ON THE DESIGN OF HYPERSONIC INLETS

3rd Symposium on Integrating CFD & Experiments in Aerodynamics

USAFA, CO

20-21 June, 2007

Capt Barry CrokerExecutive Officer to the AFRL Vice Commander

Air Force Research Laboratory

2

Acknowledgements

• Dr. Datta GaitondeMs. Heidi MeicenheimerMr. Pete KutschenreuterAir Vehicles Directorate, AFRL

• Dr. John SchmisseurAFOSR

• DoD HPCMO, ASC MSRC

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Overview

• USAF High Speed Vision

• Hypersonic Design Process

• JAWS Inlet Program

– Design Methodology

– CFD Verification & Validation

– Experimental Test Program

• Conclusions

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Future Capabilities: Prompt Global StrikeLong Range StrikeOperationally Responsive Access to Space

USAF High Speed Mission

Hypersonic flight will enable unparalleled global reach and power

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Balance engine/airframeover entire speed regime

Cowl lip dragand heat transfer

Boundary layertransition on external surfaces and inlet

Fuel injection drag,mixing and heat transfer

Nozzle over-expansionat transonic speeds

External burning ignitionand flame-holding

Mass capture, contractionlimits in inlet

Nozzle recombinationlosses

Isolator performanceand operability

Shock/boundary layerinteractions

Challenges of High Speed Flight

Key enabling technologies need to be developed to make sustained hypersonic flight feasible!

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AFRL Design Core Competency

EngineeringDesign Tools

High-FidelityCFD

ExperimentalGround Testing

“…to establish a core-competency in hypersonic vehicle inlet design…”

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Engineering Design

X

Y

Z

0

2

R

X 1

X 2

Y0

b

4

SHOCK BOX

1

2

1

2

R

Y1

Y0

X1

UPSTREAM X-Y PLANE

3

4

3

4

R

Z4

b

X2

DO W NSTREAM X-Z PLANE

Invisicid Streamtracing

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Computational Verification

AVUSDesign Space Exploration2nd Order Unstructured RANS + SA or BL

FDL3DIHigh-Fidelity Analysis3rd Order Structured RANS + k-

EulerStream Trace VerificationShock Location

TurbulentViscous CorrectionsNonlinear Effects

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Centerline X-Y Plane

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2D Centerline X-Y Plane

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2D Centerline X-Y Plane

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JAWS

Inward-Turning, Circular Cross Section M = 5 - 10Q = 1000-1500 psf

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Planar Shock Topology

X

Z

Y

Quarter-SectionRectangular Analogy

Full Topology

Primary Shock

Primary Reflection

Secondary Shock

Secondary Reflection

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Inviscid Results

Mach Number along X-Z Centerline Plane

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Inviscid Results

Mach Number along X-Y Centerline Plane

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Viscous Correction

JAWS3 Windtunnel Model - Inviscid/Viscous

0.0

0.5

1.0

1.5

0.0 0.5 1.0 1.5

Z - Inches

Y -

In

ches

Lip

Shk2 Impingement

Shk4 Impingement & Exit

Viscous Shk2 Impingement

Viscous exit

Boundary layer momentum thickness accounted for through each shock

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Turbulent Results

Mach Number along X-Y Centerline Plane

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Turbulent Results

Mach Number along X-Z Centerline Plane

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Comparison of Results

Invisicid

Viscous

Mach Number along X-Y Centerline Plane

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Comparison of Results

Invisicid Viscous

Mach Number at Exit Plane

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Swept-Shock Boundary Layer Interaction

Isosurface of TKE in Boundary Layer

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Swept-Shock Boundary Layer Interaction

• Separated Boundary Layer• Centerline Vortex• Interaction Flows

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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

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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 & Minf

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Model Fabrication

• Instrumentation location based on CFD predictions

• Diagnostics include:- Pressure- Temperature- Surface Oil Flow Visualization

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Conclusions & Future Work

• Functional Analytical Design

• CFD to check & improve method

• EFD to verify computations & improve method

• CFD on off-design cases

• Comparison of CFD & EFD data

EngineeringDesign Tools

High-FidelityCFD

ExperimentalGround Testing