Table of Contents

Part I Aero Engines and Gas Turbines
Chapter 1 History and Classifications of Aero Engines  . .  . 3
1.1 Prejet Engines—History 4
1.1.1 Early Activities in Egypt and China 4
1.1.2 Leonardo da Vinci .  ..  ...  .5
1.1.3 Branca’s Stamping Mill .  . . 5
1.1.4 Newton’s SteamWagon .  . . 6
1.1.5 Barber’s Gas Turbine .  .. 6
1.1.6 Miscellaneous Aero-Vehicles’Activities in the Eighteenth and Nineteenth
Centuries .  ..  . 7
1.1.7 TheWright Brothers .  ..  . 8
1.1.8 Significant Events up to 1940s .  .. 10
1.1.8.1 Aero-Vehicle Activities .  . 10
1.1.8.2 Reciprocating Engines .  . . 12
1.2 Jet Engines .  . .  . 13
1.2.1 Jet Engine Inventors: Dr. Hans von Ohain and Sir FrankWhittle .  . 13
1.2.1.1 Sir Frank Whittle (1907–1996) .  .. 13
1.2.1.2 Dr. Hans von Ohain (1911–1998) .  . . 14
1.2.2 Turbojet Engines.  ..  .. 15
1.2.3 Turboprop and Turboshaft Engines . 18
1.2.4 Turbofan Engines .  ..  .21
1.2.5 Propfan Engine 23
1.2.6 Pulsejet, Ramjet, and Scramjet Engines .  ..  . . 24
1.2.6.1 Pulsejet Engine .  ..  .. 24
1.2.6.2 Ramjet and Scramjet Engines .  ..  . 25
1.2.7 Industrial Gas Turbine Engines .  .27
1.3 Classifications of Aerospace Engines .  ..  . . 28
1.4 Classification of Jet Engines.  ..  . . 29
1.4.1 Ramjet.  ..  .29
1.4.2 Pulsejet .  ..  . .  . 30
1.4.3 Scramjet .  ..  . . 31
1.4.4 Turboramjet .  . .  . 31
1.4.5 Turborocket .  . .  . 32
1.5 Classification of Gas Turbine Engines .  ..  . 32
1.5.1 Turbojet Engines.  ..  .. 33
1.5.2 Turboprop .  .. 34
1.5.3 Turboshaft.  .. 35
1.5.4 Turbofan Engines .  ..  .37
1.5.5 Propfan Engines .  ..  .. 41
1.5.6 Advanced Ducted Fan .  .42
1.6 Industrial Gas Turbines . 43
1.7 Non–Air-Breathing Engines .  ..  . . 44
1.8 Future of Aircraft and Power Plant Industries .  ..  .. 44
Closure .  . .  . 52
Problems .  . 52
References 54
Chapter 2 Performance Parameters of Jet Engines .  ..  . .  . 57
2.1 Introduction .  . . 57
2.2 Thrust Force .  . . 57
2.3 Factors Affecting Thrust 67
2.3.1 Jet Nozzle .  .. 67
2.3.2 Air Speed .  ..  . 68
2.3.3 Mass Air Flow . 68
2.3.4 Altitude .  ..  . .  . 68
2.3.5 Ram Effect .  .69
2.4 Engine Performance Parameters .  . . 70
2.4.1 Propulsive Efficiency .  .. 70
2.4.2 Thermal Efficiency .  ..  . . 75
2.4.3 Propeller Efficiency.  ..  . . 76
2.4.4 Overall Efficiency .  ..  . .  . 77
2.4.5 Takeoff Thrust . 80
2.4.6 Specific Fuel Consumption .  ..  . .  . 81
2.4.7 Aircraft Range . 82
2.4.8 Range Factor .  . . 85
2.4.9 Endurance Factor .  ..  .85
2.4.10 Specific Impulse .  ..  .. 87
Problems .  . 91
References 94
Chapter 3 Pulsejet and Ramjet Engines .  ..  . .  . 97
3.1 Introduction .  . . 97
3.2 Pulsejet Engines.  ..  . .  . 97
3.2.1 Introduction .  . .  . 97
3.2.2 Valved Pulsejet 98
3.2.3 Valveless Pulsejet.  ..  .102
3.2.4 Pulse Detonation Engine .  . 103
3.3 Ramjet Engines .  ..  . .  . 106
3.3.1 Ideal Ramjet .  . . 107
3.3.2 Real Cycle .  .110
3.4 Case Study.  .129
3.5 Summary and Governing Equations for ShockWaves and Isentropic Flow .  ..  .. 141
3.5.1 Summary .  ..  . 141
3.5.2 Normal ShockWave Relations .  .141
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3.5.3 Oblique ShockWave Relations .  .142
3.5.4 Rayleigh-Flow Equations .  ..  .. 142
3.5.5 Isentropic Relation .  ..  . . 142
Problems .  . 143
References 145
Chapter 4 Turbojet Engine . 147
4.1 Introduction .  . . 147
4.2 Single Spool .  . . 149
4.2.1 Examples of Engines .  .. 149
4.2.2 Thermodynamic Analysis .  ..  .. 150
4.2.3 Ideal Case .  .. 150
4.2.4 Actual Case .  . .  . 165
4.2.5 Comparison Between Operative and Inoperative Afterburner .  ..  . 175
4.3 Two-Spool Engine .  .. 178
4.3.1 Nonafterburning Engine.  . . 179
4.3.1.1 Example of Engines .  .. 179
4.3.2.2 Thermodynamic Analysis 180
4.3.3 Afterburning Engine .  ..  . 183
4.3.3.1 Examples for Two-Spool Afterburning Turbojet Engines .  ..  .183
4.3.2.2 Thermodynamic Analysis 184
4.4 Statistical Analysis .  .. 188
4.5 Thrust Augmentation .  . . 189
4.5.1 Water Injection 189
4.5.2 Afterburning .  . . 190
4.5.3 Pressure Loss in Afterburning Engine .  ..  .191
4.6 Supersonic Turbojet .  .195
4.7 Optimization of the Turbojet Cycle .  ..  .198
Problems .  . 209
References 213
Chapter 5 Turbofan Engines .  ..  .. 215
5.1 Introduction .  . . 215
5.2 Forward Fan Unmixed Single-Spool Configuration.  .216
5.3 Forward Fan Unmixed Two-Spool Engines . 221
5.3.1 The Fan and Low-Pressure Compressor on One Shaft.  . . 221
5.3.2 Fan Driven by the LPT and the Compressor Driven by the HPT .  . . 232
5.3.3 A Geared Fan Driven by the LPT and the Compressor Driven
by the HPT.  .233
5.4 Forward Fan Unmixed Three-Spool Engine . 235
5.5 Forward Fan Mixed-Flow Engine .  . 242
5.5.1 Mixed-Flow Two-Spool Engine .  . .  . 242
5.6 Mixed Turbofan with Afterburner .  . 255
5.6.1 Introduction .  . .  . 255
5.6.2 Ideal Cycle .  .256
5.6.3 Real Cycle .  .258
5.7 AFT Fan .  ..  . 258
5.8 V/STOL.  ..  . . 261
5.8.1 Swiveling Nozzles .  ..  . .  . 261
5.8.2 Switch-In Deflector System .  ..  . .  . 266
5.9 Performance Analysis.  . . 273
Summary.  . 294
Problems .  . 297
References 305
Chapter 6 Turboprop, Turboshaft, and Propfan Engines .  . . 307
6.1 Introduction to Turboprop Engines .  ..  .307
6.2 Classification of Turboprop Engines .  ..  . .  . 310
6.3 Thermodynamic Analysis of Turboprop Engines.  ..  . . 312
6.3.1 Single-Spool Turboprop .  . . 312
6.3.2 Two-Spool Turboprop .  .316
6.4 Analogy with Turbofan Engines.  . .  . 319
6.5 Equivalent Engine Power .  ..  .. 320
6.5.1 Static Condition320
6.5.2 Flight Operation .  ..  .. 320
6.6 Fuel Consumption .  .. 320
6.7 Turboprop Installation .  . 321
6.8 Performance Analysis.  . . 329
6.9 Comparison Between Turbojet, Turbofan, and Turboprop Engines .  ..  .330
6.10 Turboshaft Engines .  .333
6.11 Power Generated by Turboshaft Engines .  . .  . 334
6.11.1 Single-Spool Turboshaft .  . 334
6.11.2 Double-Spool Turboshaft .  ..  .. 335
6.12 Examples for Turboshaft Engines .  . 336
6.13 Propfan Engines.  ..  . .  . 337
Summary of Turboprop Relations .  ..  . .  . 340
Problems .  . 340
References 344
Chapter 7 High-Speed Supersonic and Hypersonic Engines .  ..  . .  . 345
7.1 Introduction .  . . 345
7.2 Supersonic Aircraft and Programs .  ..  .. 345
7.2.1 Anglo-French Activities .  . . 346
7.2.2 Russian Activities .  ..  .347
7.2.3 The U.S. Activities .  ..  . .  . 347
7.3 Future of Commercial Supersonic Technology .  ..  .349
7.4 Technology Challenges of the Future Flight . 350
7.5 High-Speed Supersonic and Hypersonic Propulsion .  . .  . 350
7.5.1 Introduction .  . .  . 350
7.5.2 Hybrid Cycle Engine .  .. 351
7.6 Turboramjet Engine .  .352
7.7 Wraparound Turboramjet .  ..  .. 352
7.7.1 Operation as a Turbojet Engine .  .352
7.7.2 Operation as a Ramjet Engine .  .. 355
7.8 Over/Under Turboramjet .  ..  .. 356
7.8.1 Turbojet Mode . 358
7.8.2 Dual Mode .  .358
7.8.3 Ramjet Mode .  . 358
7.9 Turboramjet Performance .  ..  .358
7.9.1 Turbojet Mode . 358
7.9.2 Ramjet Mode .  . 359
7.9.3 Dual Mode .  .359
7.10 Case Study.  .360
7.11 Examples for Turboramjet Engines .  ..  .365
7.12 Hypersonic Flight .  ..  . 367
7.12.1 History of Hypersonic Vehicles.  .367
7.12.2 Hypersonic Commercial Transport . 369
7.12.3 Military Applications .  .. 370
7.13 Scramjet Engines.  ..  . . 370
7.13.1 Introduction .  . .  . 370
7.13.2 Thermodynamics .  ..  .372
7.14 Intake of a Scramjet Engine .  ..  . . 372
7.15 Combustion Chamber.  . . 373
7.16 Nozzle .  ..  . .  . 376
7.17 Performance Parameters 376
Problems .  . 380
References 383
Chapter 8 Industrial Gas Turbines .  .385
8.1 Introduction .  . . 385
8.2 Categories of Gas Turbines .  ..  . .  . 386
8.3 Types of Industrial Gas Turbines .  . . 387
8.4 Single-Shaft Engine.  .388
8.4.1 Single Compressor and Turbine .  . .  . 389
8.4.1.1 Ideal Cycle.  .. 389
8.4.1.2 Real Cycle .  .. 392
8.4.2 Regeneration .  . . 395
8.4.3 Reheat .  ..  .398
8.4.4 Intercooling .  . .  . 399
8.4.5 Combined Intercooling, Regeneration, and Reheat .  .. 401
8.5 Double-Shaft Engine.  . .  . 406
8.5.1 Free Power Turbine .  ..  . . 406
8.5.2 Two Discrete Shafts (Spools) .  ..  . 408
8.6 Three Spool .  . . 415
8.7 Combined Gas Turbine . 422
8.8 Marine Applications .  . .  . 423
8.8.1 Additional Components for Marine Applications .  ..  . . 424
8.8.2 Examples for Marine Gas Turbines . 426
8.9 Offshore Gas Turbines .  . 427
8.10 Micro Gas Turbines (μ-Gas Turbines) .  ..  . 428
8.10.1 Microturbines versus Typical Gas Turbines .  . .  . 429
8.10.2 Design Challenges .  ..  . .  . 429
8.10.3 Applications .  . .  . 430
Problems .  . 431
References 433
Part II Component Design .  ..  .435
Chapter 9 Power Plant Installation and Intakes . 437
9.1 Introduction .  . . 437
9.2 Power Plant Installation 437
9.3 Subsonic Aircraft.  ..  . . 437
9.3.1 Turbojet and Turbofan Engines .  .438
9.3.1.1 Wing Installation .  ..  . .  . 438
9.3.1.2 Fuselage Installation .  .442
9.3.1.3 CombinedWing and Tail Installation (Three Engines) .  . . 443
9.3.1.4 Combined Fuselage and Tail Installation .  .444
9.3.2 Turboprop Installation .  .444
9.4 Supersonic Aircraft .  .446
9.4.1 Civil Transports 446
9.4.2 Military Aircrafts .  ..  .447
9.5 Air Intakes or Inlets .  .448
9.6 Subsonic Intakes .  ..  . . 449
9.6.1 Inlet Performance .  ..  .451
9.6.2 Performance Parameters .  . . 453
9.6.3 Turboprop Inlets .  ..  .. 457
9.7 Supersonic Intakes .  .. 457
9.7.1 Review of Gas Dynamic Relations for Normal and Oblique Shocks .  ..  . .  . 460
9.7.1.1 Normal ShockWaves .  . .  . 460
9.7.1.2 Oblique ShockWaves .  . .  . 461
9.7.2 External Compression Intake (Inlet) 462
9.7.3 Internal Compression Inlet (Intake) 467
9.7.4 Mixed Compression Intakes .  ..  . . 468
9.8 Matching Between Intake and Engine .  ..  . 470
9.9 Case Study.  .472
Problems .  . 475
References 479
Chapter 10 Combustion Systems.  ..  . . 481
10.1 Introduction .  . . 481
10.2 Subsonic Combustion Chambers .  . . 482
10.2.1 Tubular (or Multiple) Combustion Chambers .  . 482
10.2.2 Tubo-Annular Combustion Chambers .  ..  .483
10.2.3 Annular Combustion Chambers.  .484
10.3 Supersonic Combustion Chamber.  . 485
10.4 Combustion Process .  . .  . 485
10.5 The Chemistry of Combustion .  .487
10.6 Combustion Chamber Performance .  ..  .490
10.6.1 Pressure Losses 490
10.6.2 Combustion Efficiency .  . .  . 491
10.6.3 Combustion Stability .  .. 491
10.6.4 Combustion Intensity .  .. 492
10.7 Cooling .  ..  . . 493
10.8 Material .  ..  . . 495
10.9 Aircraft Fuels .  . 496
10.10 Emissions and Pollutants .  ..  .. 497
10.10.1 Pollutant Formation .  ..  . 497
10.11 The Afterburner .  ..  . .  . 498
10.12 Supersonic Combustion System.  . .  . 499
Problems .  . 501
References 503
Chapter 11 Exhaust System . 505
11.1 Introduction .  . . 505
11.2 Nozzle .  ..  . .  . 507
11.2.1 Governing Equations .  .. 508
11.2.1.1 Convergent–Divergent Nozzle .  .. 508
11.2.1.2 Convergent Nozzle .  ..  . 511
11.2.2 Variable Geometry Nozzles .  ..  . .  . 512
11.2.3 Afterburning Nozzles .  .. 514
11.3 Calculation of the Two-Dimensional Supersonic Nozzle .  ..  . .  . 517
11.3.1 Convergent Nozzle .  ..  . . 518
11.3.2 Divergent Nozzle .  ..  .522
11.3.2.1 Analytical Determination of the Contour of a Nozzle .  . .  . 525
11.3.2.2 Design Procedure for a Minimum Length Divergent Nozzle .  .. 527
11.3.2.3 Procedure of Drawing the ExpansionWaves Inside the Nozzle .  . . 528
11.4 Thrust Reversal .  ..  . .  . 529
11.4.1 Classification of Thrust Reverser Systems .  .531
11.4.2 Calculation of Ground Roll Distance .  ..  .. 536
11.5 Thrust Vectoring .  ..  . . 537
11.5.1 Governing Equations .  .. 540
11.6 Noise.  ..  .. 541
11.6.1 Introduction .  . .  . 541
11.6.2 Acoustics Model Theory .  . 543
11.6.3 Methods Used to Decrease the Jet Noise .  ..  . 544
Problems .  . 547
References 548
Chapter 12 Centrifugal Compressors .  . . 551
12.1 Introduction .  . . 551
12.2 Layout of Compressor .  . 553
12.2.1 Impeller .  ..  . . 553
12.2.2 Diffuser .  ..  . . 554
12.2.3 Scroll or Manifold .  ..  . .  . 556
12.3 Classification of Centrifugal Compressors .  . 556
12.4 Governing Equations .  . . 559
12.4.1 The Continuity Equation .  . 562
12.4.2 The Momentum Equation or Euler’s Equation for Turbomachinery .  ..  .562
12.4.3 The Energy Equation or the First Law of Thermodynamics .  ..  . .  . 563
12.4.4 Slip Factor σ .  . . 567
12.4.5 Prewhirl .  ..  . . 570
12.4.6 Types of Impeller .  ..  .581
12.5 Diffuser .  ..  . . 589
12.5.1 Vaneless Diffuser .  ..  .590
12.5.2 Vaned Diffuser. 592
12.6 Discharge Systems .  .. 598
12.7 Characteristic Performance of a Centrifugal Compressor .  ..  . . 598
12.8 Erosion .  ..  . . 602
12.8.1 Introduction .  . .  . 602
12.8.2 Theoretical Estimation of Erosion .  . 605
Problems .  . 609
References 616
Chapter 13 Axial-Flow Compressors and Fans.  . . 619
13.1 Introduction .  . . 619
13.2 Comparison Between Axial and Centrifugal Compressors .  ..  . 621
13.2.1 Advantages of the Axial-Flow Compressor Over
the Centrifugal Compressor .  ..  . .  . 621
13.2.2 Advantages of Centrifugal-Flow Compressor Over the Axial-Flow
Compressor .  . .  . 622
13.2.3 Main Points for Comparison Between Centrifugal and Axial Compressors .  . 623
13.3 Mean Flow (Two-Dimensional Approach) .  . 623
13.3.1 Types of Velocity Triangles .  ..  . .  . 625
13.3.2 Variation of Enthalpy Velocity and Pressure of an
Axial Compressor .  ..  .627
13.4 Basic Design Parameters .  ..  .. 635
13.4.1 Centrifugal Stress .  ..  .635
13.4.2 Tip Mach Number .  ..  . .  . 637
13.4.3 Fluid Deflection638
13.5 Design Parameters .  .. 639
13.5.1 Degree of Reaction .  ..  . . 640
13.6 Three-Dimensional Flow .  ..  .. 642
13.6.1 Axisymmetric Flow.  ..  . . 643
13.6.2 Simplified Radial Equilibrium Equation .  ..  . 644
13.6.3 Free Vortex Method .  ..  . 646
13.6.4 General Design Procedure .  ..  .651
13.7 Complete Design Process for Compressor.  . . 659
13.8 Rotational Speed (RPM) and Annulus Dimensions .  .659
13.9 Determine Number of Stages (Assuming Stage Efficiency) .  .. 662
13.10 Calculation of Air Angles for Each Stage at the Mean Section .  . . 663
13.10.1 First Stage .  .. 663
13.10.2 Stages from (2) to (n−1) .  ..  .. 664
13.10.3 Last Stage .  .. 665
13.11 Variation of Air Angles from Root to Tip Based on the Type of Blading (Free
Vortex-Exponential-First Power) .  . . 666
13.12 Blade Design .  . 667
13.12.1 Cascade Measurements.  . .  . 667
13.12.2 Choosing the Type of Airfoil .  ..  . . 672
13.12.3 Stage Performance .  ..  . .  . 672
13.12.3.1 Blade Efficiency and Stage Efficiency .  ..  . . 677
13.13 Compressibility Effects . 679
13.14 Performance .  . . 687
13.14.1 Single Stage .  . .  . 687
13.14.2 Multistage Compressor .  . .  . 689
13.14.3 Compressor Map .  ..  .690
13.14.4 Stall and Surge . 691
13.14.5 Surge Control Methods.  . .  . 694
13.14.5.1 Multispool Compressor .  . 694
13.14.5.2 Variable Vanes .  . 694
13.14.5.3 Air Bleed.  ..  . . 695
13.15 Case Study.  .701
13.15.1 Mean Section Data .  ..  . . 701
13.15.2 Variations from Hub to Tip .  ..  . .  . 701
13.15.3 Details of Flow in Stage Number 2 . 703
13.15.4 Number of Blades and Stresses of the Seven Stages.  .704
13.15.5 Compressor Layout .  ..  . . 705
13.16 Erosion .  ..  . . 708
13.17 Fouling .  ..  . . 712
Problems .  . 714
References 725
Chapter 14 Axial Turbines.  . . 727
14.1 Introduction .  . . 727
14.2 Comparison Between Axial Flow Compressors and Turbines .  . .  . 729
14.3 Aerodynamics and Thermodynamics for a Two-Dimensional Flow .  ..  . .  . 730
14.3.1 Velocity Triangles .  ..  . .  . 730
14.3.2 Euler’s Equation .  ..  .. 732
14.3.3 Efficiency, Losses, and Pressure Ratio .  ..  . .  . 734
14.3.4 Nondimensional Quantities .  ..  . .  . 738
14.3.5 Several Remarks .  ..  .. 746
14.4 Three Dimensional .  .. 752
14.4.1 Free Vortex Design .  ..  . . 753
14.4.2 Constant Nozzle Angle Design (α2) 753
14.4.3 General Case .  . . 756
14.4.4 Constant Specific Mass Flow Stage 757
14.5 Preliminary Design .  .772
14.5.1 Main Design Steps.  ..  . .  . 772
14.5.2 Aerodynamic Design .  .. 772
14.5.3 Blade Profile Selection .  . .  . 774
14.5.4 Mechanical and Structural Designs . 775
14.5.4.1 Centrifugal Stresses .  .. 775
14.5.4.2 Centrifugal Stresses on Blades .  .. 776
14.5.4.3 Centrifugal Stresses on Discs .  ..  . . 777
14.5.4.4 Gas Bending Stress .  ..  . 779
14.5.4.5 Centrifugal Bending Stress .  ..  .781
14.5.4.6 Thermal Stress .  . 781
14.5.5 Turbine Cooling .  ..  .. 782
14.5.5.1 Turbine Cooling Techniques .  ..  . .  . 782
14.5.5.2 Mathematical Modeling.  . 784
14.5.6 Losses and Efficiency .  .790
14.5.6.1 Profile Loss (Yp) .  ..  . .  . 790
14.5.6.2 Annulus Loss .  . . 791
14.5.6.3 Secondary Flow Loss .  . .  . 791
14.5.6.4 Tip Clearance Loss (Yk) . 792
14.6 Turbine Map.  . . 793
14.7 Case Study.  .797
14.7.1 Design Point .  . . 797
Summary.  . 804
Problems .  . 805
References 811
Chapter 15 Radial Inflow Turbines .  .813
15.1 Introduction .  . . 813
15.2 Thermodynamics.  ..  . . 814
15.3 Dimensionless Parameters .  ..  .818
15.4 Preliminary Design .  .819
15.5 Breakdown of Losses .  . . 822
15.6 Design for Optimum Efficiency .  . .  . 825
15.7 Cooling .  ..  . . 829
Problems .  . 830
References 832
Chapter 16 Module Matching .  ..  .. 833
16.1 Introduction .  . . 833
16.2 Off-Design Operation of a Single-Shaft Gas Turbine Driving a Load .  ..  . 833
16.2.1 Matching Procedure .  ..  . 834
16.2.2 Different Loads 839
16.3 Off Design of Free Turbine Engine .  ..  .839
16.3.1 Gas Generator.  . 840
16.3.2 Free Power Turbine .  ..  . . 841
16.4 Off Design of Turbojet Engine .  .846
Problems .  . 851
References 853
Appendix A Glossary
Appendix B Data base for turbofan engines
Appendix C Gas Turbines