CN110173391A - A kind of Large marine Axis Wind Turbine With A Tip Vane fusion winglet and wind energy conversion system - Google Patents

Abstract

The invention relates to a large-scale offshore wind turbine blade tip fusion winglet and a wind turbine, wherein the winglet and the blade tip part of the wind turbine have the same airfoil shape and a smooth transition, the winglet bends toward the suction surface of the blade, and the curvature of the winglet The inclination angle is 50°～60°. Compared with the prior art, the present invention can effectively reduce the reduction of blade tip vortex to the power of blade tip when the deep-sea wind turbine is affected by the ocean environment and produces motion conditions such as yaw, pitch, and surge. The tip winglet has good aerodynamic performance and can increase the torque of the wind turbine blade. Significantly increase the total output power of the wind turbine.

Description

A large offshore wind turbine blade tip fusion winglet and wind turbine

technical field

The invention relates to a large-scale offshore wind turbine blade tip fusion winglet and a wind turbine in particular.

Background technique

For wind turbine blades of limited length, pressure differences will occur on the upper and lower surfaces of the blades under the operating conditions of the wind turbine. As the flow goes away, the pressure on the suction side increases and the pressure on the pressure side decreases, so the pressure difference on the surface of the blade tip decreases, and the blade torque decreases. At the same time, the blade tip vortex will also generate induced resistance, which will reduce the lift force of the blade and have an adverse effect on the power output of the blade. For large wind turbines, the blade size is very large, and the impact of the blade tip vortex on the blade power cannot be ignored.

Installing the winglet structure on the blade tip of the wind turbine is an important means to improve the aerodynamic performance of the wind turbine. After installing the blade tip winglet, the strength of the blade tip vortex can be effectively suppressed. The outward bending and extension of the blade tip vortex shifts the generation position of the blade tip vortex to the outside of the wind rotor, reducing the impact of the blade tip turbulence on the pressure difference of the blade tip. impact, increasing tip power output. Since the blade tip winglet and the blade body are in a smooth transition, which is equivalent to the extension and bending of the blade, the winglet can also generate torque to increase the total power output of the wind turbine. Compared with fixed-based wind turbines on land, deep-sea wind turbines will produce yaw, pitch, surge and other movements under the influence of the marine environment, which will affect the inflow wind speed at the plane of the wind rotor, thereby affecting the aerodynamic performance of the wind turbine. Therefore, the power response of wind turbines under motion conditions is quite different from that of fixed land wind turbines.

Because the end of the blade where the tiplet is installed will generate a large swinging moment to the root of the blade, which puts forward higher requirements for the structural strength of the wind turbine blade. The existing design of the tiplet does not incorporate The weight increase of the blade tip structure and the force on the blade are considered in a comprehensive balance, resulting in the performance of the blade tip winglet not being fully utilized.

Contents of the invention

Purpose of the present invention is exactly to provide a kind of large offshore wind turbine blade tip fusion winglet and wind turbine in order to overcome the defective that above-mentioned prior art exists.

The purpose of the present invention can be achieved through the following technical solutions:

A large-scale offshore wind turbine blade tip fusion winglet, the winglet has the same airfoil shape as the blade tip part of the wind turbine and has a smooth transition, the winglet is curved toward the suction surface of the blade, and the angle of inclination of the winglet is 50° ° ~ 60 °.

The airfoil of the winglet is NACA64 airfoil.

The spanwise length of the winglet is 3%-5% of the radius of the wind rotor.

The bending radius of the winglet is 1%-3% of the radius of the rotor of the wind turbine.

A large offshore wind turbine, comprising a plurality of blades, the tip of the blade is provided with a small wing, the winglet is the same as the airfoil of the tip and transitions smoothly, and the winglet is bent towards the suction surface of the blade, And the bending angle of the winglet is 50°-60°.

The airfoil of the winglet is NACA64 airfoil.

The spanwise length of the winglet is 3%-5% of the radius of the wind rotor.

The bending radius of the winglet is 1%-3% of the radius of the rotor of the wind turbine.

Compared with the prior art, the present invention has the following beneficial effects:

1) It has a smooth transition and the same airfoil shape as the tip of the blade, and is bent towards the suction surface of the blade, and the bending angle of the winglet is 50°-60°, which realizes the fusion design of the winglet and the tip, and can improve the Sharp power output, significantly increasing the total output power of offshore wind turbines.

2) The spanwise length is 3% to 5% of the radius of the wind rotor, and the bending radius is 1% to 3% of the radius of the wind rotor of the wind turbine. The fused winglet has a good aerodynamic shape and can increase power.

Description of drawings

Fig. 1 is the blade with tip fusion winglet;

Fig. 2 is a partial schematic view of the winglet;

Fig. 3(a) is the pressure cloud diagram of the pressure surface of the tipless winglet;

Fig. 3(b) is a cloud diagram of the pressure surface of the blade with tiplet;

Fig. 3(c) is a cloud diagram of pressure on the suction surface of a blade without a tip;

Fig. 3(d) is a cloud diagram of pressure on the suction surface of a blade with a tiplet;

Figure 4 shows the pressure values on the upper and lower surfaces of the tip section of the tipped winglet blade.

Detailed ways

The present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments. This embodiment is implemented on the premise of the technical solution of the present invention, and detailed implementation and specific operation process are provided, but the protection scope of the present invention is not limited to the following embodiments.

A large-scale offshore wind turbine blade tip fusion winglet, as shown in Figure 1, the winglet has the same airfoil shape as the blade tip part of the wind turbine and has a smooth transition, the winglet is curved towards the suction surface of the blade, and the curvature of the winglet The inclination angle is 50°～60°. The airfoil of the winglet is NACA64 airfoil. The spanwise length of the winglet is 3% to 5% of the radius of the rotor, and the bending radius of the winglet is 1% to 3% of the radius of the rotor of the wind turbine.

Under the condition of keeping the sweeping area of the wind rotor constant, the optimal winglet inclination angle maximizes the total power generated by the blade and the winglet.

Fig. 1 is the blade tip fusion winglet of the present application, and the winglet is bent towards the suction surface, and Fig. 2 is a partial view of the blade tip winglet of an offshore wind turbine blade.

The blade tip fusion winglet of the present application is determined by the wing root and wing tip airfoil and the equivalent length, bending radius and inclination angle. The important plane geometric parameters of the blade tip winglet are:

1) Winglet orientation: the winglet faces the suction surface, that is, toward the downstream of the wind turbine;

2) Bending radius: the arc bending radius of the connection between the winglet and the blade body;

3) Equivalent length: the projected length of the winglet in the length direction of the blade;

4) Inclination angle: the angle between the bending length direction of the winglet and the blade;

5) Small wing airfoil: Refers to the blade tip winglet adopting NACA64 airfoil.

The blades containing the winglets of the present application were tested, and the new fusion tip winglets were added under the conditions of yaw, pitch, surge and other motions of the deep-sea wind turbine under the influence of the marine environment. The specific parameters are shown in Table 1. Show. Wind turbine A represents an offshore wind turbine without tip fusion winglets, and wind turbine B represents a wind turbine with blade tip fusion winglets added. Under the condition of wind turbine rated wind speed of 11.4m/s, CFD (Computational FluidDynamic) method is used to calculate the power coefficient C _p and axial thrust coefficient C _t of these two wind turbines, and compare and analyze their aerodynamic performance. The calculation results are shown in the table 1.

Table 1 Aerodynamic performance results of offshore wind turbines with or without fused winglets

offshore wind turbine C_p C_t A 0.4608 0.7040 B 0.4807 0.7342

It can be seen from Table 1 that under the rated operating conditions of the wind turbine, compared with the wind turbine A, the power coefficient of the B wind turbine is increased by 4.30%, and the axial thrust coefficient is increased by 4.29%. The power increase rate of the engine is greater than the axial thrust increase rate.

Under the conditions of yaw, pitch, surge and other motions of deep-sea wind turbines affected by the marine environment, as shown in Figure 3(a) and 3(b), on the pressure surface of the blade, the pressure distribution of the two blades is basically the same, The pressure value on the surface of the fused winglet is greater than that on the surface of the blade; as shown in Figure 3(c) and 3(d), on the suction surface of the blade, the negative pressure area of the blade with the tip fused winglet is larger and the pressure value is lower than that without the small winglet. Wing blades, so with fused winglet blades the surface pressure difference is greater and the power output is increased. As shown in Figure 4, the airfoil surface pressure distribution of the blade section at 1m from the blade tip is intercepted. It can be seen that at the front of the airfoil, the suction surface pressure value of the blade with fused winglets is lower than that of the blade without winglets.

Claims (8)

1. A large offshore wind turbine blade tip fusion winglet is characterized in that the winglet is identical to the airfoil profile of the blade tip part of the wind turbine and transitions smoothly, and the winglet is curved towards the suction surface of the blade, and the winglet The bending inclination angle is 50°～60°. 2. A large offshore wind turbine blade tip fused winglet according to claim 1, characterized in that the airfoil of said winglet is a NACA64 airfoil. 3 . The blade tip fused winglet of a large offshore wind turbine according to claim 1 , wherein the spanwise length of the winglet is 3% to 5% of the radius of the rotor of the wind turbine. 4 . 4 . A large offshore wind turbine blade tip fused winglet according to claim 1 , wherein the bending radius of the winglet is 1% to 3% of the rotor radius of the wind turbine. 5. A large offshore wind turbine, comprising a plurality of blades, characterized in that a winglet is provided on the blade tip of the blade, the winglet is the same as the airfoil of the blade tip and transitions smoothly, and the winglet It is bent toward the suction surface of the blade, and the bending angle of the winglet is 50°-60°. 6. A large offshore wind turbine according to claim 5, characterized in that the airfoil of the winglet is NACA64 airfoil. 7 . The large offshore wind turbine according to claim 5 , wherein the spanwise length of the winglets is 3% to 5% of the radius of the rotor of the wind turbine. 8 . 8 . The large offshore wind turbine according to claim 5 , wherein the bending radius of the winglet is 1% to 3% of the radius of the rotor of the wind turbine.