implications of aero-engine deterioration for a military aircraft's performance

313 Pages·2009·14.65 MB·English

CRANFIELD UNIVERSITY
SCHOOL OF MECHANICAL ENGINEERING
DEPARTMENT OF
PROPULSION, POWER, ENERGY AND
AUTOMOTIVE ENGINEERING
Ph. D. THESIS
ACADEMIC YEAR 1998-99
MUHAMMAD NAEEM
IMPLICATIONS OF AERO-ENGINE
DETERIORATION
FOR A MILITARY AIRCRAFT'S
PERFORMANCE
Supervisor: Professor Riti Singh
April, 1999
ABSTRACT
World developments have led forces become
the to
armed of many countries more
how increasingly financial budgets Major
their
aware of stringent are spent. expenditure
is Some in-service deterioration in
for
military authorities upon aero-engines. any
device, is inevitable. However, its
mechanical such as an aircraft's gas-turbine engine,
depend design
the the
extent and rate upon qualities of and manufacture, as well as on
followed by Each deterioration has
the
maintenance/repair practices users. an adverse
life
the the the thereby
effect on performance and shortens reliable operational of engine
in higher life The life-cycle be
the
resulting cycle costs. adverse effect on cost can reduced
by determining the fuel life-usage by having better knowledge the
realistic and and a of
deterioration Subsequently improvements
effects of each such on operational performance.
be in design
the
can made and manufacture of adversely-affected components as well as
/
to
with respect maintenance repair and operating practices.
For (consisting flight-segments),
a military aircraft's mission-profiles of several
deterioration
the the
using computer simulations, consequences of engine upon aircraft's
fuel life These help in
operational-effectiveness as well as and usage are predicted. will
decisions (such to the from the
making wiser management as whether remove aero-engines
for in
to them the
aircraft maintenance or continue using with some changes aircraft's
deterioration. Hence
the types
mission profile), with various and extents of engine
improved lower life-cycle
the
engine utilization, overall costs and optimal mission
for be
operational effectiveness a squadron of aircraft can achieved.
iii
ACKNOWLEDGEMENTS
I like to take this to thank Pakistan Air Force for
would opportunity my sponsor,
Cranfield University, UK.
the to
giving me chance study abroad at
Much thanks to Professor Riti Singh for his
appreciation and supervision, guidance,
help throughout the this thesis.
and support preparation of
I Dr. John Fielding College Aeronautics,
wish to express thanks to of the of
Cranfield University, for his the development the
guidance concerning of aircraft's
Dr. Pericles Pilidis
mission-profile and the performance-simulation model, and to of
School Mechanical Engineering, Cranfield University, for his instruction the
of on use of
'Turbomatch'. Many Dr.
thanks to
the engine-performance simulation computer program
John Nicholas the School Industrial Manufacturing Science Professor R. A.
of of and and
Cookson School Mechanical Engineering, both Cranfield University for their
of the of of
development for HPT blade's
the the
guidance concerning of computer model predicting a
life-usage.
Also thanks to Professor D. Probert the School
many are expressed of of
Mechanical Engineering, Cranfield University for his in
guidance writing skills.
Finally, I Farida, daughter Fatima
to
am sincerely grateful my parents, my wife and
Umer Ali for
their throughout
sons and sacrifices, patience and prayers my postgraduate
studies.
Cranfield, England Muhammad Naeem
26'h April, 1999.
iv
TABLE OF CONTENTS
Section Title Page
Abstract ii
Acknowledgements iii
Table Contents iv
of
Abbreviations Nomenclature
and x
List Figures
of xiv
List Tables
of
xxxi
Glossary Jargon
and xxxiv
Chapter I Introduction
1.0 Background I
1.1 Role Engineering Analysis 3
of
1.2 Analysis Strategy 3
1.3 Thesis Structure 3
Chapter 2 En2ine Deterioration
2.0 Introduction 5
2.1 Performance Deterioration Gas-Turbines 5
of
2.2 Types Deterioration 6
of
2.2.1 Recoverable Deterioration 6
2.2.2 Non-Recoverable Deterioration Despite
Cleaning Washing 6
and
2.2.3 Permanent Performance Deterioration 6
2.3 Rate Deterioration 7
of
2.4 Causes Deterioration 7
of
2.4.1 Flight Loads 8
2.4.2 Thermal Distortion 8
2.4.3 Erosion 9
2.4.4 Fouling 10
2.4.5 In-Service Damage Abuse 11
and
2.4.6 Type Engine Operation Duty Cycle 11
of or
2.4.7 Maintenance Practices 12
2.5 Component Deterioration 12
2.5.1 Fan Low Pressure Compressor Deterioration 13
or
2.5.2 High Pressure Compressor Deterioration 13
2.5.3 Combustor Deterioration 13
2.5.4 High Pressure Turbine Deterioration 14
2.5.5 Low Pressure Turbine Deterioration 14
2.6 Performance Deterioration Models for The JT9D
Engine's Behaviour
15
V
TABLE OF CONTENTS (CONT)
Title Page
Section
.
2.7 Describing Component-Performance Deterioration 15
2.8 Operating Procedures to Reduce Engine Deterioration 16
2.9 Influence Component-Performance Deterioration 17
of
3 Life-Usag
Chapter
3.0 Introduction 19
3.1 Need for Accurate Life-Assessment 20
3.2 Life-Limiting Failure Modes Aircraft Gas-Turbine
of
Engines 21
3.2.1 Short-Life Failures 21
3.2.2 Non-Localized Damage 21
3.2.3 Localized Damage 22
6.2.3.1 Creep 22
6.2.3.2 Fatigue 22
3.2.4 External Failure-Mechanisms 25
3.3 Potential-Failure Modes 26
3.4 Mission-Cycle Analysis 26
3.5 The Remaining Operational Lifetime 27
3.6 Safety Versus Operating Cost 28
3.6.1 Safety in Civil Aviation 29
3.6.2 Safety in Military Aviation 29
Chapter 4 Computer Modelling Simulation
and
4.0 Introduction 31
4.1 Engine Aircraft Chosen 31
and
4.1.1 F404 Aero-Engine 31
4.1.2 F-18 Aircraft 32
4.2 Computer Modeling 33
4.2.1 Engine-Simulation Program 33
4.2.2 Aircraft's Flight-Path Performance
and
Simulation Program 34
4.2.3 Aircraft Engine Performance-Simulation
and
Program 34
4.2.4 HPT Blade's Life-Usage Prediction Program 35
4.2.5 Computer Programs' Listings 36
4.2.6 Validation 37
4.3 Aircraft's Mission-Profile 38
4.3.1 Mission-Profile Types 38
4.3.2 Variability Mission-Profiles 39
of
vi
TABLE OF CONTENTS (CONT)
Section Title
Page
4.3.3 Assumed Mission-Profile 40
4.3.3.1 Mission-Profile 'A' 40
4.3.3.2 Mission-Profile 'B' 41
4.4 HPT Blade's Material Data 41
4.5 Undertaking the Computer Simulation 42
Chapter 5 Im Engine Deterioration Aircraft's
plications of upon
Op Effectiveness
erational
5.0 Introduction 45
5.1 Aircraft's Operational Effectiveness 45
5.2 Mission's Operational-Effectiveness Index 46
5.3 Discussions Analysis Results 47
and of
5.3.1 Effect Upon Net Specific Thrusts 47
and
5.3.2 Effect Upon the Take-off Phase Performance 48
5.3.3 Effect Upon the Time Taken to Climb 48
5.3.4 Effect Upon Maximum Attainable Mach
the
Number While Cruising Maximum Throttle
at
Setting
48
5.3.5 Effect Upon the Time Taken to Reach Pre-Set
a
Target
49
5.3.6 Effect Upon the Range Covered Until Pre-Set
a
Mission Time
50
5.3.7 Effect Upon the Maximum Attainable Mach
Number With Reheat-On 50
5.3.8 Effect Upon the Total Mission Time 50
5.3.9 Effect Upon the Aircraft's Overall Mission
Operational Effectiveness
51
Chapter 6 Implications Engine Deterioration Fuel-Usag
of on
6.0 Introduction
52
6.1 Why Fuel-Usage Analysis
52
6.2 Discussions Analysis Results 52
and of
6.2.1 Effect Whole Engine's Deterioration 53
of
6.2.2 Effect Engine Component's Deterioration 54
of
6.2.3 Effect Aircraft's Cruising Different Altitude 55
of at
6.2.4 Effect Aircraft's Cruising Different Mach
of
at
Number
56
6.2.5 Effect Reheat-On Duration
57
of
6.2.6 Effect Standard-Day Temperature 58
of
Vil
TABLE OF CONTENTS (CONT)
Page
Section Title
59
6.2.7 Effect Fan's Deterioration
of
6.2.8 Effect Aircraft's Weapon Carrying Capability 60
upon
Chapter 7 Implications Engine Deterioration Upon Creel) Life
of
62
7.0 Introduction
62
7.1 Creep
63
7.2 Larson-Miller Parameter
64
7.3 Mission-Creep Life
64
7.4 Cumulation Creep Damage
of
65
7.5 Stress Analysis
66
7.6 Temperature the Metal Blades
of
67
7.7 Discussions Analysis Results
and of
7.7.1 Effect Whole Engine's Deterioration 67
of
7.7.2 Effect Engine Component's Deterioration 67
of
7.7.3 Effect Aircraft's Cruising Different Altitude 68
at
of
7.7.4 Effect Aircraft's Cruising Different Mach
of at
69
number
7.7.5 Effect Reheat-On Duration 70
of
7.7.6 Effect Standard-Day Temperature 71
of
7.7.7 Effect Fan's Deterioration 72
of
7.7.8 Effect Engine's Design-Point Stress
of and
Rotational Speed 73
Chapter 8 Implications Emine Deterioration Low-Cycle Fatigue Life
of on
74
8.0 Introduction
8.1 Importance Engine Durability 74
of
8.2 Low-Cycle Fatigue 75
8.3 Measuring Low-Cycle Fatigue 76
8.4 Causes Low-Cycle Fatigue 77
of
8.4.1 Centrifugal Loads 77
8.4.2 Thermal Loads 77
8.4.3 Pressure Loads 78
8.5 Variability in Engine's LCF Life Usage 78
an
8.5.1 Factors Affecting LCF Life Usage in Civil
Aviation 78
8.5.2 Factors Affecting LCF Life Usage in Military
Aviation 78
8.6 Aircraft's Gas-Turbine Engine Low-Cycle Fatigue-Life
Consumption 80
8.6.1 Cycle Counting Methods 81
viii
TABLE OF CONTENTS (CONT)
Section Title Page
8.6.1.1 Early Cycle-Counting Methods 82
8.6.1.2 Modem Cycle-Counting Methods 82
8.6.2 Fatigue-Damage Calculation 83
8.6.2.1 The Stress-Life Method 83
8.6.2.2 The Strain-Life Method 84
8.6.3 Cumulative-Damage Laws 86
8.7 Discussions Analysis Results 87
and of
8.7.1 Effect Whole Engine's Deterioration 87
of
8.7.2 Effect Engine Component's Deterioration 88
of
8.7.3 Effect Aircraft's Cruising Different Altitude 99
of at
8.7.4 Effect Aircraft's Cruising Different Mach
of at
90
number
8.7.5 Effect Reheat-On Duration 91
of
8.7.6 Effect Standard-Day Temperature 91
of
8.7.7 Effect Fan's Deterioration 92
of
Chapter 9 Implications Enzine Deterioration Thermal-Fatimue Life
of on
9.0 Introduction 93
9.1 Thermal Fatigue 93
9.2 Equivalent Full Then-nal-Cycle 94
9.3 Discussions Analysis Results 95
and of
9.3.1 Effect Whole Engine's Deterioration 95
of
9.3.2 Effect Engine Component's Deterioration 96
of
9.3.3 Effect Aircraft's Cruising Different Altitude 97
of at
9.3.4 Effect Aircraft's Cruising Different Mach
of at
99
number
9.3.5 Effect Reheat-On Duration 100
of
8.3.6 Effect Standard-Day Temperature 101
of
8.3.7 Effect Fan's Deterioration 102
of
Chapter 10 Discussions Summary Predictions
and of
10.0 Introduction 104
10.1 Thrust Setting Parameter 104
10.2 Temperature Limit Control 105
10.3 Multiple Component Deterioration 105
10.4 Comparing Deteriorated Clean Engines 106
and
10.5 Some Considerations, Assumptions Limitations 106
and
10.6 Statistical Data 108
10.7 Summary Predictions 108
of
ix
TABLE OF CONTENTS (CONT)
Section Title Page
Chapter II Conclusions Recommendations
and
1.1.1 Conclusions 112
11.2 Recommendations 114
References 116
Appendix A Atmospheric Aerodynamic Characteristics 122
and
Appendix B Input Data for Engine Performance Simulation Program 139
Appendix C Input Data for Engine & Aircraft Performance Simulation
Program 147
Appendix D Input Data for HPT Blade's Life Usage Prediction Program 150
Appendix E Output Data for Engine & Aircraft's Performance-Simulation
Program 152
Appendix F Output Data for HPT Blade's Life Usage Prediction Program 162
Figures 163
Tables
270
x
ABBREVIATIONS AND NOMENCLATURE
Abbreviations
A/C Aircraft
ACM Air-combat
manoeuvre
BFM Basic-flight
manoeuvre
CAF Canadian Air Force
cc Contribution
coefficient
CEFF Cooling
effectiveness
CF Centrifugal force
DFD Data-flow diagram
DI Deterioration index
EDI Engine deterioration-index
EFTC Equivalent full thermal-cycle
El Erosion-index
ENG For
whole engine
EOT Engine's
time
operating
EPR Engine's
pressure-ratio
ESDU Engineering Sciences Data Unit
FF Fuel flow (kg
sec-)
F1 Fouling-index
FOD Damage from foreign in
the the
resulting presence of a object engine
GE General Electric
HCF High-cycle fatigue
HP High
pressure
HPC High-pressure
compressor
HPT High-pressure
turbine
IEPR Integrated
engine pressure-ratio
km h-' kilometres hour
per
kN kiloNewton
Kt Knot (or Nautical hour); I Kt 1.15 1.85 kni/hr
mile per mph
LCC Life-cycle
cost
LCF Low-cycle fatigue
LEFM Linear fracture
elastic mechanics
LP Low
pressure
LPC Low-pressure
compressor
LPT Low-pressure
turbine
MOE Mission's
operational-effectiveness
Miles hour
mph per
NT Net (kN)
thrust