Design method of stall type blade

Abstract

The invention belongs to the technical field of wind power generators, and particularly discloses a design method of a stall type blade of a wind power generator, which comprises the following steps: selecting a standard airfoil profile; based on airfoil aerodynamic parameters, wind driven generator parameters and blade appearance parameters, a blade element theory is used for calculation, and blade stress, main shaft torque and output power are obtained; the lift force quickly drops along with the angle of attack after stall is checked, the lift force is small under high wind speed, and meanwhile, the power generation performance meets the design requirement. The stalling performance of the blades is used for replacing a tail vane plate, the torque of the wind driven generator is reduced, the rotating speed of the wind driven generator is controlled, power balance is achieved, and therefore the cost of the wind driven generator is reduced; the stall type blade obtained through design is good in stall effect, the maximum counter torque required in the whole wind speed working interval is small, and meanwhile good power generation performance is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of wind turbine generators, and in particular to a design method for stall-type blades of a wind turbine generator. Background Art

[0002] At present, blade design is mainly aimed at controlling stall performance, which is controlled by the brake mechanism or yaw mechanism such as the tail rudder of the wind turbine. This causes the motor torque of the wind turbine to be large, thereby causing the cost of the entire wind turbine to be high.

[0003] Patent publication number CA2810157C discloses a method for preventing blade stall in a wind turbine. The patent controls blade stall through a sensor to a control system, which is costly and does not bring into play the blade's stall performance.

[0004] Patent publication number CN201810922162.9 discloses a method and device for identifying blade stall. The patent is to adjust the angle of attack of the blade to stop the stall.

[0005] Patent publication number CN202010911463.9 discloses a blade design method and a blade for a wind turbine. The blade design method of this patent mainly aims to control the stall performance of the blade, thereby improving the aerodynamic performance of the blade.

[0006] It should be noted that the information disclosed in the above background technology section is only used to enhance the understanding of the background of the present invention, and therefore may include information that does not constitute the prior art known to ordinary technicians in the field. Summary of the invention

[0007] The purpose of the present invention is to solve the technical problems existing in the background technology, and to this end, a design method for a stall-type blade is provided.

[0008] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0009] A method for designing a stall-type blade comprises:

[0010] Choose a standard airfoil with good stall performance;

[0011] Based on the airfoil aerodynamic parameters, wind turbine parameters and blade shape parameters, blade element theory is used to calculate the blade force, main shaft torque and output power.

[0012] Check that the lift decreases rapidly with the angle of attack after the stall, and the lift is small at high wind speeds. At the same time, the power generation performance meets the design requirements;

[0013] If satisfied, the design is finished;

[0014] If not satisfied, return to adjust the blade shape parameters, or select a new standard airfoil.

[0015] The following is a technical solution further defined by the present invention, which obtains aerodynamic parameters of an airfoil with a Reynolds number of 600,000 based on a stalled blade of a 10kW wind turbine.

[0016] The following is a technical solution further defined by the present invention, wherein the blade shape parameters include the relative radius position of the airfoil section, the chord length, the twist angle, the relative thickness of the airfoil and the aerodynamic center position;

[0017] The maximum chord length is designed to be 18%-22% of the relative radius;

[0018] Reduce the chord length of a single airfoil section;

[0019] The blade tip section is designed with a negative twist angle;

[0020] At 0° torsion angle, the position is controlled at 60%-80% of the relative radius;

[0021] The aerodynamic center of the blade root section occupies 50% of the airfoil, and the transition to the non-blade root section occupies 30%.

[0022] Compared with the prior art, the present invention has the following technical effects:

[0023] The present invention utilizes the stall performance of the blade to replace the tail rudder plate, reduces the torque of the wind turbine, controls the rotation speed of the wind turbine, achieves power balance, and thus reduces the cost of the wind turbine; the designed stall-type blade has a good stall effect, the maximum reaction torque required in the entire wind speed working range is small, and has good power generation performance.

[0024] The present invention is further described below in conjunction with the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0026] Figure 1 It is a schematic flow chart of the method of the present invention;

[0027] Figure 2 It is a blade performance data analysis curve diagram designed by the present invention. DETAILED DESCRIPTION

[0028] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present invention, so the present invention is not limited by the specific embodiments disclosed below.

[0029] like Figure 1 As shown, this embodiment provides a design method for a stall-type blade, which specifically includes:

[0030] Choose a standard airfoil with good stall performance.

[0031] Based on the stall blade of a 10kW wind turbine, the aerodynamic parameters of the airfoil with a Reynolds number of 600,000 are obtained.

[0032] The blade shape parameters include the airfoil section's relative radius position, chord length, twist angle, airfoil relative thickness and aerodynamic center position.

[0033] Specific design of blade shape parameters:

[0034] The maximum chord length is designed to be 18%-22% of the relative radius;

[0035] Reduce the chord length of a single airfoil section;

[0036] The blade tip section is designed with a negative twist angle;

[0037] At 0° torsion angle, the position is controlled at 60%-80% of the relative radius;

[0038] The aerodynamic center of the blade root section occupies 50% of the airfoil, and the transition to the non-blade root section occupies 30%.

[0039] Based on the aerodynamic parameters of the airfoil, the parameters of the wind turbine and the shape parameters of the blades, the blade force, the main shaft torque and the output power are calculated using the blade element theory.

[0040] Check that the lift decreases rapidly with the angle of attack after the stall, and the lift is small at high wind speeds. At the same time, the power generation performance meets the design requirements;

[0041] If the following conditions are met (good stall performance, small reaction torque, good power generation performance), the design is completed;

[0042] If not satisfied, return to adjust the blade shape parameters, or select a new standard airfoil.

[0043] Therefore, after the design is completed, the accuracy of the stall-type blade in manufacturing shape control is 2 times higher than that of the conventional blade; the surface roughness of the stall-type blade is 50% higher than that of the conventional blade.

[0044] like Figure 2 As shown, the performance data of the blade designed by the present invention is analyzed, wherein the thrust coefficient CT is a blue curve, the wind energy utilization efficiency CP is a black curve, the torque coefficient CQ is a red curve, and Y3 is a vertical straight line. In order to make the CT curve, the values ​​of the Y axis are 0, 0.20...0.80, 1.00.

[0045] The above is only a preferred embodiment of the present invention, and does not limit the present invention in any form. Any technician familiar with the art can make many possible changes and modifications to the technical solution of the present invention by using the above disclosed methods and technical contents without departing from the scope of the technical solution of the present invention, or modify it into an equivalent embodiment of equivalent changes. Therefore, all equivalent changes made according to the shape, structure and principle of the present invention without departing from the content of the technical solution of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for designing a stall-type blade, characterized in that: include: Choose a standard airfoil with good stall performance; Based on the aerodynamic parameters of the airfoil, the parameters of the wind turbine and the shape parameters of the blades, the blade element theory is used to calculate the blade force, main shaft torque and output power. Check that the lift decreases rapidly with the angle of attack after the stall, and the lift is small at high wind speeds. At the same time, the power generation performance meets the design requirements; If satisfied, the design is finished; If not satisfied, return to adjust the blade shape parameters, or select a new standard airfoil.

2. A method for designing a stall-type blade according to claim 1, characterized in that: Based on the stall blade of a 10kW wind turbine, the aerodynamic parameters of the airfoil with a Reynolds number of 600,000 are obtained.

3. A method for designing a stall-type blade according to claim 1, characterized in that: The blade shape parameters include the airfoil section position at relative radius, chord length, twist angle, airfoil relative thickness and aerodynamic center position; The maximum chord length is designed to be 18%-22% of the relative radius; Reduce the chord length of a single airfoil section; The blade tip section is designed with a negative twist angle; At 0° torsion angle, the position is controlled at 60%-80% of the relative radius; The aerodynamic center of the blade root section occupies 50% of the airfoil, and the transition to the non-blade root section occupies 30%.

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