Explore the latest edition of a leading resource on sustainable aviation, alternative jet fuels, and new propulsion systems
The newly revised Third Edition of Aircraft Propulsion delivers a comprehensive update to the successful Second Edition with a renewed focus on the integration of sustainable aviation concepts. The book tackles the impact of aviation on the environment at the engine component level, as well as the role of propulsion system integration on fuel burn. It also discusses combustion emissions, including greenhouse gases, carbon monoxide, unburned hydrocarbons (UHC), and oxides of nitrogen (NOx).
Alternative jet fuels, like second generation biofuels and hydrogen, are presented. The distinguished author covers aviation noise from airframe to engine and its impact on community noise in landing and takeoff cycles. The book includes promising new technologies for propulsion and power, like the ultra-high bypass (UHB) turbofan and hybrid-electric and electric propulsion systems.
Readers will also benefit from the inclusion of discussions of unsteady propulsion systems in wave-rotor combustion and pulse-detonation engines, as well as:
- A thorough introduction to the history of the airbreathing jet engine, including innovations in aircraft gas turbine engines, new engine concepts, and new vehicles
- An exploration of compressible flow with friction and heat, including a brief review of thermodynamics, isentropic process and flow, conservation principles, and Mach numbers
- A review of engine thrust and performance parameters, including installed thrust, rocket thrust, and modern engine architecture
- A discussion of gas turbine engine cycle analysis
Perfect for aerospace and mechanical engineering students in the United States and overseas, Aircraft Propulsion will also earn a place in the libraries of practicing engineers in the aerospace and green engineering sectors seeking the latest up to date resource on sustainable aviation technologies.
Table of Contents
Preface to the Third Edition xvii
Preface to the Second Edition xix
Preface to the First Edition xxi
About the Companion Website xxv
1 Introduction: Propulsion in Sustainable Aviation 1
1.1 History of the Airbreathing Jet Engine, a Twentieth-Century Invention - The Beginning 1
1.2 Innovations in Aircraft Gas Turbine Engines 4
1.2.1 Multispool Configuration 4
1.2.2 Variable Stator 5
1.2.3 Transonic Compressor 5
1.2.4 Low-Emission Combustor 6
1.2.5 Turbine Cooling 7
1.2.6 Exhaust Nozzles 8
1.2.7 Modern Materials and Manufacturing Techniques 8
1.3 Twenty-first Century Aviation Goal: Sustainability 10
1.3.1 Combustion Emissions 10
1.3.2 Greenhouse Gases 11
1.3.3 Fuels for Sustainable Aviation 14
1.4 New Engine Concepts in Sustainable Aviation 15
1.4.1 Advanced GT Concepts: ATP/CROR and GTF 15
1.4.2 Adaptive Cycle Engine 16
1.4.3 Advanced Airbreathing Rocket Technology 18
1.4.4 Wave Rotor Topping Cycle 18
1.4.4.1 Humphrey Cycle versus Brayton Cycle 18
1.4.5 Pulse Detonation Engine (PDE) 20
1.4.6 Millimeter-Scale Gas Turbine Engines: Triumph of MEMS and Digital Fabrication 20
1.4.7 Combined Cycle Propulsion: Engines from Takeoff to Space 21
1.4.8 Hybrid-Electric and Distributed Electric Propulsion 22
1.5 New Vehicle Technologies 30
1.6 Summary 34
1.7 Roadmap for the Third Edition 34
References 36
Problems 38
2 Compressible Flow with Friction and Heat: A Review 41
2.1 Introduction 41
2.2 A Brief Review of Thermodynamics 42
2.3 Isentropic Process and Isentropic Flow 46
2.4 Conservation Principles for Systems and Control Volumes 47
2.5 Speed of Sound and Mach Number 54
2.6 Stagnation State 56
2.7 Quasi-One-Dimensional Flow 58
2.8 Area-Mach Number Relationship 62
2.9 Sonic Throat 63
2.10 Waves in Supersonic Flow 66
2.11 Normal Shocks 67
2.12 Oblique Shocks 71
2.13 Conical Shocks 74
2.14 Expansion Waves 79
2.15 Frictionless, Constant-Area Duct Flow with Heat Transfer: Rayleigh Flow 83
2.16 Adiabatic Flow of a Calorically Perfect Gas in a Constant-Area Duct with Friction: Fanno Flow 92
2.17 Friction (drag) coefficient Cf and D’Arcy Friction Factor fD 105
2.18 Dimensionless Parameters 105
2.19 Fluid Impulse 108
2.20 Summary of Fluid Impulse 115
References 116
Problems 116
3 Engine Thrust and Performance Parameters 127
3.1 Introduction 127
3.1.1 Takeoff Thrust 133
3.2 Installed Thrust - Some Bookkeeping Issues on Thrust and Drag 133
3.3 Engine Thrust Based on the Sum of Component Impulse 138
3.4 Rocket Thrust 141
3.5 Airbreathing Engine Performance Parameters 142
3.5.1 Specific Thrust 142
3.5.2 Specific Fuel Consumption and Specific Impulse 143
3.5.3 Thermal Efficiency 144
3.5.4 Propulsive Efficiency 147
3.5.5 Engine Overall Efficiency and Its Impact on Aircraft Range and Endurance 150
3.6 Modern Engines, Their Architecture, and Some Performance Characteristics 153
3.7 Summary 156
References 157
Problems 158
4 Gas Turbine Engine Cycle Analysis 167
4.1 Introduction 167
4.2 The Gas Generator 167
4.3 Aircraft Gas Turbine Engines 169
4.3.1 The Turbojet Engine 169
4.3.1.1 The Inlet 169
4.3.1.2 The Compressor 173
4.3.1.3 The Burner 179
4.3.1.4 The Turbine 184
4.3.1.5 The Nozzle 193
4.3.1.6 Thermal Efficiency of a Turbojet Engine 200
4.3.1.7 Propulsive Efficiency of a Turbojet Engine 208
4.3.1.8 The Overall Efficiency of a Turbojet Engine 209
4.3.1.9 Performance Evaluation of a Turbojet Engine 210
4.3.2 The Turbojet Engine with an Afterburner 211
4.3.2.1 Introduction 211
4.3.2.2 Analysis 213
4.3.2.3 Optimum Compressor Pressure Ratio for Maximum (Ideal) Thrust Turbojet Engine with Afterburner 216
4.3.3 The Turbofan Engine 222
4.3.3.1 Introduction 222
4.3.3.2 Analysis of a Separate-Exhaust Turbofan Engine 223
4.3.3.3 Thermal Efficiency of a Turbofan Engine 227
4.3.3.4 Propulsive Efficiency of a Turbofan Engine 228
4.3.4 Ultra-High Bypass (UHB) Turbofan Engines 233
4.4 Analysis of a Mixed-Exhaust Turbofan Engine with an Afterburner 237
4.4.1 Mixer 238
4.4.2 Cycle Analysis 240
4.4.2.1 Solution Procedure 241
4.5 The Turboprop Engine 251
4.5.1 Introduction 251
4.5.2 Propeller Theory 252
4.5.2.1 Momentum Theory 253
4.5.2.2 Blade Element Theory 257
4.5.3 Turboprop Cycle Analysis 259
4.5.3.1 The New Parameters 259
4.5.3.2 Design Point Analysis 259
4.5.3.3 Optimum Power Split Between the Propeller and the Jet 263
4.6 Promising Propulsion and Power Technologies in Sustainable Aviation 269
4.6.1 Distributed Combustion Concepts in Advanced Gas Turbine Engine Core 269
4.6.2 Multi-Fuel (Cryogenic-Kerosene) Hybrid Propulsion Concept 272
4.6.3 Intercooled and Recuperated Turbofan Engines 274
4.6.4 Active Core Concepts 275
4.6.5 Wave-Rotor Combustion 277
4.6.6 Pulse Detonation Engine (PDE) 283
4.6.6.1 Idealized Laboratory PDE: Thrust Tube 285
4.6.6.2 Pulse Detonation Ramjet 286
4.6.6.3 Turbofan Engine with PDE 287
4.6.6.4 Pulse Detonation Rocket Engine (PDRE) 288
4.6.6.5 Vehicle-Level Performance Evaluation of PDE 288
4.6.7 Adaptive Cycle Engines (ACE) 290
4.7 Summary 294
References 295
Problems 297
5 General Aviation and Uninhabited Aerial Vehicle Propulsion System 319
5.1 Introduction 319
5.2 Cycle Analysis 320
5.2.1 Otto Cycle 320
5.2.2 Real Engine Cycles 320
5.2.2.1 Four-Stroke Cycle Engines 320
5.2.2.2 Diesel Engines 322
5.2.2.3 Two-Stroke Cycle Engines 324
5.2.2.4 Rotary (Wankel) Engines 326
5.3 Power and Efficiency 328
5.4 Engine Components and Classifications 330
5.4.1 Engine Components 330
5.4.2 Reciprocating Engine Classifications 331
5.4.2.1 Classification by Cylinder Arrangement 331
5.4.2.2 Classification by Cooling Arrangement 333
5.4.2.3 Classification by Operating Cycle 334
5.4.2.4 Classification by Ignition Type 334
5.5 Scaling of Aircraft Reciprocating Engines 335
5.5.1 Scaling of Aircraft Diesel Engines 341
5.6 Aircraft Engine Systems 343
5.6.1 Aviation Fuels and Engine Knock 343
5.6.2 Carburetion and Fuel Injection Systems 345
5.6.2.1 Float-Type Carburetors 345
5.6.2.2 Pressure Injection Carburetors 346
5.6.2.3 Fuel Injection Systems 346
5.6.2.4 Full Authority Digital Engine Control (FADEC) 346
5.6.3 Ignition Systems 346
5.6.3.1 Battery Ignition Systems 347
5.6.3.2 High Tension Ignition System 347
5.6.3.3 Low Tension Ignition System 347
5.6.3.4 Full Authority Digital Engine Control (FADEC) 347
5.6.3.5 Ignition Boosters 347
5.6.3.6 Spark Plugs 348
5.6.4 Lubrication Systems 348
5.6.5 Supercharging 349
5.7 Electric Engines 349
5.7.1 Electric Motors 350
5.7.2 Solar cells 351
5.7.3 Advanced Batteries 351
5.7.4 Fuel cells 352
5.7.5 State of the Art for Electric Propulsion - Future Technology 354
5.8 Propellers and Reduction Gears 354
References 356
Problems 359
6 Aircraft Engine Inlets and Nozzles 361
6.1 Introduction 361
6.2 The Flight Mach Number and its Impact on Inlet Duct Geometry 362
6.3 Diffusers 363
6.4 An Ideal Diffuser 364
6.5 Real Diffusers and their Stall Characteristics 365
6.6 Subsonic Diffuser Performance 367
6.7 Subsonic Cruise Inlet 372
6.8 Transition Ducts 380
6.9 An Interim Summary for Subsonic Inlets 381
6.10 Supersonic Inlets 382
6.10.1 Isentropic Convergent-Divergent Inlets 383
6.10.2 Methods to Start a Supersonic Convergent-Divergent Inlet 385
6.10.2.1 Overspeeding 386
6.10.2.2 Kantrowitz-Donaldson Inlet 388
6.10.2.3 Variable-Throat Isentropic C-D Inlet 389
6.11 Normal Shock Inlets 391
6.12 External Compression Inlets 393
6.12.1 Optimum Ramp Angles 396
6.12.2 Design and Off-Design Operation 396
6.13 Variable Geometry - External Compression Inlets 398
6.13.1 Variable Ramps 399
6.14 Mixed-Compression Inlets 399
6.15 Supersonic Inlet Types and their Performance - A Review 401
6.16 Standards for Supersonic Inlet Recovery 402
6.17 Exhaust Nozzle 404
6.18 Gross Thrust 404
6.19 Nozzle Adiabatic Efficiency 404
6.20 Nozzle Total Pressure Ratio 405
6.21 Nozzle Pressure Ratio (NPR) and Critical Nozzle Pressure Ratio (NPRcrit) 405
6.22 Relation between Nozzle Figures of Merit, ηn and πn 406
6.23 A Convergent Nozzle or a De Laval? 407
6.24 The Effect of Boundary Layer Formation on Nozzle Internal Performance 409
6.25 Nozzle Exit Flow Velocity Coefficient 409
6.26 Effect of Flow Angularity on Gross Thrust 411
6.27 Nozzle Gross Thrust Coefficient Cfg 414
6.28 Over-Expanded Nozzle Flow - Shock Losses 415
6.29 Nozzle Area Scheduling, A8 and A9 /A8 418
6.30 Nozzle Exit Area Scheduling, A9 /A8 420
6.31 Nozzle Cooling 422
6.32 Thrust Reverser and Thrust Vectoring 424
6.33 Hypersonic Nozzle 429
6.34 Exhaust Mixer and Gross Thrust Gain in a Mixed-Flow Turbofan Engine 432
6.35 Engine Noise 434
6.35.1 Subsonic Jet Noise 435
6.35.2 Chevron Nozzle 436
6.35.3 Supersonic Jet Noise 437
6.35.4 Engine Noise Mitigation through Wing Shielding 439
6.36 Nozzle-Turbine (Structural) Integration 439
6.37 Summary of Exhaust Systems 439
References 442
Problems 444
7 Combustion Chambers and Afterburners 461
7.1 Introduction 461
7.2 Laws Governing Mixture of Gases 463
7.3 Chemical Reaction and Flame Temperature 466
7.4 Chemical Equilibrium and Chemical Composition 475
7.4.1 The Law of Mass Action 476
7.4.2 Equilibrium Constant KP 478
7.5 Chemical Kinetics 487
7.5.1 Ignition and Relight Envelope 488
7.5.2 Reaction Timescale 488
7.5.3 Flammability Limits 490
7.5.4 Flame Speed 492
7.5.5 Flame Stability 494
7.5.6 Spontaneous Ignition Delay Time 498
7.5.7 Combustion-Generated Pollutants 500
7.6 Combustion Chamber 500
7.6.1 Combustion Chamber Total Pressure Loss 502
7.6.2 Combustor Flow Pattern and Temperature Profile 509
7.6.3 Combustor Liner and its Cooling Methods 511
7.6.4 Combustion Efficiency 514
7.6.5 Some Combustor Sizing and Scaling Laws 515
7.6.6 Afterburner 519
7.7 Combustion-Generated Pollutants 523
7.7.1 Greenhouse Gases, CO2 and H2 O 524
7.7.2 Carbon Monoxide, CO, and Unburned Hydrocarbons, UHC 524
7.7.3 Oxides of Nitrogen, NO and NO2 525
7.7.4 Smoke 526
7.7.5 Engine Emission Standards 527
7.7.6 Low-Emission Combustors 528
7.7.7 Impact of NO on the Ozone Layer 531
7.8 Aviation Fuels 534
7.9 Alternative Jet Fuels (AJFs) 538
7.9.1 Conversion Pathways to Jet Fuel 539
7.9.2 AJF Evaluation and Certification/Qualification 539
7.9.3 Impact of Biofuel on Emissions 540
7.10 Cryogenic Fuels 542
7.10.1 Liquefied Natural Gas (LNG) 542
7.10.1.1 Composition of Natural Gas and LNG 544
7.10.2 Hydrogen 546
7.10.2.1 Hydrogen Production 547
7.10.2.2 Hydrogen Delivery and Storage 548
7.10.3 Energy Density Comparison 549
7.11 Combustion Instability: Screech and Rumble 549
7.11.1 Screech Damper 550
7.12 Summary 550
References 551
Problems 553
8 Aerodynamics of Axial-Flow Compressors and Fans 563
8.1 Introduction 563
8.2 The Geometry 564
8.3 Rotor and Stator Frames of Reference 564
8.4 The Euler Turbine Equation 566
8.5 Axial-Flow Versus Radial-Flow Machines 568
8.6 Axial-Flow Compressors and Fans 569
8.6.1 Definition of Flow Angles 571
8.6.2 Stage Parameters 573
8.6.3 Cascade Aerodynamics 585
8.6.4 Aerodynamic Forces on Compressor Blades 598
8.6.5 Three-Dimensional Flow 605
8.6.5.1 Blade Vortex Design 606
8.6.5.2 Three-Dimensional Losses 617
8.6.5.3 Reynolds Number Effect 621
8.7 Compressor Performance Map 624
8.8 Compressor Instability - Stall and Surge 626
8.9 Multistage Compressors and their Operating Line 629
8.10 Multistage Compressor Stalling Pressure Rise and Stall Margin 634
8.11 Multistage Compressor Starting Problem 642
8.12 The Effect of Inlet Flow Condition on Compressor Performance 645
8.13 Isometric and Cutaway Views of Axial-Flow Compressor Hardware 648
8.14 Compressor Design Parameters and Principles 650
8.14.1 Blade Design - Blade Selection 654
8.14.2 Compressor Annulus Design 655
8.14.3 Compressor Stall Margin 656
8.15 Concepts in Compressor and Fan Noise Mitigation 664
8.16 Summary 668
References 671
Problems 673
9 Centrifugal Compressor Aerodynamics 689
9.1 Introduction 689
9.2 Centrifugal Compressors 690
9.3 Radial Diffuser 703
9.4 Inducer 706
9.5 Inlet Guide Vanes (IGVs) and Inducer-Less Impellers 709
9.6 Impeller Exit Flow and Blockage Effects 709
9.7 Efficiency and Performance 711
9.8 Summary 713
References 714
Problems 715
10 Aerothermodynamics of Gas Turbines 721
10.1 Introduction 721
10.2 Axial-Flow Turbines 721
10.2.1 Optimal Nozzle Exit Swirl Mach Number M θ2 733
10.2.2 Turbine Blade Losses 736
10.2.2.1 Blade Profile Loss 737
10.2.2.2 Secondary Flow Losses 739
10.2.2.3 Annulus Losses 741
10.2.3 Optimum Solidity 748
10.2.4 Turbine Cooling 752
10.2.4.1 Convective Cooling 756
10.2.4.2 Impingement Cooling 760
10.2.4.3 Film Cooling 761
10.2.4.4 Transpiration Cooling 763
10.3 Turbine Performance Map 764
10.4 The Effect of Cooling on Turbine Efficiency 765
10.5 Turbine Blade Profile Design 766
10.5.1 Angles 767
10.5.2 Other Blade Geometrical Parameters 768
10.5.3 Throat Sizing 769
10.5.4 Throat Reynolds Number Reo 770
10.5.5 Turbine Blade Profile Design 770
10.5.6 Blade Vibration and Campbell Diagram 771
10.5.7 Turbine Blade and Disk Material Selection and Design Criteria 772
10.6 Stresses in Turbine Blades and Disks and Useful Life Estimation 774
10.7 Axial-Flow Turbine Design and Practices 777
10.8 Gas Turbine Design Summary 785
10.9 Advances in Turbine Material and Cooling 787
10.10 Summary 788
References 789
Problems 791
11 Aircraft Engine Component Matching and Off -Design Analysis 803
11.1 Introduction 803
11.2 Engine (Steady-State) Component Matching 804
11.2.1 Engine Corrected Parameters 805
11.2.2 Inlet-Compressor Matching 805
11.2.3 Compressor-Combustor Matching 807
11.2.4 Combustor-Turbine Matching 809
11.2.5 Compressor-Turbine Matching and Gas Generator Pumping Characteristics 810
11.2.5.1 Gas Generator Pumping Characteristics 812
11.2.6 Turbine-Afterburner (Variable-Geometry) Nozzle Matching 818
11.2.6.1 Fixed-Geometry Convergent Nozzle Matching 819
11.3 Engine Off-Design Analysis 820
11.3.1 Off-Design Analysis of a Turbojet Engine 821
11.3.2 Off-Design Analysis of an Afterburning Turbojet Engine 824
11.3.3 Off-Design Analysis of a Separate-Flow Turbofan (Two-Spool) Engine 827
11.4 Unchoked Nozzles and Other Off-Design Iteration Strategies 832
11.4.1 Unchoked Exhaust Nozzle 833
11.4.2 Unchoked Turbine Nozzle 834
11.4.3 Turbine Efficiency at Off-Design 834
11.4.4 Variable Gas Properties 835
11.5 Principles of Engine Performance Testing 835
11.5.1 Force of Inlet Bellmouth on Engine Thrust Stand 837
11.5.1.1 Bellmouth Instrumentation 837
11.5.1.2 The Effect of Fluid Viscosity 839
11.5.1.3 The Force of Inlet Bellmouth on Engine Thrust Stand 840
11.6 Summary 843
References 845
Problems 846
12 Chemical Rocket and Hypersonic Propulsion 853
12.1 Introduction 853
12.2 From Takeoff to Earth Orbit 855
12.3 Chemical Rockets 856
12.4 Chemical Rocket Applications 857
12.4.1 Launch Engines 858
12.4.2 Boost Engines 859
12.4.3 Space Maneuver Engines 859
12.4.4 Attitude Control and Orbital Correction Rockets 860
12.5 New Parameters in Rocket Propulsion 860
12.6 Thrust Coefficient, CF 863
12.7 Characteristic Velocity, c* 866
12.8 Flight Performance 868
12.9 Multistage Rockets 876
12.10 Propulsive and Overall Efficiencies 878
12.11 Chemical Rocket Combustion Chamber 879
12.11.1 Liquid Propellant Combustion Chambers 880
12.11.1.1 Some Design Guidelines for Injector Plates 884
12.11.1.2 Combustion Instabilities 885
12.11.2 Solid Propellant Combustion Chambers 885
12.12 Thrust Chamber Cooling 892
12.12.1 Liquid Propellant Thrust Chambers 892
12.12.2 Cooling of Solid Propellant Thrust Chambers 897
12.13 Combustor Volume and Shape 898
12.14 Rocket Nozzles 899
12.14.1 Multiphase Flow in Rocket Nozzles 904
12.14.2 Flow Expansion in Rocket Nozzles 910
12.14.3 Thrust Vectoring Nozzles 911
12.15 High-Speed Airbreathing Engines 913
12.15.1 Supersonic Combustion Ramjet 917
12.15.1.1 Inlet Analysis 919
12.15.1.2 Scramjet Combustor 919
12.15.1.3 Scramjet Nozzle 921
12.16 Rocket-Based Airbreathing Propulsion 921
12.17 Compact Fusion Reactor: The Path to Clean, Unlimited Energy 924
12.18 Summary 925
References 926
Problems 927
A. U.S. Standard Atmosphere 931
B. Isentropic Table 935
C. Normal Shock Table 952
D. Rayleigh Flow 965
E. Fanno Flow 974
F. Prandtl-Meyer Function and Mach Angle 983
G. Oblique Shock Charts 986
H. Conical Shock Charts 991
Index 995
