Scott A. Berry

Transcription

1 Scott A. Berry

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3 Vehicle Design Process Aerothermodynamics

4 Synergistic Approach for Aerothermodynamic Information Ground Based Testing Computational Fluid Dynamics (CFD) Optimum Aerothermodynamic Data + = Hypersonic wind tunnels Tried proven Navier Stokes solvers Rapidly improving Safe, reliable, successful flight Basic questions Would you fly on access-to-space vehicle if: Designed flown on: Wind tunnel data only? CFD data only? /or Aerothermodynamics taken for granted; relegated to secondary technology? Can have best propulsion, structures, materials, avionics, GNδC, etc.; but if have poor aerothermodynamics, all may be nullified

5 National Aerothermodynamic Capability NASA Centers performing aerothermodynamic studies Nation s conventional hypersonic wind tunnels for aerothermodynamic testing Ames Ames Research Research Center Center (Non-metallic (Non-metallic thermal thermal protection protection system) system) Dryden Dryden Flight Flight Research Research Center Center Johnson Johnson Space Space Center Center (Crewed (Crewed Aerospace Aerospace Vehicles) Vehicles) Arnold Arnold Engineering Engineering Development Development Center Center (AEDC) (AEDC) Tunnels Tunnels B, B, C AEDC AEDC Tunnel Tunnel 9 9 Langley Langley Research Research Center Center Marshall Marshall Space Space Flight Flight Center Center Langley Aerothermodynamics Laboratory (LAL) 20-Inch Mach 6 Air 31-Inch Mach 10 Air 15-Inch Mach 6 Hi Temp. Air 20-Inch Mach Real Gas Simulation

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7 Aerothermodynamics Branch (AB) Personnel Eligible for retirement Computationalists (11) AST below 30 AST Engr. Codes DSMC Disciplines CFD Experimentalists (10) Aero Aeroheating Age distribution Administrative/other (10) Level IIIs etc. Facilities Years age Managers 31 FTE CS AST Education PhD MS BS 60 above

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11 20-Inch Mach 6 Air Tunnel Test Conditions M = 6 Re = E6 /ft P t, 1 = psia T t, 1 = F Test Gas - Air, γ = 1.4 Run times up to 15 min Runs per Day Features Ideally suited for both parametric benchmark aerodynamic, aerothermodynamic fluid dynamic studies Synergism with 31-Inch Mach 10 Air Tunnel allows assessment compressibility effects at constant Re γ Synergism with 20-Inch Mach 6 CF4 Tunnel allows determination real gas aerodynamic effects at constant M Re

12 31-Inch Mach 10 Air Tunnel Test Conditions M = 10 Re = E6 /ft P t, 1 = psia T t, 1 = 1350 ο F Test Gas - Air, γ = 1.4 Run time 120 sec Runs per Day Features Uniform, clean flow; three-dimensional, contoured, water-cooled nozzle five micron particle filter to remove flow contaminates Ideally suited for both parametric benchmark aerodynamic, aerothermodynamic fluid dynamic studies Synergism with 20-Inch Mach 6 Air Tunnel allows assessment compressibility effects at constant Re γ

13 20-Inch Mach 6 CF 4 Tunnel Test Conditions M = 6 (13-18 Simulation) Re = E6/ft P t,1 = psia T t,1 = F Test Gas - CF 4, γ = 1.2 Run times - 20 sec. 4-6 Runs per Day Features Only operational, conventional-type hypersonic facility in this country which simulates dissociative real-gas phenomena associated with hypersonic flight Synergism with 20-Inch Mach 6 Air Tunnel allows determination real gas aerodynamic effects at constant M Re Evaluating use CO 2 as a test gas to support planetary missions

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15 Testing Techniques Phosphor Phosphor thermography thermography to to obtain obtain heat heat transfer transfer Thin-film Thin-film gauges gauges to to obtain obtain heat heat transfer transfer Strain-gauge Strain-gauge balances balances to to obtain obtain aerodynamics aerodynamics Electronically Electronically scanned scanned pressure pressure (ESP) (ESP) systems systems Oil-flow Oil-flow for for surface surface streamline streamline visualization visualization Schlieren Schlierenfor for flowfield flowfield visualization visualization

16 Phosphor Thermography Vehicle Concept Aeroheating data to customers Model Model Fabrication Casting Casting ceramic ceramic models models Rapid Rapid turnaround turnaround Complex Complex shapes shapes Wind Wind Tunnel Testing Two-color Two-color fluorescence fluorescence State--art State--art computerized computerized acquisition acquisition system system Analysis Analysis Measurements Nonlinear Nonlinear theory theory to to infer infer accurate accurate temperatures temperatures User-friendly User-friendly image image program program (IHEAT) (IHEAT)

17 Thermographic Phosphor System

18 Data Reduction Analysis With IHEAT IHEAT Main Routine Analysis EXTRAP Input image data MAP3D DISPER Calibrations SYSCAL LUTCALC TRANSCAL TEMPCAL Vehicle Design Loop

19 Thin-Film/Phosphor Hemisphere Comparison Thin-film model Phosphor data h/h FR h/h h/h FR FR Angle (degrees) M = 10, Re = 1.0 x10 6 /ft. Thin-film data CFD (LATCH) Phosphor data

20 Before After Phosphor Thermography Better Faster Cheaper Before Discrete gauges 150 points/run After Global data 150,000 points/run Impact to a study Increased amount information: 1000x 50 weeks to obtain data on study 5 weeks to obtain data on study Time savings: 10x Fabrication cost: 150K (1 model) Fabrication cost: 15K (5 models) Cost reduction: 10x

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22 Computational Aerothermodynamic Creditability Flow chemistry Dissociation recombination Ionization Radiation Flow physics Transitional/turbulent Separation reattachment Shock-shock interactions Predictions Calibration/validation Comparison to: Ground-based data Previous flight data Passed Apply to flight Numerical process Non-reacting, attached, steady, laminar flow Foundation Hypersonic aerodynamic/ aeroheating data 100 Percent Ground-based experiments Failed Tried proven CFD (for full configuration) Year

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24 AB Productivity (Typical) 80 Work Days Experimental Aerodynamics Pitch-pause (8 to 10 alpha/run) Setup Remove Setup Remove Design model Fabricate/instrument metal model Testtunnel 1 70 runs Testtunnel 2 70 runs 1,120 cases Experimental aeroheating Setup Construct ceramic models (in-house) Test tunnels cases Remove Setup Phosphor thermography (one alpha/run) Test tunnel 3 75 runs 275 plus cases Computational Fluid Dynamics Tip-to tail NS solutions Generate surface grid Generate structured volume grid Run Run first two casecases Run 20 cases Work days (8 hours/day 23 cases

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26 Stardust Comet (Wild-2) Sample Return Computational Fluids Flowfield Flowfield prediction prediction Free-molecular Free-molecular rarefied rarefied (DSMC) (DSMC) aero aero heating heating calculations calculations Hypervelocity Hypervelocity aero aero heating heating CFD CFD computations computations Transonic Transonic aero aero computations computations Provided Provided computations computations to to establish establish transition transition criteria criteria Experimental Testing Program Contributions Phosphor Phosphor mapping mapping Subsonic Subsonic static static dynamic dynamic (spin (spin tunnel) tunnel) aerodynamic aerodynamic tests tests Data Data part part aerodynamic aerodynamic rs database database Thermographic Thermographic phosphor phosphor tests tests for for afterbody afterbody heating heating Identification Identification vehicle vehicle instability instability in in free-molecular free-molecular region region Proposed Proposed increased increased spin spin rate rate solution solution Identification Identification subsonic subsonic dynamic dynamic instability instability Proposed Proposed addition addition stabilizing stabilizing drogue drogue chute chute Formed Formed aerodynamic aerodynamic database database Supported Supported design design TPS TPS design design

27 Genesis Aerothermodynamics Computational Fluids Experimental Heating Program Contributions Cavity Cavity Heating Heating Phosphor Phosphor mapping mapping Turbulent Laminar Transition Transition Criteria Criteria LAURA LAURA Navier-Stokes Navier-Stokes computations computations on on forebody forebody Chemical Chemical thermal thermal nonequilibrium nonequilibrium Forebody Forebody cavities cavities modeled modeled as as axisymmetric axisymmetric grooves grooves obtained obtained LAURA LAURA laminar laminar turbulent turbulent solutions solutions Examined Examined heating heating in in vicinity vicinity edge edge cavity cavity Backshell Backshell aeroheating aeroheating predicted predicted Models Models four four different different scales scales fabricated fabricated with with 6 6 different different forebody forebody cavity cavity configurations configurations Characterized Characterized transition transition onset rs onset with with cavity cavity size size axial axial location location for for a a range range Reynolds Reynolds numbers numbers Heating Heating levels levels varied varied with with cavity cavity size size were were >3x >3x stagnation stagnation Developed Developed method method to to predict predict heating heating footprint footprint behind behind cavity cavity Computations Computations provided provided reacting reacting flow flow capability capability to to industry industry engineering engineering design design code code Backshell Backshell computations computations validated validated engineering engineering design design code code predictions predictions Provided Provided transition transition criteria criteria for for presence presence forebody forebody cavities cavities

28 Mars Microprobe Penetrator Computational Fluids Flowfield Flowfield prediction prediction Free-molecular Free-molecular rarefied rarefied (DSMC) (DSMC) aero aero heating heating calculations calculations Hypervelocity Hypervelocity aero aero heating heating CFD CFD computations computations Transonic Transonic aero aero computations computations Experimental Heating Phosphor Phosphor mapping mapping Phosphor Phosphor thermography thermography data data used used in in unique unique coupling coupling with with flight flight dynamic dynamic simulation simulation rsto to predict predict integrated integrated heating heating loads loads with with vehicle vehicle oscillations oscillations Program Contributions Proposed Proposed novel novel aeroshell aeroshell shape shape for for unique unique mission mission requirements requirements Defined Defined entry entry heating heating environment environment for for TPS TPS design design Compiled Compiled aerodynamic aerodynamic database database

29 Computational Experimental Synergism X-33 Boundary Layer Transition Methodology

30 Roughness Dominated Transition on Reentry Vehicles Recent Experiments Conducted at LaRC By: Scott A. Berry Aerothermodynamics Branch NASA Langley Research Center Nov. 28, 2001

31 LaRC Roughness Experiments 96-98: Shuttle asymmetric BLT flight anomalies 97-00: X-33 investigation discrete (CL AL) distributed (bowed-panels) BLT 98-01: X-38 BLT assessment 01-??: 5-deg Cones roughness database Nov. 28, 2001

32 Experimental Approach 20-Inch Mach 6 Tunnel (conventional) Phosphor thermography Settling chamber 20 x 20 inch test section Model injection/retraction system Flow Schlieren windows Arc sector Variable second minimum To atmosphere Discrete tripping elements Nominal Mach number: 6.0 Reynolds number (x 106/ft): 0.5 to 10.5 Dynamic pressure (psf): 69 to 1264 Total pressure (psia): 30 to 550 Total temperature ( R): 810 to 1018 Run time (minutes): 1 to 15 (mostly) Large database on various Flow L = in. L = in. shapes, trips Height = k k = , , , in. Nov. 28, 2001 s.a.berry@larc.nasa.gov

33 Shuttle Centerline at α = 40-deg AIAA Paper or JSR Vol. 35 No. 3 pp h/h ref 1 G2 Re eff 2.4x10 6 /ft Re=1.57x10 6 /ft Re=1.87x10 6 /ft 0.8 Re inc 1.6x10 6 /ft Re=2.25x10 6 /ft Re=3.17x10 6 /ft 0.6 Re=4.33x10 6 /ft Re=4.45x10 6 /ft 0.4 (x/l) trip = x/l Re θ /Me LAMINAR G1 ECL1 DE1 G2 ECL2 G3 D1 DE2 ECL3 DE3 Re θ /Me C(k/δ) -1 INCIPIENT C = 21 EFFECTIVE C = 30 TURBULENT D2 B2 DE4 D3 D k/ δ Boundary layer edge properties calculated with BLIMP Nov. 28, 2001 s.a.berry@larc.nasa.gov

34 X-33 Centerline Trip Station AIAA Paper or JSR Vol. 38 No. 5 pp α = 20, 30, Re θ /Me C(k/ δ) Incipient C = 45 α = 40-deg Re θ /Me Effective C = 60 TURBULENT Trip Station LAMINAR k/δ α = 20-deg Boundary layer edge properties Calculated with LATCH Nov. 28, 2001 s.a.berry@larc.nasa.gov

35 X-33 Attachment Lines a = 20 a = 20, 30, 40-deg 350 Old Centerline Data Req/Me ª C(k/d) Incipient C = 45 Effective C = New Attachment Line Data m No Trip Effect (Laminar) o Marginal Trip Effect n Fully Effective Trip Req/Me a = 30 a = 40 TURBULENT 200 nn on n oo o n n oo m m mm m n n n n m mm o o on o mm o m m m mo m o mmm m m n LAMINAR k/d Nov. 28, 2001 s.a.berry@larc.nasa.gov 1.2

36 X-33 Bowed Panels Side view k = in in in in in Discrete Centerline Chine Re = 3.1x10 6 /ft in Extended Extended Both 1st Row Configurations tested Re = 4x10 6 /ft Nov. 28, 2001 s.a.berry@larc.nasa.gov

37 LATCH Comparison Centerline Effective Transition Results Computed with LATCH Preliminary Shuttle α = 40-deg X-33 α = 20-deg X-33 α = 30-deg X-33 α = 40-deg X-38 α = 40-deg TURBULENT Re θ /Me 10 LAMINAR 70 ± 20% k/δ Nov. 28, 2001 s.a.berry@larc.nasa.gov

38 Quiet Tunnel Cones Model 93-10, r n = in, α = 0.0 deg GASP-Lam R3 No Trip R70 Single Diamond R118 Single Sphere R141 Dist. Spheres k = in. x = 2-in. Re = 4.4x10 6 /ft h/h ref x, inches Nov. 28, 2001 s.a.berry@larc.nasa.gov

39 Concluding Remarks Roughness effects in conventional hypersonic facility shown to be well behaved: -must use consistent approach (i.e. same computational method) -results consistent across platforms -CL AL follow same trends -discrete element worst case Noise effects needs further investigation by comparing current database to quiet tunnel flight results Nov. 28, 2001