Transcript Lesson 1 EGR 4347 - Baylor School of Engineering

EGR 4347 - Analysis and Design of
Propulsion Systems
Dr. Ken Van Treuren
Department of Engineering
Baylor University
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BEGINNINGS
Date: 17 December 1903
Location: Kitty Hawk, North Carolina
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Faster -- Higher -- Farther
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Prevailing Thoughts
“In its present state, and even considering
the improvements possible in adopting the
higher temperatures proposed for the
immediate future, the gas turbine could
hardly be considered a feasible application
of airplanes, mainly because of the
difficulty in complying with the stringent
weight requirements imposed by
aeronautics.”
National Academy of Sciences - Late 1930’s
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Sir Frank Whittle (1941)
W.1
Gloster E28/29
Experimental Aircraft
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Hans von Ohain (1937)
HeS 3B
He 178
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1940’s
Jumo 004
World’s 1st mass produced turbojet
http://www.soton.ac.uk/~aeroastr/4projects/Genesis/Level2/Engines/Jumo4.htm
ME 262
http://www.iag.net/~emccann/models/me262rec.htm
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1950’s
J-79
http://www.seattleu.edu/~jmatt/pictures/J79.gif
F-4E
http://www.wpafb.af.mil/museum/research/fighter/f4e-18.jpg
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1960’s
TF-39
http://www.seattleu.edu/~jmatt/pictures/TF39.gif
C5A
http://www.primenet.com/~gbe/Midway/C5A_Galaxy.htm
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1970’s
F100
F-15
http://www.wpafb.af.mil/museum/modern_flight/mf21b.htm
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1980’s-1990’s
F-119
F-22
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1990’s - 2000’s
YF-120, with
axisymmetric vectoring
nozzle
http://www.aeroworldnet.com/fth15.htm
JSF
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2002+
X-43, Hypersonic
Research Vehicle
Uninhabited Combat
Air Vehicle (UCAV)
http://popularmechanics.com/popmech/sci/tech/9709TUMIAM.html
Predator, Medium
Altitude Endurance UAV
http://www.fas.org/irp/agency/daro/uav95/gifs/predcomp.gif
Global Hawk, High-Alt Long
Endurance Aerial Recon UAV
Dark Star, LO High
Endurance UAV
http://www.fas.org/irp/program/collect/darkstar.htm
http://defenselink.dtic.mil/photos/Feb1997/970220-D-0000G-001.html
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2002+
Space Launch Initiative (SLI)
Airbus A-380
Aviation Week & Space Technology,
April 1, 2002, p28
Aerospace Engineering,
March 2001, p7
Boeing Sonic Cruiser
Aviation Week & Space Technology,
April 15, 2002, p69
B-X Supersonic
“Quiet” Bomber
Aviation Week & Space Technology,
May 6, 2002, p28
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M400 Skycar
Mechanical Engineering,
May 2001, p96
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Basic Turbine Engine Components
Compressor
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Turbine
Combustor
Nozzle
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Turbojet
• Advantages
–
–
–
–
Few Moving Parts
Large Operating Envelope
Static Thrust
Small Frontal Area
• Disadvantages
–
–
–
–
–
Large Number of Parts
Expensive
Low Thrust at Low Mach
High noise
High TSFC
• Application - broad range
J-79
– Small Mass to High Velocity
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Turbojet - Applications
SR-71
Harpoon
(TJ+solid fuel booster)
Concorde
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F-4
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Low Bypass Ratio Turbofan
•
•
Advantages
– Few Moving Parts
– Large Operating Envelope
– More Static Thrust
– Better Subsonic TSFC
– FOD protection of HPC
– Large Afterburner Possible
– Low Noise
Disadvantages
–
–
–
–
–
•
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Large Number of Parts
Expensive
Medium Frontal Area
Engine Response
Air Start
Application - medium mass to medium
velocity
F100
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Low Bypass Ratio Turbofan - Applications
YF-22
Tomahawk
Cruise Missile
UCAV
JSF
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High Bypass Ratio Turbofan
GE-90
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High Bypass Ratio Turbofan - Applications
A-10
KC-10
C-5A
777
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Turboprop/Turboshaft
T-800
• Advantages
–
–
–
–
–
–
–
Few Moving Parts
Large Operating Envelope
Best Static Thrust
Best Low Subsonic TSFC
Constant RPM Possible
Low Noise
Propeller Reverse
• Disadvantages
–
–
–
–
–
Large Number of Parts
Expensive
Complex Gearbox
Large Frontal Area
Propeller Governor
T-56
• Application - Low Mach (Large mass
to low velocity)
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Turboprop/Turboshaft - Applications
Saab 2000
C-130
V-22
RAH-66 Comanche
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Ramjet/SCRAMjet
• Advantages
–
–
–
–
No moving parts
Simple
Inexpensive
Small frontal area
Liquid Propellant Ramjet
Solid Fuel Ramrocket at Launch - Rocket Mode
• Disadvantages
– No accessory drive
– Optimized for design condition
– No static thrust
• Application High Mach
– Bomarc missle
– Future missles
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SCRAMjet (StrutJet)
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Ramjet/SCRAMjet - Applications
Fasthawk
Hyper -X
Bomarc
D-21 Drone
Hypersoar
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Principles of Jet Propulsion - Engine
Performance
Installed Performance
Thrust, T
m f
Thrust Specific Fuel Consumption, TSFC 
T
Uninstalled Performance
Thrust, F
m f
Thrust Specific Fuel Consumption, S 
F
Installation losses
Inlet Drag, Dinlet
Nozzle Drag, Dnozzle
Relationships
T = F - Dinlet - Dnozzle = F(1-finlet - fnozzle)
TSFC = S/ (1-finlet - fnozzle)
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Principles of Jet Propulsion - THRUST
Direction of
Movement
Escaping
Air
Opposite force causes
the balloon to move
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Forces removed by
opening the stem
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Principles of Jet Propulsion - THRUST
ma
F= g
c
1 dM
1 d(mV)
=
SF=
gc dt
gc dt
Note: Momentum = M = mV
Force = mass x acceleration
Fn =
m
gc (Vj - Va) + Aj (Pj - Patm)
Net thrust = change in momentum +
pressure force at exit
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Thrust is therefore produced when air exits the
engine faster than when it entered.
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Principles of Jet Propulsion - THRUST
From a thermodynamic perspective, the engine’s job is to convert chemical
energy of the fuel into kinetic energy of the air passing through the engine.
The following engine components enable this energy conversion and determine
the efficiency at which this conversion takes place:
INLET - Converts kinetic energy of entering air into a pressure rise by
decelerating the flow
COMPRESSOR - Increases air pressure to increase combustion cycle efficiency
COMBUSTOR - Add chemical energy to the air to provide power to the turbine
and to produce desired thrust
TURBINE - Extracts energy from the hot gases to drive the compressor and
aircraft accessories
EXHAUST DUCT AND NOZZLE - Collects, straightens, and accelerates the air
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Basic Turbine Engine Components Schematic & Numbering
Gas generator
Inlet
0
Low-pressure
compressor
1
Highpressure
compr
2.5
3
Combustor
H L
P P
T T
4 4.5 5
Nozzle
8
HPT = High-pressure turbine
LPT = Low-pressure turbine
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Static Temperature and Pressure
Variations Through Engine
Static
Temperature
(R)
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3500
350
3000
300
2500
2000
250
200
1500
150
1000
100
500
50
0
0
Static
Pressure
(psia)
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Engine Types
m
F  g (Ve - Vi)
c
Turbojet - large velocity change
Low Bypass Ratio Turbofan - large velocity change & increased mass flow
High Bypass Ratio Turbofan - very large mass flow & small velocity increases
Turboprop - energy extracted by a low pressure turbine drives a gear box which
runs a prop. Large mass flow, very small velocity change through prop
Turboshaft (similar to turboprop) - runs a rotor or power producing shaft
Ramjet - M>1 applications, large mass flow & small velocity increase
SCRAMjet - M>5 applications, very large mass flow & small velocity increase
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Engine Performance Characteristics
Specific Thrust Characteristics of Typical Engines
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Thrust/Airflow (lbf/lbm/s)
100
80
60
40
Turboprop
High BPR TF
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Turbojet
Ramjet
Low BPR TF
0
0
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0.5
1
1.5
2
2.5
3
Aircraft Mach Number (-)
3.5
4
4.5
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Engine Performance Characteristics
Thrust Specific Fuel Consumption Characteristics of Typical Engines
Thrust Specific Fuel Consumption (lb m/hr/lbf)
3
2.5
2
1.5
1
Turboprop
High BPR TF
0.5
Low BPR TF
Turbojet
Ramjet
0
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
Aircraft Mach Number (-)
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