Wind Turbine Final Report

Kristina Monakhova – Program ManagerElizabeth Yasuna – Executive DirectorDominick Farina – Business DevelopmentKyle Zalud – Technical Lead

EAS 140 D2-E, Zack Bauer, Nikita Ranjit Goraksha

WindTER – Wind Turbine Energy Resources

Project Objectives

Purpose: Design efficient wind turbines for small and large scale applications

Goals: •Build and improve a wind turbine•Strive for continuous improvement•Create a scientific foundation for

future improvements/innovations•Focus on simplcity and reliability

Source: http://learn.kidwind.org/sites/default/files/windturbinebladedesign.ppt

Background Research - Design Factors for Wind Turbines

•Number of blades•Angle of blades•Shape of blades•Blade Twist•Blade Length•Blade materials

•Generator•Gear ratios•Oil/Lubricant used•Height of tower•Rotational Speed

Initial Build - Design

•Blades▫ 3▫ Balsa wood material▫ Flat▫ Roughly 30° tilt▫ Attached to single

wooden dowel with duct tape

•Gears: largest and smallest•Base: provided, no

support structure

Initial Build - Performance

max Voltage: 3.78Vmax Current: 7mAmax Power: .026W

Bulb used: LED (lit)

Overview of Design RationaleDesign Factor Possible Influences on Performance Configurations for Experimentation

Real World Testable in Model

Research Physical Law Exp. 1 – Blade shape

Exp. 2 - # of blades

Exp. 3 – Blade Angles

Exp. 4 – Type of Blades

Number of blades

yes More = greater weight, solidity less speed, more torquefewer more speed, less inertia

Solidity = # of blades * area of blade / total swept area

Baseline (3) 2, 3, 4 Baseline (3) Baseline (3)

Angle of Blades

yes Affects angle of attack – certain tilt to capture more wind

Lift to Drag Ratio=(blade area)(net pressure)/(.5xDrag coefficient × mass density×area×velocity2),

Baseline (30) Baseline level (30)

0, 15, 30, 45 Baseline (15)

Shape of blades

yes Narrower at ends, airfoil shape to maximize lift and minimize drag

Lift to Drag Ratio=(blade area × net pressure)/(1/2 ×Drag coefficient × mass density×area×velocity^2

Rectangular, air foil

Baseline level (air foil)

Baseline (air foil

Baseline (air foil)

Blade twist yes Twisted down length to maintain angle of attack

Lift to Drag Ratio=(blade area)(net pressure)/(.5xDrag coefficient × mass density×area×velocity2),

Baseline level (none)

Baseline level (none)

Baseline level (none)

Baseline level (none)

Blade length

yes Longer blade increases swept area, but increase weight

Lift to Drag Ratio=(blade area)(net pressure)/(.5xDrag coefficient × mass density×area×velocity2), Power in wind : P=.5ρ(Πr2)v3

Baseline level Baseline level

Baseline level Baseline level (some variation)

Blade material

yes Lighter = accelerate rapidly, heavier = more stable

Rotational Inertia, I=.5mr2 , I = 1/12 ML2 +M(L/2)2

Basswood Balsa wood

Balsa wood Balsa wood, posterboard, corrugated plastic, basswood

Gear ratio yes Larger gear ratio = more speed, less torque, more resistive torque

Ressitive Torque = force × Radius, rotational speed transfer: rlωl=rsωs

Baseline (largest)

Baseline (largest)

Baseline(largest)

Baseline (largest)

Generator no

Tower Height no

Experiments – Blade Shape

Configurations: Rectangular, Air foil

Conclusions: Airfoil – maximize lift, minimize drag

Rectangular

Airfoil

Experiment 1 - Blade ShapeConfigurations: Bulb: LED Motor: B1 Fan Distance: 8ft

3 blades, 30 degrees, balsawood, large gear ratio

ShapeMax Voltage (V)

Max Current (mA)

Power (W) RPM

Cut-in Time (s)

Rectangular 3.03 17 0.05151 80 3.5

Airfoil 3.3 20 0.066 100 3.5

Experiment - Number of blades

Configurations:

Aa

Aa Aa

Conclusions: 2 blades

2 blades 3 blades 4 blades

Experiment 1 - Number of Blades

Configurations: Bulb: LED Motor: B1 Fan Distance: 8ft

30 degrees, large gear ratio, balsawood blades, rectangular shape

Number of Blades

Max Voltage (V)

Max Current (mA)

Power (W) RPM

Cut-in Time (s)

2 3.3 30.7 0.10131 110 33 2.8 25.7 0.07196 102 3.54 2.1 15.0 0.0315 98 4

3 blades

Experiment - Angles of Blades

Conclusion: 15° is optimal

Configurations: 0 °, 15 °, 30 °, 45 °

0° 15°

Top View

Side View

Experiment 2 - Blade AngleConfigurations: Bulb: LED Motor: B1 Fan Distance: 8ft

2 blades, balsawood blades, large gear ratio, rectangular shape

Angle (degrees)

Max Voltage (V)

Max Current (mA) Power (W) RPM

Cut-in Time (s)

0 0 0 0 0 15 3.3 34.1 0.11253 81 330 2.95 19 0.05605 85 345 2.8 2.3 0.00644 49 3.5

0 5 10 15 20 25 30 35 40 45 500

0.02

0.04

0.06

0.08

0.1

0.12

Power vs. Blade Angles

Blade Angles

Pow

er (W

)

Experiments – Blade Material

Configurations:

Balsawood

Posterboard

Basswood

Corrogated Plastic

Conclusions: basswood – more inertia

Experiment 3 - Blade MaterialConfigurations: Bulb: LED Motor: B1 Fan Distance: 8ft

3 blades, 15 degrees, large gear ratio, airfoil shape

MaterialMax Voltage (V)

Max Current (mA)

Power (W) RPM

Cut-in Time (s)

Balsawood 2.8 18 0.0504 81 3.5Posterboard 2 2.2 0.0044 92 3

Corrugated Plastic 2.3 1.6 0.00368 90 3Basswood 3.03 17 0.05151 80 3.5

Final Improved Design

•Blades▫ 3▫ Bass wood material▫ Flat▫ Roughly 15° tilt▫ Attached to single wooden

dowel with wood glue and duct tape

•Gears: largest and smallest•Base: duct tape and poster board

support structure

Final Improved Design – Rationale and Innovations*

•Blades – Basswood *▫ Heavier▫ Longer▫ 15° tilt

•Base*▫ stability

Results - Final Testing

•2.05Ws•3V, .02A•160rpm

Calculated Values:•Power in wind: 2.7 W•Turbine Efficiency:

▫ Relative to power available in wind : 2.2%

▫ Relative to power available at blades: 3.75%

•Rotational Speed of high speed shaft: 1011rpm

Interpretations of results

•Successful:▫ Very consistent voltage▫ Fairly consistent current/power▫ Kept on spinning after 60s

•Unsuccessful▫ Low current and power▫ High cut-in time

Source: http://learn.kidwind.org/sites/default/files/windturbinebladedesign.ppt

•Why?▫ Blades too long – larger than fan diameter▫ Blades too heavy▫ No twist to blades▫ Unbalanced▫ Tip-Speed Ratio: 3.5

Future Research

•Blade twist from root to tip•Curved Hub to guide wind to

blades•Different blade lengths for

variable wind speeds•Different blade widths

curved

Too long Too shortOptimal

Questions?