xxv
Contents
11.2.3 Infinitesimal Efficiency; Polytropic Efficiency .................. 389
11.2.4 Thermodynamic Properties of Air and Combustion Gas ... 392
11.2.5 Heat Capacity Representation ............................................ 396
11.2.6 Cooled Expansion .............................................................. 396
11.2.7 Compression with Extraction ............................................. 401
11.3 Performance of Simple-Cycle Power Gas Turbines ......................... 402
11.3.1 Idealised Simple Cycle ....................................................... 402
11.3.2 Simple Cycle with Component Efficiencies and
Different Heat Capacities of Air and Combustion Gas ...... 403
11.3.3 Simple Cycle with Component Efficiencies, Cooling
and Variable Gas Properties ............................................... 405
11.4 Performance of Power Gas Turbines with Enhanced Cycles ........... 409
11.4.1 Compression with Intercooling .......................................... 409
11.4.2 Expansion with Reheat ....................................................... 411
11.4.3 Recuperator ........................................................................ 412
11.4.4 Combined Gas and Steam Cycles ...................................... 413
11.4.5 Steam Injection ................................................................... 416
References ................................................................................................. 417
12 Thrust Gas Turbines ............................................................................... 419
12.1 Thrust Generation ............................................................................. 419
12.1.1 Screw or Propeller .............................................................. 419
12.1.2 Reactor or Jet Engine ......................................................... 423
12.1.3 Rocket ................................................................................ 426
12.2 Overview of Aircraft Gas Turbine Engines ...................................... 427
12.2.1 Turbojet .............................................................................. 427
12.2.2 Turboprop and Turbo-Shaft ................................................ 427
12.2.3 Bypass Turbojet .................................................................. 428
12.2.4 Turbofan ............................................................................. 428
12.2.5 Prop-fan and Unducted Fan ............................................... 429
12.2.6 Geared Turbofan ................................................................. 432
12.3 Performance Parameters of Aircraft Propulsion Systems ................ 432
12.3.1 Specific Thrust ................................................................... 432
12.3.2 Dynamic Power .................................................................. 433
12.3.3 Gas Power and Dynamic Efficiency .................................. 433
12.3.4 Thermal Power, Thermodynamic Efficiency and
Thermal Efficiency ............................................................. 433
12.3.5 Propulsive Power and Propulsive Efficiency ..................... 434
12.3.6 Overall Efficiency .............................................................. 434
12.3.7 Rocket ................................................................................ 435
12.3.8 Generalisation for Double-Flow Engines ........................... 435
12.3.9 Specific Fuel Consumption ................................................ 437
12.4 Performance of the Gas Generator
and the Single-Jet Engine ................................................................. 438
12.4.1 Analysis with Loss-Free Components ................................ 439
12.4.2 Analysis with Component Losses ...................................... 441
Contents
11.2.3 Infinitesimal Efficiency; Polytropic Efficiency .................. 389
11.2.4 Thermodynamic Properties of Air and Combustion Gas ... 392
11.2.5 Heat Capacity Representation ............................................ 396
11.2.6 Cooled Expansion .............................................................. 396
11.2.7 Compression with Extraction ............................................. 401
11.3 Performance of Simple-Cycle Power Gas Turbines ......................... 402
11.3.1 Idealised Simple Cycle ....................................................... 402
11.3.2 Simple Cycle with Component Efficiencies and
Different Heat Capacities of Air and Combustion Gas ...... 403
11.3.3 Simple Cycle with Component Efficiencies, Cooling
and Variable Gas Properties ............................................... 405
11.4 Performance of Power Gas Turbines with Enhanced Cycles ........... 409
11.4.1 Compression with Intercooling .......................................... 409
11.4.2 Expansion with Reheat ....................................................... 411
11.4.3 Recuperator ........................................................................ 412
11.4.4 Combined Gas and Steam Cycles ...................................... 413
11.4.5 Steam Injection ................................................................... 416
References ................................................................................................. 417
12 Thrust Gas Turbines ............................................................................... 419
12.1 Thrust Generation ............................................................................. 419
12.1.1 Screw or Propeller .............................................................. 419
12.1.2 Reactor or Jet Engine ......................................................... 423
12.1.3 Rocket ................................................................................ 426
12.2 Overview of Aircraft Gas Turbine Engines ...................................... 427
12.2.1 Turbojet .............................................................................. 427
12.2.2 Turboprop and Turbo-Shaft ................................................ 427
12.2.3 Bypass Turbojet .................................................................. 428
12.2.4 Turbofan ............................................................................. 428
12.2.5 Prop-fan and Unducted Fan ............................................... 429
12.2.6 Geared Turbofan ................................................................. 432
12.3 Performance Parameters of Aircraft Propulsion Systems ................ 432
12.3.1 Specific Thrust ................................................................... 432
12.3.2 Dynamic Power .................................................................. 433
12.3.3 Gas Power and Dynamic Efficiency .................................. 433
12.3.4 Thermal Power, Thermodynamic Efficiency and
Thermal Efficiency ............................................................. 433
12.3.5 Propulsive Power and Propulsive Efficiency ..................... 434
12.3.6 Overall Efficiency .............................................................. 434
12.3.7 Rocket ................................................................................ 435
12.3.8 Generalisation for Double-Flow Engines ........................... 435
12.3.9 Specific Fuel Consumption ................................................ 437
12.4 Performance of the Gas Generator
and the Single-Jet Engine ................................................................. 438
12.4.1 Analysis with Loss-Free Components ................................ 439
12.4.2 Analysis with Component Losses ...................................... 441