Document
Aircraft Electric Propulsion Systems: Applied Research at NASA
Sean Clarke, P.E.
Senior Systems Development Engineer, CEPT Principal Investigator Aeronautics Research Mission Directorate, Armstrong Flight Research Center 2015 IEEE Transportation Electrification Conference and Expo, Dearborn, Michigan, June 17, 2015 Graphic: NASA/Maria Werries
Who is NASA Aeronautics?
Engineers, pilots, managers, programmers -- we are proud of our legacy of technology contributions to aviation.
Why is aviation so important?
The air transportation system is critical to U.S. economic vitality.
$1.5 TRILLION
TOTAL U.S. ECONOMIC ACTIVITY ( civil aviation - related goods and services, 2012)
$75.1 BILLION
POSITIVE TRADE BALANCE ( aerospace industry, 2013 )
11.8 MILLION
DIRECT AND INDIRECT JOBS ( civil and general aviation, 2012 ) ($847.1 BILLION)
5.4%
OF TOTAL U.S. GROSS DOMESTIC PRODUCT (GDP) (civil and general aviation, 2012)
Why should I care?
Take the system view. You may not have flown today but something you needed did.
17.7 BILLION
TONS OF FREIGHT TRANSPORTED BY AIR (all U.S. carriers, 2013)
$670.8 BILLION
SPENT BY AIR TRAVELERS IN U.S. ECONOMY (domestic and foreign travelers, 2012)
741 MILLION
PASSENGERS ON U.S. CARRIERS (domestic and foreign, 2013)
What are the challenges?
Challenges are driven by emerging global trends.
16 BILLION
GALLONS OF JET FUEL BURNED IN 2013 (U.S. airlines)
$8.1 BILLION
COST OF DELAYS TO U.S. AIRLINES IN 2013
$9.3 BILLION
SPENT BY AIRPORTS ON NOISE ABATEMENT SINCE 1982 AND
3%
5%
OF GLOBAL CO WARMING EFFECTS PROJECTED FROM AVIATION BY
360 MILLION
PASSENGERS BEING ADDED IN ASIA PACIFIC FROM 2009 TO 2014 (market is growing and moving East)
Has NASA Aeronautics made a difference?
NASA - developed technology is on board every U.S. commercial aircraft and control tower.
+ NASA STRUCTURAL ANALYSIS (NASTRAN) + COMPUTATIONAL FLUID DYNAMICS (CFD) – 1970s - Today – 1960s - Today + AIR TRAFFIC MANAGEMENT + COMPOSITE STRUCTURES + AIRBORNE WIND SHEAR DETECTION • Center TRACON Automation System (CTAS) – 1990s – 1980s - 1990s – 1970s - Today • Traffic Management Advisor (TMA) – 1990s • Surface Management System (SMS) – 2000s • Future Air Traffic Management Concepts Evaluation Tool (FACET) – 2000s + TURBO AE + LIGHTNING PROTECTION STANDARDS – 1990s – 1970s - 1980s + DIGITAL FLY - BY - WIRE – 1960s - 1970s + WINGLETS – 1970s - 1980s + SUPERCRITICAL AIRFOIL – 1960s - 1970s + JET ENGINE + AREA RULE COMBUSTORS – 1950s + GLASS COCKPIT + ICING DETECTION – 1990s - 2000s – 1970s - 1980s – 1990s - 2000s + ENGINE NOZZLE CHEVRONS + DAMAGE - TOLERANT FAN CASING – 1990s - 2000s – 2000s - Today + WIND TUNNELS – 1930s - Today + RUNWAY GROOVES – 1960s - 1980s
Where do we see NASA’s benefits today?
NASA’s research has positive impacts on the aviation industry, government and the flying public.
NASA technologies tech transfer 16% to 20 % more fuel efficient & • Advanced composite structures • Chevrons reduced CO emissions • Laminar flow aerodynamics 28 % to 30% reduction in NO emissions • Advanced CFD and numeric simulation tools x Boeing 787 • Advanced ice protection system 30% to 60 % smaller noise footprint Source: Boeing Boeing 747 - 8 NASA technologies 15% to 16 % reduction in fuel • Low NOx combustors burn/reduced C0 emissions • Low pressure turbine blade materials 2 tech transfer • Fan aerodynamic and acoustic 50% reduction in NO emissions x measurements P&W PurePower 1000G Geared Turbofan • Low noise, high efficiency fan design 15 dB to 20dB noise reduction • Ultra High Bypass technology • High pressure turbine shroud materials CFM LEAP - 1B Sources: CFM and Pratt & Whitney • Acoustics modeling and simulation tools NASA technologies • Potential for $300M jet fuel savings per year • Reduced delays, noise and emissions • Massive datasets • High - end computing • Increased identification of safety - related tech transfer • Data mining algorithms incidents • Knowledge discovery of anomalies • S haring of safety - related trends across airlines • Human - in - the - loop simulations • Reduced rate of incidents system wide • Automated decision support tools • Trajectory and arrival modeling Sources: FAA and Southwest Airlines
What does NASA Aeronautics do?
NASA is with you when you fly.
What vision has NASA set for aviation?
A revolution in sustainable global air mobility.
TRANSFORMATIVE
On Demand Fast
SUSTAINABLE
Low Carbon Intelligent
GLOBAL
Safety, NextGen Efficiency, Environment
What is NASA Aeronautics working on?
Our research continues to show how we’re with you when you fly.
Air traffic management tools that reduce delays and save fuel A lower sonic boom to possibly enable supersonic flight over land Ultra - efficient commercial aircraft Transition to low - carbon propulsion Technologies to keep aviation safe (sensors, networking, data mining) Safe integration of more autonomy/autonomous functions in the airspace system
What is special about 2015?
March 3, 2015, represents 100 years since the founding of NACA, which became NASA in 1958.
Where can I get NASA Aeronautics news?
The web and Twitter: articles, news releases, images and videos.
www.nasa.gov/aero @ NASAAero
How is NASA improving aviation today?
We are meeting global aviation challenges by using six research thrust areas to organize our research.
Safe, Efficient Growth in Global Operations
• Enable full NextGen and develop technologies to substantially reduce aircraft safety risks
Innovation in Commercial Supersonic Aircraft
• Achieve a low - boom standard
Ultra - Efficient Commercial Vehicles
• Pioneer technologies for big leaps in efficiency and environmental performance
Transition to Low - Carbon Propulsion
• Characterize drop - in alternative fuels and pioneer low - carbon propulsion technology
Real - Time System - Wide Safety Assurance
• Develop an integrated prototype of a real - time safety monitoring and assurance system
Assured Autonomy for Aviation Transformation
• Develop high - impact aviation autonomy applications
Where does NASA aeronautics research happen?
Aeronautics research takes place at four of NASA’s centers.
ARMSTRONG LANGLEY AMES GLENN
Hybrid Electric Propulsion (HEP) Vehicles
Develop and demonstrate technologies that will revolutionize commercial transport
aircraft propulsion and accelerate development of all - electric aircraft architectures
• Why electric?
– Fewer emissions (cleaner skies)
– Less atmospheric heat release (less global warming)
– Quieter flight (community and passenger comfort)
– Better energy conservation (less dependence on fossil fuels)
– More reliable systems (more efficiency and fewer delays)
• Considerable success in development of “all - electric” light GA aircraft
and UAVs
• Creative ideas and technology advances needed to exploit full potential
• NASA can help accelerate key technologies in collaboration with OGAs,
industry, and academia
Projected Timeline to Tech. Readiness Level 6
Technologies benefit more electric and • Turbo/hybrid electric Superconducting all - electric aircraft architectures: distributed propulsion Machines 300 PAX • High - power density electric motors replacing hydraulic actuation • Electrical component and
>10 MW
Propulsion transmission system weight reduction
5 to 10
• Hybrid electric 150 PAX • Turboelectric 150 PAX
MW
• Hybrid electric 100 PAX regional
2 to 5
• Turboelectric distributed propulsion 150 PAX
MW class
• All electric 50 PAX regional (500 mile range) • Hybrid electric 50 PAX regional
1 to 2
• Turboelectric distributed propulsion 100 PAX regional
MW class
• All - electric, full - range general aviation Power Level for Electrical • All - electric and hybrid - electric
kW class
general aviation (limited range)
Today 10 Year 20 Year 30 Year 40 Year
Hybrid Electric Propulsion Vehicles
NASA’s Current Investments
• Advanced Air Transport Technology
– Targets single aisle passenger aircraft – Goal of current work is to develop enabling technologies and to validate vehicle concepts
• Convergent Electric Propulsion Technology
– Targets distributed propulsion vehicle architectures – Flight validation of transformational electric propulsion integration capabilities
• Vertical Lift Hybrid Autonomy
– Targets long range, high endurance rotocraft missions – Goal of current work is to demonstrate cryogenic HEP power system to inform propulsion system models
Possible Future Commercial Large Transport Aircraft
Architectures
Hybrid Electric
Battery Electric Bus (Transmission Turbine Engine Motor Line) Fuel Non - Energy S torage for Prop Power Management Power Fuel Line Fan Both concepts can use either non - superconducting motors or cryogenic superconducting motors
Turboelectric
Electric Bus Motor Turbine Engine Generator (Transmission Line)
NEED
NEW
PHOTO
Non - Energy S torage for Prop Power Management Fuel Power Fan
Estimated Benefits From Systems Studies
SUGAR (baseline Boeing 737 – 800)
• ~60% fuel burn reduction
• ~53% energy use reduction
• 77 to 87% reduction in NOx
• 24 - 31 EPNdB cum noise reduction
N3 – X (baseline Boeing 777 – 200)
• ~63% energy use reduction
• ~90% NOx reduction
• 32 - 64 EPNdB cum noise reduction
CEPT (baseline Tecnam P2006T)
• 5x lower energy use
• 30% DOC Reduction
• 1 5 dB lower community noise
• Propulsion redundancy, improved ride quality,
and control robustness
Investment in Hybrid and Turbo - Electric
Aircraft Technologies
High Efficiency, Efficient, Low High Power Density Noise Propulsors Electric Machines Integrated Vehicles & Concepts Evaluation Boundary - Layer Ingestion Systems Highly Efficient Flightweight Power Gas Generator Mgt. & Electronics
Flightweight Power Management and Electronics
Lightweight power Superconducting transmission transmission line • Multi - megawatt aircraft propulsion power system architecture • Power management, distribution and control at MW and subscale (kW) levels • Integrated thermal management and motor Integrated motor w/ high power density power electronics control schemes Lightweight • Flightweight conductors, advanced magnetic Cryocooler materials and insulators Lightweight power electronics Distributed propulsion control and power systems architectures
High Efficiency, High Power Density Electric
Machines
Low A/C loss High thermal conductivity stator coil insulation superconducting filament • Develop High efficiency, high specific power electric machines Cryogenic , superconducting motors for farther term Non - superconducting motors for near and intermediate term Superconducting electromagnetic model • Advance Materials and manufacturing technologies • Design and test 1 MW non - superconducting electric motors starting in FY2015 Normal conductor 1 - MW rim - driven motor/fan Flux density for rim - driven motor Fully superconducting motor
Enabling System Testing & Validation
hardware - in - the - loop electrical grid • Develop Megawatt Power System Testbed and Modeling Capability Fully cryogenic motor testing NASA GRC • Key Performance Parameter - driven requirements definition and portfolio management • Technology demonstration at multiple scales • Identification of system - level issues early • Develop validated tools and data that industry and future government projects can use for further development Integrated thermal management system Energy GTE Rectifier storage Electrical distribution VF motor/ Gen.
Load Engine Research Testbed controls inverter simulator controls Motor FD&C controls simulator Eventual flight simulation testing at NASA Armstrong Flight Research Center Integrated controls
Projected Timeline to Tech. Readiness Level 6
Technologies benefit more electric and • Turbo/hybrid electric Superconducting all - electric aircraft architectures: distributed propulsion Machines 300 PAX • High - power density electric motors replacing hydraulic actuation • Electrical component and
>10 MW
Propulsion transmission system weight reduction
5 to 10
• Hybrid electric 150 PAX • Turboelectric 150 PAX
MW
• Hybrid electric 100 PAX regional
2 to 5
• Turboelectric distributed propulsion 150 PAX
MW class
• All electric 50 PAX regional (500 mile range) • Hybrid electric 50 PAX regional
1 to 2
• Turboelectric distributed propulsion 100 PAX regional
MW class
• All - electric, full - range general aviation Power Level for Electrical • All - electric and hybrid - electric
kW class
general aviation (limited range)
Today 10 Year 20 Year 30 Year 40 Year
Armstrong Electric Propulsion Roadmap
FY13 FY14 FY15 FY16 FY17 FY18 FY19 FY20 1 - 2 MW Flight Project Adv Air Capturing Transport Complexities of Technology Hybrid AFRC/GRC Architectures Performance and Control of Integrated Systems Testing in Preparation for 1 - 2MW flight demonstrator Convergent Aeronautics Solutions Spiral Development AFRC/LARC/GRC for MW scale ESAero / Joby Aviation ~2500lb Team Seedling Risk Reduction for AFRC/LARC kW airplane ESAero / Joby Risk Reduction Testing for Airplane
LEAPTech
Leading Edge Asynchronous Propeller Technology
Primary Objective
• Goal: 5x Lower Energy Use
Derivative Objectives
• 30% Lower Total Operating
Cost
• Zero In - flight Carbon Emissions
Secondary Objectives
• 15 dB Lower community noise.
• Flight control redundancy,
reliability
• Certification basis for DEP
technologies.
• Scaling study for commuter and
regional turbo - prop research
investments .
Photo Courtesy of Tom Tschida NASA AFRC
First High Speed LEAPTech Test
Convergent Aeronautics Solutions DEP Airplane
PHASE I
PHASE II PHASE III PHASE IV
Requirements Definition, Systems Analysis, Wing System Design, Design Reviews DEP wing development and fabrication Flight test with integrated DEP motors and folding props (cruise motors remain Ground validation of Flight t est e lectric m otors in wing - tips).
DEP highlift system relocated to wing - tips, with DEP wing including nacelles (but no DEP motors, controllers, or folding props).
Ground and flight test validation of electric motors, battery, and Flight testing of Achieves Primary instrumentation. baseline Tecnam Achieves Secondary Objective of High Speed P2006T Objectives Cruise Efficiency Goals: • DEP Acoustics • Establish Electric Goals: Testing Power System Flight • Establish Baseline • Low Speed Control Safety Tecnam Robustness • Establish Electric Performance • Certification Basis of Tecnam Retrofit • Test Pilot DEP Technologies Baseline Familiarity
Spiral Development
From Ground to Flight kW System Understanding • Lessons learned on Packaging distributed electric propulsion wiring, instrumentation and non - propulsion electrical systems in a high aspect ratio wing • Aero and Acoustic Tool Validation • Verification and Validation of Flight Motors and Motor Controller • Establish Standards for Air Worthiness Propulsion Motors • Battery weight/capacity for various flight profiles • Weight/Volume R estrictions • Thermal Management, Cooling for Motor/Motor Controller and DEP • Dynamic Aero/Propulsive L oading • DEP C rossflow C haracterization and A ero/Propulsion interaction Thrust/ S tall M argins and Cruise • EMI C oncerns • Pilot I nput to Basic Fly - By - Wire P ropulsion Control, not autonomous • Emergency Recover from DEP Motors and Wing - Tip C ruise Motors failures
Hybrid Electric Integrated Systems Testbed (HEIST)
Integration and Performance Challenges are Studied so Larger, More Advanced System Testbeds Can Be Designed Autonomous Flight Controller Study system complexities of 2 power sources COTS and low TRL components Laid out in the actual configuration of the aircraft, using real line lengths Verify vital aircraft system Effects of failure and subsequent treatment Electric switch w/variable interruptions, times are studied to assess their impact on the computers and components EMI/EMC effects Ironbird is controlled from a flight simulator Provides configurable test configurations and conditions
Hybrid Electric Integrated Systems Testbed (HEIST)
Modular Architecture to Allow for Multiple Configurations ( TeDP /Hybrid/All - electric; serial; or parallel buses ) Two redundant power sources to balance power regeneration and load shedding Verify any failure in one path will not cause an overload on the alternate path Each path capable of handling entire power load Using distributed electric propulsion for flight control by nature are dynamic, with lots of moves, adds and changes going on all the time
AirVolt
Single - String Electric Propulsor Test Stand Collect high - fidelity data of motor, motor controller, battery system efficiencies, thermal dynamics and acoustics V&V of components and system interfaces Evaluation of low TRL components Model single system before transitioning to multiple motors Gain knowledge in test methodologies, processes, and lessons learned Measurements 300 lbf thrust, 500 ft * lbs torque, 0 - Static and Dynamic Testing 40,000 RPM , 500V , 500 Amps
Spiral Development
From kW to MW System Interfaces
kW System Integration
• EMI Concerns
• Pilot I nput to autonomous Fly - By - Wire P ropulsion Control
– Flight control development for propulsion coupled pitch, yaw and roll
– Emergency Recover
• Understand cooling systems for motors and batteries
• System controllers for bus a rchitectures with multiple power sources
• Verification and validation of Hybrid Electric turbine/motors, DEP and
controllers for air airworthiness
Small Business Initiative Research
SBIR/METIS/Phase II
Turbo - Generator
Lightweight turbine generator (40 kW)
SBIR/ ESAero /GA/Phase II
e PHM
Fault tree and failure mode, effects
and criticality analysis
SBIR/ ESAero /Phase III
HEIST
IronBird instrumentation and data
acquisition
LEARN/RHRC/Phase II
Boundary
Characterize propulsion airframe
Layer Ingestion Efficiency
interaction using closely spaced
ducted electric motors
STTR/RHRC/Phase II
A/C Conversion
Modular flight testbed for studying
Study
various hybrid architectures
Technologies that can enable or accelerate
hybrid, turbo - and all electric Aircraft
• Electric Machine Topologies: – Higher efficiency designs: reduce the losses in the motor through better topologies without sacrificing power density – I ronless or low magnetic loss – Concepts which allow motor to be integrated into the existing rotating machinery (shared structure) – Concepts which decouple motor speed and compressor speed
• Electric Machine Components and Materials
– Flux diverters or shielding to reduce AC loss or increase performance – Composite support structures – Improvements in superconducting wire: especially wire systems designed for lower AC losses – Rotating Cryogenic seals Vehicle and thermal management – Bearings: cold ball bearings, active & passive magnetic bearings; concepts need to be defined hydrostatic or hydrodynamic or foil for systems w/ a pressurized LH2 alongside propulsion systems to source assure that the full system is – Flight qualification of new components lightweight and thermally
• Cryocoolers
balanced.
– Flight weight systems for superconducting and cryogenic machines, converters and transmission lines
Technologies that can enable or accelerate
hybrid, turbo - and all electric Aircraft
• Power electronics
– More efficient topologies – Compact, highly integrated controller electronics – Flight certifiable, high voltage devices – Cryogenic compatible devices
• Power transmission
• Thermal Management
– Light weight, low - loss power transmission Transport class HE aircraft will need to reject 50 to 800 kW – Light - weight, low - loss protection and switching of heat in flight components – Cooling for electric machines with integrated power
electronics • Better conductors
– Advanced lightweight cold plates for power – Carbon nano - tube or graphene augmented wires electronics cooling – Robust, high temperature superconducting wires – High performance light - weight heat exchangers
• Energy storage
– Lightweight, low aerodynamic loss, low drag heat – increased battery energy density rejection systems – multifunctional energy storage – Materials for improved thermal performance – rapidly charging and/or rapidly swapable
• System - level enablers
– Flight - weight, air cooled, direct shaft coupled turbo - electric generation in the above 500kW range – Regenerative power absorbing propeller and ducted fan designs (efficient wind - milling)