Turbine Blades

Consider the Shape and Number of Blades

The image of this blade shows that the cross section has a streamlined asymmetrical shape. The flattest side of the blade faces the oncoming wind. See this movie that explains this design: New Blade Design for Wind Turbine.

According to https://www.turbinesinfo.com, "a blade designer does not merely sit down and outline the shape when designing a new blade. The shape must be chosen with great care on the basis of past experience. For this reason blade profiles were previously chosen from a widely used catalogue of airfoil profiles developed in wind tunnel research by NACA (The United States National Advisory Committee for Aeronautics) around the time of the Second World War."

See these wind tree turbines in Paris, France made. The system is called "New Wind". The blades turn easily in wind that is blowing at 5 mph. Here is another movie but they call them micro turbine leaves.

A modern wind turbine blade is similar to the wings of an airplane. Airplane wings are very aerodynamic, able to let wind pass by at very high speeds.

Wind turbine blades have been designed in many different shapes. Today blades of modern wind turbines are lighter than older wind turbines so they can accelerate quickly at lower wind speeds.

Most horizontal axis wind turbines will have two to three blades. Most vertical axis wind turbines will usually have two or more blades.

The diagram shows a cut section of a wind turbine blade with air flowing over it and air coming from below, you can see that the blade has one flat side and one more rounded side.

Harmony VAWT design can withstand very high winds!

Vocabulary:

Aerodynamics- the science and study of the physical laws of the behavior of objects in an air flow and the forces that are produced by air flows.

Accelerate- speed up quickly

Asymmetrical shape-unequal in some way.

Wind turbine rotor blade-The front and rear sides of a wind turbine rotor blade have a shape roughly similar to that of a long rectangle, with the edges bounded by the leading edge, the trailing edge, the blade tip and the blade root.

Blade root- is bolted to the hub.

Wind turbine designers are experimenting with different shapes of blades. For example, this movie shows a wind turbine with sideways blades.

Here is a PPT presentation from KidWind that addresses types of blade design.

In KidWind Challenges, teams have entered wind turbines with all kinds of turbine blade designs. See images of some of the 2018 entries.

Each team member will create a blade design that will be tested out. Sketch out your design and then make a prototype. Consider making your prototype blades from:

  • Cardboard
  • baking tin foil cookie sheets
  • balsa wood
  • foam board