Why is the wind turbine designed with three impellers?

Through experimental verification, it has been found that the more impellers a wind turbine has, the better; The wind energy utilization coefficient of the three bladed wind turbine has been reached, and the design of the blade shape of the wind turbine should be optimized for the rest.

The wind energy utilization coefficient curve of a single blade to five blade horizontal axis wind turbine shows that as the number of blades increases, the wind energy utilization coefficient also increases, but the increase from 3 to 4 to 5 blades is much smaller than before. But we also need to consider cost factors, so adding too many blades is not cost-effective.

For wind turbines, the advantage of multiple blades is their high 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. This is mainly because multi blade fans have high resistance, which causes a significant amount of disturbance to the rotation of the blades, thereby reducing the energy conversion rate.

In this regard, three bladed wind turbines are much better than four bladed and five bladed turbines. After comparison, experts also found that under the same wind speed conditions, the speed of a two blade wind turbine is significantly higher than that of a three blade wind turbine. However, due to the fast rotation, the two blade wind turbine will generate a lot of noise. Therefore, it is recommended to reduce the operating speed as much as possible to reduce the noise generated by the wind turbine operation.

In addition, excessive blade speed can increase centrifugal force, so the central axis and blades of wind turbines need to be stronger to resist the increased centrifugal force, which also increases costs. Therefore, various indications suggest that three bladed turbines are the ideal design for wind turbines.