Exploring Wind Turbines – Blades

Introduction

For thousands of years, we have been using wind energy from sailing ships, to milling grain into flour in windmills. The biggest downside of these methods is that the output has to be close to the wind source.  Since the invention of electricity and then the Wind Turbine it’s now possible to generate in place X and transmit and use the energy in place  Y.

A Wind turbine has 4 basic parts, a tower, turbine blades, a gearbox, and a generator. The generator converts the kinetic energy from the wind into electrical energy. Wind causes the blades to turn, this causes the gearbox to turn via a shaft, the gearbox then turns the generator by a second shaft. This turning generates electricity. Each of these 4 basic parts can affect the amount of electrical power that can be generated.

In this experiment, we will use the Kidwind Basic Wind Experiment Kit, which contains everything you need except for the Go Direct Energy Sensor and a Fan. This could also be used a STEM activity.

Techniques/skills covered 

• use ICT such as computer modeling, or data logger with a variety of sensors to collect data, or use of software to process data

Objectives

In this experiment, you will

• Investigate wind turbine blade design
• Take measurements using a sensor

Equipment needed

Go Direct® Energy Sensor
Laptop/ PC/ Chromebook/ Tablet/ Smart phone
Desktop Fan
Scissors
Tape/Double-sided tape
Pencil
Ruler

Variations

In these experiments, we are looking at the wind turbine blades specifically. Here is a short list of things we will alter.

• Number of Blades
• Blade pitch angle
• Surface area

Additional possibilities

• Profile of a blade (See Kidwind Aerofoil blades)
• Material of Blades (Chipboard Blades, Basla Blades)

Method

General setup

Setup the fan and KidWind turbine as per the instructions. The fan should be positioned about 15cm from the center of the hub on the Turbine. On the Go Direct® Energy Sensor, press the power button once. The LED will blink red. Launch the Graphical Analysis App. Click Sensor Data Collection.  Now select GDX-NRG in the list (if you have more than one device, select the serial number corresponding to that on the case). The LED on the connected sensor(s) will now blink Green.  Make sure the Switch on the Energy sensor is on “Internal 30Ohm load”. Click Done

Select Mode from the bottom left of the graph screen. Change from Time Based to Event-Based in the top of the dialogue box. In the Event Name field type Volume, and in the Units field cm³. Change the Average over 10s  so it is ticked

Variation 1: Number of Blades

1. Label the event “Number of Blade”
2. Press Collect
3. Unscrew the Hub slightly. Insert 6 equally spaced blades into the Hub at a 30° pitch. Retighten the hub.
4.  Put the hub onto the Wind turbine shaft.
5. Step away and Switch on the fan. Wait 30 seconds for the turbine to get to an optimal speed.
6. Press collect. Allow the Data to be collected over 10 seconds
7. Enter the number of blades and press ok
8. Switch off the fan.
9. Once the Fan and Windturbine have stoped.  Remove the hub.
10. Repeat from step 3 with a reduced number of blades. (4,3,2 and 1* are other possibilities)
11. Press Stop

Variation 2: Variation  Blade pitch angle

1. Label the event “Blade pitch angle”
2. Press Collect
3. Unscrew the Hub slightly. Insert 3 blades into the Hub, using the Blade pitch protractor set the pitch angle of the blades to 0°. Retighten the hub.
4.  Put the hub onto the Wind turbine shaft.
5. Step away and Switch on the fan. Wait 30 seconds for the turbine to get to an optimal speed.
6. Press collect. Allow the Data to be collected over 10 seconds
7. Enter the angle of blades and press ok
8. Switch off the fan.
9. Once the Fan and Windturbine have stoped.  Remove the hub
10. Repeat from step 3 and vary the blade pitch angle  (15° ,30°, 45° ,60° ,75°, 90°)
11. Press Stop

Variation 3: Surface Area

Note: This can be achieved by various different methods, in this experiment we are going to keep the width constant and vary the length only. Before you begin you need to have prepared different sized blades in advance. To keep things simple we will run the experiment with a 100%, 75% 50% 25% blade length, based on the standard  Kidwind Chipbaord blade.

1. Label the event “Surface Area”
2. Press Collect
3. Unscrew the Hub slightly. Insert 3 blades of 100% length into the Hub at 15°. Retighten the hub.
4.  Put the hub onto the Wind turbine shaft.
5. Step away and Switch on the fan. Wait 30 seconds for the turbine to get to an optimal speed.
6. Press collect. Allow the Data to be collected over 10 seconds
7. Enter the Area of the blade and press ok
8. Switch off the fan.
9. Once the Fan and Windturbine have stoped.  Remove the hub
10. Repeat from step 3 and vary the blade angle  (75%, 50% and 25%)
11. Press Stop

* with one blade you need to create a counterweight this can be achieved by using a wooden dowel with some Bluetac®

Sensors and Equipment Featured