Thermal & Fluids Analysis Workshop TFAWS 2004 Jet Propulsion Laboratory Pasadena, CA. August 31, 2004 COMPARISON OF ENGINEERING LEVEL AND FULL NAVIER STOKES PREDICTIONS WITH TEST DATA AT THE NAVY’S AIR BREATHING ENGINE AND AEROTHERMAL TEST FACILITY T-RANGE Ron Schultz & Dr. Warren Jaul Naval Air Warfare Center China Lake, CA Dr. Gerald Russell U.S. Army Aviation and Missile Research Development, and Engineering Center
Overview • A comparison of engineering level and full Navier-Stokes predictions of flow-field heating conditions was made for a series of aerothermal tests performed at the Naval Air Warfare Center Air Breathing Engine and Aerothermal Test Facility, T-Range, in China Lake CA. • Thin skin calorimeters were used to quantify the aerothermal boundary conditions imparted to a test fixture. • The engineering level analysis code ATAC3D, developed under an Army SBIR, was used to derive the local boundary conditions. • The full Navier-Stokes computational fluid dynamics code OVERFLOW was used to quantify the relative flow field and resulting heat fluxes for comparison to the engineering predictions and data • This presentation will discuss the analytic and experimental methods utilized to determine boundary conditions and possible flowfield effects on a complex test fixture.
T-Range Capabilities • High-Pressure Air Blow Down Facility • 2900 cu ft of air stored at 3000psia • Propane/Air combustion used to raise enthalpy of air increased • Air exhausted to atmosphere at 2300 ft above sea level • Makeup oxygen used for engine testing to replace that used in propane/air combustion
T-Range Capabilities • Air, propane and O 2 digitally Test article in Test article in controlled by PC running LabView nozzle free- nozzle free- with full proportion-integral- jet jet differential gain control loops • T t of air adjusted w/mass flow to match hot wall heat fluxes and surface temperatures in flight • Free-jet nozzles: P t in air heater held constant so flow is perfectly expanded to avoid shocks and expansion waves • Direct-connect engines: Computer control used to vary P t and T to match variation due to missile altitude and velocity changes
T-Range Enhancements O P E R A T IN G E N V E L O P E M O D E L 2 0 0 0 F L - 4 0 0 - 3 0 0 0 1 0 0 0 • New air heater and nozzle being installed – Capable of continuous operation at 4500 °F 1 0 0 – Nozzle (13.4” exit) will M a s s F lo w operate at Mach 3.65 ( lb m /s e c ) 5 0 0 0 R – SUE burner uses a replaceable 4 0 0 0 R water-cooled liner to increase 1 0 3 0 0 0 R mass flow and T t for both test 2 0 0 0 R cells • Additional air storage, totaling 4650 cu. ft. 1 1 0 1 0 0 1 0 0 0 1 0 0 0 0 P r e s s u r e ( p s ia )
T-Range Enhancements • Stagnation heating rates up to 1000 btu/ft 2 -sec (ref: 2-inch diameter hemisphere)
T-Range Flow Conditions • Facility Conditions for Current Test – Mach 1.9 Semi-Contoured Nozzle, P CHAMBER =90 psi (mass flow, m DOT , and T CHAMBER were variable to match transient environment of interest) – Facility channel labeled TPL-1 was used as a measure of chamber temperature. The value of TPL-1 was used as the total temperature in both ATAC3D and OVERFLOW 9” Nozzle Exit Mach 1.9 Nozzle Contour 4” Nozzle Throat 18”
Wedge Test Fixture 1.83” 2.29” 3.53” 5.0” Flat Plate Test Section 9” 15° Half Angle 1.5” 0.03” Radius LE 3.35° Half Angle 12° Half Angle Wedge Test Section 1.34” 4.89” Nozzle Exit
Thin Skin Calorimeter Design 5.0” 0.187” 4.5” Thin Skin Wall Thickness A 0.125” for Wedge Calorimeter Includes 2 Pressure Ports 9 Welded Backside Thermocouples 3.700” Pressure Port 3.5” 5.0” 0.069” for Flat Calorimeter No Pressure Ports 9 Welded Backside Thermocouples 1.375” A 0.625” Section A-A Flow 1.750” 2.500” 4.375” Thermocouples 4,14 1,11 7,17 #s correspond to 5,15 2,12 8,18 Wedge,Flat 3,13 6,16 9,19
3-D Finite Element Analysis FEA provided comparison of 1-D versus 3-D thermal response of calorimeter Detailed FEA provided confidence in calorimeter thermostructural response
ATAC3D Analysis Configurations • 0.03” Radius LE Plane of Symmetry • 3.35° Fin Leading Edge Half Angle • 15° 2 nd Wedge • 12° Test Section Wedge Plane of Symmetry • 0.03” Radius LE • 3.35° Fin Leading Edge Half Angle • 15° 2 nd Wedge • Flat Test Section Wedge
Comparison of Thin Skin Data and Predictions Profile 3 Wedge Data Compared With Predictions for Profile 3 Data Profile 3 Wedge 0.125" Wedge Thin Skin Tests Using TPL-1 Chamber Condition Data Profile 3 Wedge 0.069" 0.125" & 0.069" Thin Skin ATAC3D 069 TC6 ATAC3D 125 TC6 1100 1000 900 800 700 Temperature (F) 600 500 Acceptable agreement between 400 analysis and measured test data 300 for wedge configuration 200 100 0 0 5 10 15 20 25 30 35 40 Time (sec)
Comparison of Thin Skin Data and Predictions Profile 4 Wedge Data Compared With Predictions for Profile 4 Data Profile 4 Wedge 0.125" Wedge Thin Skin Tests Using TPL-1 Chamber Condition Data Profile 4 Wedge 0.069" 0.125" & 0.069" Thin Skin ATAC3D Wedge 0.069" ATAC3D Wedge 0.125" 800 700 600 Temperature (F) 500 400 300 Acceptable agreement between 200 analysis and measured test data for wedge configuration 100 0 0 5 10 15 20 25 30 Time (sec)
Profile 1 Predictions and Data Flat Test Section Data Thin Skin TC16 CMA 55% of h/cp Baseline Prediction 1000 TC15 Modified 900 TC15 Baseline Analysis Prediction h/cp Prediction 800 700 Temperature (F) 600 500 TC16 Data 400 300 200 100 0 0 5 10 15 20 25 30 35 40 Time (sec)
Profile 2 Predictions and Data Flat Test Section Data Profile 2 TC15 ATAC3D Baseline DATA Thin Skin TC11 CMA 55% h/cp 1000 Baseline TC15 900 55% Modified h/cp TC15 800 700 TC11,15 Temperature (F) 600 500 400 300 200 100 0 0 5 10 15 20 25 30 35 40 45 Time (sec)
Predictions and Data Comparison • Why does ATAC3D provide good agreement for the 12 degree wedge calorimeter data but over predicts the thermal response for the flat configuration? – Laminar versus Turbulent flow? – Flow separation? – Prandlt-Meyer expansion fan causing below ambient pressure distribution? – Need to assess engineering method for predicting heating • CFD was utilized to visualize the flowfield over the 2 configurations and provide a more rigorous characterization of the aerothermal environment
CFD Modeling Assumptions • OVERFLOW full Navier-Stokes code • 3-dimensional flow • Real gas effects • Nozzle contour modeled • Boundary layer resolved for various chamber and wall temperatures of interest: (1200°F-300°F,600°F:1800°F-300°F, 800°F)
Velocity Contours Non-dimensionalized by the free-stream speed of sound (337.9 m/s, 1108.6 ft/s)
Mach Number Profile T0=1200F, Twall = 300F Boundary Layer well resolved at the wall for both velocity and temperature. No Flow Separation & Verified Uniform Flow
Static Pressure (P amb. = 1.0) Low pressure on the bottom, flat, surface
Static Temperature (T amb. = 511R).
CFD Static Pressure on Flat Test Fixture 0.5<Ps (atm)<2.5 0.5<Ps (atm)<1.0 Sub-ambient and variable pressure at calorimeter station
CFD Surface Static Pressure (psia) FLAT WEDGE
CFD Surface Recovery Temperature FLAT WEDGE Note: Trec is computed by extrapolating from two isothermal wall solutions (300F and 600F) to the adiabatic wall temperature.
CFD Convective Heat Flux at Twall = 300°F FLAT WEDGE
FLAT CFD Shear Stress WEDGE
ATAC3D Shear Stress Plane of Symmetry 1200 F Total Temperature Wall Shear at 300 F Wall 30 Wedge ATAC3D 28 Flat ATAC3D Cal Plate Center for Wedge 26 24 Wall Shear (psf) 22 20 18 16 CFD Wedge : 17 psf 14 CFD Flat: 13 psf 12 Cal Plate Center for Flat 10 0 2 4 6 8 10 12 14 16 Axial Station (in)
ATAC3D Edge Pressure 1800 F Total Temperature Edge Pressure 20 Wedge ATAC3D Cal Plate Center for Wedge Flat ATAC3D 18 16 E d g e P ressu re (psi) 14 12 CFD Wedge : 17 psi CFD Flat: 9 psi 10 8 Cal Plate Center for Flat 6 0 2 4 6 8 10 12 14 16 Axial Station (in)
Heat Flux Comparison of Plane of Symmetry Plane of Symmetry ATAC3D and CFD 1200 F Total Temperature Heat Flux 300 F Wall 80 Flat CFD C old W all H eat Flux (B tu/ft2-sec) Wedge CFD Cal Plate Center for Wedge 70 Wedge ATAC3D 60 Flat ATAC3D 50 40 30 20 10 Cal Plate Center for Flat 0 0 2 4 6 8 10 12 14 16 Axial Station (in)
Heat Flux Comparison of ATAC3D and CFD 1200 F Total Temperature Wall Heat Flux 600 Wall 50 Flat CFD Wedge CFD 45 Wedge ATAC3D Cal Plate Center for Wedge 40 Flat ATAC3D Heat Flux (Btu/ft2-sec) 35 30 25 20 15 10 5 Cal Plate Center for Flat 0 0 2 4 6 8 10 12 14 16 Axial Station (in)
Heat Flux Comparison of ATAC3D and CFD 1800 F Total Temperature Wall Heat Flux 300 F Wall 120 Flat CFD Wedge CFD Cal Plate Center for Wedge Wedge ATAC3D 100 Flat ATAC3D H eat Flux (B tu/ft2-sec) 80 60 40 20 Cal Plate Center for Flat 0 0 2 4 6 8 10 12 14 16 Axial Station (in)
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