Gas Turbine Combustion: Alternative Fuels and Emissions, Third Edition

560 Pages·2010·8.52 MB·English

by  Arthur H. Lefebvre

THIRD EDITION
GAS
Turbine
Combustion
Alternative Fuels and Emissions

THIRD EDITION
GAS
Turbine
Combustion
Alternative Fuels and Emissions
Arthur H. Lefebvre
and
Dilip R. Ballal
Boca Raton London New York
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Contents
Preface ..................................................................................................................xvii
Authors .................................................................................................................xix
1. Basic Considerations ......................................................................................1
1.1 Introduction ...........................................................................................1
1.2 Early Combustor Developments .........................................................2
1.2.1 Britain ........................................................................................3
1.2.2 Germany ....................................................................................5
1.2.2.1 Jumo 004 ....................................................................5
1.2.2.2 BMW 003 ...................................................................6
1.2.3 The United States .....................................................................6
1.3 Basic Design Features ...........................................................................8
1.4 Combustor Requirements ....................................................................9
1.5 Combustor Types ................................................................................10
1.5.1 Tubular ....................................................................................11
1.5.2 Tuboannular ...........................................................................11
1.5.3 Annular ...................................................................................12
1.6 Diffuser .................................................................................................14
1.7 Primary Zone .......................................................................................15
1.8 Intermediate Zone ...............................................................................16
1.9 Dilution Zone .......................................................................................17
1.10 Fuel Preparation ..................................................................................18
1.10.1 Pressure-Swirl Atomizers ....................................................18
1.10.2 Airblast Atomizer .................................................................19
1.10.3 Gas Injection ..........................................................................20
1.11 Wall Cooling ........................................................................................20
1.11.1 Wall-Cooling Techniques ....................................................22
1.12 Combustors for Low Emissions ........................................................23
1.13 Combustors for Small Engines ..........................................................26
1.14 Industrial Chambers ...........................................................................28
1.14.1 Aeroderivative Engines .......................................................31
References .......................................................................................................33
Bibliography ....................................................................................................33
2. Combustion Fundamentals ........................................................................35
2.1 Introduction .........................................................................................35
2.1.1 Deflagration ............................................................................35
2.1.2 Detonation...............................................................................35
2.2 Classification of Flames ......................................................................36
2.3 Physics or Chemistry? ........................................................................37
v
vi Contents
2.4 Flammability Limits ...........................................................................37
2.5 Global Reaction-Rate Theory .............................................................38
2.5.1 Weak Mixtures .......................................................................39
2.5.2 Rich Mixtures .........................................................................39
2.6 Laminar Premixed Flames ................................................................41
2.6.1 Factors Influencing Laminar Flame Speed ........................41
2.6.1.1 Equivalence Ratio ...................................................41
2.6.1.2 Initial Temperature ................................................42
2.6.1.3 Pressure ...................................................................42
2.7 Laminar Diffusion Flames.................................................................42
2.8 Turbulent Premixed Flames ..............................................................43
2.9 Flame Propagation in Heterogeneous Mixtures of Fuel
Drops, Fuel Vapor, and Air ................................................................45
2.10 Droplet and Spray Evaporation .........................................................49
2.10.1 Heat-Up Period ......................................................................50
2.10.2 Evaporation Constant ...........................................................51
2.10.3 Convective Effects ................................................................52
2.10.4 Effective Evaporation Constant ..........................................52
2.10.5 Spray Evaporation .................................................................54
2.10.6 Some Recent Developments ................................................54
2.11 Ignition Theory ....................................................................................55
2.11.1 Gaseous Mixtures .................................................................55
2.11.2 Heterogeneous Mixtures .....................................................56
2.12 Spontaneous Ignition .........................................................................64
2.13 Flashback ..............................................................................................69
2.14 Stoichiometry .......................................................................................70
2.15 Adiabatic Flame Temperature ...........................................................71
2.15.1 Factors Influencing the Adiabatic Flame
Temperature ....................................................................71
2.15.1.1 Fuel/Air Ratio ......................................................71
2.15.1.2 Initial Air Temperature ......................................71
2.15.1.3 Pressure ................................................................72
2.15.1.4 Inlet-Air Vitiation ................................................72
Nomenclature .................................................................................................73
References .......................................................................................................74
Bibliography ....................................................................................................77
3. Diffusers .........................................................................................................79
3.1 Introduction .........................................................................................79
3.2 Diffuser Geometry ..............................................................................81
3.3 Flow Regimes ......................................................................................82
3.4 Performance Criteria ..........................................................................83
3.4.1 Pressure-Recovery Coefficient .............................................84
3.4.2 Ideal Pressure-Recovery Coefficient ...................................84
Contents vii
3.4.3 Overall Effectiveness .............................................................85
3.4.4 Loss Coefficient ......................................................................85
3.4.5 Kinetic-Energy Coefficient ...................................................86
3.5 Performance .........................................................................................86
3.5.1 Conical Diffusers ...................................................................87
3.5.2 Two-Dimensional Diffusers .................................................88
3.5.3 Annular Diffusers ..................................................................89
3.6 Effect of Inlet Flow Conditions .........................................................90
3.6.1 Reynolds Number ..................................................................91
3.6.2 Mach Number ........................................................................91
3.6.3 Turbulence ..............................................................................92
3.6.4 Swirl .........................................................................................93
3.7 Design Considerations .......................................................................93
3.7.1 Faired Diffusers .....................................................................93
3.7.2 Dump Diffusers .....................................................................97
3.7.2.1 Influence of Liner Depth Ratio .............................98
3.7.3 Splitter Vanes ..........................................................................99
3.7.4 Vortex-Controlled Diffuser ................................................100
3.7.5 Hybrid Diffuser ....................................................................101
3.7.6 Diffusers for Tubular and Tuboannular
Combustors .......................................................................104
3.7.7 Testing of Diffusers .............................................................105
3.8 Numerical Simulations.....................................................................106
Nomenclature ...............................................................................................108
References .....................................................................................................109
4. Aerodynamics..............................................................................................113
4.1 Introduction .......................................................................................113
4.2 Reference Quantities .........................................................................114
4.3 Pressure-Loss Parameters ................................................................114
4.4 Relationship between Size and Pressure Loss ..............................117
4.5 Flow in the Annulus .........................................................................118
4.6 Flow through Liner Holes................................................................120
4.6.1 Discharge Coefficient ..........................................................120
4.6.2 Initial Jet Angle ....................................................................123
4.7 Jet Trajectories ....................................................................................124
4.7.1 Experiments on Single Jets .................................................124
4.7.2 Penetration of Multiple Jets ................................................126
4.8 Jet Mixing ...........................................................................................129
4.8.1 Cylindrical Ducts .................................................................129
4.8.2 Rectangular Ducts ...............................................................131
4.8.2.1 Influence of Density Ratio ...................................132
4.8.3 Annular Ducts ......................................................................133
viii Contents
4.9 Temperature Traverse Quality ........................................................133
4.10 Dilution Zone Design .......................................................................135
4.10.1 Cranfield Design Method ..................................................136
4.10.2 NASA Design Method .......................................................137
4.10.3 Comparison of Cranfield and NASA
Design Methods ...............................................................137
4.11 Correlation of Pattern Factor Data ..................................................138
4.12 Rig Testing for Pattern Factor ..........................................................140
4.13 Swirler Aerodynamics ......................................................................140
4.14 Axial Swirlers ....................................................................................142
4.14.1 Swirl Number ......................................................................143
4.14.2 Size of Recirculation Zone .................................................144
4.14.3 Flow Reversal ......................................................................145
4.14.4 Influence of Swirler Exit Geometry ..................................146
4.15 Radial Swirlers...................................................................................146
4.16 Flat Vanes Versus Curved Vanes ....................................................147
Nomenclature ...............................................................................................147
References .....................................................................................................149
5. Combustion Performance .........................................................................153
5.1 Introduction .......................................................................................153
5.2 Combustion Efficiency .....................................................................153
5.2.1 The Combustion Process ....................................................154
5.3 Reaction-Controlled Systems ..........................................................154
5.3.1 Burning Velocity Model ......................................................155
5.3.2 Stirred Reactor Model .........................................................159
5.4 Mixing-Controlled Systems .............................................................160
5.5 Evaporation-Controlled Systems ....................................................161
5.6 Reaction- and Evaporation-Controlled Systems ...........................165
5.7 Flame Stabilization ...........................................................................167
5.7.1 Definition of Stability Performance...................................167
5.7.2 Measurement of Stability Performance ............................168
5.7.3 Water Injection Technique ..................................................170
5.8 Bluff-Body Flameholders .................................................................173
5.8.1 Experimental Findings on Bluff-Body Flame
Stabilization ..........................................................................173
5.8.1.1 Homogeneous Mixtures ......................................173
5.8.1.2 Heterogeneous Mixtures .....................................177
5.8.2 Summary of Experimental Findings ................................179
5.9 Mechanisms of Flame Stabilization ...............................................179
5.9.1 Homogeneous Mixtures .....................................................181
5.9.2 Heterogeneous Mixtures ....................................................182
5.10 Flame Stabilization in Combustion Chambers .............................183
Contents ix
5.10.1 Influence of Mode of Fuel Injection .................................184
5.10.2 Correlation of Experimental Data ....................................185
5.11 Ignition ...............................................................................................188
5.12 Assessment of Ignition Performance .............................................189
5.13 Spark Ignition ....................................................................................190
5.13.1 The High-Energy Ignition Unit ........................................190
5.13.2 The Surface Discharge Igniter ..........................................191
5.13.2.1 Igniter Performance ..........................................192
5.13.2.2 Igniter Design ....................................................193
5.13.2.3 Igniter Life ..........................................................194
5.14 Other Forms of Ignition ...................................................................195
5.14.1 Torch Igniter ........................................................................195
5.14.2 Glow Plug .............................................................................196
5.14.3 Hot-Surface Ignition ...........................................................196
5.14.4 Plasma Jet .............................................................................197
5.14.5 Laser Ignition ......................................................................197
5.14.6 Chemical Ignition ...............................................................198
5.14.7 Gas Addition .......................................................................199
5.14.8 Oxygen Injection .................................................................199
5.15 Factors Influencing Ignition Performance .....................................199
5.15.1 Ignition System ...................................................................200
5.15.1.1 Spark Energy ......................................................200
5.15.1.2 Spark Duration ...................................................200
5.15.1.3 Sparking Rate .....................................................202
5.15.1.4 Igniter Location ..................................................202
5.15.2 Flow Variables .....................................................................203
5.15.2.1 Air Pressure ........................................................203
5.15.2.2 Air Temperature ................................................204
5.15.2.3 Air Velocity .........................................................205
5.15.2.4 Turbulence ..........................................................206
5.15.3 Fuel Parameters ...................................................................207
5.15.3.1 Fuel Type .............................................................207
5.15.3.2 Fuel/Air Ratio ....................................................207
5.15.3.3 Spray Characteristics ........................................208
5.15.3.4 Fuel Temperature ...............................................209
5.16 The Ignition Process .........................................................................209
5.16.1 Factors Influencing Phase 1 ...............................................210
5.16.2 Factors Influencing Phase 2 ...............................................210
5.16.3 Factors Influencing Phase 3 ...............................................211
5.17 Methods of Improving Ignition Performance ...............................211
5.17.1 Correlation of Experimental Data ....................................212
Nomenclature ...............................................................................................214
References .....................................................................................................216