Wind power generation is the process of converting wind kinetic energy into mechanical kinetic energy, and then converting mechanical energy into electrical kinetic energy. The principle (or process) of wind power generation is to use wind power to drive the windmill blades to rotate, and then use a speed increaser to increase the speed of rotation to prompt the generator to generate electricity. According to current windmill technology, power generation can begin at a breeze speed of approximately 3 meters per second. But from an economic point of view, wind speeds greater than 4 meters per second are suitable for power generation. One of the advantages of wind power is that no fuel is used and no radiation or air pollution is produced.
With the development of the times, the functions of these machines and equipment have been continuously upgraded, such as grain grinding, water transportation, power generation, etc. Traditional wind turbines come in a variety of shapes and designs, but they are all currently being replaced by the same design. Wind energy, as a clean and renewable new energy source, has become a popular energy source in recent years. When you are walking near the wind turbine and admiring the sight of the wind leaves turning leisurely under the blue sky and white clouds, are you also curious about the difference between the 3 leaves and the 5 leaves of the wind turbine?
As a clean and renewable new energy, wind energy has received great attention in recent years. When you are walking near the wind turbine and admiring the sight of the wind leaves turning leisurely under the blue sky and white clouds, are you also curious about the difference between the 3 leaves and the 5 leaves of the wind turbine?
To put it simply, three leaves are easy to balance, but if there are too many leaves, it will be difficult to balance and the cost will be high.
At rated wind speed, the generated power is proportional to the swept area of the wind rotor, that is, a wind rotor with 200 blades and a wind rotor with 1 blade can produce the same power.
It can be seen from the above figure that as the number of blades increases, the wind energy utilization coefficient also increases, but in the process from 3 blades to 4 blades to 5 blades, the wind energy utilization coefficient increases by a large margin , compared with the increase from 1 leaf to 2 leaves to 3 leaves, the increase is much smaller. From a cost perspective, the gain outweighs the loss.
So, the fewer blades of a wind turbine, the better?
First of all, the advantage of multi-blade is the larger torque conversion rate, but in terms of energy conversion rate, the efficiency of 4-blade and 5-blade fans is lower than that of 3-blade fans.
The main reason is that the large resistance of multi-blade fans causes a considerable amount of turbulence that interferes with the rotation of the blades, thus reducing the energy conversion rate.
So it is much better to choose 3 leaves than 4 or 5 leaves. (Well, the same is true for electric fans); Secondly, too few blades will affect power generation efficiency.
In fact, there is currently a patent in Europe that has two leaves, placed vertically, which can double the efficiency! However, the 2-blade wheel hub has a special structure with a seesaw structure, and the fatigue problem is worse than that of the 3-blade wheel.
Moreover, the fewer blades, the higher the rated speed. When the speed is high to a certain extent, the circumferential linear speed of the blade tip is very large, causing large wind resistance. The drag torque limits the further increase in power generation power and speed. Therefore, it is not good to have too few blades. Three blades are mainly for good balance and low cost. After a long period of verification, they have become a common fan form today.