Tackling the Extreme Challenges of Air-Breathing Hypersonic Vehicle Design, Technology, and Flight Mathematics, Computing & Design Symposium Honoring Antony Jameson’s 80 th Birthday Stanford University, CA 21 November, 2014 Dr. Kevin G. Bowcutt Senior Technical Fellow Chief Scientist of Hypersonics The Boeing Company BOEING is a trademark of Boeing Management Company. Copyright © 2014 Boeing. All rights reserved. VKI STO-AVT-234 | 3/26/2014 | 1 Past Hypersonics – Rocket-Boosted Gliders Engineering, Operations & Technology | Boeing Research & Technology Platform Performance Technology X-15 Rocket Plane Space Shuttle Orbiter Space Capsules Ballistic Reentry Vehicles BOEING is a trademark of Boeing Management Company. Copyright © 2014 Boeing. All rights reserved. VKI STO-AVT-234 | 2 Extremely High Boost Speed Required to Glide Across Continents or Oceans Engineering, Operations & Technology | Boeing Research & Technology Platform Performance Technology BOEING is a trademark of Boeing Management Company. Copyright © 2014 Boeing. All rights reserved. VKI STO-AVT-234 | 3 Present and Future Hypersonics – The Development and Application of Hypersonic Air-Breathing Propulsion Engineering, Operations & Technology | Boeing Research & Technology Platform Performance Technology High Speed Missiles High Speed A/C Affordable Space Access Large (10-20 klb) Small (100-500 lb) Mach 5-7 Cruise Mach 10-20 Glide Mach 6-7 Cruise Payload Payload • Hundreds of miles in • Global range • Routine and affordable minutes/global range in in ~ 2 hours space launch under an hour • High utilization • Lighter weight permits • High kinetic energy rate horizontal takeoff • Increased survivability • Aircraft-like operations and maintenance • Throttling provides flexible operation • Operational flexibility and safety BOEING is a trademark of Boeing Management Company. Copyright © 2014 Boeing. All rights reserved. VKI STO-AVT-234 | 4 Dramatically Changing Flow Physics With Mach Number Makes Hypersonic Vehicle Design Challenging Engineering, Operations & Technology | Boeing Research & Technology Platform Performance Technology BOEING is a trademark of Boeing Management Company. Copyright © 2014 Boeing. All rights reserved. VKI STO-AVT-234 | 5 Extreme Aero Heating Adds to the Hypersonic Vehicle Design Challenge Engineering, Operations & Technology | Boeing Research & Technology Platform Performance Technology • Aerodynamic heating increases in proportion to − Cube of air speed at constant density (i.e., altitude) − Air speed at constant dynamic pressure BOEING is a trademark of Boeing Management Company. Copyright © 2014 Boeing. All rights reserved. VKI STO-AVT-234 | 6 Technology Demands Also Challenge Hypersonic Vehicle Design Engineering, Operations & Technology | Boeing Research & Technology Platform Performance Technology • Large scramjet engines • Ground test limitations: High flow energy limits test engine size and test time • Must develop via flight test and computer simulation • Integrating low- and high-speed propulsion systems • Turbine engines, ramjets, scramjets, rockets, combined cycles • Durable high-temperature materials • Durability and maintainability similar to metals but capable of 2500 – 5000 °F operation • Designing highly integrated (blended) vehicles BOEING is a trademark of Boeing Management Company. Copyright © 2014 Boeing. All rights reserved. VKI STO-AVT-234 | 7 Supersonic Combustion Ramjets (Scramjets) the Key to Efficient Air-Breathing Hypersonic Flight Engineering, Operations & Technology | Boeing Research & Technology Platform Performance Technology • Shock waves must efficiently compress, heat and slow air • Turbulence must mix and burn air to near completion in ~ 1 msec Performance levels verified in flight by X-43A and X-51A BOEING is a trademark of Boeing Management Company. Copyright © 2014 Boeing. All rights reserved. VKI STO-AVT-234 | 8 Low-Speed Engines Required to Accelerate Vehicles to Scramjet Starting Speed of About Mach 4 Engineering, Operations & Technology | Boeing Research & Technology Platform Performance Technology BOEING is a trademark of Boeing Management Company. Copyright © 2014 Boeing. All rights reserved. VKI STO-AVT-234 | 9 Ceramic Composites Required to Accommodate High Temperatures – Leading Edges Engineering, Operations & Technology | Boeing Research & Technology Platform Performance Technology • State of the art • Space shuttle orbiter RCC • X-43A single use • Requirement • Multi-use Space shuttle Orbiter Leading Edge • Light weight • High heat flux/temperature • Sharp • Technical challenges • Durability X-43A Leading Edge • Life • Manufacturing • Current advanced material capability • DARPA HTV-2 3600°F Ultra-High Temp Ceramic Test Article BOEING is a trademark of Boeing Management Company. Copyright © 2014 Boeing. All rights reserved. VKI STO-AVT-234 | 10 Ceramic Composites Required to Accommodate High Temperatures – Surface Panels & Components Engineering, Operations & Technology | Boeing Research & Technology Platform Performance Technology C/SiC Body Flaps N610/AS Oxide-Oxide CMC • N610 alumina fabric- reinforced aluminosilicate matrix • Density similar to aluminum Mechanically Attached • Layup and cure similar to CMC Panels polymer based composites BOEING is a trademark of Boeing Management Company. Copyright © 2014 Boeing. All rights reserved. VKI STO-AVT-234 | 11 Hypersonic Vehicle Shapes Require Use of Conformal Tanks to Achieve High Propellant Mass Fraction Engineering, Operations & Technology | Boeing Research & Technology Platform Performance Technology • Tanks must be lightweight, robust and long-life • Joint design critical to non-round tanks Mid LH2 Tank Cross Section 550 in Baseline Orbiter 96 in 30 in (typ) Baseline Booster Mid LH2 Fuel Tank Selected Joints Retain Shape of Pressurized Air-breathing RLV Booster Composite Cryotank Courtesy David Glass, NASA Langley BOEING is a trademark of Boeing Management Company. Copyright © 2014 Boeing. All rights reserved. VKI STO-AVT-234 | 12 Air-Breathing Propulsion Integration Critical to Efficient Hypersonic Flight Engineering, Operations & Technology | Boeing Research & Technology Platform Performance Technology Body-Integrated Scramjets Pod-Mounted Scramjets Outward Turning Inlets Inward Turning Inlets • Engine flowpath topology options • Low drag integration • Large inlet and engine for high thrust/drag • Optimal propulsion contribution to vehicle lift and trim BOEING is a trademark of Boeing Management Company. Copyright © 2014 Boeing. All rights reserved. VKI STO-AVT-234 | 13 High Thrust-to-Drag Ratio a Critical Requirement for Air- Breathing Accelerators Engineering, Operations & Technology | Boeing Research & Technology Platform Performance Technology BOEING is a trademark of Boeing Management Company. Copyright © 2014 Boeing. All rights reserved. VKI STO-AVT-234 | 14 Highly Integrated Nature of Hypersonic Vehicles Makes Them Difficult to Design Engineering, Operations & Technology | Boeing Research & Technology Platform Performance Technology • Highly integrated = all vehicle parts and functions interact • Aero, propulsion, control, structure, tank, thermal protection, etc. • A flying engine: – Most of the aircraft is part of the engine inlet or nozzle – Engine produces lift and rotational torque as well as thrust • A flying fuel tank: most of internal volume filled with fuel • High temperature insulated structure or thermal protection shell that limits heat penetration inside vehicle Inlet Combustor Nozzle BOEING is a trademark of Boeing Management Company. Copyright © 2014 Boeing. All rights reserved. VKI STO-AVT-234 | 15 New Design Approach Essential for Highly Integrated Systems Such as Hypersonic Vehicles Engineering, Operations & Technology | Boeing Research & Technology Platform Performance Technology SYSTEM Aero Propulsion Aero Prop SYSTEM Control Structure Control Structures Conventional Design Highly Integrated Design • Conventional airplane design approach cannot be used for highly integrated hypersonic vehicles • New design approach requires integrated computer design tools and mathematical optimization –Multidisciplinary Design Optimization (MDO) BOEING is a trademark of Boeing Management Company. Copyright © 2013 Boeing. All rights reserved. MS&T 2013 | 16 Numerical Example Illustrates Integrated Vehicle Design Challenge Engineering, Operations & Technology | Boeing Research & Technology Platform Performance Technology • Design Challenge: “Needle in a haystack problem” • Large number of variables (V) • Several permutations (P) of each variable required to capture interactions V • Number of possible designs, N D = P P V 3 4 5 243 1024 10 59,049 1.05 x 10 6 15 1.43 x 10 6 1.07 x 10 9 • Optimization algorithms permit efficient design space searches BOEING is a trademark of Boeing Management Company. Copyright © 2013 Boeing. All rights reserved. MS&T 2013 | 17 Feasible/Superior Hypersonic Vehicle Design Enabled by Multidisciplinary Design Analysis & Optimization Engineering, Operations & Technology | Boeing Research & Technology Platform Performance Technology Develop Parametric Vehicle Construct Design of Perform Model & Select Parameters Experiments – Defines Multidisciplinary (Variables) for Optimization Vehicle Set for Analysis Analysis of Vehicle Set Add Configuration Refine Optimization Design Details Expensive Expensive Analysis Analysis Expensive Expensive Analysis Analysis Run Optimizer to Find Best Analyze Model Quality Create Mathematical Model of Design (Analysis of Variance) Analysis Output BOEING is a trademark