They must be the same length. The three blades are arranged at 120° to each other and rotate in a circle. The reason is very simple. The same length is for balancing. The wind reception area is the same. The force on the hub is naturally balanced. As for why it's round Yes, that's easy to understand, haha, because it rotates! ! !
Why do wind turbines only have three blades? Isn’t it better to have more blades?
Personally, I think that if the wind turbine blades are made like the blades of an electric fan, the first reason is that the weight is too high, and the second reason is that the direct connecting rod will explode. when the wind is strong. Fan blades are made like wind turbines, which must spin at high speeds to be efficient. This will inevitably consume energy and require higher structural strength of the blades.
With the changing times, the functions of these machines and equipment have been continuously improved, such as grain grinding, water transportation, power generation, etc. Traditional wind turbines come in various shapes and designs, but they are all currently being replaced by the same design. As a new clean and renewable energy, wind power has received much attention in recent years. When you walk near the wind turbine and admire the view of the wind leaves spinning quietly 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? wind turbine ?
Wind energy, as a new clean and renewable energy, has received great attention in recent years. When you walk near the wind turbine and admire the view of the wind leaves spinning quietly under the blue skyand white clouds, are you also curious to know the difference between the 3 leaves and the 5 leaves of the wind turbine?
To put it simply, three sheets are easy to balance, but if there are too many sheets, it will be difficult to balance and the cost will be high.
At the rated wind speed, the power generated is proportional to the swept area of the wind rotor, i.e. a wind rotor with 200 blades and a wind rotor with 1 blade can produce the same power.
The above figure shows that as the number of blades increases, the wind power utilization coefficient also increases, but in the process from 3 blades to 4 blades to 5 blades , the wind power utilization coefficient increases significantly, compared with the increase from 1 leaf to 2 leaves to 3 leaves, the increase is much smaller from the cost perspective, the gain exceeds the loss.
So, the less a wind turbine hase blades, the better?
First of all, the advantage of multi-blade fans is the higher 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. blade fans.
The main reason is that the high resistance of multi-blade fans causes a considerable amount of turbulence which interferes with the rotation of the blades, thereby reducing the energy conversion rate.
It is therefore much better to choose 3 sheets than 4 or 5 sheets. (Well, the same goes for electric fans); Second, an insufficient number of blades will affect the efficiency of power generation.
In fact, there is currently a patent in Europe that has two leaves, placed vertically, which can double the effectiveness! However, the 2 blade wheel hub has a special structure with a rocker structure, and theThe fatigue problem is worse than that of the 3-blade impeller.
In addition, 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. further increasing the power and speed of electricity production. 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 form of fan today.