Airframe Technologies for Aerodynamic and Structural Efficiency of N+3 Subsonic Transport Aircraft

Transcription

1 National Aeronautics and Space Administration Airframe Technologies for Aerodynamic and Structural Efficiency of N+3 Subsonic Transport Aircraft Dr. Richard A. Wahls, Project Scientist, Subsonic Fixed Wing Dr. Michael M. Rogers, Technical Lead Efficient Aerodynamics, Subsonic Fixed Wing Ms. Karen M. Taminger, Technical Lead Lightweight Airframe & Propulsion Structures, Subsonic Fixed Wing 3 rd UTIAS International Workshop on Aviation and Climate Change Toronto, Ontario, Canada May 2-4,

2 Outline Introduction Goal-Driven Advanced Concept Studies Enabling Technologies Concluding Remarks 2

3 Major Challenges for Aviation 3

4 Major Challenges for Aviation - part 2 Contain objectionable noise within airport boundary Change in noise footprint area for a single event landing and takeoff Current Rule: Stage 4 Baseline Area N+1 - NEAR TERM GOAL Area = 15% Baseline N+3 - FAR TERM GOAL Area < 2% Baseline Relative ground contour areas for notional Stage 4 and near, mid, and far-term goals Independent of aircraft type/weight Independent of baseline noise level N+2 - MID-TERM GOAL Area = 8% Baseline AVERAGE AIRPORT BOUNDARY Noise reduction assumed to be evenly distributed between the three certification points Simplified model: Effects of source directivity, wind, etc. not included N: Stage 4 10 db CUM Area = 55% of Baseline 4

5 NASA Aeronautics Programs Subsonic Fixed Wing and other NASA Green Aviation emphasis Fundamental Aeronautics Program Conduct fundamental research that will produce innovative concepts, tools, and technologies to enable revolutionary changes for vehicles that fly in all speed regimes. Integrated Systems Research Program Conduct research at an integrated system-level on promising concepts and technologies and explore/assess/demonstrate the benefits in a relevant environment Airspace Systems Program Directly address the fundamental ATM research needs for NextGen by developing revolutionary concepts, capabilities, and technologies that will enable significant increases in the capacity, efficiency and flexibility of the NAS. Aviation Safety Program Conduct cutting-edge research that will produce innovative concepts, tools, and technologies to improve the intrinsic safety attributes of current and future aircraft. Aeronautics Test Program Preserve and promote the testing capabilities of one of the United States! largest, most versatile and comprehensive set of flight and ground-based research facilities. 5

6 SFW Strategic Framework/Linkage Strategic Thrusts Strategic Goals System Level Metrics 1. Energy Efficiency 1.1 Reduce the energy intensity of air transportation Fuel Burn Energy Efficiency 2. Environmental Compatibility 2.1 Reduce the impact of aircraft on air quality around airports 2.2 Contain objectionable aircraft noise within airport boundaries 2.3 Reduce the impact of aircraft operations on global climate LTO NO X Emissions Other LTO Emissions Aircraft Certification Noise Cruise NO X Emissions Life-cycle CO 2 e per Unit of Energy Used 6

7 The NASA Explore and Develop Tools, Technologies, and Concepts for Improved Energy Efficiency and Environmental Compatibility for Objectives Sustained Growth of Commercial Aviation! Prediction and analysis tools for reduced uncertainty! Concepts and technologies for dramatic improvements in noise, emissions and performance Relevance! Address daunting energy and environmental challenges for aviation! Enable growth in mobility/aviation/transportation! Subsonic air transportation vital to our economy and quality of life Evolution of Subsonic Transports Transports DC-3 B-707 B s 1950s 2000s 7

8 NASA Subsonic Transport System Level Metrics. technology for dramatically improving noise, emissions, & performance Research addressing revolutionary N+3 Goals with opportunities for near term impact 8

9 Outline Introduction Goal-Driven Advanced Concept Studies Enabling Technologies Concluding Remarks 9

10 Goal-Driven Advanced Vehicle Concept Studies (N+3) purpose/approach Leverage external and in-house expertise Stimulate thinking to determine potential aircraft solutions to address significant performance, environmental, and operations issues of the future Identify advanced airframe and propulsion concepts and corresponding enabling technologies for commercial aircraft anticipated for EIS (market conditions permitting) Identify key driving technologies (traded at the system level) Prime the pipeline for future, revolutionary aircraft technology developments Use to inform and define SFW research portfolio and investments 10

11 Goal-Driven Advanced Vehicle Concept Studies (N+3) summary Boeing, GE, GA Tech Advanced concept studies for commercial subsonic transport aircraft for EIS NG, RR, Tufts, Sensis, Spirit Trends: Tailored/Multifunctional Structures High AR/Active Structural Control Highly Integrated Propulsion Systems Ultra-high BPR (20+ w/ small cores) GE, Cessna, GA Tech MIT, Aurora, P&W, Aerodyne Alternative fuels and emerging hybrid electric concepts Noise reduction by component, configuration, and operations NASA, VA Tech, GT NASA Copyright, The McGraw-Hill Companies. Used with permission. Advances required on multiple fronts 11

12 Diversified Portfolio Addressing N+3 Goals broadly applicable subsystems technical challenges N+3 Vehicle Concepts Technical Challenges Reduce Drag, Weight, TSEC, Emissions and Noise SX/PX Rim 1500F PM Bore 1300F Tailored Fuselage High AR Elastic Wing Quiet, Simplified High-Lift High Eff. Small Gas Generator Hybrid Electric Propulsion Propulsion Airframe Integration Tools Alternative Fuels Research Areas 12

13 Outline Introduction Goal-Driven Advanced Concept Studies Enabling Technologies Overview Examples Concluding Remarks 13

14 Tailored Fuselage opportunity to reduce large structural weight, large wetted area Objective Drag Explore and develop technologies to enable direct structural weight and skin friction reduction Approach/Challenges Weight TSEC Tailored Load Path Concepts & Design Clean Noise large structure large area conventional and unconventional Designer Materials Turbulent Skin Friction Drag Reduction Benefit/Pay-off 25% fuselage structural weight reduction 10% fuselage turbulent boundary-layer drag reduction metallic & composites tailored load path design/build tailored materials 14

15 High Aspect Ratio Elastic Wing changing the drag/weight trade space Objective Drag Explore and develop technologies to enable lightweight high aspect ratio wings Approach/Challenges Weight TSEC Tailored Load Path Concepts & Design Clean Noise braced cantilever Designer Materials Active Structural Control Aerodynamic Shaping active controls load alleviation Elastic Aircraft Flight Control tailored multifunctional Benefit/Pay-off 25% wing structural weight reduction AR increase of 30-40% for cantilever wings, 2X+ for braced passive/active advanced aerodynamics 15

16 Propulsion Airframe Integration increasingly synergistic integration Objective Drag Explore and develop technologies to enable highly coupled, synergistic aero-propulsive-control Approach/Challenges Weight Aerodynamic Configuration TSEC Clean Noise boundary-layer ingesting concepts thrust vectoring Adaptive, Lightweight Fan Blade Distortion-Tolerant Fan distortion tolerance Acoustic Liners Propulsion Airframe Aeroacoustics Benefit/Pay-off Improved multidisciplinary performance and noise characteristics; benefits tradable for specific missions jet/surface interaction acoustics adaptive fan blades 16

17 Weight Reduction and Manufacturing tailored metallic structures via electron beam free form fabrication (EBF3) structural design optimization with curvilinear stiffeners fabrication & testing of structural designs lightweight aeroelastically tailored wing structure with integral control surfaces!" 17

18 Weight Reduction via Advanced Multifunctional and Tailored Materials Variable Stiffness Hybrid CNT CFRP/ All CNT Designer Metallics Functionally Graded Metal Alloys 2 mm Hardness, VHN100gf_ Al 1100 Al 2219 deposit Al Distance from top of deposit, mm >?@.@$5,'.$#-.A$)#'..&.!"#$%$&'()*%+#$,$-.*/ #$#%&'()*+(*),-.,/,0,#('.12(32#.$+(24, 5%/60,)2+.0$(,)2$/'.7%).$+(24,.12#8.'92# :/%$-.;,$)2#8.<.,/,+()2+.+%#-*+(242(6= ($2/%),-.0,($/.$//%6' 4$)6.0$(,)2$/.5)%5,)(2,'.+%#(2#*%*'/6 (3)%*83%*(.$.'()*+(*), POCs: E. Siochi, K. Taminger (NASA LaRC) 18

19 Metallic Fuselage Design and Fabrication Engineered materials coupled with tailored structural design enable reduced weight and improved performance Multi-objective optimization: " Structural load path " Acoustic transmission " Durability and damage tolerance " Minimum weight " Materials functionally graded to satisfy local design constraints Additive manufacturing using new alloys enables unitized structure with functionally graded, curved stiffeners Weight reduction by combined tailoring structural design and designer materials Design optimization tools developed at VA Tech through NRA contract High toughness alloy at stiffener base for damage tolerance, transitioning to metal matrix composite for increased stiffness and acoustic damping POCs: R. Kapania (VA Tech), R. Olliffe (Lockheed Martin), K. Taminger (NASA LaRC) 19

20 Validated Design Tool for Improved Structural Efficiency EBF3PanelOPT OBJECTIVE Structural design and optimization for aircraft structures using novel materials, manufacturing methods and structural configurations to carry comparable loads at significantly lower weight. APPROACH Validate EBF3PanelOpt (developed under NRA with Virginia Tech) design and optimization tool by designing, fabricating, and testing panel with six individually optimized T-stiffeners for a high compression load case with optimization constraints on buckling, stress, and crippling. RESULTS EBF3PanelOpt was validated by experiment for several load conditions and multi-objective optimization. The final validation test showed that the aluminum panel with individually optimized stiffeners and skin thickness is 20% lighter than baseline with uniform stiffeners optimized with conventional design methods. Vertical Stabilizer Skin Panel T-stiffened panel designed and optimized using EBF3PanelOpt, in compression test system Design Candidates Using Several Variations of Geometry Input Parameters 8.98 lb 9.25 lb 9.89 lb 8.30 lb POCs: R. Kapania (VA Tech), R. Olliffe (Lockheed Martin), K. Taminger (NASA LaRC) 20

21 Composite Structural Design and Analysis Tool Development Fiber winding and automatic tape placement are industry standards Fiber tow steering places individual fiber tows, enabling tighter radii curves and control of fiber distribution Fiber tow steering equipment exists, but design and analysis tools to effectively tailor localized laminate properties are lacking Develop analysis and design tools to optimize structures through tailored placement of fibers within composite Fibers from axial along keel and crown to 45 along sides for shear; steer fibers around cutouts for continuity POCs: C. Wu (NASA LaRC) Fabrication at NCAM/MAF Fiber tow placement plan within a single ply (cylinder split along keel for purposes of image); validate through test of cylinders 28 dia. x 40 21

22 Composite Protective Skin Smoothing, Thermal, Absorbing, Reflective, Conductive, Cosmetic (STAR C 2 ) Composite primary structure with external protective skin Multifunctional skin provides protection external to primary structure: B Cosmetic finish B Acoustic treatment B Thermal insulation B Lightning strike protection B Smoothness to facilitate laminar flow B Impact detection/indication B Ice protection B Easily produced and repaired Weight reduced by driving towards lighter gage primary structure and combining other functions in multifunctional skin STAR-C 2 Concept N+3 Phase 2 Cessna, NASA collaboration exploration and development; panel tests Conductive skin (Lightning, EMI, Paint, Smoothness for laminar flow) Energy Absorbing Foam (Impact, Sound, Thermal, etc.) Stringer Skin Frame POCs: V. Johnson (Cessna), E. Siochi (NASA LaRC) 22

23 Elastically Shaped Aircraft Concept (ESAC) Opportunity Leverage increasing flexibility of wing structures for weight and drag reduction Approach MDAO solutions (aerodynamics, structures, aeroelasticity, control) Active aeroelastic structural control for weight reduction Load alleviation Modal suppression Mission-adaptive shaping for cruise drag optimization Variable Camber Continuous TE Define flight/structural control system Investigate actuation strategies, weight/power requirements VCCTE Flap Device Wing Camber, Curvature, and Twist Optimized for Drag POCs: N.Nguyen (NASA ARC), J. Urnes (Boeing) 23

24 Circulation Control Research High Rn Technical Objectives Cruise Drag Reduction Low-Speed CLmax Rn Scale Effects, Blowing Effects Test Technique National Transonic Facility Sidewall Model Support System Flow Control System FAST-MAC Model Mach 0.85 design, open geometry Supercritical airfoil Modular future flow control and PAI research Fundamental Aerodynamics Subsonic/Transonic-Modular Active Control POCs: W.Milholen, G.Jones, (NASA LaRC); see AIAA

25 Design Point Wing Pressures (M! =0.85, " = 3.00,Rn=10x10 6 ) DESIGN MACH NUMBER AND C L ~ 0.5 GOOD PERFORMANCE NPR Cµ CFD POCs: W.Milholen, G.Jones, (NASA LaRC); see AIAA

26 Effect of Low Blowing on Wing Pressures (M! =0.85, " = 3.00,Rn=10x10 6 ) LOW BLOWING MOVES SHOCK FORWARD LOSS OF LIFT SHOCK NPR Cµ POCs: W.Milholen, G.Jones, (NASA LaRC); see AIAA

27 Effect of Moderate Blowing on Wing Pressures (M! =0.85, " = 3.00,Rn=10x10 6 ) MODERATE BLOWING MOVES SHOCK LOCATION AFT RESTORES LIFT TO BASELINE NPR Cµ C P C P POCs: W.Milholen, G.Jones, (NASA LaRC); see AIAA

28 Effect of Elevated Blowing on Wing Pressures (M! =0.85, " = 3.00,Rn=10x10 6 ) ELEVATED BLOWING MOVES SHOCK AFT FURTHER INCREASING LIFT ABOVE BASELINE SHOCK NPR Cµ C P C P POCs: W.Milholen, G.Jones, (NASA LaRC); see AIAA

29 Effect of Blowing on Off-Design Wing Pressures (M! =0.85, " = 3.92,Rn=30x10 6 ) NPR Cµ OFF-DESIGN C L ~ 0.7 SIGNIFICANT SHOCK WAVE MOVEMENT LITTLE CHANGE IN SHOCK STRENGTH 5% 10% C P C P SEPARATED ATTACHED x/c x/c POCs: W.Milholen, G.Jones, (NASA LaRC); see AIAA

30 Effect of Blowing on Low-Speed Performance 60 Flap (M! =0.20,Rn=15x10 6 ) NPR Cµ #C L ~ 30% UNCORRECTED POCs: W.Milholen, G.Jones, (NASA LaRC); see AIAA

31 AMELIA CESTOL Research Low-Speed Performance and Acoustics w/ Flow Control Technical Objectives Low-Speed Performance Low-Speed Acoustics Configuration, Flow Control, Propulsion Test Technique National Full-Scale Aerodynamic Complex (40!x80!) Turbine Powered Simulators Force/moment/pressures/skin friction/acoustics, smoke/oil flow visualization AMELIA Model CESTOL, open geometry AMELIA Model at Air Force s NFAC 40x80 Wind Tunnel Advanced Model for Extreme Lift and Improved Acoustics POCs: D. Marshall, T. Jameson (Cal Poly); R. Fong, N. Burnside, C. Horne (NASA ARC) 31

32 AMELIA sample flow visualization POCs: D. Marshall, T. Jameson (Cal Poly); C. Hange, C. Horne (NASA ARC) 32

33 AMELIA sample performance preliminary data Leading-edge blowing is important to overall system benefit POCs: D. Marshall, T. Jameson (Cal Poly); C. Hange, C. Horne (NASA ARC) 33

34 AMELIA sample acoustics data preliminary data db Freq (Hz) Array beamform map of active lift regions POCs: D. Marshall, T. Jameson (Cal Poly); C. Hange, C. Horne (NASA ARC) 34

35 Aero-Structures changing the multidisciplinary trade space Multi-Objective Leading Edge balancing aero, structures, acoustics slat cove unsteady aero Truss-Braced Wing balancing drag, weight, speed bench-top demo hardware slat main element cove filler assembly low drag strut wing/strut/truss optimization wing weight uncertainty Truss-Braced Wing N+3 Phase 2 Boeing Team, NASA collaboration concept refinement;high-fidelity FEM experimental validation to reduce structural weight uncertainty; high CL, supercritical airfoil design AHLLE (Adv High Lift LE) N+3 Phase 2 Northrop Grumman, NASA collaboration Slat-less high-lift, quiet, compatible with cruise laminar flow, low-speed ground test 35

36 N+3 Integrated Vehicle Concepts technology collectors revolutionary performance low TRL Significant technology development required by 2030, but in the realm of the possible 36

37 Concluding Remarks Exciting times Many opportunities many challenges Technologies Many broadly applicable technologies Some uniquely enabling technologies Vehicles, Operations, Energy no silver bullet for more information: SFW presentations from AIAA Nashville Jan!12 N+3 NRA Phase 1 studies see: Green Aviation Summit (Sept 8-9, 2010) 37

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