Darrieus Rotor Vertical Axis Wind Turbine

The Darrieus rotor is a type of vertical axis wind turbine (VAWT) known for its distinctive eggbeater shape. It consists of curved airfoil blades that are arranged in a vertical orientation around the central axis.

Darrieus rotors are named after Georges Jean Marie Darrieus, a French engineer who patented the design in 1926.

Darrieus rotors belong to the category of lift-based rotors, which means that they use the aerodynamic force of lift to spin the blades. Unlike drag-based rotors, which have blades that face the wind directly, lift-based rotors have blades that are tilted at an angle to the wind. This allows the wind to flow smoothly over the blade surface, creating a pressure difference that generates lift.

Lift-based rotors can rotate much faster than the wind speed, which increases the power output and efficiency of the wind turbine. The power coefficient is a measure of how much of the available wind energy the rotor can capture. Most modern wind turbines, whether they have a vertical or a horizontal axis, are lift-based rotors.

The Darrieus rotor comes in various subforms, including helix-shaped, disc-like, and the H-rotor with straight blades. These turbines typically have three slim rotor blades driven by lift forces, allowing them to achieve high speeds. The aerodynamic properties, including wind pressure and lift effects, contribute to their efficiency, reaching a maximum of around 40% with the physically possible maximum for wind turbines being 59%.