Jet Engine Operation As An Integrated System INME5702 Class 1 Bob McGurgan Pratt

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Jet Engine OperationAs An Integrated
SystemINME5702Class 1Bob McGurganPratt
Whitney
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Agenda For Class 1

• Course Objectives and Description
• Course Norms
• Jet Engine Components and Their Functions
• Design vs. Off-Design
• Compressor Operating Lines As Indicators of
  System Behavior
• How We Will Learn About System Behavior

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INME5702 Course Objective
INME5701, Cycle Analysis, examines engine cycle
definition and optimization.

• Turbine Inlet Temperature
• Bypass Ratio
• Compressor Pressure Ratio
• Fan Pressure Ratio

Cycle Definition
Airflow size
Thrust A/C Drag
Turbine Nozzles
Primary Exhaust Nozzle
Fan Exhaust Nozzle
Key Areas
DESIGN SETS FLOW PATH GEOMETRY
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Course Objective
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Course Objective
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At the End of the Semester You Should Be Able To

• Know where to begin and what path to take in
  analyzing engine performance data.
• Recommend component or configuration changes to
  improve the performance of an existing model.
• Identify critical operating regions which need to
  be defined for a new or modified engine design.
• Interpret and verify detailed simulation computer
  model calculations.
• Determine root causes of performance and
  operability escapes.

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Class Norms

• Complete and submit all homework assignments on
  time. Later course material builds on early
  classes.
• Do not fall behind !!
• Ask questions your enjoyment and the learning
  you accomplish will both benefit.
• Do your own work.
• Discussion of assignments, lectures, and course
  content is encouraged, but do your own work.
• Use email to contact me. My practice will be to
  send both questions and responses to the entire
  class, as though the questions are asked in
  class.

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Class Norms

• Please do the following today
• Send an email to
• robert.mcgurgan_at_pw.utc.com
• ute.winebrenner_at_pw.utc.com
• Identify the email address you want to use for
  communications about the class.

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Class Norms

• Grading
• 3 Quizzes 30 Weight in Final Grade
• Mid-Term Exam 30
• Final Exam 40
• Homework will be used to influence borderline
  grades.
• Success in quizzes and exams will follow from
  careful attention to homework.

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Jet Engine Operation as an Integrated System
(Course INME5702)
MODULE 2
MODULE 3
MODULE 4
MODULE 6
MODULE 1
MODULE 5
Course Preview
(4) Equilibrium Systems
(7) Twin-spool turbojet Development of constraints
(10) Turbofan Development of constraints
(13) Transient Development of constraints
(16) Mixed-Flow Common Nozzle Configurations
(1) Definitions and objectives
(5) Single-spool Turbojet as Equilibrium System
(14) Transient exercise
(17) Unchoked Nozzle Effects
(11) Turbofan Graphical solution
(8) Twin-spool turbojet Graphical solution
(2) Flow Parameters
(15) Control and Operability Requirements
(18) Industrial Gas Trends
(6) Single-spool Turbojet Graphical solution
(12) Turbofan Analysis of change effects
(3) Component maps
(9) Twin-spool turbojet Analysis of change effects
(19) Mathematical Solution Techniques
QUIZ 3
QUIZ 1
QUIZ 2
FINAL EXAM
EXAM 1
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OVERALL COURSE OUTLINE
INTRODUCTION
GENERAL EQUILIBRIUM PRINCIPLES FOR PHYSICAL
SYSTEMS
SIMPLIFIED TURBOJET
SINGLE SPOOL TURBOJET WITH MAPS
TWIN-SPOOL TURBOJET
BUILDING FROM SIMPLE
TO MORE COMPLEX
FAN- HI TURBOFAN
FAN-LO-HI TURBOFAN
TRANSIENT / MIXING/NOZZLE UNCHOKING
COURSE WRAP-UP
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SINGLE-SPOOL TURBOJET
DUAL-SPOOL TURBOJET
FAN-HI TURBOFAN
FAN-LO-HI TURBOFAN
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Here Is a Typical System That We Will Study A
Two-Spool, Turbofan Engine
Can you name the 9 components that comprise the
system and define their functions ?
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Here are the 9 components. Two next three slides
define their functions. Study this material
thoroughly !! There will be a closed-book quiz
during the semester.
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Turbofan Components and Their Functions

• Component Function
• Inlet Decelerates incoming air to supply
  conditions required at the engine face.
• Kinetic energy decreases, thermal
  enegry increases. Total Pressure loss is
  minimized.
• Low Pressure Compressor Pressurizes incoming air.
  
• High Pressure Compressor Pressurizes incoming
  air.
• Combustor ( Burner ) Converts fuel energy to
  thermal energy.
• High Pressure Turbine Drives HPC by extracting
  energy from incoming air. Air expands,
  pressure drops, energy is transferred to the
  HPC through the high spool.

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Turbofan Components and Their Functions

• Component Function
• Low Pressure Turbine Drives LPC by extracting
  energy from incoming air. Air expands,
  pressure drops, energy is transferred to the
  LPC through the low spool.
• Primary Exhaust Nozzle Converts incoming thermal
  energy to velocity and so produces thrust.
• Fan Pressurizes incoming air
• Fan Fxhaust Nozzle Converts incoming thermal
  energy to velocity and so produces thrust.

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The h-s Diagram Shows the Energy History of Each
lbm of Air That Passes Through The Engine and
Indicates Component Functions.
BYPASS STREAM
CORE STREAM
1 ?qREJ, FAN INLET
2 ?qREJ, FAN
ETRANSFER
3 ?qREJ, ?P125 14
P14
P125
4 ?qREJ, BYPASS NOZZLE
h
h
?gREJ, FAN TURB
P12
4
3
?gREJ, CORE NOZZLE
2
1
S
S
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• Design vs. Off-Design
• Jet engines are designed to a complex set of
  requirements.
• Mission Military vs. commercial, long-range vs.
  short range.
• Operating Environment Sea Level, hot-day to
  high-altitude.
• Operating Range Starting from zero-speed to
  full-power takeoff.
• It is not possible to optimize the system for all
  of these requirements, so each engine is designed
  provide a best overall compromise for its
  particular application. The resulting flow path,
  turbomachinery, and subsystems are known as the
  engine design. Often a single critical point in
  the operating regime of the engine is designated
  the design point.
• Tests are then conducted to assure that the
  off-design operation of the engine is acceptable
  
• Operates reliably.
• Has adequate fuel consumption.
• Meets applicable noise regulations.
• Has sufficient structural integrity

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AN ENGINES HISTORY.
ABOUT FIVE YEARS CONCEPT
DESIGN DETAILED DESIGN HARDWARE
FABRICATION DEVELOPMENT TESTS
FLIGHT TESTING
FAA ACCEPTANCE TESTS
BILL-OF MATERIAL
INTRODUCTION TO SERVICE

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Example of Design vs. Off-Design
This Fan is designed to provide maximum
efficiency at the Design Point.
h Fan
Efficiency decreases as the fan moves to points
either above or below its design point.
Design Point Level of Corrected Air Flow
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Design vs. Off-Design

• Any time the system functions with either an
  input or a characteristic that is different from
  its design level, the system is said to be
  operating off-design.

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DESIGN VS. OFF-DESIGN
Station 2.0 12.5 3.0
4.0 5.0
TEMPERATURES
519
1245
635
1287
2168
AT DESIGN Pressures, Temperatures, Airflows, RPMs
Fuel flow
Wf8129
FAN EXHAUST NOZZLE
FAN
COMBUSTOR
519o R
CORE EXHAUST NOZZLE
Ambient
LPC
HPT
HPC
INLET
LPT
14.7 psia
RPM211485
RPM17376
26.9
270.8
254.6
PRESSURES
14.7
24.8
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DESIGN VS. OFF-DESIGN
Station 2.0 12.5
3.0 4.0
5.0
TEMPERATURES
519
635
1287
2168
1245
AT DESIGN Pressures, Temperatures, Airflows, RPMs
Fuel flow
Wf 8129
FAN EXHAUST NOZZLE
FAN
COMBUSTOR
519o R
CORE EXHAUST NOZZLE
Ambient
LPC
HPC
LPT
INLET
HPT
14.7 psia
RPM211485
RPM17376
PRESSURES
26.9
270.8
254.6
24.8
14.7
Same Hardware

• Different
• Fuel Flow (Throttle)
• Other external influences

90 Wf
Station 2.0 12.5
3.0 4.0
5.0
TEMPERATURES
519
626
1257
2108
1216
AT OFF-DESIGN Pressures, Temperatures, Airflows, R
PMs Fuel flow
Wf 7316
FAN EXHAUST NOZZLE
FAN
COMBUSTOR
519o R
CORE EXHAUST NOZZLE
Ambient
LPC
INLET
HPC
LPT
HPT
14.7 psia
RPM211341
RPM17076
PRESSURES
25.9
250.4
235.5
23.6
14.7
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System Inputs and Characteristics
VARIATIONS FROM DESIGN CONDITIONS-

• Off-take bleed

• Power Extraction

• Pressure Loss

• Throttle

• Flight condition
• (Tamb, Pamb,
• Mach No., Humidity)

• Area or efficiency changes

• Efficiency or
• Flow capacity shifts

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OPERATING LINES AS PICTURES OF MATCHING
For Compressors or Fans
Varying Throttle
Stability Limit
Operating Line (Steady-State)
(Design)
(Transient)
Single equilibrium setting
W
Varying System Characteristic
W
(- Referred to standard day ambient conditions)
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OPERATING LINES AS PICTURES OF MATCHING
For reasons which will become clear as the
semester progresses, compressor operating line
levels are often taken as the prime indicator of
engine health, and are often called the engine
match.
Varying System Characteristic
New
Base
W
(- Referred to standard day ambient conditions)
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MATCHING OF COMPRESSOR OPERATING LINES
We speak of operating lines as increased or
decreased, raised or lowered, NOT moving right or
left. Operating line shifts are quoted at
constant flow. The New configuration in this
example has caused this operating line level to
increase.
Varying System Characteristic
W
(- Referred to standard day ambient conditions)
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Consider That The Design Exists at a Single,
Unique Value of All Inputs and at a Fixed Level
of Each System Characteristic, The Design Point
System Model
How would you propose to learn about this system ?
Characteristic 1
y1
Input 1
Output 1
x1
...
Input 2
Output 2
...
...
Characteristic m
ym
Input n
Output p
xm
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Information Can Be Learned About the System By
Varying Its Inputs and Its Characteristics and
Monitoring the System Responses
System Model
Characteristic 1
Base Level
Base
y1
Input 1
Output 1
Modified Level
x1
...
Input 2
Output 2
...
...
Characteristic m
ym
Input n
Output p
xm
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Information Can Be Learned About the System By
Varying Its Inputs and Its Characteristics and
Monitoring the System Responses
System Model
Characteristic 1
y1
Base
Input 1
Modified
Output 1
x1
...
Input 2
Output 2
...
...
Characteristic m
ym
Input n
Output p
xm
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COMPONENTS WORKING TOGETHER MAKE UP THE SYSTEM

• BASIC PHYSICS/THERMODYNAMICS/AERODYNAMICS GOVERN
  COMPONENT OPERATION

(Mixing Balances)



SHAFT

• Inlet RAM
• Isentropic
• compression

• Compressor Maps
• Adiabatic
• compression

• Energy
• Balance

• Turbine Maps
• Adiabatic
• expansion

• Isentropic
• expansion
• Nozzle coefficients

Choked Flow

• MASS CONSERVATION