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P14651: Drop Tower for Microgravity Simulation

P14651: Drop Tower for Microgravity Simulation. Adam Hertzlin Dustin Bordonaro Jake Gray Santiago Murcia Yoem Clara. Project Summary. Problem Goals Design & Build Drop Tower Vacuum Piping Structure Cost Effective Effective Cycle Time Aesthetically Pleasing Precision in Measurements

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P14651: Drop Tower for Microgravity Simulation

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  1. P14651: Drop Tower for Microgravity Simulation Adam Hertzlin Dustin Bordonaro Jake Gray Santiago Murcia Yoem Clara

  2. Project Summary • Problem Goals • Design & Build Drop Tower • Vacuum Piping Structure • Cost Effective • Effective Cycle Time • Aesthetically Pleasing • Precision in Measurements • Educational User Interface • Access for Object Transfer • Adaptability for Future Development • Constraints • Location and design approval from the dean(s) • Material availability/size (ex. tube, pump) • The device is aesthetically pleasing • The tower 6” – 12” Diameter • The device can be operated year round. • The system is safe to operate. • The project budget is $3,000. Team must justify the need for additional funds. • The project must be completed in 2 semesters.

  3. Project Deliverables • Installed drop tower • Detailed design drawings and assembly manual • Bill of materials • User’s Guide for operation • Designed Lab Experiments • Determine gravity in the vacuum within 1% error • Compare drag at different pressures and drag vs. acceleration • Additional vacuum related experiments • Fun and Educational Experience for Middle School Students • Technical Paper • Poster

  4. Agenda • Customer Meeting Updates • Customer Requirements • Engineering Requirements • Proposed Concept Design • Isolation Valve Cost Analysis • List of experiments • Concept and Architecture Development • System Block • Sub-systems • Summary • Risk Assessment • Test Plan • Bill of Materials

  5. Customer Meeting Notes • Account for Pipe Fitting Leaks in calculations • How does Ultimate Pressure change with Leak Rate? • Limit design to one tower • Simple Prototype • Fit two objects in one tower • Allow for lift mechanism • Design Concepts to Future Tower Development • Go with 6-8 in. Diameter, approx. 10-15 ft. Tall Tower • Measure new location heights • Dr. K Lab • Talk with Mark Smith about using MSD space • Does Ultimate Pressure Effect object drop times • Feather vs. Ball Bearing • Use only one laser when dropping items to measure gravity • Keep the educational aspect in mind

  6. Customer Requirements

  7. Engineering Requirements

  8. Tube Diameter Selection

  9. List of Experiments • Dropping two objects simultaneously • Measure Gravity • Measure Drag • Balloon Expansion • Marshmallow Expansion • Sound Insulator • Plastic Bottle Compression Note: The following slides will attempt to justify the required tower pressure and size to complete these experiments

  10. CONCEPT & ARCHITECTURE DEVELOPMENT

  11. Proposed Concept Designs

  12. Proposed Base Structure

  13. Selected Concept Designs (part 1)

  14. Selected Concept Designs (part 2)

  15. Continuous Lift Concept #1

  16. Continuous Lift Concept #2 • Use pressure to control the up and down movement of a piston. • The piston would transport the objects back to the top of the tower post drop. Air Seal

  17. Sub-Systems Release Mechanism • Release system Calculations Error Propagation • Ultimate Pressure • Sensors Air Control • Evacuation time • Leak Rate Analysis Catching Mechanism • Energy dissipation Calculations Piping system • Critical external Pressure Structure • Tower height calculations • Support Buckling

  18. Tower Height Distribution

  19. Critical heights Total height drop at Dr. Kandlikar: • Critical Length of pipe lengths L1 and L2 • Assuming a clearing of 12” • Assuming L1= 1 Ft • L2= 7.692 Ft • Assuming L1= 2 Ft • L2= 6.693 Ft • Height of lab= 11’ 7” = 139” • With a ceiling clearing of 12” • Drop height = 93.5” = 7.791 Ft • Drop time= 0.696 Seconds • With a ceiling clearing of 22” • Drop Height = 83.5” = 0.657Ft • Drop Time = 0.657 Seconds • Total height required for a 10 Ft drop height: • H=13.79 Ft

  20. Engineering Analysis Release Mechanism

  21. Base Specifications Polycarbonate Diameter = 6.0 in Thickness = 0.375 in ρ = 1.22 g/cm3 (0.0441 lb/in3) Hatch Doors Length = 1.5 in Width =4.0 in Thickness = 0.375 in 6.0” 0.375” 4.0” 0.375” 1.5” 1.5”

  22. Electrical Specifications 12 VDC Operating temperature of -40F to 140F Holding Force 4.5lbs Physical Specifications Weight – 0.06lbs Diameter – 0.75in Height – 0.62in Other Specifications Quick Release Mechanism Electromagnet Specifications

  23. Physical Specifications Height – 3.5in Width – 1.5in Depth – 0.21in Radius – 5/16in (0.3125in) Pin Specifications Length – 3.5in Radius – 9/16in (0.5625in) Hinges Specifications

  24. FBD

  25. Important Result • Maximum object weight before magnets will disengage prematurely • 5.6 lbs • Does not include Factor of Safety • Weight of both object combined

  26. Engineering Analysis – StructureTower Height

  27. Free Fall – No Air Resistance (Vacuum Conditions) Applies to All Objects: • Vi=0 • g=32.2ft/s2 Example: y = 15 ft Vf = 31.081 m/s

  28. Free Fall –Air Resistance (Atmospheric Conditions) • ρ is the Density of Air • is the Drag Coefficient • A is the Projected Area of the Falling Object

  29. Free Fall – Vacuum vs. Atmospheric Conditions

  30. Engineering Analysis - Air Control Ultimate Pressure & Gravity Error Effect

  31. Gravity Calculation with 1% Error • Constant Acceleration Equations • Assumes no air resistance / perfect vacuum • , where x is position and t is time • 1% Error g = % Error x + 2(% Error t) • % Error x: Laser • % Error t: Laser & Pressure (Drag)

  32. Free Body Diagram of Object • Force Balance • At Terminal Velocity • Acceleration = 0 • At Vacuum Pressure, drag force = 0 • , where a is downward (negative)

  33. Drag Force (Air Resistance) • FD = Drag Force • ρ = Air Density • V = Velocity of Object • CD = Drag Coefficient (Fudge Factor) • A = Projected Area of Object • P = Air Pressure (Pa) • R = Specific Gas Constant = 287.05 J/kg*K • T = Air Temperature = 21°C = 274K

  34. Objects to calculate gravity • Not all objects may be suitable for gravity calculations • Objects vary by their mass, projected area and drag coefficient • Assumptions: • Max Tube Height = 15 ft • Ideal Gas • Room Temperature • Standard Gravity • Error in Time vs. Chamber Pressure is as follows for each object:

  35. % Error in Time vs. Chamber Pressure (Graphically)

  36. Engineering Analysis – Laser SensorSensor

  37. Laser Distance Sensor Specs Micro-Epsilon ILR-1030 15m Range 4-20mA Output 10ms Response time Tolerance Error in position +/- 5 mm (0.0164 ft) Error in time none

  38. % Error in Gravity Summary

  39. Engineering Analysis - Air Control Evacuation Time

  40. Conductance • The flow of air in a tube, at constant temperature, is dependent on the pressure drop as well as the cross sectional geometry. • Viscous Flow: Pressure (micron) * Diameter (in) > 200 • Transitional Flow: 6.0 < Pressure (micron) * Diameter (in) < 200 • , • Molecular Flow: Pressure (micron) * Diameter (in) < 6.0 • C = Conductance (cfm) • F1 = Viscous/Transitional Flow Scale Factor = 0.52 • F2 = Transitional Flow Scale Factor = 12.2 • F3 = Molecular Flow Scale Factor = 13.6 • D = Pipe Diameter (in) • L = Pipe Length (ft) Viscous Molecular

  41. Equivalent Pipe Length • Pipe fittings can cause losses within a piping system • These include: elbows, tees, couplings, valves, diameters changes, etc. • Tabulated values for Le/D can be used to adjust L in the conductance equations • D = Diameter of Pipe • Le = Equivalent Length • Total Length = L + Le1 + Le2 + Le3 + ….

  42. Effective Pump Speed • SEff for each flow regime • Viscous, Transitional, & Molecular • n = number of pipe diameters • C = Conductance (cfm) • = Given Pump Speed (cfm) • = Effective Pump Speed for Tube Dimensions

  43. Evacuation Time • = 760 Torr (Atmospheric) • = Viscous–Transitional Pressure • = Transitional-Molecular Pressure • = Ultimate Pressure • Example: Single 6” x 15’ Tube • Pump used on left • See Spreadsheet for: • Fittings • Individual conductance • Individual flow regime time VP6D CPS Vacuum Pump 2 Stage Rotary Pump 15 micron Ultimate Vacuum Pump Speed – 6.25 cfm Price: $268.92

  44. Engineering Analysis - Air Control Leak Rate

  45. Chamber Leak Rate • Constants: • Chamber Volume • Temperature • Atmospheric Pressure • Leak Area • Time Variables: • Mass Flow Rate • Chamber Pressure • Throughput, Q Units: (Pressure * Volume) / Time • Pump Throughput, QP Where: Seff = Effective Pump Speed P = Pressure • Leak Throughput, QL Where: dP/dt = Differential Pressure V = Chamber Volume Leak V Pump

  46. Flow Regime Change Note: Assumes linear relationship (mass flow rate constant)

  47. Engineering Analysis - Catching Mechanism Energy Dissipation

  48. Critical Dimensions of Impact Absorption material

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