Can a wind turbine generate electricity at such a slow speed?

Can a wind turbine generate electricity at such a slow speed? Wind energy is a renewable and clean energy source. With the continuous increase in human demand for energy, humans are gradually increasing their utilization of wind energy. Wind turbines often appear on vast grasslands, mountain slopes, and even sea surfaces, but we can see that rotating turbines may have such problems. Why do the blades of wind turbines rotate so slowly? Can this generate electricity?

Adjusting the speed of the wind turbine to what we see is actually a combination of many factors.

Wind turbine blades have a large mass and require a lot of effort to rotate.

Many people think that a wind turbine is like a small windmill, not very big, especially when we see a large wind turbine from a distance. We have this feeling, but in fact, wind turbines can be called behemoths. The blades of a wind turbine are up to 60 meters long. It is known that the wingspan of a medium-sized passenger plane is about 30 meters, and the wingspan of an ordinary large passenger plane can hardly reach 60 meters. Although such large blades use high-strength and low-density materials, their mass is not too small, usually weighing over ten tons. Three such high-quality blades are naturally difficult to rotate.

Some people may think so. Since such a large fan is difficult to turn, why not make it smaller? This is related to the windward area of the generator. When the blades are too small, the windward area is naturally too small, and the wind on the blades becomes less and less, the electricity generated by a single generator becomes less and less. If the number of generators increases, can it be compensated for? In fact, the increase in quantity also increases construction costs. Generally speaking, if the same power source is used, the cost of a small blade generator will be higher. However, the fan cannot be too large. On the one hand, it is limited by materials, and on the other hand, installation will be more difficult. After comprehensive consideration, we have now used fans of different sizes.

A higher rotational speed does not necessarily mean more power generation.

When the blades of a wind turbine rotate, it drives a huge internal gear to rotate together, and when the large gear drives the small gear, the rotational speed also changes significantly. This structure is expressed in the most familiar way, equivalent to a gearbox. We see that the blades rotate slowly, but the fan actually drives the generator to rotate at high speed through a gearbox.

Of course, the power generation of wind turbines is not only related to speed, but also to torque. Power=torque speed K, which is a constant. When the speed is low, increasing torque can also increase output power. Therefore, in order to prolong the durability of wind turbines, the blades are usually not rotated too fast, because the blades of wind turbines are huge and the centrifugal force of high-speed rotation is also large. Long term high-intensity centrifugal motion can also damage the life of the blades, and serious damage may occur directly. Therefore, when the wind turbine encounters strong winds, it will turn on the protection mode and stop generating electricity to protect the fan.

Excessive speed can also affect power generation efficiency.

In fact, when the blades of the fan rotate, they also hinder the movement of the wind. The faster the speed, the stronger the obstacles. When a certain value is reached, the utilization rate of wind energy will also begin to decrease. For the convenience of everyone's understanding, we can imagine two extreme examples. If the fan speed approaches infinity, the rotation of the blades is equivalent to directly forming a sealing plate, blocking the airflow. At this point, the wind must take a detour, so it is naturally not possible to make good use of this wind energy. At this point, the utilization rate of wind energy is equivalent to zero. Another scenario is when the fan speed is directly zero. At this point, wind energy has not been utilized at all. The speed with the highest wind energy utilization rate exists within the range of zero speed and infinite speed. This speed is related to many factors. We only discussed a lot here. Therefore, the fan speed we see is not significantly different from the theoretical optimal speed. By adjusting to the optimal speed, the wind energy utilization rate is also highest at this time.

summarize

Therefore, wind turbines appear to be slow, while the actual body is efficiently generating electricity. Seemingly simple fan generators, in fact, various factors were considered at the beginning of the design to affect the efficiency of fan power generation. Behind the simple phenomenon, there are complex and strict scientific truths.