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Flow Simulation of a Maple Seed. Jake Holden Thomas Caley Dr. Mark Turner. Goals & Objectives. Question to answer: “How has time optimized this natural wind turbine? ” Understand/discover the physical and rotational properties of the maple seed - PowerPoint PPT Presentation
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Flow Simulation of a Maple Seed
Jake HoldenThomas CaleyDr. Mark Turner
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Goals & Objectives• Question to answer: “How has time
optimized this natural wind turbine?”• Understand/discover the physical and
rotational properties of the maple seed• Simulate the flow field of a falling maple
seed • Post-process the results to analyze and
understand the flow field• Modify standard conditions and design to
explore wind turbine potentials
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Timeline
Task 1 2 3 4 5 6 7 8 9 10
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Understand goals and review literature
Quantify seed specimens
Learn CFD tools
Simple ducted flow simulations
Full falling seed simulation
Solution analysis and concept testing
Final takeaways and deliverables
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Accomplishments• Collected Seed samples (12)• CT Scans of seeds to acquire 3D model• Recorded falling maple seeds with high-
speed camera at 3000 frames/second• Quantified high-speed data (rotation
speed, angle of rotation, and fluid velocity)• Computational Fluid Dynamics (CFD)
simulation of seed falling in duct to analyze work done by seed
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1. Seeds were placed in foam fixture on their back edge to prevent blade distortion and allow multiple parts per scan.2. Fixture was placed in machine on turntable
CT Scans
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3D Geometry
*All geometry thanks to Exact Metrology donating time and expertise
CT scanning time takes about 1.5 hours, then final model must be constructed in proprietary software
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High-Speed Data (1 of 2)
Species 1 Species 2 Species 3
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High-Speed Data (2 of 2)
Species 1 Species 2 Species 3
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Flow Physics
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Computational Fluid DynamicsWorkflowGeometry (CT
Scans)
Grid Fluid Volume
Establish Models & Assumptions
Run CFD Solver
Post Process Solution
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Assumptions/Model
• Pressure outlet wall and rotating seed body
• Incompressible Flow • Steady Flow• Three-Dimensional• Turbulence Modeling (k-ε)• No structural deflection (rigid body)
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CFD Simulation (1 of 8)
Cylindrical Domain Grid Generation≈ 2 million pts
CFD Simulation (2 of 8)
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Relative Velocity Stream tubes extended in both directions to show fluid as seen by the seed
CFD Simulation (3 of 8)
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Relative Velocity Stream tubes on Pressure (bottom) and Suction (top) sides
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CFD Simulation (4 of 8)
Relative Velocity Stream tubes on Pressure (bottom) and Suction (top) sides
CFD Simulation (5 of 8)
Relative Velocity Stream tubes at Leading Edge
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CFD Simulation (6 of 8)
Relative Velocity Stream tubes looking from tip to seed illustrating Leading Edge incidences
Seed Static Pressure Contours
CFD Simulation (7 of 8)
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Suction Side (Top)
Pressure Side (Bottom)
CFD Simulation (8 of 8)
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InletOutlet
Relative Total Pressure contours on the inlet and outlet of the duct (*notice the average drop in Pt)
Performance Analysis (1 of 2)
• Figures of Merit:– Axial Induction Factor– Lift vs. Weight
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Performance Analysis (2 of 2)
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Next Steps• Balance Lift & Weight by tweaking
flow velocity and rotational velocity• Modify geometry to observe how
specific features impact flow characteristics
• Draw comparisons and continue analyzing in terms of wind turbine performance
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References• Sairam, K. (2013) “The influence of Radial Area Variation on Wind
Turbines to the Axial Induction Factor”, M.S. Thesis, University of Cincinnati, Cincinnati, Ohio
• Normberg, R. A. “Auto-Rotation, Self-Stability, and Structure of Single-winged Fruits and Seeds (Samaras) with Comparative Remarks on Animal Flight” Biology Review 48 (1973), 561-96. Print.
• www.exactmetrology.com/ *Special Acknowledgement to Exact Metrology for scanning images
• http://www.compadre.org/informal/features/featureSummary.cfm?FID=1227
• http://preachrr.wordpress.com/2011/04/07/maple-seed-design-really-%E2%80%9Ctakes-off%E2%80%9D/
• http://apps.carleton.edu/campus/facilities/sustainability/wind_turbine/