Document
National Aeronautics and Space Administration !
Hybrid-Electric and Distributed Propulsion Technologies
for Large Commercial Air Transports: A NASA
Perspective "
Nateri Madavan !
Associate Project Manager for Technology !
Advanced Air Transport Technology Project !
NASA Advanced Air Vehicles Program !
NASA Ames Research Center, Moffett Field, California !
Special Session on Future Electric Aircraft - Systems !
IEEE ECCE 2015 !
Montreal, Canada !
September 20-24, 2015 !
Advanced Air Transport Technology Project "
Explore and Develop Technologies and Concepts for "
Improved Energy Efficiency and Environmental Compatibility for "
Fixed Wing Subsonic Transports "
! Early stage exploration and initial development of game-changing
technologies and concepts for fixed wing vehicles and propulsion systems "
! One of two NASA Aeronautics projects (along with Environmentally
Responsible Aviation (ERA) project) focused on subsonic commercial
transport vehicles !
! Commercial focus, but dual use with military !
! Gen N+3 time horizon; ERA project horizon is Gen N+2 !
! Research vision guided by vehicle performance metrics developed for
reducing noise, emissions, and fuel burn !
Evolution of Subsonic Transports Transports DC-3 B-787 B-707 National Aeronautics and Space Administration ! 2 1903 2000s 1950s 1930s
The Case for Hybrid Electric Propulsion "
• 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 !
• Advanced concept studies commissioned by NASA for the N+3/N+4 generation have identified promising aircraft and propulsion systems !
• Industry roadmaps acknowledge need to shift in direction toward electric technologies !
• Creative ideas and technology advances needed to exploit full potential !
• NASA can help accelerate key technologies in collaboration with OGAs, industry, and academia !
National Aeronautics and Space Administration ! 3
Estimated Benefits From Systems Studies "
Boeing/GE 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 !
!
NASA N3X (baseline Boeing 777–200) !
• ~63% energy use reduction !
• ~90% NOx reduction !
• 32-64 EPNdB cum noise reduction !
NASA CEPT for GA (baseline Tecnam P2006T) !
• 5x lower energy use/cost and emission !
• 15 dB lower community noise !
• Propulsion redundancy, improved ride quality, and control robustness !
National Aeronautics and Space Administration ! 4
The NASA Perspective "
• Develop and demonstrate technologies that will revolutionize
commercial transport aircraft propulsion and accelerate development
of all-electric aircraft architectures !
• Enable radically different propulsion systems that can meet national
environmental and fuel burn reduction goals for subsonic commercial
aircraft !
• Focus on future large regional jets and single-aisle twin (Boeing 737-
class) aircraft for greatest impact on fuel burn, noise and emissions !
• Research horizon is long-term but with periodic spinoff of technologies
for introduction in aircraft with more- and all-electric architectures !
• Research aligned with new NASA Aeronautics strategic R&T thrusts in
areas of transition to low-carbon propulsion and ultra-efficient
commercial transports !
National Aeronautics and Space Administration ! 5
Fuel Use by Vehicle Classes "
100% !
90% !
80% !
70% !
PAX !
!
" VLA !
400+ !
60% !
!
LTA ! 300-400 !
!
50% !
STA ! 210-300 !
!
Fuel Use 150-210 !
LSA !
40% !
!
100-150 !
SSA !
!
30% !
50-100 !
RJ !
!
20-50 !
TP !
20% !
10% !
0% !
Year " Based on FAA Terminal Area Forecast (TAF) for US Operations; Courtesy of GA Tech !
85% of fuel use is in small single-aisle (100-150 pax ) and larger classes; regional jets and turboprops account for only 15% of fuel use " National Aeronautics and Space Administration ! 6
Progression of Electric Technology for
Commercial Transport Aircraft "
National Aeronautics and Space Administration ! 7
Possible Hybrid Electric Aircraft Configurations "
Hybrid Electric !
Battery !
Electric Bus !
(Transmission !
Turbine Engine !
Motor !
Line) !
Fuel !
Non-Prop ! Energy Storage for Power ! Power Management !
Fuel Line !
Fan !
Both concepts can use either non-cryogenic motors or cryogenic superconducting motors. !
Turbo Electric !
Electric Bus !
Motor ! Turbine Engine ! Generator !
(Transmission !
Line) !
NEED $
NEW$
PHOTO $
Non-Prop ! Energy Storage for Power ! Power Management !
Fuel !
Fan !
National Aeronautics and Space Administration ! 8
Hybrid Electric Propulsion Technology Projections "
Projected Timeframe for Achieving Technology Readiness Level (TRL) 6 "
Technologies benefit more electric and
!
• Turbo/hybrid electric all-electric aircraft architectures: !
distributed propulsion • High-power density electric motors 300 PAX !
replacing hydraulic actuation !
• Electrical component and transmission
>10 MW !
system weight reduction !
• Hybrid electric 150 PAX !
5 to 10 • Turboelectric 150 PAX !
MW !
• Hybrid electric 100 PAX regional !
• Turboelectric distributed propulsion 150 PAX !
2 to 5
• All electric 50 PAX regional (500 mile range) !
MW class !
• 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 Propulsion
• All-electric and hybrid-electric
kW class !
general aviation (limited range) !
Today ! ! ! 10 Year 20 Year 30 Year 40 Year !
National Aeronautics and Space Administration ! 9
Electric Drives Tied to Aircraft Classes
Electric Drive Technology Development Impacts Propulsion & Vehicle Suite
Electric Drives enable distributed propulsion, improve concentrated propulsion
1 MW electric machines are
identified as a reasonable feasibility
study point
National Aeronautics and Space Administration 10 KPP Driven Technology Goals for Electric Machines and Power Systems
Transitioning to Electric Propulsion "
" " " All " More Electric " Electric Conventional " Electric " Hybrid Gas Turbine/Electric Propulsion " Architecture " Propulsion " " Architecture " " " “Turboelectric " Distributed” " “Hybrid Electric” " Gas Turbine Gas Turbine and Power, Decoupled Electric Dual Power, Distributed Coupled Propulsor " Electric " Propulsors " Ambient Temperature or " Cryogenic and Superconducting " Propulsive Gas Turbine + Gas Turbine + Power Gas Turbine " Gas Turbine " Gas Turbine " Electric " Electric " Electric " Source " Non- Propulsive Gas Turbine Gas Turbine + Gas Turbine + Gas Turbine " Electric " Electric " Power " + Electric " Electric " Electric " Source " Generation " < N " N, N+1 " N+2,N+3 " N+3, N+4 " > N+4 " Recommended NASA Investment Target " Seeking spin-off or demo opportunities " National Aeronautics and Space Administration ! 11
Hybrid-electric configurations and concepts "
National Aeronautics and Space Administration ! 12
Boeing-GE “SUGAR-Volt” Hybrid Electric Propulsion
Configuration "
SUGAR 2030 Assumption (Wh/kg) … CAP - ion - Poly Plus ion Quallion - Ion (today) - Lithium Air - ion - Air (evtech) - Air (mpower) - Lithium Air (Energizer) - Lithium Air Zinc (Stanford, Yi Cui) Zinc Lithium Coated Nanonets) Lithium - Sulfur, Oxis Energy Lithium Zinc - University of Dayton Lithium Air (SuperCapacitor) Supercapacitor, X Lithium Carbon Flouride Sulfur, (in 2014) Oxis, Sion (Silicon Lithium Carbon Phosphate (South Korea, Jaephil Cho) Lithium Lithium Sulfur (Sion Power) - Electrostatic nanocapacitors Lithium Thionyl Chloride (Tadiran) Lithium Lithium Air, Carbon Nanotube, MIT National Aeronautics and Space Administration ! 13
ESAero ECO-150 and Dual-Use Split-Wing
Ambient Temperature Turboelectric Configuration "
ECO+150$ DU+Civil$ 737+700$ (3+3)$ (2+3+2)$ (3+3)$ TOGW% 139,700% 142,400% 154,500% Propulsion% 28,350% 27,820% 10,430% Wt %(“dry”)% Payload*% 30,000% 30,000% 24,000% Fuel*% 28,900% 28,900% 46,612% SeatFMile/ 121% 118% 65% Gal% Motor% hp / lb % 2.46% Gen% hp / lb % 4.30% * At 3440 nm range !
National Aeronautics and Space Administration ! 14
NASA N3X Distributed Turboelectric Propulsion System "
Wing-tip mounted superconducting turbogenerators !
Superconducting motor driven fans in a continuous nacelle !
Power is distributed electrically from turbine-driven !
generators to motors that drive the propulsive fans. !
National Aeronautics and Space Administration ! 15
NASA Convergent Electric Propulsion Technology
(CEPT) Concept "
Concept Flight Validation of Transformational Electric Propulsion Integration Capabilities through a Low Cost On-Demand Aviation Demonstrator as a Pathway to Ultra-Low Emission Commercial Aviation !
National Aeronautics and Space Administration ! 16
EADS VoltAir Concept "
• EADS VoltAir all-electric 50 pax concept for 2035 EIS !
• Displayed at the 2011 Paris airshow !
• Next-gen Li-air batteries, two HTS electric motors driving two coaxial, counter-rotating shrouded propellers !
• Easy battery swap for quick airport turnaround !
• EADS predicts technology improvements will lead to HTS motors with power-to-weight ratios eventually exceeding gas turbines of today !
National Aeronautics and Space Administration ! 17
Bauhaus Luftfahrt Ce -Liner Concept "
• All-electric concept for 2035 EIS !
• 200 Pax capacity !
• C-Wing design based on Kroo and McMasters (Stanford/Boeing/UWA) !
• Twin HTS electric motors supplied by advanced Li-ion batteries !
• Cargo containers for batteries will quick allow airport turnaround with no recharging time !
• Predict battery technology will allow 700 nm range by 2030, 1000 nm by 2035, 1600 nm by 2040 !
• Company also has the Claire Liner concept vehicle – box-wing, extreme STOL aircraft with laminar flow and integrated wing fans !
National Aeronautics and Space Administration ! 18
EADS/Rolls-Royce eConcept "
• EADS/RR distributed hybrid-electric propulsion concept for 2050 EIS !
• Single large turbine engine embedded in tail generates electricity to six ducted fans (20+ effective BPR) !
• Turbine engine drives hub-mounted bidirectional superconducting motor !
• Structural stator vanes used to extract power and circulate cryo coolant !
• Advanced Li-air batteries for storage; anticipate 1000 Wh /kg energy densities achievable in 20 years !
• Turbine+battery power for takeoff and climb; batteries recharged during cruise and during gliding descent with windmilling fans; turbine power during landing !
• Cranfield and Cambridge U partners !
National Aeronautics and Space Administration ! 19
Hybrid-electric propulsion research portfolio "
National Aeronautics and Space Administration ! 20
Battery Technology: Beyond Li-Ion "
Practical values for Li-Air, Li-S and Zn-Air are optimistic projections. " Significant technical challenges must be overcome to achieve these values . !
National Aeronautics and Space Administration ! 21
NASA Technology Investment Strategy "
MW Size Motors !
10 hp / lb 12 hp / lb 8 hp / lb 4 hp / lb Non-Cryogenic !
(16.5 kW/kg) (19.7 kW/kg) (13.2 kW/kg) (6.6 kW/kg)
2020 % 2025 % 2030 % 2035 % Today %
4 hp / lb (6.6 kW/ 20 hp / lb 25 hp / lb kg), partially Cryogenic, Superconducting !
(33.0 kW/kg) (41.1 kW/kg) superconducting 2X increase in 5X increase in 10X increase in Power power density ! power density ! power density !
Electronics !
Increase$in$power$density$and$reducFon$of$weight$of$other$electrical$components $
Power !
Transmission 2X decrease in 5X decrease in 10X decrease in System !
weight ! weight !
weight !
Perf . and control Perf . and control Subscale flight test !
Electric system verification system verification Propulsion- in KW scale ! in MW scale !
Aircraft
Distributed$electric$propulsion$performance$and$control $
Integration !
National Aeronautics and Space Administration ! 22
Projected Power Density Increase – 1-10MW Motors "
15 Year Power Density Projections - Select Motor Technology Contributions Hp / lb In addition to advances in 2 individual 2012 SOA Structural Permanent Bearingless Power Thermal Nanowire Insulator technologies, Materials Magnets Electronics Management integration of 30 Year Power Density Projections - Select Motor Technology Contributions functions can offer further increase in power density !
Hp / lb 2012 SOA Structural Permanent Bearingless Power Thermal Nanowire Insulator Materials Magnets Electronics Management National Aeronautics and Space Administration ! 23 23
Enabling Technologies for Hybrid-Electric Propulsion "
• Electric Machine Architectures !
– Alternate topologies for higher efficiency and power density !
– Ironless or low magnetic loss !
– Concepts that allow motor to be integrated into the existing rotating machinery (shared structure) !
– Concepts that 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 !
– Bearings: cold ball bearings, active & passive magnetic bearings; hydrostatic or hydrodynamic or foil for systems with a pressurized LH2 source !
– Flight qualification of new components !
!
• Cryocoolers !
– Flightweight systems for superconducting and cryogenic machines, converters, and transmission lines !
National Aeronautics and Space Administration ! 24
Enabling Technologies for Hybrid-Electric Propulsion "
• Power electronics !
• Thermal management !
• More efficient topologies !
• Cooling for electric machines with integrated power electronics !
• Compact, highly integrated controller electronics !
• Advanced lightweight cold plates for power • Flight certifiable, high voltage devices !
electronics cooling !
• Cryogenic compatible devices !
• High performance lightweight heat exchangers !
• Lightweight, low aerodynamic loss, low drag
• Power transmission !
heat rejection systems !
• Light weight, low-loss power transmission !
• Materials for improved thermal performance !
• Light-weight, low-loss protection and switching components !
• System-level enablers !
• Flight-weight, air cooled, direct shaft-coupled
• Better conductors !
turbo-electric generation in 500kW and above • Carbon nano -tube or graphene augmented wires !
range !
• Robust, high temperature superconducting wires !
• Regenerative power-absorbing propeller and ducted-fan designs for efficient wind-milling !
• Energy storage !
• Increased battery energy density !
• Multifunctional energy storage !
• Rapidly charging and/or rapidly swappable !
National Aeronautics and Space Administration ! 25
High Efficiency, High Power Density Electric Machines "
Nanoscale ultra-high strength low • Cryogenic, superconducting motors for percent rare-earth composite magnets !
long term !
High thermal conductivity • Normal conductor motors for near and stator coil insulation !
intermediate term !
• High power to weight ratio is enabling !
• Materials and manufacturing technologies advances required !
Low A/C loss Superconducting electromagnetic model !
superconducting filament !
• Design and test 1-MW noncryogenic electric motor starting in FY2015; fully superconducting motor in FY2017 !
Normal conductor 1-MW rim-driven motor/fan !
Flux density for rim-driven motor ! Fully superconducting motor !
National Aeronautics and Space Administration ! 26
High Power Density MW Class Non-Cryogenic Motor "
• Design and test scalable high efficiency and power density (96%, 8 hp / lb ) MW-class non-cryogenic motor for aircraft propulsion !
• U of Illinois, UTRC, Automated Dynamics !
• Migrate from from traditional “metal-intense” to composite and silicon-intense design !
• High fundamental frequency (10X conventional) !
• High pole-count, ironless motor with composite rotor !
• Modular, air-core armature !
• Modular, passively cooled drive with wide-band-gap devices integrated with motor !
!
• Ohio State University !
• Design a motor for integration on LPT spool of CFM56 class engine !
• Reversed (ring) concept with cooling based on Variable Cross-Section Wet Coils (VCSW) coil design with integrated, direct cooling !
• Extensive design trade-space analysis and testing of motor concept at three power levels !
National Aeronautics and Space Administration ! 27
High Efficiency, High Power Density Superconducting
Machines "
• Advance SOA for crucial components to
minimize power loss and enable thermal
management !
• Detailed concept design completed of
AML model for magnetic fields !
12MW fully superconducting machine
achieving 25 hp / lb !
• In collaboration with Navy, Air Force,
Creare , HyperTech , Advanced Magnet
Lab, U of FL !
• Fabricating and testing superconducting
machine components at laboratory scale !
• Developing system for FY17 fully
superconducting electric machine test at 1
MW design level !
National Aeronautics and Space Administration ! 28
Enabling System Testing and Validation "
hardware-in-the-loop electrical grid !
• Develop Megawatt Power System Testing and Modeling Capability !
• Key Performance Parameter-driven Fully cryogenic motor testing NASA GRC !
requirements definition and portfolio management !
• Technology demonstration at multiple scales !
• Early identification of system-level issues !
• 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 !
inverter ! controls !
simulator !
controls !
Motor FD&C controls ! simulator !
Eventual flight simulation testing at NASA Armstrong Flight Research Center ! Integrated controls !
National Aeronautics and Space Administration ! 29
Flight-weight Power Management and Electronics "
• Multi-KV, Multi-MW power system architecture Lightweight power Superconducting transmission !
transmission line !
for aircraft applications !
• Power management, distribution and control at MW and subscale (kW) levels !
• Integrated thermal management and motor control schemes !
Integrated motor with high power density power electronics !
• Flightweight conductors, advanced magnetic Lightweight materials and insulators !
Cryocooler !
Lightweight power electronics !
Distributed propulsion control and power systems architectures !
National Aeronautics and Space Administration ! 30
System Testing and Validation "
• Use system-level simulation capability Propulsion Electric Grid Simulator—hardware-in- to emerge requirements. !
the-loop electrical grid !
• Demonstrate technology at appropriate scale for best research value. !
Fully cryogenic motor testing !
Glenn/SMIRF !
• Integrate power, controls, and thermal management into system testing. !
• Validated tools and data that industry and future government projects can use for further development. !
Integrated thermal management system !
Energy Rectifier !
GTE ! storage !
Electrical distribution !
VF motor/ Gen.
Load Engine inverter ! controls ! Research simulator !
controls !
Testbed !
Motor FD&C controls ! simulator !
Eventual flight simulation testing at NASA Armstrong Flight Research Integrated controls !
Center !
National Aeronautics and Space Administration ! 31
Integrated Vehicles and Concept Evaluations "
• Determine design requirements and trade space for hybrid electric propulsion vehicles !
GTE/generator, distribution !
and motor drive !
• Identify near-term technologies that can benefit aircraft non-propulsive electric power !
• Enhance analysis capabilities to model non- traditional vehicle configurations with hybrid electric systems " Fully electric GA/ • Establish vehicle conceptual designs that commuter !
span power requirements from general aviation (<1 MW) to regional jets (1-2 MW) to single-aisle transports (5-10 MW) !
GTE and energy !
storage (battery) !
National Aeronautics and Space Administration ! 32
Hybrid Electric Propulsion System Conceptual Design "
• Hybrid-electric geared turbofan conceptual design !
• UTRC, Pratt and Whitney, UTC Aerospace Systems !
• High Efficiency Drive Gear integrating high speed motor and low pressure turbine !
• Bi-directional flow of power !
• Hybrid battery/fuel cell for high density energy storage !
• Combined fuel/fan thermal management system !
!
• Hybrid-electric geared turbofan conceptual design !
• Rolls Royce, Boeing, GA Tech !
• Identify best performing architecture based on engine cycles, motor, power conversion, energy storage, and thermal management !
• Innovative integration of novel gas turbine cycles and electrical drives !
• Potential side effects of system design considerations !
• Provide roadmap and technology maturation plan !
National Aeronautics and Space Administration ! 33
Looking to the Future… "
• Exciting challenges for an industry that was deemed “mature” !
• Conceptual designs and trade studies for electric-based concepts !
• Tech development and demonstration for N+3 MW class aircraft !
• Development of core technologies - turbine coupled motors, propulsion systems modeling, power architecture, power electronics, thermal management, and flight controls !
• Multiplatform technology testbeds demonstrating !
• Fully superconducting motor !
• 8 hp / lb (2x SOA) non-cryogenic electric motors !
• 2x power density increase for power electronics !
• Performance and control system verification for distributed electric propulsion at kW scale !
• Development of multi-scale modeling and simulations tools !
• Focus on future large regional jets and single aisle twin-engine aircraft for greatest impact !
National Aeronautics and Space Administration ! 34
What is special about 2015? "
March 3, 2015, represents 100 years since the founding of NACA, which became NASA in 1958. !
National Aeronautics and Space Administration ! 35