1. Advanced Design Applications Power and Energy © 2014 International Technology and Engineering Educators Association STEM  Center for Teaching and Learning™ Advanced Design Applications Teacher Resource Primary Challenge – What About All This Wind?

2. The BIG Idea  Big Idea: Knowledge of energy and power technologies along with the transfer and manipulation of those technologies will be essential for student success in the design of the Primary Challenge device. © 2014 International Technology and Engineering Educators Association STEM  Center for Teaching and Learning™ Advanced Design Applications

3. Multi-Task Windmill Competition  It’s All About Energy and Power!  “LIFTING” TEST - Greatest Average Power  mgh / t = mgv AVE (g=9.8 m/s, h =.75 m)  ELECTRICAL POWER - Greatest average power  V 1 A 1 + V 2 A 2 = Average Power © 2014 International Technology and Engineering Educators Association STEM  Center for Teaching and Learning™ Advanced Design Applications

4. Multi-Task Windmill Challenge Lakewood 101 Box Fan ~1/2m x 1/2m 3.1 m/s air speed © 2014 International Technology and Engineering Educators Association STEM  Center for Teaching and Learning™ Advanced Design Applications

5. © STEM  Center for Teaching and Learning™ Example of Device © 2014 International Technology and Engineering Educators Association STEM  Center for Teaching and Learning™ Advanced Design Applications

6. Motion  An object’s motion is fully described by translation of its Center of Mass and rotation about its Center of Mass (CM) © 2014 International Technology and Engineering Educators Association STEM  Center for Teaching and Learning™ Advanced Design Applications

7. Motion Continued  Translation Can Occur in 3 Dimensions  Rotation Can Occur in 3 Dimensions  Full Description of Motion is referred to as 6 Degrees of Freedom (6- DOF) © 2014 International Technology and Engineering Educators Association STEM  Center for Teaching and Learning™ Advanced Design Applications

8. Forces and Motion  Forces Acting through CM only causes translation  Forces acting a distance (torque  ) from CM will also cause rotation F F r  = rF F=ma  = I © 2014 International Technology and Engineering Educators Association STEM  Center for Teaching and Learning™ Advanced Design Applications

9. Translation and Rotation for Challenge  Generally center of mass is pinned for rotating elements so motions are either pure translation or pure rotation in this challenge  Trick is to convert Power and Energy from Translation to Rotation, vice-versa, and to other forms © 2014 International Technology and Engineering Educators Association STEM  Center for Teaching and Learning™ Advanced Design Applications

10. Energy  Energy is required to do Work  Work is done when an object is moved a distance against a force  Lift a 1 kg mass 1 m against gravity  Force = mg = 1 kg x 9.8 m/s 2 = 9.8 Newtons  Work = Force x Distance = 9.8 N-m = 9.8 Joules  Work = mgh = Energy  Not Surprisingly an object h meters off ground has Gravitational Energy = mgh  If dropped will convert to kinetic energy  Kinetic Energy on Ground = ½ mv 2 = mgh © 2014 International Technology and Engineering Educators Association STEM  Center for Teaching and Learning™ Advanced Design Applications

11. © STEM  Center for Teaching and Learning™ 1 kg g = 9.8 m/s 2 F = 9.8 N © 2014 International Technology and Engineering Educators Association STEM  Center for Teaching and Learning™ Advanced Design Applications

12. © STEM  Center for Teaching and Learning™ 1 kg g = 9.8 m/s 2 F = 9.8 N h = 1 m Work = Fh = Energy = 9.8 Joules © 2014 International Technology and Engineering Educators Association STEM  Center for Teaching and Learning™ Advanced Design Applications

13. Rotational Work  Its takes energy to rotate an object against a torque  Work = Energy =     F, h   © 2014 International Technology and Engineering Educators Association STEM  Center for Teaching and Learning™ Advanced Design Applications

14. Power  Power is Required to Work Quickly  Power = Energy / Time  Power is required to sustain a velocity against a force  If we want to raise the rock at 1 m/s then  Power = Force x Velocity = Fv = mgv = 9.8 N-m/s = 9.8 Joules/s = 9.8 Watts  Rotational Power  Power is required to sustain an angular velocity against a torque  Power = Torque x Angular Velocity, P=  © 2014 International Technology and Engineering Educators Association STEM  Center for Teaching and Learning™ Advanced Design Applications

15. © STEM  Center for Teaching and Learning™ 1 kg g = 9.8 m/s 2 F = 9.8 N © 2014 International Technology and Engineering Educators Association STEM  Center for Teaching and Learning™ Advanced Design Applications

16. © STEM  Center for Teaching and Learning™ 1 kg g = 9.8 m/s 2 F = 9.8 N © 2014 International Technology and Engineering Educators Association STEM  Center for Teaching and Learning™ Advanced Design Applications

17. © STEM  Center for Teaching and Learning™ 1 kg g = 9.8 m/s 2 F = 9.8 N © 2014 International Technology and Engineering Educators Association STEM  Center for Teaching and Learning™ Advanced Design Applications

18. © STEM  Center for Teaching and Learning™ 1 kg g = 9.8 m/s 2 F = 9.8 N © 2014 International Technology and Engineering Educators Association STEM  Center for Teaching and Learning™ Advanced Design Applications

19. © STEM  Center for Teaching and Learning™ 1 kg g = 9.8 m/s 2 F = 9.8 N 1 m/s Power = Fv = Energy/s = 9.8 Watts © 2014 International Technology and Engineering Educators Association STEM  Center for Teaching and Learning™ Advanced Design Applications

20. Power – Rotating Shaft to Move a Mass r F=mg  = Fr = mgr =v/r P =  = Fr = Fv = mgv © 2014 International Technology and Engineering Educators Association STEM  Center for Teaching and Learning™ Advanced Design Applications

21. Electrical Power  Power = Voltage x Amperage, P=VA  Voltage = Energy / # of Electrons  Joules / Coulomb of Electrons  Amperage = # of Electrons / s  Coulomb of Electrons / s  Voltage x Amperage = Joules / s = Watts  Measure V = 1 Volt, A = 1 Amp  P = VA = 1 Watt © 2014 International Technology and Engineering Educators Association STEM  Center for Teaching and Learning™ Advanced Design Applications

22. Energy and Power are Convertible  Gravitational Potential to Kinetic Energy  mgh -> ½ mv 2  Rotational Power to Mechanical Power   -> Fv = mgv  Torque x Angular Velocity = Force x Velocity  Rotational Power to Electrical Power   -> VA  Without losses replace -> with =  Want to eliminate losses due to friction, drag etcetera © 2014 International Technology and Engineering Educators Association STEM  Center for Teaching and Learning™ Advanced Design Applications

23. Windmill Design Two Components  Power Generation  Convert wind power to mechanical power  Wind -> Pushes Wind Mill Blades -> Wind Mill Shaft Turns  Power Distribution  Use power of rotating shaft to  Transfer power by moving mass  Generate Electricity © 2014 International Technology and Engineering Educators Association STEM  Center for Teaching and Learning™ Advanced Design Applications

24. How Much Power in Moving Air?  Power is Energy / Time  How much Energy in Moving Air? © 2014 International Technology and Engineering Educators Association STEM  Center for Teaching and Learning™ Advanced Design Applications

25. © STEM  Center for Teaching and Learning™ Fan ½ m 3.1 m/s 1/8 m 3 Density of Air - 1.225 kg/m 3 Mass = 1.225 kg/m 3 x 1/8 m 3 =.153 kg © 2014 International Technology and Engineering Educators Association STEM  Center for Teaching and Learning™ Advanced Design Applications

26. © STEM  Center for Teaching and Learning™ Fan ½ m 3.1 m/s.153 kg Kinetic Energy = ½ mv 2 = ½ x.153 kg x 3.1 m/s x 3.1 m/s =.74 Joules 3.1 m/s © 2014 International Technology and Engineering Educators Association STEM  Center for Teaching and Learning™ Advanced Design Applications

27. © STEM  Center for Teaching and Learning™ Fan ½ m 3.1 m/s.75 Joules.74 Joules t = ½ m / 3.1 m/s =.16 s ½ m 3.1 m/s Power = Energy / Time =.74 Joules /.16 s = 4.6 Watts © 2014 International Technology and Engineering Educators Association STEM  Center for Teaching and Learning™ Advanced Design Applications

28. Betz’s Law Windmill Deflects Air © 2014 International Technology and Engineering Educators Association STEM  Center for Teaching and Learning™ Advanced Design Applications

29. © STEM  Center for Teaching and Learning™ Cowling? © 2014 International Technology and Engineering Educators Association STEM  Center for Teaching and Learning™ Advanced Design Applications

30. © STEM  Center for Teaching and Learning™ Cowling Used on a Device for the MESA Competition © 2014 International Technology and Engineering Educators Association STEM  Center for Teaching and Learning™ Advanced Design Applications

31. Two Windmill Types Horizontal Rotating Shaft Vertical Rotating Shaft © 2014 International Technology and Engineering Educators Association STEM  Center for Teaching and Learning™ Advanced Design Applications

32. Simplified Horizontal Wind Mill Lift Force distance r Lift Force rL =  = I r-distance, L-Lift, -torque, I-Moment of Inertia, -angular acceleration Side View Wind Front View © 2014 International Technology and Engineering Educators Association STEM  Center for Teaching and Learning™ Advanced Design Applications

33. Factors for a Good Turbine Blade  Airfoil Design – “Design from the Side”  Planform – “Design from the Top”  Aspect Ratio – “Squat or Elongated”  Blade Twist © 2014 International Technology and Engineering Educators Association STEM  Center for Teaching and Learning™ Advanced Design Applications

34. Airfoil – Design from the Side Airfoil works by redirecting moving air downward (Action) resulting in Lift (Reaction). The Bernoulli Effect - Loss of Pressure with increase in velocity is a small effect. © 2014 International Technology and Engineering Educators Association STEM  Center for Teaching and Learning™ Advanced Design Applications

35. © STEM  Center for Teaching and Learning™ The key effect contributing to Lift is Leading Edge Suction due to turning off moving air about leading edge of wing without increase in speed. The so called “Coanda Effect” results from the Viscosity of Air. Airfoil © 2014 International Technology and Engineering Educators Association STEM  Center for Teaching and Learning™ Advanced Design Applications

36. © STEM  Center for Teaching and Learning™ A key airfoil characteristic is angle of attack . This allows the airfoil to redirect moving air downward. Thus even a flat plate can generate lift.  Airfoil © 2014 International Technology and Engineering Educators Association STEM  Center for Teaching and Learning™ Advanced Design Applications

37. © STEM  Center for Teaching and Learning™ Camber or curvature of the wing allows more effective redirection of the air without flow detaching. Airfoil © 2014 International Technology and Engineering Educators Association STEM  Center for Teaching and Learning™ Advanced Design Applications

38. © STEM  Center for Teaching and Learning™ Thickness about camber is also a Factor. A blunt leading edge with Maximum thickness ~1/3 way back and tapered trailing edge maximizes lift and minimizes drag. Airfoil © 2014 International Technology and Engineering Educators Association STEM  Center for Teaching and Learning™ Advanced Design Applications

39. Planform – Design from the Top Rectangular Tapered Elliptical © 2014 International Technology and Engineering Educators Association STEM  Center for Teaching and Learning™ Advanced Design Applications

40. Induced Drag High Pressure Low Pressure Wing Tip Vortex © 2014 International Technology and Engineering Educators Association STEM  Center for Teaching and Learning™ Advanced Design Applications

41. Wing Tip Vortex © 2014 International Technology and Engineering Educators Association STEM  Center for Teaching and Learning™ Advanced Design Applications

42. Minimizing Induced Drag  Rectangle Maximizes Induced Drag  Although easy to construct  Ellipse Minimizes Induced Drag  But can be hard to construct  Tapered Planform Frequently Chosen  Almost as good as ellipse in minimizing drag  Reasonably easy to construct © 2014 International Technology and Engineering Educators Association STEM  Center for Teaching and Learning™ Advanced Design Applications

43. Aspect Ratio  Aspect Ratio  Length of Wing / Average Width (Chord) Low Aspect Ratio High Aspect Ratio © 2014 International Technology and Engineering Educators Association STEM  Center for Teaching and Learning™ Advanced Design Applications

44. Best Aspect Ratio?  Low Speed  High Aspect Ratio*  High Speed  Low Aspect Ratio © 2014 International Technology and Engineering Educators Association STEM  Center for Teaching and Learning™ Advanced Design Applications

45. Windmill Blade Twist  Angle of Attack is dependent on the speed of the blade with respect to the air  If the blade is moving perpendicular to the wind the angle of attack will change © 2014 International Technology and Engineering Educators Association STEM  Center for Teaching and Learning™ Advanced Design Applications

46. © STEM  Center for Teaching and Learning™ Rotor Aerodynamics Blade must be twisted maintain optimum angle of attack Electricity Generating Wind Turbines Use an odd number of blades to avoid harmonics Problem – Won’t know rotational speed  until windmill is built. So twist should be adjustable! © 2014 International Technology and Engineering Educators Association STEM  Center for Teaching and Learning™ Advanced Design Applications

47. Blade Twist Diagram © 2014 International Technology and Engineering Educators Association STEM  Center for Teaching and Learning™ Advanced Design Applications

48. Typical Horizontal Windmill © 2014 International Technology and Engineering Educators Association STEM  Center for Teaching and Learning™ Advanced Design Applications

49. Blade Design Materials  Pink or Blue Foam Board  3-D Printer  Balsa Wood / Shrink Wrap  What other materials can you use? © 2014 International Technology and Engineering Educators Association STEM  Center for Teaching and Learning™ Advanced Design Applications

50. Vertical Windmills Drag Type Vertical Windmill Lift Type Vertical Windmill © 2014 International Technology and Engineering Educators Association STEM  Center for Teaching and Learning™ Advanced Design Applications

51. Vertical Wind Turbines  Have not caught on in the commercial market  Drag Type has low efficiency  Lift Type efficiency better  Optimal Design is not Clear  However  May be well matched for this contest  Insensitive to Wind Direction  Flow Field is Rectangular © 2014 International Technology and Engineering Educators Association STEM  Center for Teaching and Learning™ Advanced Design Applications

52. © 2014 International Technology and Engineering Educators Association STEM  Center for Teaching and Learning™ Advanced Design Applications

53. Weight Lifting Challenge  h = 75 cm  Want to maximize Power = Weight x Velocity  Weight = mg, Velocity = h/t  Mass is team’s choice  Windmill is intrinsically a high torque, low- speed device  Best strategy is to lift large Weight at low speed  Attempt to increase speed leads to power losses © 2014 International Technology and Engineering Educators Association STEM  Center for Teaching and Learning™ Advanced Design Applications

54. Weight Lifting Challenge © 2014 International Technology and Engineering Educators Association STEM  Center for Teaching and Learning™ Advanced Design Applications

55. © STEM  Center for Teaching and Learning™ Wind Changing Electric Power © 2014 International Technology and Engineering Educators Association STEM  Center for Teaching and Learning™ Advanced Design Applications

56. Generating Electrical Power © 2014 International Technology and Engineering Educators Association STEM  Center for Teaching and Learning™ Advanced Design Applications

57. Electrical Power Generation  High rotational speeds are required for efficient electrical generation  Windmills are high torque – low- speed devices  How can rotational speed be increased.  Proper gearing! © 2014 International Technology and Engineering Educators Association STEM  Center for Teaching and Learning™ Advanced Design Applications

58. Step Up Gearing 12 Teeth 8 Teeth © 2014 International Technology and Engineering Educators Association STEM  Center for Teaching and Learning™ Advanced Design Applications

59. Kid Wind Gear Kit 8:1 Rotational Speed Gain © 2014 International Technology and Engineering Educators Association STEM  Center for Teaching and Learning™ Advanced Design Applications

60. Step Down Pulleys © 2014 International Technology and Engineering Educators Association STEM  Center for Teaching and Learning™ Advanced Design Applications

61. Power Losses  Must carefully watch for power losses in every stage  Rotating Shaft, Pulleys, Rotating Bearings  Must Minimize Rotational Inertia I in Rotating Elements  Eliminate unneeded mass © 2014 International Technology and Engineering Educators Association STEM  Center for Teaching and Learning™ Advanced Design Applications

62. Performance Scoring  Mass Lift  Electrical Power © 2014 International Technology and Engineering Educators Association STEM  Center for Teaching and Learning™ Advanced Design Applications

63. Parts to the Challenge  The design of your device  Operation of your device  Measurements (power and weight) for the two tasks  Documentation  Design process, ideas, selection of ideas, cost, drawings/sketches  Presentation © 2014 International Technology and Engineering Educators Association STEM  Center for Teaching and Learning™ Advanced Design Applications