ON THE DESIGN OF HYPERSONIC INLETS

Transcription

1 ON THE DESIGN OF HYPERSONIC INLETS 3rd Symposium on Integrating CFD & Experiments in Aerodynamics USAFA, CO June, 2007 Capt Barry Croker Executive Officer to the AFRL Vice Commander Air Force Research Laboratory

2 Acknowledgements Dr. Datta Gaitonde Ms. Heidi Meicenheimer Mr. Pete Kutschenreuter Air Vehicles Directorate, AFRL Dr. John Schmisseur AFOSR DoD HPCMO, ASC MSRC 2

3 Overview USAF High Speed Vision Hypersonic Design Process JAWS Inlet Program Design Methodology CFD Verification & Validation Experimental Test Program Conclusions 3

4 USAF High Speed Mission Future Capabilities: Prompt Global Strike Long Range Strike Operationally Responsive Access to Space Hypersonic flight will enable unparalleled global reach and power 4

5 Challenges of High Speed Flight Boundary layer transition on external surfaces and inlet Balance engine/airframe over entire speed regime Shock/boundary layer interactions Mass capture, contraction limits in inlet Cowl lip drag and heat transfer Isolator performance and operability Fuel injection drag, mixing and heat transfer External burning ignition and flame-holding Nozzle over-expansion at transonic speeds Nozzle recombination losses Key enabling technologies need to be developed to make sustained hypersonic flight feasible! 5

6 AFRL Design Core Competency Engineering Design Tools Experimental Ground Testing High-Fidelity CFD to establish a core-competency in hypersonic vehicle inlet design 6

7 Engineering Design SHOCK BOX R X Y Y 0 X X 1 Z b Invisicid Streamtracing UPSTREAM X-Y PLANE θ 2 Y 0 θ 1 δ 1 X 1 δ 2 R Y 1 DOWNSTREAM X-Z PLANE b θ 4 θ 3 δ 3 X 2 δ 4 R Z 4 7

8 Computational Verification AVUS Design Space Exploration 2 nd Order Unstructured RANS + SA or BL FDL3DI High-Fidelity Analysis 3 rd Order Structured RANS + k-ε Euler Stream Trace Verification Shock Location Turbulent Viscous Corrections Nonlinear Effects 8

9 Centerline X-Y Plane 9

10 2D Centerline X-Y Plane 10

11 2D Centerline X-Y Plane 11

12 JAWS Inward-Turning, Circular Cross Section M = 5-10 Q = psf 12

13 Planar Shock Topology Quarter-Section Rectangular Analogy Secondary Reflection Y Secondary Shock X Z Primary Reflection Primary Shock Full Topology 13

14 Inviscid Results Mach Number along X-Z Centerline Plane 14

15 Inviscid Results Mach Number along X-Y Centerline Plane 15

16 Viscous Correction JAWS3 Windtunnel Model - Inviscid/Viscous 1.5 Y - Inches Lip Shk2 Impingement Shk4 Impingement & Exit Viscous Shk2 Impingement Viscous exit Z - Inches Boundary layer momentum thickness accounted for through each shock 16

17 Turbulent Results Mach Number along X-Y Centerline Plane 17

18 Turbulent Results Mach Number along X-Z Centerline Plane 18

19 Comparison of Results Mach Number along X-Y Centerline Plane Invisicid Viscous 19

20 Comparison of Results Mach Number at Exit Plane Invisicid Viscous 20

21 Swept-Shock Boundary Layer Interaction Isosurface of TKE in Boundary Layer 21

22 Swept-Shock Boundary Layer Interaction Separated Boundary Layer Centerline Vortex Interaction Flows 22

23 Conclusions of CFD Overall shock structure well aligned with prediction Viscous correction adequate for shock location Influence of Swept-Shock Boundary Layer Interaction could have implications on performance 23

24 Experimental Test Program NASA Langley Aerothermodynamics Branch 20 Mach 6 Tunnel Originally Planned for May, Slipped to August Test Goals: Establish inlet starting parameters Back-pressure study Evaluate on and off design performance Angle of Attack/Yaw Re & M inf 24

25 Model Fabrication Instrumentation location based on CFD predictions Diagnostics include: - Pressure - Temperature - Surface Oil Flow Visualization 25

26 Conclusions & Future Work Functional Analytical Design CFD to check & improve method EFD to verify computations & improve method Engineering Design Tools Experimental Ground Testing High-Fidelity CFD CFD on off-design cases Comparison of CFD & EFD data 26