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, and conservation principles

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.

Saeed Farokhi, PhD, is Professor Emeritus of Aerospace Engineering at the University of Kansas, USA. His main areas of research focus are propulsion systems, flow control, renewable energy, and computational fluid dynamics. He is Fellow of the Royal Aeronautical Society and the American Society of Mechanical Engineers. He is Associate Fellow of the American Institute of Aeronautics and Astronautics.

Preface to the Third Edition

Preface to the Second Edition

Preface to the First Edition

1. Introduction

1.1 History of the Airbreathing Jet Engine, a Twentieth-Century Invention—The Beginning

1.2 Innovations in Aircraft Gas Turbine Engines

1.2.1 Multispool Configuration

1.2.2 Variable Stator

1.2.3 Transonic Compressor

1.2.4 Low-Emission Combustor

1.2.5 Turbine Cooling

1.2.6 Exhaust Nozzles

1.2.7 Modern Materials and Manufacturing Techniques

1.3 Twenty-first Century Aviation Goal: Sustainability

1.3.1 Combustion Emissions

1.3.2 Greenhouse Gases

1.3.3 Fuels for Sustainable Aviation

1.4 New Engine Concepts in Sustainable Aviation

1.4.1 Advanced GT Concepts: ATP/CROR and GTF

1.4.2 Adaptive Cycle Engine

1.4.3 Advanced Airbreathing Rocket Technology

1.4.4 Wave Rotor Topping Cycle

1.4.5 Pulse Detonation Engine (PDE)

1.4.6  Millimeter-Scale Gas Turbine Engines: Triumph of MEMS and Digital Fabrication

1.4.7 Combined Cycle Propulsion: Engines from Takeoff to Space

1.4.8 Hybrid-Electric and Distributed Electric Propulsion

1.5 New Vehicle Technologies

1.6 Summary

1.7 Roadmap for the Third Edition

References

Problems

2. Compressible Flow with Heat and Friction: A Review

2.1 Introduction

2.2 A Brief Review of Thermodynamics

2.3 Isentropic Process and Isentropic Flow

2.4 Conservation Principles for Systems and Control Volumes

2.5 Speed of Sound & Mach Number

2.6 Stagnation State

2.7 Quasi-One-Dimensional Flow

2.8 Area–Mach Number Relationship

2.9 Sonic Throat

2.10 Waves in Supersonic Flow

2.11 Normal Shocks

2.12 Oblique Shocks

2.13 Conical Shocks

2.14 Expansion Waves

2.15 Frictionless, Constant-Area Duct Flow with Heat Transfer: Rayleigh Flow

2.16 Adiabatic Flow of a Calorically Perfect Gas in a Constant-Area Duct with Friction: Fanno Flow

2.17 Friction (Drag) Coefficient C_f and D’Arcy Friction Factor f_D

2.18 Dimensionless Parameters

2.19 Fluid Impulse

2.20 Summary of Fluid Impulse

References

Problems

3. Engine Thrust and Performance Parameters

3.1 Introduction

3.1.1 Takeoff Thrust

3.2 Installed Thrust—Some Bookkeeping Issues on Thrust and Drag

3.3 Engine Thrust Based on the Sum of Component Impulse

3.4 Rocket Thrust

3.5 Airbreathing Engine Performance Parameters

3.5.1 Specific Thrust

3.5.2 Specific Fuel Consumption and Specific Impulse

3.5.3 Thermal Efficiency

3.5.4 Propulsive Efficiency

3.5.5 Engine Overall Efficiency and Its Impact on Aircraft Range and Endurance

3.6 Modern Engines, Their Architecture, and Some Performance Characteristics

3.7 Summary

References

Problems

4. Gas Turbine Engine Cycle Analysis

4.1 Introduction

4.2 The Gas Generator

4.3 Aircraft Gas Turbine Engines

4.3.1 The Turbojet Engine

4.3.1.1 The Inlet

4.3.1.2 The Compressor

4.3.1.3 The Burner

4.3.1.4 The Turbine

4.3.1.5 The Nozzle

4.3.1.6 Thermal Efficiency of a Turbojet Engine

4.3.1.7 Propulsive Efficiency of a Turbojet Engine

4.3.1.8 The Overall Efficiency of a Turbojet Engine

4.3.1.9 Performance Evaluation of a Turbojet Engine

4.3.2 The Turbojet Engine with an Afterburner

4.3.2.1 Introduction

4.3.2.2 Analysis

4.3.2.3 Optimum Compressor Pressure Ratio for Maximum (Ideal) Thrust Turbojet Engine with Afterburner

4.3.3 The Turbofan Engine

4.3.3.1 Introduction

4.3.3.2 Analysis of a Separate-Exhaust Turbofan Engine

4.3.3.3 Thermal Efficiency of a Turbofan Engine

4.3.3.4 Propulsive Efficiency of a Turbofan Engine

4.3.4 Ultra-High Bypass (UHB) Turbofan Engines

4.4 Analysis of a Mixed-Exhaust Turbofan Engine with an Afterburner

4.4.1 Mixer

4.4.2 Cycle Analysis

4.4.2.1 Solution Procedure

4.5 The Turboprop Engine

4.5.1 Introduction

4.5.2 Propeller Theory

4.5.2.1 Momentum Theory

4.5.2.2 Blade Element Theory

4.5.3 Turboprop Cycle Analysis

4.5.3.1 The New Parameters

4.5.3.2 Design Point Analysis

4.5.3.3 Optimum Power Split Between the Propeller and the Jet

4.6 Promising Propulsion and Power Technologies in Sustainable Aviation

4.6.1 Distributed Combustion Concepts in Advanced Gas Turbine Engine Core

4.6.2 Multi-Fuel (Cryogenic-Kerosene) Hybrid Propulsion Concept

4.6.3 Intercooled and Recuperated Turbofan Engines

4.6.4 Active Core Concepts

4.6.5 Wave Rotor Combustion

4.6.6 Pulse Detonation Engine (PDE)

4.6.6.1 Idealized Laboratory PDE: Thrust Tube

4.6.6.2 Pulse Detonation Ramjet

4.6.6.3 Turbofan Engine with PDE

4.6.6.4 Pulse Detonation Rocket Engine (PDRE)

4.6.6.5 Vehicle-Level Performance Evaluation of PDE

4.6.7 Adaptive Cycle Engines (ACE)

4.7 Summary

References

Problems

5. General Aviation and Uninhabited Aerial Vehicle Propulsion System

5.1 Introduction

5.2 Cycle Analysis

5.2.1 Otto Cycle

5.2.2 Real Engine Cycles

5.2.2.1 Four-Stroke Cycle Engines

5.2.2.2 Diesel Engines

5.2.2.3 Two-Stroke Cycle Engines

5.2.2.4 Rotary (Wankel) Engines

5.3 Power and Efficiency

5.4 Engine Components and Classifications

5.4.1 Engine Components

5.4.2 Reciprocating Engine Classifications

5.4.2.1 Classification by Cylinder Arrangement

5.4.2.2 Classification by Cooling Arrangement

5.4.2.3 Classification by Operating Cycle

5.4.2.4 Classification by Ignition Type

5.5 Scaling of Aircraft Reciprocating Engines

5.5.1 Scaling of Aircraft Diesel Engines

5.6 Aircraft Engine Systems

5.6.1 Aviation Fuels and Engine Knock

5.6.2 Carburetion and Fuel Injection Systems

5.6.2.1 Float-Type Carburetors

5.6.2.2 Pressure Injection Carburetors

5.6.2.3 Fuel Injection Systems

5.6.2.4 Full Authority Digital Engine Control (FADEC)

5.6.3 Ignition Systems

5.6.3.1 Battery Ignition Systems

5.6.3.2 High Tension Ignition System

5.6.3.3 Low Tension Ignition System

5.6.3.4 Full Authority Digital Engine Control (FADEC)

5.6.3.5 Ignition Boosters

5.6.3.6 Spark Plugs

5.6.4 Lubrication Systems

5.6.5 Supercharging

5.7 Electric Engines

5.7.1 Electric Motors

5.7.2 Solar cells

5.7.3 Advanced Batteries

5.7.4 Fuel cells

5.7.5 State of the Art for Electric Propulsion – Future Technology

5.8 Propellers and Reduction Gears

References

Problems

6. Aircraft Engine Inlets and Nozzles

6.1 Introduction

6.2 The Flight Mach Number and its Impact on Inlet Duct Geometry

6.3 Diffusers

6.4 An Ideal Diffuser

6.5 Real Diffusers and their Stall Characteristics

6.6 Subsonic Diffuser Performance

6.7 Subsonic Cruise Inlet

6.8 Transition Ducts

6.9 An Interim Summary for Subsonic Inlets

6.10 Supersonic Inlets

6.10.1 Isentropic Convergent–Divergent Inlets

6.10.2 Methods to Start a Supersonic Convergent–Divergent Inlet

6.10.2.1 Overspeeding

6.10.2.2 Kantrowitz–Donaldson Inlet

6.10.2.3 Variable-Throat Isentropic C–D Inlet

6.11 Normal Shock Inlets

6.12 External Compression Inlets

6.12.1 Optimum Ramp Angles

6.12.2 Design and Off-Design Operation

6.13 Variable Geometry—External Compression Inlets

6.13.1 Variable Ramps

6.14 Mixed-Compression Inlets

6.15 Supersonic Inlet Types and their Performance—A Review

6.16 Standards for Supersonic Inlet Recovery

6.17 Exhaust Nozzle

6.18 Gross Thrust

6.19 Nozzle Adiabatic Efficiency

6.20 Nozzle Total Pressure Ratio

6.21 Nozzle Pressure Ratio (NPR) and Critical Nozzle Pressure Ratio (NPRcrit.)

6.22 Relation between Nozzle Figures of Merit, 𝜂n and 𝜋n

6.23 A Convergent Nozzle or a De Laval?

6.24 The Effect of Boundary Layer Formation on Nozzle Internal Performance

6.25 Nozzle Exit Flow Velocity Coefficient

6.26 Effect of Flow Angularity on Gross Thrust

6.27 Nozzle Gross Thrust Coefficient C_fg

6.28 Overexpanded Nozzle Flow—Shock Losses

6.29 Nozzle Area Scheduling, A₈ and A₉/A₈

6.30 Nozzle Exit Area Scheduling, A₉/A₈

6.31 Nozzle Cooling

6.32 Thrust Reverser and Thrust Vectoring

6.33 Hypersonic Nozzle

6.34 Exhaust Mixer and Gross Thrust Gain in a Mixed-Flow Turbofan Engine

6.35 Engine Noise

6.35.1 Subsonic Jet Noise

6.35.2 Chevron Nozzle

6.35.3 Supersonic Jet Noise

6.35.4 Engine Noise Mitigation through Wing Shielding

6.36 Nozzle-Turbine (Structural) Integration

6.37 Summary of Exhaust Systems

References

Problems

7. Combustion Chambers and Afterburners

7.1 Introduction

7.2 Laws Governing Mixture of Gases

7.3 Chemical Reaction and Flame Temperature

7.4 Chemical Equilibrium and Chemical Composition

7.4.1 The Law of Mass Action

7.4.2 Equilibrium Constant KP

7.5 Chemical Kinetics

7.5.1 Ignition and Relight Envelope

7.5.2 Reaction Timescale

7.5.3 Flammability Limits

7.5.4 Flame Speed

7.5.5 Flame Stability

7.5.6 Spontaneous Ignition Delay Time

7.5.7 Combustion-Generated Pollutants

7.6 Combustion Chamber

7.6.1 Combustion Chamber Total Pressure Loss

7.6.2 Combustor Flow Pattern and Temperature Profile

7.6.3 Combustor Liner and its Cooling Methods

7.6.4 Combustion Efficiency

7.6.5 Some Combustor Sizing and Scaling Laws

7.6.6 Afterburner

7.7 Combustion-Generated Pollutants

7.7.1 Greenhouse Gases, CO₂ and H₂O

7.7.2 Carbon Monoxide, CO, and Unburned Hydrocarbons, UHC

7.7.3 Oxides of Nitrogen, NO and NO₂

7.7.4 Smoke

7.7.5 Engine Emission Standards

7.7.6 Low-Emission Combustors

7.7.7 Impact of NO on the Ozone Layer

7.8 Aviation Fuels

7.9 Alternative Jet Fuels (AJFs)

7.9.1 Conversion Pathways to Jet Fuel

7.9.2 AJF Evaluation and Certification/Qualification

7.9.3 Impact of Biofuel on Emissions

7.10 Cryogenic Fuels

7.10.1 Liquefied Natural Gas (LNG)

7.10.1.1 Composition of Natural Gas and LNG

7.10.2 Hydrogen

7.10.2.1 Hydrogen Production

7.10.2.2 Hydrogen Delivery and Storage

7.10.3 Energy Density Comparison

7.11 Combustion Instability: Screech and Rumble

7.11.1 Screech Damper

7.12 Summary

References

Problems

8. Aerodynamics of Axial-Flow Compressors and Fans

8.1 Introduction

8.2 The Geometry

8.3 Rotor and Stator Frames of Reference

8.4 The Euler Turbine Equation

8.5 Axial-Flow Versus Radial-Flow Machines

8.6 Axial-Flow Compressors and Fans

8.6.1 Definition of Flow Angles

8.6.2 Stage Parameters

8.6.3 Cascade Aerodynamics

8.6.4 Aerodynamic Forces on Compressor Blades

8.6.5 Three-Dimensional Flow

8.6.5.1 Blade Vortex Design

8.6.5.2 Three-Dimensional Losses

8.6.5.3 Reynolds Number Effect

8.7 Compressor Performance Map

8.8 Compressor Instability – Stall and Surge

8.9 Multistage Compressors and their Operating Line

8.10 Multistage Compressor Stalling Pressure Rise and Stall Margin

8.11 Multistage Compressor Starting Problem

8.12 The Effect of Inlet Flow Condition on Compressor Performance

8.13 Isometric and Cutaway Views of Axial-Flow Compressor Hardware

8.14 Compressor Design Parameters and Principles

8.14.1 Blade Design – Blade Selection

8.14.2 Compressor Annulus Design

8.14.3 Compressor Stall Margin

8.15 Concepts in Compressor and Fan Noise Mitigation

8.16 Summary

References

Problems

9. Centrifugal Compressor Aerodynamics

9.1 Introduction

9.2 Centrifugal Compressors

9.3 Radial Diffuser

9.4 Inducer

9.5 Inlet Guide Vanes (IGVs) and Inducer-Less Impellers

9.6 Impeller Exit Flow and Blockage Effects

9.7 Efficiency and Performance

9.8 Summary

References

Problems

10. Aerothermodynamics of Gas Turbines

10.1 Introduction

10.2 Axial-Flow Turbines

10.2.1 Optimal Nozzle Exit Swirl Mach Number M𝜃2

10.2.2 Turbine Blade Losses

10.2.2.1 Blade Profile Loss

10.2.2.2 Secondary Flow Losses

10.2.2.3 Annulus Losses

10.2.3 Optimum Solidity

10.2.4 Turbine Cooling

10.2.4.1 Convective Cooling

10.2.4.2 Impingement Cooling

10.2.4.3 Film Cooling

10.2.4.4 Transpiration Cooling

10.3 Turbine Performance Map

10.4 The Effect of Cooling on Turbine Efficiency

10.5 Turbine Blade Profile Design

10.5.1 Angles

10.5.2 Other Blade Geometrical Parameters

10.5.3 Throat Sizing

10.5.4 Throat Reynolds Number Reo

10.5.5 Turbine Blade Profile Design

10.5.6 Blade Vibration and Campbell Diagram

10.5.7 Turbine Blade and Disk Material Selection and Design Criteria

10.6 Stresses in Turbine Blades and Disks and Useful Life Estimation

10.7 Axial-Flow Turbine Design and Practices

10.8 Gas Turbine Design Summary

10.9 Advances in Turbine Material and Cooling

10.10 Summary

References

Problems

11. Aircraft Engine Component Matching and Off-Design Analysis

11.1 Introduction

11.2 Engine (Steady-State) Component Matching

11.2.1 Engine Corrected Parameters

11.2.2 Inlet-Compressor Matching

11.2.3 Compressor–Combustor Matching

11.2.4 Combustor–Turbine Matching

11.2.5 Compressor–Turbine Matching and Gas Generator Pumping Characteristics

11.2.5.1 Gas Generator Pumping Characteristics

11.2.6 Turbine–Afterburner (Variable-Geometry) Nozzle Matching

11.2.6.1 Fixed-Geometry Convergent Nozzle Matching

11.3 Engine Off-Design Analysis

11.3.1 Off-Design Analysis of a Turbojet Engine

11.3.2 Off-Design Analysis of an Afterburning Turbojet Engine

11.3.3 Off-Design Analysis of a Separate-Flow Turbofan (Two-Spool) Engine

11.4 Unchoked Nozzles and Other Off-Design Iteration Strategies

11.4.1 Unchoked Exhaust Nozzle

11.4.2 Unchoked Turbine Nozzle

11.4.3 Turbine Efficiency at Off-Design

11.4.4 Variable Gas Properties

11.5 Principles of Engine Performance Testing

11.5.1 Force of Inlet Bellmouth on Engine Thrust Stand

11.5.1.1 Bellmouth Instrumentation

11.5.1.2 The Effect of Fluid Viscosity

11.5.1.3 The Force of Inlet Bellmouth on Engine Thrust Stand

11.6 Summary

References

Problems

12. Chemical Rocket and Hypersonic Propulsion

12.1 Introduction

12.2 From Takeoff to Earth Orbit

12.3 Chemical Rockets

12.4 Chemical Rocket Applications

12.4.1 Launch Engines

12.4.2 Boost Engines

12.4.3 Space Maneuver Engines

12.4.4 Attitude Control and Orbital Correction Rockets

12.5 New Parameters in Rocket Propulsion

12.6 Thrust Coefficient, C_F

12.7 Characteristic Velocity, c*

12.8 Flight Performance

12.9 Multistage Rockets

12.10 Propulsive and Overall Efficiencies

12.11 Chemical Rocket Combustion Chamber

12.11.1 Liquid Propellant Combustion Chambers

12.11.1.1 Some Design Guidelines for Injector Plates

12.11.1.2 Combustion Instabilities

12.11.2 Solid Propellant Combustion Chambers

12.12 Thrust Chamber Cooling

12.12.1 Liquid Propellant Thrust Chambers

12.12.2 Cooling of Solid Propellant Thrust Chambers

12.13 Combustor Volume and Shape

12.14 Rocket Nozzles

12.14.1 Multiphase Flow in Rocket Nozzles

12.14.2 Flow Expansion in Rocket Nozzles

12.14.3 Thrust Vectoring Nozzles

12.15 High-Speed Airbreathing Engines

12.15.1 Supersonic Combustion Ramjet

12.15.1.1 Inlet Analysis

12.15.1.2 Scramjet Combustor

12.15.1.3 Scramjet Nozzle

12.16 Rocket-Based Airbreathing Propulsion

12.17 Compact Fusion Reactor: The Path to Clean, Unlimited Energy

12.18 Summary

References

Problems