The blades, which rotate the rotor shaft of the generator by moving with the power of the wind, convert the kinetic energy of the air into mechanical energy and then into electrical energy.
The three-bladed design is very important in increasing energy efficiency. In addition to efficiency, cost, low noise level and durability factors were also taken into account.
One side of the wings is straight, the other side is curved outward.
They have a structure similar to airplane wings. Thanks to this aerodynamic design, the wind moves faster, taking longer distances in the curved part of the wing. The pressure on the curved side is greater than on the straight side, which increases the force and allows the blades to turn better.
These systems generate the necessary torque for electricity generation with every 120 degree rotation.
If there are more than three blades, more wind will hit the blades, but it will not affect the number of turns. As the number increases, each wing blocks the wind of the wing below it. Since it will cause the rotation speed to slow down, electricity production will also be less. This reduces energy efficiency.
If multiple wings are inefficient, then why not one wing or two wings?
If it were a single wing, a faster turn would be achieved, but this would cause stability and noise issues.
Two blades are actually more efficient, but these turbines require special shock absorbers and a specially designed hub to maintain balance and generate electricity. This situation is not preferred as it increases the cost.
It is also important to prefer odd numbers instead of even numbers.
If there are even numbers, one of the blades is at the top while one of the blades is at the bottom (in line with the mast of the turbine) during rotation. In such a case, more wind force is applied to the upper wing than the lower wing.
Because the foot of the wind turbine negatively affects the movement of the air around the lower blade. The blades would move back and forth in the vertical position, destabilizing the turbine. When there is an odd number, balance is achieved as in a wheel.
In summary; Thanks to the three-bladed design, energy efficiency, durability, balance and noise level are optimized.
Sources: TUBITAK, Engineer
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