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Wind Turbine Project

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San José State University

Charles W. Davidson College of Engineering

E10 Introduction to Engineering

Jay Solanki, Justin-Tam Nghi, Christian Pedrigal,

Kwok Him Tse, Adam Najib

E10-Section 8

Professor Ken Youssefi

12 October 2018

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Introduction

  • Goals for Turbine:
    • Maximize efficiency
    • Maximize stiffness
    • Maximize power
    • Minimize net weight

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  • Overview:
    • Create blades
    • Light & Sturdy Structure
    • Calculate Stiffness
    • Find Voltage, Current, Power, and RPM

Purpose: Design a Wind Turbine to generate high power

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Design of Turbine Blade

  • Parameters of optimization:
  • Number of blades
  • Blade profile
  • Angle of attack

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4. Weight (Blade material)

5. Blade length

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4. Weight (Blade material)

5. Blade length

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6. 1-week time constraint

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  • How?
    • Designed using SolidWorks
    • Constructed by 3D Printer in CoE

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    • Reasoned through theory and practicality

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Blade Profile

  • Blade profile based on Internet design
  • Not 100% accurate, but quite there

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Blade Profile

Angle of Attack

# of Blades

Final Design

Figure 1. Cross sections of all profiles

Figure 2. Blade Cross-Section by Niall McHamon (2016)

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Blade Profile

  • In theory: more profiles, the better
  • In practice: 3 is enough

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Blade Profile

Angle of Attack

# of Blades

Final Design

Figure 3. Three profiles at an angled view on Solidworks

Figure 4. 3D Section Curves from ScienceDirect (2017)

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Angle of Attack

  • Theoretically, typical numbers range from 1.0 to 15.0 degrees
  • Our profiles’ angles range from 1.0 to 17.0 degrees
    • 1st plane ~ 16˚
    • 2nd plane ~ 17˚
    • 3rd plane ~ 1˚

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Blade Profile

Angle of Attack

# of Blades

Final Design

Figure 1. Cross sections of all profiles

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Number of Blades

  • Based on the industry, three blades is the optimal number
  • We’re not in the industry.
  • Any number is fine, profile is more important

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Blade Profile

Angle of Attack

# of Blades

Final Design

Figure 5. Final 3D design

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Final Design

  • 3-blade design
  • 2.5 inch length
  • 0.25 inch height (hub)
  • 0.7 inch width
  • 6 in. diameter swept area

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Blade Profile

Angle of Attack

# of Blades

Final Design

Figure 5. Final 3D design

Figure 6. Photo of turbine blade

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Design of Support Tower

Aim:

  • Maximize stiffness
  • Minimize weight

Our Strategy:

•Create a structure that is stable and rigid

•Choose light but strong materials

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Structure of the Support Tower

  • Design: Central pole made of PVC supported by round wooden sticks placed in a tripod formation in order to maximize stability.
  • Instead of placing the wooden sticks perpendicular to the support plates, we placed them at an angle.
  • Popsicle sticks for interior support

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Figure 7. Base of Tower

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Support Tower Materials

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  • Density of balsa wood: 160 Kg/m3
  • Density of PVC: 1467 Kg/m3

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Figure 9. PVC pipe

Figure 10. balsa wood

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  • Popsicle sticks – extra support to the tower which have negligible weight.
  • Glue gun – works better with tripod design, lighter than screws
  • Saw – used to shape the ends of the wooden pillars at an angle parallel to plates.

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Figure 11. Popsicle Sticks

Figure 12. Glue Gun

Figure 12. Saw

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PVC pipe central tower

Balsa wood support tower

Popsicle sticks

Bottom support plate (metal)

Top support plate (metal)

Figure 8. Final Tower Design

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Measuring Stiffness

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Pulley

Instrument to measure displacement

Support tower

Weights (100 g)

Screws

Figure 12. Stiffness test of Tower

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Performance: Height, Weight, Stiffness

Tower Height: 17.0 inches

Tower Net Weight: 445 g

Stiffness (k) = 4007.7 N/mm

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Performance: Blade Efficiency

  • Max Theoretical Power
    • ½ (ρ)(A)(V)^3 (η) = 8.52 W
    • ρ = 1.2 kg/m^3
    • A = 0.018 m^2
    • V = 10.997 m/s
    • η = 0.593 (Betz limit)
  • Theoretical maximum power(W)/Actual(W)=1.71/8.52=20.1% eff
  • Did not meet 2 W or 35-45% typical efficiency

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Conclusions

  • The side we intended to spin ended up stalling.
  • Popsicle sticks adjusted for uneven height
  • Were our goals achieved?
    • No, maximum power output was 1.71W
    • Didn’t reach typical efficiency goal (35%-40%)
    • The stiffness and weight of our tower design was ideal

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Recommendations

  • Sketch more accurate blade profiles, instead of just “eyeing” it during the lab
  • Saw straighter balsa wood edges to prevent crookedness
  • Popsicle sticks are your best friend.

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References

  • “Innovative Approach to Computer-Aided Design of Horizontal Axis Wind Turbine Blades.” Journal of Computational Design and Engineering, Elsevier, 18 Nov. 2016, www.sciencedirect.com/science/article/pii/S2288430016300793.
  • McHamon, Niall. “Blade Cross-Section.” Distributed Wind Wiki, WordPress, 8 Jan. 2016, niallmcmahon.com/wiki/blade-cross-section/.

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