Why do most installations such as wind power or electric fans have three leaves?

In fact, there have also been one-blade and two-blade wind turbines. But the most common number of blades in modern wind turbines is three, the result of a compromise of various aspects and parameters in the design process. These aspects include, but are not limited to:

Aerodynamics, energy conversion efficiency, manufacturing and maintenance costs, system reliability, noise, aesthetics. From a simple analysis of technical parameters, a larger number of blades can: 1) increase mechanical torque; 2) Increase the output power; But at the same time it will:

3) reduce the maximum rotation speed; 4) It brings heavier manufacturing costs, and maintenance is more complex and difficult. Therefore, motors with a high number of blades are more suitable for operation at low speeds, such as water pumps and motors for grinding grain.

Wind turbines, on the other hand, expect the blades to rotate at higher speeds, so that the generator located in the center of the blades (at the top of the tower) does not need to be manufactured to be large to meet the grid frequency requirements. In addition, the higher the altitude, the higher the wind speed, the higher the wind speed. Due to the high towers of the wind turbines, the blades are also long (40m-60m*).

There is a significant difference in wind speed between blades that rotate high and blades that rotate low. If the generator has only two blades, then when the blades are rotated to one high and one low, their force is obviously not uniform, so a stronger and more stable tower needs to be designed to support the generator and the blades. The three-blade generator can alleviate this imbalance to a certain extent, so the operation is relatively smooth and smooth.

Smooth smoothness means less noise, less wear. The number of blades of the mainstream wind turbine in the industry is 3, which is the optimal result of a combination of factors, the main factor of which is the optimization and balance between aerodynamic efficiency and structural complexity, which determines the important indicator of manufacturing and maintenance costs. According to Betz's Elementary Momentum Theory, fluid mechanics are theoretically capable of capturing up to 16 27 approx. kinetic energy carried by a stream of air flowing through one section.

This theory determines the upper limit of the energy conversion efficiency of the wind turbine impeller. <>

It can be seen that although the optimal is also in an increasing trend with the increase of the number, compared with the improvement of 3 blades to 2 blades, the improvement of 4 blades to 3 blades is already very limited (1%), and from the perspective of cost, it is not worth adding a blade and the corresponding support and pitch mechanism for a little improvement in efficiency (cost increase 1 3). The advantage of multi-blade is that the torque conversion efficiency is larger, so it is understandable that older wind turbines have more blades, which can push primitive machinery such as heavy stone mills. However, in terms of energy conversion efficiency, the improvement is very limited, and the efficiency of some modern multi-blade fans is lower than that of 3-blade fans, which is related to factors such as mutual interference around the flow of blades.

The wind is the most powerful in a few leaves of the fan??? A few blades of the fan blow the farthest away.

Fan 5 leaves of the wind is strong. The amount of air volume is closely related to the rotation speed, the number of blades, the shape of the blades, etc. At the same speed, the air volume with a large number of blades is large; But more leaves are not always better.

Fans are usually seen with three or five blades. The advantages of three leaves are good stability, low power consumption, and beautiful appearance; The disadvantage is that the noise is relatively large. The advantage of the five-blade fan is that the windshield can be set more, the operating noise is relatively small, and the air volume is larger.

In addition, with the improvement of science and technology, some four-blade and six-blade fans are slowly beginning to appear.

Summary. Extended information: At the beginning of the 21st century, a new type of wind turbine was invented by China, RI and Europe almost at the same time, which is different from the early vertical axis wind turbine (Darieu type), the efficiency is higher than that of horizontal axis wind turbines, no noise and steering mechanism, and simple maintenance.

It has become the first choice for small and medium-sized wind turbines in the European and American markets. At present, the world's high power is a 50 kilowatt vertical axis wind turbine produced by Shanghai Mos Electronic Equipment **** (MUSE), and the high power of 30 kilowatts. <>

<> wind turbine fan blades are multiple.

Hello, kiss <>

The weight of a wind turbine fan blade is about 10 tons, and the blades of different power generators are different in size and quality, taking the blades of 50 meters long as an example, <>

Extended information: At the beginning of the 21st century, a new type of wind turbine was invented by China, RI and Europe almost at the same time, which is different from the early vertical axis wind turbine (Darieu type), the efficiency is higher than that of horizontal axis wind turbines, no noise and steering mechanism, and simple maintenance. It has become the first choice for small and medium-sized wind turbines in the European and American markets.

At present, the world's high power is a 50 kilowatt vertical axis wind turbine produced by Shanghai Mos Electronic Equipment **** (MUSE), and the high power of 30 kilowatts. <>