2. Main technical parameters of the unit:
1. Machine type: horizontal axis facing wind
2. Blade type: propeller type
3. Number of blades: 3
4. Wind wheel diameter: 6 meters
5. Rated speed: 400 rpm
6.
7. Output voltage: DC220 (v)
8. Support battery: 12V100AH eighteen pieces
9. wheel)
10. Start wind speed: 3 meters/second
11. Rated wind speed: 9 meters/second
12. ~25 meters/second
13. Wind energy utilization coefficient: 0.4
14. Blade tip speed ratio: 6:1
15. method: partial tail + magnetic resistance
16. Height of the tower: 9 meters
17. Power curve (see photo)
There is a reason. for that. The old electric fan is made up of three blades.
A few days ago the old electric fan in the house broke down, then I bought onen new. This fan no longer has just three blades like the traditional electric fan, but is made up of many small blades. This design looks much better than a traditional electric fan. At the same time, this also reminds me of another problem, that is, wind turbines used in wind power generation, without exception, are made of three blades. Why is it? You can't create energy from nothing, so wind power doesn't create electricity from nothing, it just converts energy and turns wind energy into electricity. Since it is about energy conversion, it will inevitably involve a problem, namely the conversion efficiency. The wind energy conversion rate is closely related to two factors, one is wind energy and the other is wind speed.
Wind force is equal to wind power multiplied by wind speed.
Now imagine that our wind turbine has many blades that combine to form a closed disk. What about wind energy conversion? Basically zero. Because when the wind turbine becomes a closed disk, the wind force acting on the disk can actually be maximized, but no wind can pass through the disk and can only go around the disk, so the wind speed acting on the disk is zero. Any number multiplied by zero is zero, so even if the wind is very strong and there is no wind speed, there is no way to make the conversion. We see that to convert wind energy into electrical energy, the number of blades must be reduced so that the wind can pass quickly. As the number of blades decreases, the wind speed will gradually increase and the wind force acting on them will gradually decrease. In order to achieve maximum conversion power, a balance point mustbe found.
Now you might think that since a wind turbine has three blades, it must be because the wind is strongest with three blades, but that's not the case.
Calculations show that the wind energy conversion rate of the four blades is the highest. So why do wind turbines have three blades instead of four? When we encounter a problem, if we cannot find the answer in scientific principles, then the answer must be related to another factor, namely money. The fan is not an electric fan. It must withstand a lot of force and bending moment when working, so the material must be hard. The blades of modern large-scale wind turbines generally use steel pipes or D-shaped steel as longitudinal beams, steel plates as transverse beams, filled with foam inside, and covered with skin of fiberglass'outside.