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Supersonic Wind and Imaging Flow Tunnel. Kendria Alt Joshua Clement Shannon Fortenberry Katelynn Greer. David McNeill Charlie Murphy Matthew Osborn David Springer. Content. Background Objective Tunnel Design Visualization Design Current Configuration Project Management. Objective.
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Supersonic Wind and Imaging Flow Tunnel Kendria Alt Joshua Clement Shannon Fortenberry Katelynn Greer • David McNeill • Charlie Murphy • Matthew Osborn • David Springer
Content • Background • Objective • Tunnel Design • Visualization Design • Current Configuration • Project Management
Objective • Supersonic wind tunnel and flow visualization system • Operable by engineering undergraduates • Mach 1.5 – 3 in 0.5 increments • Mach ±0.05 accuracy • Customer: Dr. Brian Argrow Home
Background • Project attempted 6 years ago • Failed due to choked flow before nozzle • Commercially available supersonic wind tunnels • Aerolab 1” x 1” with Schlieren and 4 models • $127,213.00 • Footprint ≈ 30 ft2 • Noise ≈ 120 dB • Commercially available Schlieren system • Focal length longer than cart top • Low quality • Edmund Optics Home
Requirements Home
Tunnel System Valve Regulator Matt Osborn David Springer Nozzle and Test Section Settling Tank Pressure Reservoir **Conceptual Representation Only Home
V R Pressure Reservoir ST Conceptual Representation Only Tunnel Decision Flowdown Home
V R Pressure Reservoir ST Conceptual Representation Only Tunnel Configuration Alternatives Home
Pressure Reservoir Steady State(Appendix B) Not Feasible Vacuum Tunnel(Appendix B) Not Feasible Blowdown Tunnel (Appendix B) Compressor Atmosphere V Nozzle Nozzle Nozzle V Atmosphere Atmosphere Vacuum Reservoir • Too large of a compressor at Mach 3 • Complicated • Huge 21 ft3 required • Need large vacuum pump • Condensation and Icing • Much smaller reservoir (high pressure) • No condensation or icing • Commercial gas (no pumps) Tunnel Configuration Alternatives Home
Initial Analysis Conclusions Full Mach Range Home
V R Pressure Reservoir ST Conceptual Representation Only Gas Selection Home
Gas Selection • Specifics • Oxygen eliminated on safety • Nitrogen selected over air based on cost • 2200 psi: $6.45 • 3500 psi: $138 • 6000 psi: $198 Conclusions Nitrogen available in both liquid and gaseous forms. Purchase through AirGas or on campus. Home
V R Pressure Reservoir ST Conceptual Representation Only Liquid vs. Gas Nitrogen Home
V R Pressure Reservoir ST Conceptual Representation Only Regulators vs. Second Tank Home
R R R R R R R V R V R V Regulators vs. Second Tank 8 Tanks – 8 Regulators • Requirement • 0.0183 slugs/s → 29,000 scfh • Tanks: 4000 scfh • Minimum 8 tanks • Regulators: 6000 scfh • Minimum 6 regulators • Each regulator > $300 • 48 Runs at Mach 2 • Constant test section properties 8 Tanks – 1 Regulator – Second Tank – 2 Valves • Second tank • 4 cubic feet @ 1000 psi maximum • Can manufacture for ~ $700 • 12 Runs at Mach 2 • Properties in test section change Conceptual Representations Only Appendix C Home
V R Pressure Reservoir ST Conceptual Representation Only Liquid vs. Gaseous Nitrogen Home
V R V V V Liquid vs. Gaseous Nitrogen • Gaseous Nitrogen • 8 Tanks – One Regulator – Two Gaseous Valves • 8 Hoses and Manifold – Complicated ($$) • Liquid Nitrogen • 1 Tank –Cryogenic Valve – Heater Element – Gaseous Valve • Hours of run time • 11,430.67 BTU/hr → $200 heater • Liquid Nitrogen available on campus • Thermal Fatigue on 2nd Tank • Currently not enough information to decide • Parallel Paths • Drop Dead Date of Oct. 26 Home
V R Pressure Reservoir ST Conceptual Representation Only Nozzle Material Home
Nozzle Material Selection V∞ 447.2°R 190.4°R Not to Scale • Temperature differences at throat and test section • Contraction differences modify Mach number Home
Nozzle Material Selection • Specifics • CTE: Coefficient of Thermal Expansion • Specific Strength: lightweight under pressure • Hardness affects machinability • Assumed 120 sec of continuous Mach 2 flow • Conclusions • Sensitivity analysis supports Invar for CTE > 43% Material Specs:Appendix D Home
V R Pressure Reservoir ST Conceptual Representation Only Test Section Sidewall Home
Test Section Material Selection • Test section cross section • Grey: Transparent windows • Green: Metal • Materials contract at different rates 190.4°R Not to Scale Home
Test Section Material Selection • Specifics • k: Conductivity affects condensation • n: Refractive Index - visualization • % Visible - transparency • Hardness - scratch resistance • Assumed 120 sec of continuous Mach 2 flow • Conclusions • Sensitivity analysis shows Plexiglass and Glass ~50/50 Material Specs :Appendix D Home
V R Pressure Reservoir ST Conceptual Representation Only Test Section / Nozzle Structure Home
Test Section / Nozzle Structure • Requirement: 3 objects, 4 Mach numbers each • Test Section/Nozzle configuration • 4 Nozzles with 3 interchangeable test sections • 12 Fixed nozzle / test section combos • Less complex • Nozzle / Settling Tank Connection • Round nozzle w/ pipe threads • Slip connector • Flanges w/ clamps • Easy to use • Quick change out of nozzle Home
Additional Requirements & Risks • Noise Constraints • EH&S guidelines • 85 dB • Ability to Troubleshoot • In the event of initial failure to achieve supersonic flow • Reservoir pressure and temperature measurements • Risks • Budget • Manufacturing • Safety Home
Noise Ref [7] Ref [7] Home
Troubleshooting Instrumentation • Settling Tank Thermocouple • Easily integrated with LabView • K type • NPT fitting for pressure vessels • Settling Tank Pressure Transducer • Commercially available • Compact • Easily integrated with LabView • 0 - 2000 psi • NPT fitting • Pitot TubeAppendix E Ref [8] Ref [9] Home
Tunnel Risks Home
Tunnel Risk • Liquid Nitrogen Heater (11/01) • Inadequate specifications • Thoroughly research heater options • Settling Tank Design and Thermal Fatigue (10/26) • Inadequate specifications and cost • Custom or in-house • Contact vendors and Matt Rhode • Cryogenic Valve (10/26) • Inadequate specifications • Continue dialog with AirGas vendor Home
Visualization System Kendria Alt Josh Clement Home
Schlieren, Shadowgraph, Interferometer • Shadow Graph • 2nd derivative of density • Simplest method • Lower contrast • Schlieren • 1st derivative of density • Small increase in complexity • Increase in contrast • Interferometer • Density • Sum of path differences < λ/10th • Least familiarity Example Pictures: Appendix F Home Ref [1]
Schlieren Layout Home
Schlieren Layouts • Z • Precise angles prevent coma aberration • Large footprint • Double Pass • Nonparallel light in test section • Advantage of size • Straight Schlieren • Smaller focal length • Ease of integration Ref [2] Home
Schlieren Layout • Specifics • Clarity: most important, verification • Size: must be able to fit on cart top • Stability: must be able to withstand movement without quality loss • Time to build: number of parts, complexity, and tolerances • Ease of design: depth of calculations • Conclusions • Straight setup has high accuracy and small footprint • Straight setup is easy to use and calibrate Home
Lenses • Types • Focusing Lens • Different wavelengths have different focal lengths • Achromatic Lens • Reduces chromatic aberration • Dual lenses • Achromatic Objective Lens • Changes orientation of aberrations • Two lenses separated by air or oil • Expensive ~$500 to $1000 • Specifications • Diameter: 3 in • Focal Length: 0 to 6 in Home
Refraction Detection • Knife Edge • Clear black and white visualization • Vertical or horizontal placement show different details • Radial Color Filter • Density variations stand out • Linear Color Filter • Provides color and intensity differences for high and low densities Ref [14 ] Ref [15 ] Ref [16 ] Home
Refraction Detection • Manual Three Axis Support • Easy calibration within 7.87 10-5 in • Calibration performed once per semester • Cost ~ $500 • Motorized Mounts • Expensive ~ $1000 • Accurate to 3.94 10-3 in • Interchange • Provide 3 filters for the 4 visualization methods • Filters mount on a 3-axis adjustable support Home
Capture Method Home
Capture Method • Specifics • Requirement: 2 fps • Resolution normalized to 3 Mega pixels • Frames per second normalized to 20 fps • Prices normalized to a $1500 camera • Conclusions • CMOS and CCD comparable • Final decision based on individual specifications Ref [18] Home
File Transfer Method • Specifics • Speed normalized to 10 Mbytes/s • Cable cost includes max length and durability • Only USB and GPIB are immediately compatible with LS • FireWire cards $50 • Ethernet activation- $350 • Conclusions • The ideal file transfer method will be FireWire • Other constraints may require a less desirable method Home
Camera Adjustability • 2-Axis Adjustability • Ability to focus 3rd dimension with camera • Ease of use • Locking • Commercial Mount • Expensive ~ $350 • Custom Mount • Complicated design • Intricate Fabrication Ref [12] Home
Schlieren Base and Encasing • Base • Use the cart top • Use a metal foundation to secure optical components • Encasing • Plastic is light and inexpensive • Metal and wood heavy • Protection of lenses and camera • Students • Dust, scratches, etc. • Light tight during testing • Window for educational purpose • Opening for T.A.s to access instrumentation Home
Visualization Risks Home