If the angle between the blades is 90°, what will be the power generation effect? When the wind acts at an angle of 90 degrees to one blade, it is 0° to the next blade. While the wind still acts on the first blade, it will also act on the second blade.
If the wind force at that time is different, one blade will be pushed forward while the other blade will be stopped. This is not only detrimental to wind power generation, but also consumes more equipment. What can be concluded is that the interaction between the four blades is relatively large, which affects the result of their interaction and reduces the power. The blades of the two blades interfere with each other, and the interaction between them is also obvious, which is also undesirable. Therefore, the three-blade type is reasonable.
Actually, there are single-blade and two-blade wind turbines. Buthe most common number of blades in modern wind turbines is three, the result of compromises between various aspects and parameters during the design process. These aspects include, but are not limited to: aerodynamics, energy conversion efficiency, manufacturing and maintenance costs, system reliability, noise and aesthetics.
From a simple analysis of the technical parameters, a larger number of blades can:
(1) Increase the mechanical torque
(2) Increase power output;
But a greater number of blades will also:
(3) reduce the maximum rotation speed;
(4) result in higher manufacturing costs heavy. Repairs are also more complex and difficult.
Therefore, motors with a large number of blades are more suitable for operation in low-speed locations, such as water pumps and grain grinding motors.
Wind turbinesexpect the blades to rotate at a relatively high speed, so the size of the generator located in the center of the blades (at the top of the tower) does not need to be large to meet the frequency. grid requirements.
In addition, wind speeds generally increase at higher altitudes. As the wind turbine tower is very high, the blades are also very long (40m-60m*). There is a significant difference in wind speed between blades rotating to a high position and blades rotating to a low position.
If the generator has only two blades, then when the blades rotate to a high position and a low position, the force exerted on them is obviously not uniform enough, so a tower must be designed stronger and more stable. to hold it in place. Generator and blades. The three-blade generator can alleviate this imbalance to some extent, allowing it to operate more easily.ilement. Smooth means less noise and less wear.
The efficiency of wind turbines in absorbing energy from wind speed is related to the tip speed ratio. A certain top speed ratio must be maintained to achieve higher efficiency. As for the engine, it is already quite efficient and is not the center of attention.
In order to maintain the peak speed ratio, the rotational speed must change in direct proportion to the wind speed. To put it bluntly, it needs to be sometimes faster and sometimes slower. It doesn't matter if it's slow, but it spins fast and dies quickly, so I hope the resistance of the single chip will be higher, so the single chip will have to be wider. The choice is therefore limited to one, two or three pieces. A single piece is unbalanced, and a double piece is reasonable. Theoretically, it is a balance, but in practice it is difficult to make, so you have to use 3 fteces, which is a compromise between economy and feasibility.