An Introduction to Aircraft Thermal Management

Cover
Table of Contents
Introduction
CHAPTER 1 Why Aircraft Thermal Management Matters
1.1 Introduction
1.2 Temperature Requirements
1.3 Removing Heat
1.4 Protection
1.5 Increased Importance
1.5.1 Composite Materials
1.5.1.1 Advantages over Metals
1.5.1.2 Disadvantages of Using Composites
1.5.2 Higher Heat Loads
1.5.3 More Electric Aircraft
1.5.3.1 No-Bleed Systems
1.5.3.2 Electric Actuators
1.5.3.3 Challenges
References
CHAPTER 2 Temperature and Thermal-Related Requirements
2.1 Introduct ion
2.2 Outside Ambient Conditions
2.2.1 Climate and Aircraft Performance
2.2.1.1 Standard Day
2.2.1.2 Environmental Envelope
2.2.1.3 Safe Operations
2.2.1.4 Performance
2.2.1.5 Operational Requirements and Limits
2.2.1.6 OAT and Airplane Performance
2.2.1.7 MIL-HDBK-310
2.2.2 Boundary Temperature Calculations
2.2.2.1 Ground
2.2.2.2 Sky
2.2.2.3 Ram Air
2.2.3 Boundary Pressure Calculations
2.2.3.1 Pounds Mass versus Pounds Force
2.2.3.2 Total (Ram) Pressure
2.2.4 Humidity
2.2.5 Solar Flux
2.2.6 Wind Speed
2.3 Pressurized Volume
2.3.1 Passenger Cabin and Flight Deck (Thermal Comfort)
2.3.1.1 Thermal Comfort Parameters
2.3.1.2 Thermal Load
2.3.1.3 Predicted Mean Vote
2.3.1.4 Predicted Percentage Dissatisfied
2.3.2 Cargo Compartments
2.3.3 Equipment
2.4 Unpressurized Area
2.4.1 Fuel
2.4.2 Hydraulics
2.5 Structure
2.5.1 External Bulk
2.5.2 Internal
References
CHAPTER 3 Airplane-Generated Heat Sources
3.1 Introduction
3.2 Occupants
3.2.1 Sensible Heat
3.2.2 Latent Heat
3.2.3 Passengers and Crew
3.2.4 Live Animal Cargo
3.2.5 Avionics and Electrical Equipment
3.3 Flight Controls and Hydraulic Systems
3.3.1 Hydraulic
3.3.2 Electric
3.3.3 Flight Control Thermal Impact
3.4 Lights
3.5 Power Feeders
3.5.1 Electromagnetic Interference
3.5.2 Inductive Loads
3.6 Brakes
3.6.1 Brake Heat Sink
3.6.2 Brake Temperatures
3.6.3 Brake Heating during Successive Missions
3.6.4 MLG Wheel Well
3.6.5 BTMS Selection at Gate Release
3.6.6 Brake Fans
3.6.7 Thrust Reverses
3.6.8 Fuse Plugs
3.7 Environmental Control System
3.7.1 Air Supply
3.7.2 Packs
3.7.3 Fans
3.7.4 Anti-icing/Deicing Systems
References
CHAPTER 4 External Heat Sources
4.1 Introduction
4.2 Solar Heating
4.2.1 The Sun
4.2.2 Incident Solar Load
4.2.3 Time of Day and Surface Orientation
4.2.4 Solar Absorptance and Reflectance
4.2.5 Transmittance
4.2.6 Modeling Terrestrial Radiation
4.2.6.1 Extraterrestrial Radiation
4.2.6.2 Declination Angle
4.2.6.3 Solar Time
4.2.6.4 Zenith Angle
4.2.6.5 Altitude or Elevation Angle
4.2.6.6 Air Mass Model
4.2.6.7 Clear Sky Model
4.3 Aerodynamic Heating
4.3.1 Subsonic Flight
4.3.2 Supersonic Flight
4.4 Lightning
References
CHAPTER 5 Aircraft Heat Sinks
5.1 Introduction
5.2 Ambient Air
5.2.1 Structure and Unpressurized Ambient Cooling
5.2.2 Systems Cooling
5.2.2.1 Ram-Air Systems
5.2.2.2 Skin Heat Exchangers
5.2.2.3 Cabin Exhaust
5.3 Sky
5.4 Fuel
5.4.1 Thermal Capacitance
5.4.2 Fuel Supply Line and Energy Recovery
Reference
CHAPTER 6 Fires and Failures
6.1 Introduction
6.2 Fires
6.2.1 MLG Wheel Well
6.2.2 Engine and APU
6.2.3 Cargo Compartment
6.2.3.1 Class A
6.2.3.2 Class B
6.2.3.3 Class C
6.2.3.4 Class E
6.2.3.5 Class F
6.2.3.6 Cargo Liners
6.2.4 Passenger and Crew Area
6.2.4.1 Prevention
6.2.4.2 Fire Detection
6.2.4.3 Fire Suppression
6.2.5 Electrical/Electronic Bay and Lower Lobe
6.2.5.1 787 Lithium-Ion Battery Fires
6.2.5.2 Why Lithium Ion?
6.2.6 Fuel Tank Fires
6.2.7 External Fuel Fire
6.3 System Failures
6.3.1 Burst Ducts
6.3.2 Leaking Ducts
References
CHAPTER 7 Environmental Control Systems
7.1 Introduction
7.2 Cabin Temperature and Pressure Control
7.2.1 Air Supply (1 to 2)
7.2.1.1 No-Bleed System
7.2.1.2 Ground-Based Operation
7.2.2 Air Conditioning (3)
7.2.2.1 AIR Cycle Machine
7.2.2.2 Vapor Cycle Machine
7.2.2.3 AIR Cycle Versus Vapor Cycle Machine
7.2.3 Air Distribution (4-8)
7.2.3.1 Recirculation System
7.2.3.2 Main Cabin
7.2.3.3 Flight Deck
7.2.4 Cargo Heat and Cargo Air Conditioning
7.2.5 Cabin Pressure Control
7.3 Venting and Chiller Exhaust
7.4 EE Cooling
7.4.1 Active Cooling
7.4.2 Passive Cooling
7.4.3 Flight Critical Equipment
7.5 Protective Systems
7.5.1 Wing Anti-ice
7.5.1.1 Thermal
7.5.1.2 Chemical
7.5.1.3 Mechanical
7.5.2 Engine Anti-ice
7.5.3 Ice Detection
7.5.4 Air Data Sensors
7.5.5 Windshields
References
CHAPTER 8 Thermal Design
8.1 Introduction
8.2 Insulation Types
8.2.1 Fiberglass
8.2.2 Open Cell Foams
8.2.2.1 Polyimide
8.2.2.2 Melamine
8.2.3 Closed Cell Foams
8.2.4 Ceramics
8.2.5 Felt
8.2.6 Aerogels
8.3 Insulation Applications
8.3.1 Fuselage
8.3.2 Ducting and Hot Pack Components
8.3.3 Engine and Auxiliary Power Unit (APU)
8.3.4 Cargo Compartments
8.3.5 Insulation Placement: Heat Source or Receiver
8.4 Surface Coatings and Applications
8.4.1 Low Solar Absorptivity Paints
8.4.2 Low Emissivity Coatings
8.5 Radiation Shields
8.6 Phase-Change Materials
8.7 Intumescent Paints
8.8 Ablation Materials
8.9 Increase Heat Sink
8.9.1 Ram Air
8.9.2 Fuel
8.9.2.1 Fuel Flammability
8.9.2.2 Nitrogen-Generating Systems
8.9.2.3 Systems Cooling
8.9.2.4 Increasing Ambient Cooling
8.10 Reduce Heat Generation
8.11 Spot Cooling
8.11.1 Unpressurized Air
8.11.2 Pressurized Air
8.12 Modify Material
References
CHAPTER 9 Analytical Modeling
9.1 Introduction
9.2 Mathematical Modeling of Heat Transfer
9.2.1 Thermal Resistances
9.2.1.1 Conduction
9.2.1.2 Convection
9.2.1.3 Radiation
9.2.2 Thermal Capacitance
9.2.3 Energy Sources
9.2.4 Mass Transfer (Fluid Flow)
9.2.5 Analytical Modeling Using the Electrical Analogy
9.2.5.1 Series Resistance
9.2.5.2 Parallel Resistance
9.2.5.3 Example: Heat Transfer from an Insulated Hot-Air Duct
9.2.5.4 Iterative Method
9.3 Mathematical Modeling of Airflow Systems
9.3.1 Bernoulli’s Equation
9.3.1.1 Head
9.3.1.2 Gases
9.3.2 Pressure Generation: Fans and Pumps
9.3.2.1 Fan Pressure
9.3.2.2 Pump Head
9.3.3 System Pressure Drop
9.3.3.1 Frictional Losses
9.3.3.2 Loss Coefficients
9.3.4 Flow Calculation
References
CHAPTER 10 Analytical Software
10.1 Introduction
10.2 Thermal/Fluid Systems
10.2.1 SINDA
10.2.2 Computer-Aided Design (CAD) Embedded
10.3 1-D Network Flow
10.3.1 System 1-D CFD
10.3.2 Component 3-D CFD
10.4 Multi-domain/Co-simulation
10.5 Computational Fluid Dynamics
10.5.1 External Flows
10.5.2 Internal Flows
10.5.3 Advantages and Limitations
10.5.4 Expanded Use
10.6 Pre-processing
10.7 Post-processing
10.8 General Programming Environments
10.9 Tool Source
10.9.1 In-house
10.9.2 In-house versus COTS Software
10.9.3 Open Source
10.9.4 Government
10.10 Software Evaluation and Selection
References
CHAPTER 11 Testing
11.1 Introduction
11.2 Identifying the Need
11.2.1 Analytical Uncertainty and Design Margins
11.2.2 Certification Requirements
11.2.3 System Criticality
11.3 Material Thermal and Surface Optical Properties
11.3.1 Thermal Conductivity
11.3.1.1 Guarded Hot Plate
11.3.1.2 Comparative Cut-Bar Method
11.3.1.3 Composite Materials
11.3.2 Specific Heat
11.3.3 Infrared Emissivity and Reflectivity
11.3.4 Solar Absorptance and Reflectance
11.3.5 In-Service Degradation of Properties
11.3.5.1 Materials
11.3.5.2 Surfaces
11.4 FAA Fire Testing
11.4.1 Materials
11.4.1.1 FAA Fire Test Handbook
11.4.1.2 Burn Resistance
11.4.1.3 BurnThrough
11.4.2 Systems
11.4.2.1 Cargo
11.4.2.2 Heat Generation
11.5 Model Validation
11.5.1 Temperatures
11.5.1.1 Thermometers
11.5.1.2 Probes
11.5.2 Fluid Flow and Pressure Drops
11.5.2.1 Pitot Tube
11.5.2.2 Manometers
11.5.2.3 Mechanical Pressure Gauges
11.5.2.4 Electromechanical
11.5.2.5 Hot-Wire Anemometers
11.5.2.6 Ultrasonic Meters
11.6 Testing Boundary Conditions
11.7 Testing Standards and Procedures
11.7.1 Industry Trade Organizations
11.7.2 Engineering Societies
11.7.3 Military
11.8 Systems Testing
11.9 Airplane Testing
11.9.1 Data Extrapolation
References
CHAPTER 12 Military Aircraft Thermal Management
12.1 Introduction
12.2 Commercial Airframes
12.2.1 Advantages
12.2.2 Disadvantages
12.2.3 Military Avionics
12.3 Bombers
12.4 Fighters
12.5 Vertical Lift
12.6 Directed Energy Weapons (DEWs)
References
Nomenclature
About the Author
Index