 Fuel Preparation ...................................... 210
10.6 Ignition Timing ....................................... 213
10.7 Flame Propagation in SI Engines ....................... 214
10.8 Modeling of Combustion Processes in IС Engines ........ 215
10.8.1 A Simplified Two-Zone Model of Engine
Combustion ..................................... 216
10.9 Emissions and Their Control ........................... 219
10.9.1 Three-Way Catalyst ............................. 220
10.10 Gasoline Direct Injection (GDI) Engines .............. 221
Exercises .................................................. 224
References ................................................. 226
11 Diesel Engines ............................................. 227
11.1 Overall Comparisons to SI Engines ..................... 227
11.1.1 Advantages of Diesel Engines as Compared
to SI Engines .................................. 228
11.1.2 Disadvantages of Diesel Engines as Compared
to SI Engines .................................. 228
11.2 Thermodynamics of Diesel Engines ...................... 229
11.3 Diesel Spray and Combustion ........................... 230
11.4 Cetane Number ......................................... 235
11.5 Diesel Emissions ...................................... 237
11.6 Homogeneous Charge Compression Ignition (HCCI) ........ 238
11.6.1 HCCI Overview .................................. 238
11.6.2 HCCI Emissions ................................. 238
11.6.3 Challenges with HCCI ........................... 240
References ................................................. 241
Appendices .................................................... 243
Index ......................................................... 299
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