This cute "little rabbit" can actually generate electricity? That's right! While it is shaking its "wings" with the wind, it is constantly exporting electricity.

When you think of "wind turbines", do you immediately think of "three-bladed white windmills"?

In addition to this classic shape, the real wind turbine also has a variety of magical shapes.

Why Three-Bladed?

As the "originator" of wind turbines, windmills have played a huge drainage role in Netherlands and are famous all over the world. The image of the four-bladed Netherlands windmill is also deeply rooted in people's hearts.

The multi-blade water-lifting windmill in the western United States was also popular. Multiple blades can make the whole rotor generate more power and provide more power.

Four-blade or even multi-blade windmills have been formed, why do they become three-blades on wind turbines?

The number of blades does not directly affect energy utilization, on the contrary, too many blades can interfere with air flow and reduce the utilization rate of wind energy. Wind energy utilization equipment can only capture up to 59.3% of the kinetic energy in the wind and utilize it. In this way, a wind turbine can produce just as much electricity with even one blade.

However, single-blade wind turbines have not become mainstream. A single blade can cause extreme imbalance in the wind turbine and seriously threaten the safety of the entire wind turbine. Imagine a large mass of clothes wrapped up and spun dry...... The entire washing machine vibrates violently and even strikes directly.

Symmetrical two blades can improve this imbalance, but they are still not stable enough, and the application of two-blade wind turbines will be limited until more ideal load control technology is available.

The three-blade wind turbine solves the problem of balance because of its optimal layout form, but "heavy" has also become one of the "pain points". A single wind turbine blade weighs 20 tons, and the wind wheel composed of three blades is more than 60 tons. Once there is a quality problem with the foundation on the ground, the entire unit may overturn and collapse.

Some manufacturers "break the wind turbine into zero", using multiple small blades and transforming it into four heads and twelve arms. In 2016, wind power leader Vestas installed a wind turbine with four wind turbines at the Technical University of Denmark in Denmark, which was completely dismantled after two years of quiet operation. Due to the scarcity of models, the data is extremely valuable, and the two institutions have almost never disclosed any data to the public.

There are no blades, and there is electricity

Mad scientists are not willing to accept mediocre blades, so they come up with the "bladeless" scheme. Nikola Tesla, the legendary magnate of electricity, once applied for a patent for a bladeless turbine, but it was ultimately rejected due to a lack of suitable manufacturing materials.

Based on this idea, a bladeless wind turbine in the shape of a volute was developed. The wind pushes the disc inside to rotate, driving the generator to generate electricity. However, this kind of "Peppa Pig"-like wind turbine needs to strictly ensure the accuracy of the processing and manufacturing of each component, and at the same time, the wind must be aligned with the air inlet, which restricts its development under such harsh conditions.

In order to take advantage of the incoming wind from all directions, bladeless wind turbines in the shape of "inverted horns" have been developed. The wind turbine, installed in Hengshui City, captures wind energy in all directions and makes full use of the breeze, and when the air flow enters the interior, the air velocity is gradually increased as the pipes slowly shrink along the way, and finally the generator located at the narrowest part of the section is pushed to generate electricity.

In addition to "tricking" the wind into their own internal power generation, some companies have gone one step further and returned to the simplest cylindrical structure and launched the "Ruyi Golden Hoop Rod" - Vortex Bladeless.

It takes advantage of the "Karmen vortex street" phenomenon: when air flows through, it creates a "vortex" that induces reciprocating vibrations in the columns. To put it simply, when the pillar is shaken, electricity is emitted. However, the efficiency of this model is extremely limited, and long-term vibration will aggravate the wear of the material, so it is not yet commercially applicable.

Also with the help of the "vortex shedding effect", there is another bladeless wind turbine "Saphonian bladeless". In contrast to the Golden Hoop Rod, the Safinia is topped with a movable disc and a tail rudder (erected trapezoidal plate).

Vertical axis wind turbines in the future

In 2016, a wind-powered bus station near the Iceland National Music Centre was put into operation, with strangely shaped vertical-axis wind turbines above the kiosk powering lighting and electronics. The unit is not only capable of accommodating low wind speeds (2 m/s), but also in cold winds with hurricane ratings (over 50 m/s).

The axis of rotation of a vertical-axis wind turbine is perpendicular to the direction of the air flow and generally perpendicular to the ground level. The traditional horizontal axis wind turbine needs to face the strong wind, while the vertical axis wind turbine will not refuse the wind in any wind direction and accept it as ordered.

The structural load-bearing capacity of the vertical axis generator has also been greatly enhanced, allowing it to cope with stronger wind levels. These characteristics allow the vertical shaft generator to come to life in the vast oceans.

A new type of wind turbine with a big brain

The "EWICON" designed by Netherlands architects is a static net, with multiple horizontal insulating pipes placed in a rectangular steel frame outer net, each of which is densely arranged with nozzles, through which a charged water mist is generated, and the wind blows the water mist to form an electric current, thereby generating electricity.

In the movie "Super Marines", there are many motorboat generators floating in the sky to power the city, but this technology has been realized in real life. The average wind speed at high altitude is much larger than that at the surface, and the wind speed fluctuations are more stable, and many companies have set their sights on high-altitude wind power, which has great potential value, and made commercial "motor boat generators".

In order to make the overall structure lighter, the "kite wind turbine" came into being.

Although these "brain-opening" wind turbines seem to be beautiful, how to transmit power efficiently and stably is still a big problem, hindering large-scale applications.

Today, the mature three-blade wind turbine technology is in use on a large scale, but scientists are still exploring new types of generators. The strange appearance is only a superficial phenomenon, and infinitely approaching the limit of wind energy utilization is the eternal goal of wind energy research. These extreme pursuits under the façade of art are precisely where the romance of scientists lies.