Preface to the Fourth Edition xv
Acknowledgments xvii
About the Companion Website xix
1 Introduction: Propulsion in Sustainable Aviation 1
1.1 History of the Airbreathing Jet Engine, a Twentieth-Century Inventionâ"The Beginning 1
1.2 Innovations in Aircraft Gas Turbine Engines 4
1.2.1 Multi-spool Configuration 5
1.2.2 Variable Stator 5
1.2.3 Transonic Compressor 5
1.2.4 Low-Emission Combustor 6
1.2.5 Turbine Cooling 6
1.2.6 Exhaust Nozzles 7
1.2.7 Modern Materials and Manufacturing Techniques 8
1.3 Twenty-First-Century Aviation Goal: Sustainability 10
1.3.1 Combustion Emissions 11
1.3.2 Greenhouse Gases 12
1.3.3 Fuels for Sustainable Aviation 14
1.3.4 Emerging Technologies in Sustainable Manufacturing 15
1.4 New Engine Concepts in Sustainable Aviation 16
1.4.1 Advanced GT Concepts: ATP/CROR and GTF 16
1.4.2 Advanced Airbreathing Rocket Technology 17
1.4.3 Wave Rotor Topping Cycle 18
1.4.3.1 Humphrey Cycle Versus Brayton Cycle 18
1.4.4 Pulse Detonation Engine (PDE) 20
1.4.5 Millimeter-Scale Gas Turbine Engines: Triumph of Micro- Electro-Mechanical Systems and Digital Fabrication 20
1.4.6 Combined Cycle Propulsion: Engines from Takeoff to Space 21
1.4.7 Hybrid-Electric and Distributed Electric Propulsion 21
1.5 New Vehicle Technologies 30
1.6 Summary 33
1.7 Roadmap for the Fourth Edition 34
References 36
Suggested Additional Reading 37
Problems 38
2 Engine Thrust and Performance Parameters 41
2.1 Introduction 41
2.1.1 Takeoff Thrust 47
2.2 Installed Thrustâ"Some Bookkeeping Issues on Thrust and Drag 47
2.3 Engine Thrust Based on the Sum of Component Impulse 52
2.4 Rocket Thrust 55
2.5 Airbreathing Engine Performance Parameters 56
2.5.1 Specific Thrust 56
2.5.2 Specific Fuel Consumption and Specific Impulse 57
2.5.3 Thermal Efficiency 58
2.5.4 Propulsive Efficiency 62
2.5.5 Engine Overall Efficiency and Its Impact on Aircraft Range and Endurance 64
2.6 Modern Engines, Their Architecture, and Some Performance Characteristics 68
2.7 Summary 72
References 73
Problems 74
3 Aircraft Engine Cycle Analysis 83
3.1 Introduction 83
3.2 The Gas Generator 83
3.3 Aircraft Gas Turbine Engines 85
3.3.1 The Turbojet Engine 85
3.3.1.1 The Inlet 85
3.3.1.2 The Compressor 90
3.3.1.3 The Burner 95
3.3.1.4 The Turbine 100
3.3.1.5 The Nozzle 109
3.3.1.6 Thermal Efficiency of a Turbojet Engine 116
3.3.1.7 Propulsive Efficiency of a Turbojet Engine 124
3.3.1.8 The Overall Efficiency of a Turbojet Engine 125
3.3.1.9 Performance Evaluation of a Turbojet Engine 126
3.3.2 The Turbojet Engine with an Afterburner 127
3.3.2.1 Introduction 127
3.3.2.2 Analysis 129
3.3.2.3 Optimum Compressor Pressure Ratio for Maximum (Ideal) Thrust Turbojet Engine with Afterburner 132
3.3.3 The Turbofan Engine 138
3.3.3.1 Introduction 138
3.3.3.2 Analysis of a Separate-Exhaust Turbofan Engine 139
3.3.3.3 Thermal Efficiency of a Turbofan Engine 143
3.3.3.4 Propulsive Efficiency of a Turbofan Engine 144
3.3.4 Ultra-High Bypass (UHB) Turbofan Engines 149
3.4 Analysis of a Mixed-Exhaust Turbofan Engine with an Afterburner 153
3.4.1 Mixer 154
3.4.2 Cycle Analysis 156
3.4.2.1 Solution Procedure 157
3.5 The Turboprop Engine 167
3.5.1 Introduction 167
3.5.2 Turboprop Cycle Analysis 169
3.5.2.1 The New Parameters 169
3.5.2.2 Design Point Analysis 169
3.5.2.3 Optimum Power Split Between the Propeller and the Jet 173
3.6 Promising Propulsion and Power Technologies in Sustainable Aviation 179
3.6.1 Distributed Combustion Concepts in Advanced Gas Turbine Engine Core 179
3.6.2 Multi-fuel (Cryogenic-Kerosene) Hybrid Propulsion Concept 182
3.6.3 Intercooled and Recuperated Turbofan Engines 184
3.6.4 Active Core Concepts 185
3.6.5 Wave-Rotor Combustion 187
3.6.6 Pulse Detonation Engine (PDE) 193
3.6.6.1 Idealized Laboratory PDE: Thrust Tube 195
3.6.6.2 Pulse Detonation Ramjet 196
3.6.6.3 Turbofan Engine with PDE 197
3.6.6.4 Pulse Detonation Rocket Engine (PDRE) 198
3.6.6.5 Vehicle-Level Performance Evaluation of PDE 198
3.7 Summary 200
References 201
Suggested Additional Reading 203
Problems 204
4 Aircraft Engine Inlets and Nozzles 225
4.1 Introduction 225
4.2 The Flight Mach Number and Its Impact on Inlet Duct Geometry 226
4.3 Diffusers 227
4.4 An Ideal Diffuser 228
4.5 Real Diffusers and Their Stall Characteristics 229
4.6 Subsonic Diffuser Performance 231
4.7 Subsonic Cruise Inlet 236
4.8 Transition Ducts 245
4.9 An Interim Summary for Subsonic Inlets 245
4.10 Supersonic Inlets 247
4.10.1 Isentropic Convergentâ"Divergent Inlets 247
4.10.2 Methods to Start a Supersonic Convergentâ"Divergent Inlet 249
4.10.2.1 Overspeeding 251
4.10.2.2 Kantrowitzâ"Donaldson Inlet 252
4.10.2.3 Variable-Throat Isentropic Câ"D Inlet 254
4.11 Normal Shock Inlets 255
4.12 External Compression Inlets 258
4.12.1 Optimum Ramp Angles 261
4.12.2 Design and Off-Design Operation 261
4.13 Variable Geometryâ"External Compression Inlets 264
4.13.1 Variable Ramps 264
4.14 Mixed-Compression Inlets 265
4.15 Supersonic Inlet Types and Their Performanceâ"A Review 266
4.16 Standards for Supersonic Inlet Recovery 268
4.17 Exhaust Nozzle 268
4.18 Gross Thrust 269
4.19 Nozzle Adiabatic Efficiency 269
4.20 Nozzle Total Pressure Ratio 270
4.21 Nozzle Pressure Ratio (NPR) and Critical Nozzle Pressure Ratio (NPR crit) 270
4.22 Relation Between Nozzle Figures of Merit, η n and Ï n 271
4.23 A Convergent Nozzle or a De Laval? 272
4.24 The Effect of Boundary Layer Formation on Nozzle Internal Performance 274
4.25 Nozzle Exit Flow Velocity Coefficient 274
4.26 Effect of Flow Angularity on Gross Thrust 276
4.27 Nozzle Gross Thrust Coefficient C fg 279
4.28 Overexpanded Nozzle Flowâ"Shock Losses 280
4.29 Nozzle Area Scheduling, A 8 and A 9 /A 8 283
4.30 Nozzle Exit Area Scheduling, A 9 /A 8 285
4.31 Nozzle Cooling 287
4.32 Thrust Reverser and Thrust Vectoring 289
4.33 Hypersonic Nozzle 294
4.34 Exhaust Mixer and Gross Thrust Gain in a Mixed-Flow Turbofan Engine 297
4.35 Engine Noise 299
4.35.1 Subsonic Jet Noise 300
4.35.2 Chevron Nozzle 301
4.35.3 Engine Noise Mitigation Through Wing Shielding 302
4.36 Nozzle-Turbine (Structural) Integration 304
4.37 Summary of Exhaust Systems 305
References 306
Suggested Additional Reading 308
Problems 308
5 Combustion Chambers and Afterburners 323
5.1 Introduction 323
5.2 Laws Governing Mixture of Gases 325
5.3 Chemical Reaction and Flame Temperature 328
5.4 Chemical Equilibrium and Chemical Composition 338
5.4.1 The Law of Mass Action 339
5.4.2 Equilibrium Constant K p 341
5.5 Chemical Kinetics 350
5.5.1 Ignition and Relight Envelope 351
5.5.2 Reaction Timescale 352
5.5.3 Flammability Limits 352
5.5.4 Flame Speed 355
5.5.5 Flame Stability 357
5.5.6 Spontaneous Ignition Delay Time 360
5.5.7 Combustion-Generated Pollutants 362
5.6 Combustion Chamber 363
5.6.1 Combustion Chamber Total Pressure Loss 365
5.6.2 Combustor Flow Pattern and Temperature Profile 373
5.6.3 Combustor Liner and Its Cooling Methods 374
5.6.4 Combustion Efficiency 377
5.6.5 Some Combustor Sizing and Scaling Laws 378
5.6.6 Afterburner 382
5.7 Combustion-Generated Pollutants 386
5.7.1 Greenhouse Gases, CO 2 and H 2 O 387
5.7.2 Carbon Monoxide, CO, and Unburned Hydrocarbons (UHCs) 388
5.7.3 Oxides of Nitrogen, NO and NO 2 389
5.7.4 Smoke 389
5.7.5 Engine Emission Standards 391
5.7.6 Low-Emission Combustors 391
5.7.7 Impact of NO on the Ozone Layer 394
5.7.7.1 Lower Atmosphere 395
5.7.7.2 Upper Atmosphere 395
5.8 Aviation Fuels 397
5.9 Sustainable Aviation Fuel (SAF) 402
5.9.1 SAF Evaluation and Certification/Qualification 402
5.9.2 Impact of SAF on Emissions 404
5.9.3 Net-Zero Carbon Emission in 2050 405
5.10 Cryogenic Fuels 406
5.10.1 Liquefied Natural Gas (LNG) 406
5.10.1.1 Composition of Natural Gas and LNG 407
5.10.2 Hydrogen 409
5.10.2.1 Hydrogen Production 410
5.10.2.2 Hydrogen Delivery and Storage 412
5.10.3 Energy Density Comparison 412
5.11 Combustion Instability: Screech and Rumble 413
5.11.1 Screech Damper 413
5.12 Summary 414
References 414
Suggested Additional Reading 417
Problems 417
6 Aerodynamics of Axial-Flow Compressors and Fans 425
6.1 Introduction 425
6.2 The Geometry 426
6.3 Rotor and Stator Frames of Reference 426
6.4 The Euler Turbine Equation 429
6.5 Axial-Flow Versus Radial-Flow Machines 430
6.6 Axial-Flow Compressors and Fans 431
6.6.1 Definition of Flow Angles 433
6.6.2 Stage Parameters 435
6.6.3 Cascade Aerodynamics 449
6.6.4 Aerodynamic Forces on Compressor Blades 461
6.6.5 Three-Dimensional Flow 468
6.6.5.1 Blade Vortex Design 469
6.6.5.2 Three-Dimensional Losses 480
6.6.5.3 Reynolds Number Effect 485
6.7 Compressor Performance Map 486
6.8 Compressor Instabilityâ"Stall and Surge 490
6.9 Multistage Compressors and Their Operating Line 493
6.10 Multistage Compressor Stalling Pressure Rise and Stall Margin 498
6.11 Multistage Compressor Starting Problem 506
6.12 The Effect of Inlet Flow Condition on Compressor Performance 509
6.13 Isometric and Cutaway Views of Axial-Flow Compressor Hardware 513
6.14 Compressor Design Parameters and Principles 513
6.14.1 Blade Designâ"Blade Selection 519
6.14.2 Compressor Annulus Design 520
6.14.3 Compressor Stall Margin 520
6.15 Concepts in Compressor and Fan Noise Mitigation 529
6.16 Summary 534
References 536
Problems 538
7 Centrifugal-Compressor Aerodynamics 553
7.1 Introduction 553
7.2 Centrifugal Compressors 554
7.3 Radial Diffuser 567
7.4 Inducer 572
7.5 Inlet Guide Vanes (IGVs) and Inducer-Less Impellers 574
7.6 Impeller Exit Flow and Blockage Effects 575
7.7 Efficiency and Performance 576
7.8 Summary 578
References 579
Problems 580
8 Aerothermodynamics of Gas Turbines 587
8.1 Introduction 587
8.2 Axial-Flow Turbines 587
8.2.1 Optimal Nozzle Exit Swirl Mach Number M θ 2 599
8.2.2 Turbine Blade Losses 602
8.2.2.1 Blade Profile Loss 603
8.2.2.2 Secondary Flow Losses 605
8.2.2.3 Annulus Losses 606
8.2.3 Optimum Solidity 614
8.2.4 Turbine Cooling 618
8.2.4.1 Convective Cooling 622
8.2.4.2 Impingement Cooling 626
8.2.4.3 Film Cooling 627
8.2.4.4 Transpiration Cooling 630
8.3 Turbine Performance Map 631
8.4 The Effect of Cooling on Turbine Efficiency 632
8.5 Turbine Blade Profile Design 634
8.5.1 Angles 634
8.5.2 Other Blade Geometrical Parameters 635
8.5.3 Throat Sizing 636
8.5.4 Throat Reynolds Number Re o 636
8.5.5 Turbine Blade Profile Design 637
8.5.6 Blade Vibration and Campbell Diagram 637
8.5.7 Turbine Blade and Disk Material Selection and Design Criteria 638
8.6 Stresses in Turbine Blades and Disks and Useful Life Estimation 641
8.7 Axial-Flow Turbine Design and Practices 644
8.8 Gas Turbine Design Summary 651
8.9 Advances in Turbine Material and Cooling 652
8.10 Summary 654
References 655
Suggested Additional Reading 657
Problems 657
9 Aircraft Engine Component Matching and Off-Design Analysis 669
9.1 Introduction 669
9.2 Engine (Steady-State) Component Matching 670
9.2.1 Engine-Corrected Parameters 671
9.2.2 Inletâ"Compressor Matching 671
9.2.3 Compressorâ"Combustor Matching 673
9.2.4 Combustorâ"Turbine Matching 675
9.2.5 Compressorâ"Turbine Matching and Gas Generator Pumping Characteristics 676
9.2.5.1 Gas Generator Pumping Characteristics 678
9.2.6 Turbineâ"Afterburner (Variable-Geometry) Nozzle Matching 684
9.2.6.1 Fixed-Geometry Convergent Nozzle Matching 685
9.3 Engine Off-Design Analysis 686
9.3.1 Off-Design Analysis of a Turbojet Engine 687
9.3.2 Off-Design Analysis of an Afterburning Turbojet Engine 690
9.3.3 Off-Design Analysis of a Separate-Flow Turbofan (Two-Spool) Engine 693
9.4 Unchoked Nozzles and Other Off-Design Iteration Strategies 699
9.4.1 Unchoked Exhaust Nozzle 699
9.4.2 Unchoked Turbine Nozzle 700
9.4.3 Turbine Efficiency at Off-Design 701
9.4.4 Variable Gas Properties 701
9.5 Principles of Engine Performance Testing 702
9.5.1 Force of Inlet Bellmouth on Engine Thrust Stand 706
9.5.1.1 Bellmouth Instrumentation 706
9.5.1.2 The Effect of Fluid Viscosity 707
9.5.1.3 The Force of Inlet Bellmouth on Engine Thrust Stand 707
9.6 Summary 710
References 712
Problems 713
10 Supersonic and Hypersonic Propulsion 721
10.1 Introduction 721
10.1.1 Flow Control (FC) Strategies 723
10.1.2 Low-Boom Supersonic Aircraft 728
10.1.3 Thermal Management in High-Speed Propulsion 730
10.1.4 Lessons Learned from Hypersonic Flight Accidents 732
10.2 Promising Propulsion Concepts in High-Speed Aircraft 733
10.3 Adaptive Cycle Engine (ACE) 734
10.3.1 Transatlantic Mission 737
10.3.2 Mission Overland 737
10.4 Subsonic-Combustion Ramjet 738
10.5 Supersonic-Combustion Ramjet (Scramjet) 743
10.5.1 Inlet Analysis 744
10.5.2 Scramjet Combustor 745
10.5.3 Scramjet Fuel 747
10.5.4 Scramjet Nozzle 748
10.5.5 Flight Test of a Scramjet-Powered Hypersonic Aircraft 748
10.5.6 Supersonic Jet Noise 748
10.5.7 Supersonic Jet Noise Mitigation 750
10.6 Rocket-Based Airbreathing Propulsion 751
10.7 Advanced Hypersonic Propulsion from Takeoff to Cruise 754
10.7.1 Dual-Mode Ramjet (DMRJ) 754
10.7.2 Rotating Detonation Wave Combustor 755
10.7.3 Dual-Mode Ramjet with Rotating Detonation Combustion 755
10.7.4 Hypersonic Propulsion from Takeoff to Cruise 756
10.8 Compact Fusion Reactor: The Path to Clean, Unlimited Energy 757
10.8.1 Fuels for the Compact Fusion Reactor (CFR) 757
10.9 Summary 759
References 760
Problems 763
Index 769
