PME 5142
Jet Propulsion
Course Offered in English
NTHU 2024-2025 Academic Calendar
Hsiao-Wei David Chiang
09/13/2024
Homework#1 (09/13 due)
A 747 aircraft is cruising at Mz=0.85. The 2.38 meter diameter fan is
rotating at 3888 rpm. Please calculate the relative tip Mach number Mtip
through the fan blade to see whether supersonic flow exists through the
fan blade. If it is supersonic flow, first draw a velocity triangle
(including Mz, Mtip, and MT) and then calculate Mtip. (speed of
sound=340m/s)
MZ
MT
Mtip
M=0.85
Saeed Farokhi, PhD
School of Engineering –
Aerospace Engineering Professor
sfarokhi@ku.edu
Primary office:
785-864-2966
2120D Learned Hall
University of Kansas
1530 West 15th Street
Lawrence, KS 66045 3
Table of Contents
Chapter 1. Introduction
Chapter 2. Gas Dynamics
Chapter 3. Engine Thrust and
Performance Parameters
Chapter 4. Gas Turbine Engine Cycle
Analysis
Chapter 5 Conclusion
Aerospace Propulsion Systems Thomas A. Ward
© 2010 John Wiley & Sons (Asia) Pte Ltd 1-4
Aircraft Propulsion
CHAPTER 1 – INTRODUCTION :
PROPULSION IN SUSTAINABLE AVIATION
Table of Contents
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 New Engine Concepts
1.3.1 Advanced Turboprop (ATP) and Geared Turbofan (GTF)
1.3.2 Advanced Airbreathing Rocket Technology
1.3.3 Wave Rotor Topping Cycle
1.3.3.1 Humphrey Cycle versus Brayton Cycle
1.3.4 Pulse Detonation Engine (PDE)
1.3.5 Millimeter-Scale Gas Turbine Engines: Triumph of MEMS and Digital Fabrication
1.3.6 Combined Cycle Propulsion: Engines from Takeoff to Space
1.4 New Vehicles
1.5 Summary
1.6 Roadmap for the Second Edition
Aerospace Propulsion Systems Thomas A. Ward
© 2010 John Wiley & Sons (Asia) Pte Ltd 1-6
• ±20° vector thrust in F119 engine developed by Pratt
& Whitney for F-22 “supercruise” aircraft.
• GE video to show a
variable-geometry nozzle
and multitasked in modern
designs.
Table of Contents
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 New Engine Concepts
1.3.1 Advanced Turboprop (ATP) and Geared Turbofan (GTF)
1.3.2 Advanced Airbreathing Rocket Technology
1.3.3 Wave Rotor Topping Cycle
1.3.3.1 Humphrey Cycle versus Brayton Cycle
1.3.4 Pulse Detonation Engine (PDE)
1.3.5 Millimeter-Scale Gas Turbine Engines: Triumph of MEMS and Digital Fabrication
1.3.6 Combined Cycle Propulsion: Engines from Takeoff to Space
1.4 New Vehicles
1.5 Summary
1.6 Roadmap for the Second Edition
Aerospace Propulsion Systems Thomas A. Ward
© 2010 John Wiley & Sons (Asia) Pte Ltd 1-9
1.3 New Engine Concepts
1. Advanced TurboProp (ATP) and Geared TurboFan
(GTF) engines.
- ATP pushes turboprops from low speed flight into
high subsonic cruise Mach numbers (M0~0.8) and
- GTF to use a gearbox and achieve high-efficiency
Ultra-High Bypass (UHB) ratio capability.
12
1.3.1 Advanced Turboprop (ATP)
• Conventional propellers lose thrust capability when
their tip operates in supersonic flow and stalls.
• Pratt & Whitney/Allison, GE Aviation, and NASA
collaborated in developing technology of advanced
turboprop engines in the 1970s and 1980s.
1.3.1 Advanced Turboprop (ATP)
• Generally called Propfan, while GE’s gearless,
direct-drive ATP called Unducted Fan (UDF).
• ATP’s operate with relative supersonic tip Mach
number (MT ~ 1.1—1.15) without stalling!
• With increasing relative tip Mach number capability,
cruise flight Mach no. increased to M0~0.8-0.82.
• The General Electric GE36 was an experimental
aircraft engine, a hybrid between a turbofan and a
turboprop, known as an unducted fan (UDF) or
propfan.
• The GE36 was developed by General Electric
Aircraft Engines, with its CFM International equal
partner Snecma taking a 35% share of development.
1.3.1 Advanced Turboprop (ATP)
• Several configurations in co- and counterrotating
propeller sets and pusher vs tractor configurations
were developed and tested.
• The advanced propellers are highly swept at the tip
(between 30-40°) to improve tip efficiency at high
relative Mach numbers.
Sweeping The Wing Back Delays Supersonic Flow
•A swept wing just looks like it has less drag. Explaining why is
more difficult - and the answer may surprise you.
•Sweeping the wings makes the wing feel like it's flying slower.
•That, in turn, delays the onset of supersonic airflow over the
wing - which delays wave drag.
•But it's not all benefit - there's a hefty price which shows up at
slow speeds. Flying Almost Supersonic Means The Air's
Going Supersonic
Sweeping The Wing Back Delays Supersonic Flow
•How does wing sweep help prevent wave drag? It delays the
start of supersonic flow, by reducing the amount of acceleration
over the wing.
•On a straight wing airplane, all of the airflow over the wing
travels parallel to the aircraft's chord line.
•But, on a swept wing, only some of the air flows parallel to the
chord line. The other part flows perpendicular to the chord -
this is called spanwise flow.
UDF – UnDucted Fan
• first-class cabin was installed inside the aft fuselage
for airline executives to experience first-hand.
• "Demo Aircraft" concluded in 1988, demonstrating
30% reduction in fuel burn over turbo-fan powered
MD-80, full Stage III noise compliance.
Prop powered Boeing 727
amazing sound on low level
flypast air-to-air (2:31)
https://www.youtube.com/watch?v
=APzO7OVGakw
UDF – UnDucted Fan
• Due to jet-fuel price drops and shifting
marketing priorities, Douglas shelved the
program the following year.
20 years later
CFM Details Open-Fan Plan For Next-gen Engine
• Open Fan aimed at 20,000-35,000-lb.-thrust sector
• Flight tests targeted by 2025
The open fan puller engine has a single rotating stage and a second
nonrotating set of variable-pitch stators. Credit: CFM Concept
Safran Counter-rotating Open Rotor To
Complete Ground Tests
Counter-rotating open rotor (CROR) engine architecture with bypass
ratio in 30+ range features 12 front and 10 aft rotor blades, 4m diameter
and 100-kN (22,000 lbf) thrust @ takeoff (SSL) (Safran Aircraft Engines)
33
BPR=5.15
BPR=9.00
777 747
777 vs 747
GE's Big Bet on Goliath Engines
6:44
(1645) GE's Big Bet on Goliath
Engines - YouTube
