When you mention "wind turbine", does the "three-blade white windmill" immediately pop up in your mind? In addition to this classic shape, the real wind turbine also has various magical shapes.
Why three blades?
As the "originator" of wind turbines, windmills have played a huge role in drainage in the Netherlands, and are thus famous all over the world. The image of the four-blade Dutch windmill is also deeply rooted in the hearts of the people. The multi-blade water-lifting windmills of the western United States were once also popular. Multiple blades can make the whole rotor generate more power and provide more sufficient power.
Four-blade or even multi-blade windmills have been formed. Why did they become three-blade wind turbines? The number of blades will not directly affect the energy utilization rate. On the contrary, too many blades will interfere with the airflow and reduce the utilization rate of wind energy. Wind energy utilization equipment can only capture at most 59.3% of the kinetic energy in the wind and use it. So a wind turbine with just one blade can generate the same amount of electricity.
However, single-blade wind turbines have not become mainstream. A single blade will make the rotor extremely unbalanced, which seriously threatens the safety of the entire wind turbine. Imagine a big clump of clothes tangled together to dry... the whole washing machine vibrates violently, or even goes out of business. Symmetrical two blades can improve this unbalanced force, but it is still not stable enough, and the application of two-blade wind turbines will still be limited until a more ideal load control technology appears.
The three-blade wind turbine solves the problem of balance because of its optimal layout, but "heavy" has also become one of the "pain points". A single wind turbine blade weighs 20 tons, and the rotor composed of three blades exceeds 60 tons, which is really a heavy big guy. Once the foundation on the ground has quality problems, the entire unit may overturn and collapse.
Some manufacturers "break down the wind turbine into parts" and use multiple small blades to transform it into four heads and twelve arms. In 2016, wind power leader Vestas installed a wind turbine with four rotors at the Technical University of Denmark, which was completely dismantled after two years of quiet operation. . Due to the scarcity of models, the relevant data is extremely valuable, and the two institutions have almost never disclosed any data to the public.
No blades, No electricity
Mad scientists are not willing to accept mediocre leaves, and thus come up with the "no leaves" plan. The legendary electrical giant Nikola Tesla once applied for a patent for a bladeless turbine, but it was eventually abandoned due to a lack of suitable manufacturing materials. Based on this idea, people have developed a bladeless wind turbine with a volute shape. The wind pushes the inner disc to rotate, which drives the generator to generate electricity. However, this kind of "piggy page"-like wind motor needs to strictly ensure the precision of each component's processing and manufacturing, and at the same time requires that the wind must be aligned with the air inlet, such harsh conditions restrict its development.
In order to take advantage of the incoming wind from all directions, people have developed a bladeless wind turbine in the shape of an "inverted big horn". This wind turbine installed and used in Hengshui City can capture wind energy in all directions and make full use of the breeze. After the airflow enters the interior, the airflow speed is gradually increased along with the slowly shrinking pipeline along the way, and finally pushes it to the narrowest part of the section. generator to generate electricity.
In addition to generating power by "cheating" the wind into their own interiors, some companies have gone a step further, returning to the simplest columnar structure and launching the "ruyi golden hoop rod" - Vortex Bladeless.
It exploits the phenomenon of "Karman Vortex Street": when air flows through, it creates "vortices" that induce the column to vibrate back and forth. Simply put, when the column is shaken, electricity is emitted. However, the efficiency of this model is extremely limited, and the long-term vibration will aggravate the wear of materials, so it does not have commercial application value yet.
Also using the "vortex shedding effect", there is another bladeless wind turbine "Saphonian bladeless". Compared with the "Golden Hoop" wind turbine, the top of the "Safinia" is equipped with a movable disc and a tail rudder (a vertical trapezoidal plate).
The future of vertical axis wind turbines
In 2016, a wind-powered bus station near the Icelandic National Music Centre went into operation, with oddly shaped vertical-axis wind turbines above the bus pavilion providing electricity for lighting and electronics. This unit can not only adapt to the low wind speed environment (2 m/s), but also can work normally in the cold wind of hurricane level (over 50 m/s).
The rotation axis of the vertical axis wind turbine is perpendicular to the direction of the airflow and is generally also perpendicular to the ground plane. Traditional horizontal-axis wind turbines need to face strong winds, while vertical-axis wind turbines are open to the wind in any wind direction and accept all orders. The structural bearing capacity of the vertical axis generator is also greatly enhanced, allowing it to cope with stronger wind levels. These characteristics make the vertical axis generator come to life in the vast ocean.
A new type of wind turbine with a big brain
"EWICON" designed by Dutch architects is a static net, with a number of horizontal insulating tubes placed in the rectangular steel frame outer net, and nozzles are densely arranged on each insulating tube, which is generated by electrodes. The charged water mist, 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 supply power to the city. In fact, this technology has been realized in real life. The average wind speed at a high altitude is much greater than that on the surface, and the fluctuation of wind speed is more stable. Many companies have turned their attention to high-altitude wind power with great potential value and manufactured commercialized "motorboat generators".
In order to make the overall structure lighter, the "kite wind turbine" came into being. Although these "brain-opened" wind turbines seem to be beautiful, how to transmit power efficiently and stably is still a big problem, hindering large-scale applications. Today, mature three-blade wind turbine technology is in large-scale use, but scientists are still exploring new generators. The strange shape is only a superficial phenomenon, and the infinite approach to the limit of wind energy utilization is the eternal goal of wind energy research. The ultimate pursuit of these artistic appearances is exactly the romance of scientists.
Comments