CN201621016U - Wind power blades in low wind speed areas - Google Patents

Abstract

The utility model discloses a wind power generation blade suitable for low wind speed areas, which is characterized in that: the blade root is an S823 airfoil, the blade tip is an S822 airfoil, and the blade tip is provided with a sharpened transition section. The wind power generation blade of the utility model is suitable for use in low wind speed areas with an annual average wind speed of 4m/s to 6m/s, and is suitable for wind power generators with a wind rotor diameter of 10 to 20 meters and a rated power of wind power generation between 10kW and 50kW. Due to the combination of S823 and S822 airfoils, it can ensure the maximum wind energy absorption and the best output power of the wind turbine in the environment of low wind speed, and at the same time ensure the safety under the condition of occasional strong wind.

Description

Wind power blades in low wind speed areas

technical field

The invention relates to a wind power generation system blade, in particular to a wind power generation blade in a low wind speed area, and belongs to the technical field of wind power generation systems.

Background technique

The terrestrial wind energy resource area can be divided into four areas based on the annual average wind power density, namely the area rich in wind energy resources, the area rich in wind energy resources, the area with available wind energy resources, and the area with poor wind energy resources. Taking China as an example, the zoning of land wind energy resources and the percentage of the national land area are shown in Table 1. The area where China's land wind energy resources can be utilized accounts for about 76% of the country's land area. Table 1 shows the zoning of China's terrestrial wind energy resources and their percentages in the national land area.

Table 1

serial number area Annual average wind power density (W/m2) Percentage of national land area 1 rich area ≥200 8% 2 richer area 200～150 18% 3 available area 150～50 50% 4 poor area ≤50 twenty four%

At present, the large-scale development and utilization of wind energy is mainly in the high wind speed areas with rich wind energy resources, that is, concentrated in the three northern regions and the southeast coast, which only account for 8% of the country's land area; , which is a low wind speed area with an annual average wind speed ≥ 3.5m/s and hours of 2000-5000 hours. Wind energy resources have not been effectively developed and utilized.

In order to realize the effective utilization of wind energy resources in low wind speed areas, there must be applicable low rated wind speed wind turbines. The application of existing wind power technology in low wind speed areas has the following limitations:

(1) The rated wind speed is high, generally between 8 and 12m/s. In areas with low wind speed, especially in areas where wind energy resources are available, the annual average wind speed is generally at Beaufort 3 (3.4m/s-5.4m/s) or slightly higher, and high-rated wind speed wind turbines are not suitable.

(2) Medium and small power (50kW and below) wind turbines generally use direct drive. For use in low wind speed areas, due to the low fan speed (below 80rpm), it is difficult to meet the matching requirements with conventional high rated speed generators (150rpm and above), and the configuration of low rated speed generators has the disadvantages of large volume, weight and high cost. question.

(3) For direct-drive wind motors, when the diameter of the impeller is too large, such as exceeding 10 meters, the rotational speed is high under occasional strong winds, and the safety hazard of the impeller is too large.

(4) For existing wind turbine blade airfoils, the wind speed section of the best wind energy utilization coefficient is generally between 8 and 12m/s. Under low wind speed conditions, especially when the wind speed section is lower than 6m/s, the wind energy utilization coefficient It is poor, and it is difficult to maximize the capture of wind energy under low wind speed conditions.

(5) Conventional medium and small power wind turbines generally use permanent magnet synchronous generators. Due to the cogging effect, when the generator starts or runs, it will generate a large starting torque, and the electromagnetic torque will pulsate. At the same time, the application of the iron core increases the weight of the generator, and the existence of the iron core loss increases the loss.

To sum up, conventional high-rated wind-speed wind turbines are not suitable for areas with abundant wind energy resources and areas where wind energy resources are available. For low-wind-speed areas, it is necessary to develop suitable low-rated speed, high-efficiency, economical and reliable wind power generation systems. To achieve efficient and reliable wind power conversion in low wind speed environments.

As the improvement and supplement of the current gap in wind energy utilization and the limitations of wind energy utilization, the development and promotion of low rated wind speed wind power generation has extensive economic and social value.

The fan blades of the power generation system in low wind speed areas need to be specially designed. If the rated wind speed is too high, the number of operating hours at the rated power of the unit will be reduced, and the cost of the transmission system and generator will be high, which will increase the energy cost. If the rated wind speed is too low, the impeller The cost of its support is too high relative to the wind power.

Contents of the invention

The technical problem to be solved by the invention is to provide an economical and reliable wind power generation system blade suitable for low wind speed areas.

In order to solve the above technical problems, the utility model provides a wind power generation blade in a low wind speed area, including a blade root and a blade tip, which is characterized in that: the blade root is an S823 airfoil, the blade tip is an S822 airfoil, The tip is provided with a sharpened transition section. When the tip speed ratio of the blade is 5-8, the wind energy utilization of the blade is the best, and the maximum wind energy utilization coefficient is 0.46.

The above-mentioned wind power generation blades in low wind speed areas are characterized in that: along the blade height direction, the proportion of the S823 airfoil and the S822 airfoil is equal, the two airfoils in the middle section adopt an equal proportion transition, and the middle section of the blade goes to the root of the blade. The proportion of S823 gradually increases, and the proportion of S822 gradually decreases; from the middle section to the tip, the proportion of S823 gradually decreases, and the proportion of S822 gradually increases; there is a 100mm sharpened transition section at the tip

The beneficial effects achieved by the utility model:

The wind power generation blade of the utility model adopts the combined airfoil design of S823 and S822, which is suitable for use in low wind speed areas with an annual average wind speed of 4m/s to 6m/s, and is suitable for wind turbines with a diameter of 10 to 20 meters and rated wind power generation. Wind turbines with a power between 10kW and 50kW. When the tip speed ratio of the blade is 5-8, the wind energy utilization of the blade is the best, and the maximum wind energy utilization coefficient is 0.46. It can ensure the maximum wind energy absorption and the best output power of the wind turbine in the environment of low wind speed, and at the same time ensure the safety under the condition of occasional strong wind.

Description of drawings

Fig. 1 is a schematic structural diagram of a wind power generation system;

Fig. 2 is the airfoil schematic diagram, wherein (a) is the S822 airfoil schematic diagram; (b) is the S823 airfoil schematic diagram;

Fig. 3 is the blade schematic diagram of the utility model design;

Fig. 4 is a partial view of the blade tip of the utility model design;

Fig. 5 is a partially enlarged view of the blade root of a wind rotor composed of three blades;

Figure 6 is the relationship between the chord length and the radius of the 6-meter blade, and the other blades are in equal proportions to the length direction of the 6-meter blade;

Figure 7 is the relationship between the twist angle and the radius of the 6-meter blade, and the other blades are in equal proportions to the length direction of the 6-meter blade;

Figure 8 shows the relationship between blade tip speed ratio and wind energy utilization coefficient.

Detailed ways

Below in conjunction with accompanying drawing, the utility model is further described.

Figure 1 is a schematic structural diagram of a wind power generation system. The wind power generation system includes wind blades (blade 1 and hub 2), brake mechanism 3, speed increasing mechanism 4, generator 5, yaw mechanism 6, structural support beam 7, base plate 8, concrete pole tower 9 and so on. The blade root is S823 airfoil, and the blade tip is S822. There is a 100mm sharpened transition section at the blade tip.

In order to design wind turbine blades suitable for low wind speed environments, a blade optimization design platform is constructed, which consists of four functional modules: ① Genetic algorithm numerical optimization module; ② Wind rotor performance calculation module; ③ Blade twist angle and chord length parameters ④ Objective function setting module.

According to the design requirements, the design wind speed is 6m/s, the radius of the wind rotor is 6m, 9m or other lengths, the number of wind rotor blades is 3, and the design goal is to maximize the output power of the wind rotor. Apply the blade optimization design platform to obtain the three-dimensional shape of the blade, and then Computer numerical simulation is used to obtain the relationship curve between the output power of the wind turbine, the speed of the wind rotor and the wind speed within the range of the operating wind speed of the wind turbine, which is the load (generator and grid-connected inverter power combination) and the wind rotor at the design wind speed and non-design wind speed Provide a basis for the matching of all working conditions.

In order to further increase the output power of the wind turbine and reduce the noise generated by the blade tip vortex, a 100mm sharpened transition section is added at the blade tip.

The protection scope of the present utility model is not limited to the protection scope of the specific implementation, and the deformations made to the specific implementation that do not require creative labor all belong to the protection scope of the present utility model.

Claims (2)

1. A blade for wind power generation in a low wind speed area, comprising a blade root and a blade tip, characterized in that: the blade root is an S823 airfoil, and the blade tip is an S822 airfoil with a sharpened transition section. 2. The blade for wind power generation in a low wind speed area according to claim 1, characterized in that: along the blade height direction, the proportions of the S823 airfoil and the S822 airfoil are equal, and the two airfoils in the middle section are in an equal proportion transition, and the blade From the middle section to the blade root, the proportion of S823 gradually increases, and the proportion of S822 gradually decreases; from the middle section to the blade tip, the proportion of S823 gradually decreases, and the proportion of S822 gradually increases; the sharpened transition section at the blade tip is 100mm.

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