A fan blade and a wind turbine

Abstract

The application relates to the technical field of wind power generation equipment, in particular to a fan blade and a wind driven generator. The fan blade of the application adopts a symmetrical airfoil design and has obvious aerodynamic performance advantages. The symmetrical airfoil makes the fan blade maintain relatively uniform airflow distribution in the rotating process regardless of the angle, thereby reducing turbulence and resistance and improving wind energy conversion efficiency. In addition, the head and tail design of the symmetrical airfoil makes the fan blade more balanced under stress, enhances the structural stability and service life of the fan blade. Through real-time optimization of the airfoil by a curve equation, the current environmental wind power conditions can be further matched, so that the fan can maintain the best operating state under different wind speeds.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of wind power generation equipment, in particular to a fan blade and a wind driven generator. BACKGROUND

[0002] The working principle of the vertical axis wind driven generator is to use aerodynamics to drive the generator through the impeller. Specifically, the vertical axis wind driven generator is composed of a wind wheel, a generator, a controller and a storage battery. The impeller is composed of a plurality of fan blades, the fan blades are generally in the shape of an airplane wing, the fan blades are fixed on the hub, and the hub is connected together through connecting rods. When the wind blows through the impeller, the fan blades are rotated under the action of the wind, thereby driving the generator to generate electricity.

[0003] In the design of the wind driven generator, the airfoil of the fan blade is one of the key factors, which directly affects the aerodynamic performance and power generation efficiency of the wind driven generator. The conventional fan blade airfoil of the wind driven generator usually adopts a standard or standardized design, which is usually based on experience or extensive industry practice and can be applicable to most regions. However, for individual regions, due to the unusual topography and climate of the region, the use of standard or standardized types of fan blades results in a decrease in power generation efficiency, and therefore it is necessary to optimize the airfoil of the fan blade.

[0004] The commonly used optimization method is to simulate the existing fan blade to obtain the most suitable fan blade for individual regions. However, this method still selects from the original airfoil and does not improve the old airfoil, thereby resulting in a small improvement in the optimal airfoil selected for power generation efficiency, and also failing to effectively optimize the airfoil according to the actual situation, thereby failing to well solve the problem of mismatch between the airfoil and the current environment. SUMMARY

[0005] In order to avoid and overcome the technical problems existing in the prior art, the present application provides a fan blade and a wind driven generator. The present application can optimize the airfoil in real time through a curve equation, thereby better matching the optimized airfoil with the current environment.

[0006] To achieve the above object, the present application provides the following technical scheme:

[0007] A fan blade, the airfoil of the fan blade is a symmetrical airfoil, the symmetrical airfoil includes an upper camber line and a lower camber line which are directly connected at the head and connected to each other through a tail edge at the tail; the upper camber line and the lower camber line are arranged symmetrically with the chord line as the axis of symmetry, and the chord line intersects the midpoint of the tail edge perpendicularly; the curve equation of the upper camber line is expressed as follows in the rectangular coordinate system O-XY:

[0008]

[0009] In the formula, the head intersection point of the upper bone line and the lower bone line is the origin O, the straight line where the chord line is located is the X axis, and the straight line passing through the origin O and perpendicular to the X axis is the Y axis;

[0010] y represents the longitudinal coordinate of the upper bone line, and the unit is m; x represents the transverse coordinate of the upper bone line, and the unit is m; a1, a2, b1, b2, and b3 all represent model parameters of the upper bone line.

[0011] As a further scheme of the present application: the value range of the model parameters is specifically: the value range of a1 is [-0.086, -0.08]; the value range of a2 is [0.086, 0.09]; the value range of b1 is [-1, -0.9]; the value range of b2 is [0.7, 0.8]; and the value range of b3 is [0.05, 0.06].

[0012] A wind turbine, which applies the above-mentioned wind turbine blade, comprises a tower that can stand on the ground, a generator connected with an electric power control system is fixedly installed on the top of the tower, a hub is drivingly installed on the motor shaft of the generator, and a plurality of the wind turbine blades are installed on the hub.

[0013] As a further scheme of the present application: each of the wind turbine blades is uniformly distributed on the outer cylindrical surface of the hub in sequence in the circumferential direction of the hub.

[0014] As a further scheme of the present application: the hub is fixedly installed on a main shaft, the main shaft is rotatably installed on the tower, and the main shaft and the motor shaft are drivingly matched through a gear set.

[0015] As a further scheme of the present application: the wind turbine blade is made of glass fiber reinforced plastic composite material or carbon fiber composite material.

[0016] As a further scheme of the present application: a wind speed meter is installed on the top of the tower.

[0017] As a further scheme of the present application: a wind direction meter is installed on the top of the tower.

[0018] As a further scheme of the present application: a machine cabin cover is installed on the top of the tower, and the generator is installed in the machine cabin cover.

[0019] As a further scheme of the present application: the output shaft of the gear set and the motor shaft are connected with each other through a shaft coupling.

[0020] Compared with the prior art, the present application has the following advantages:

[0021] 1、The fan blades of the present application adopt a symmetrical airfoil design, which has significant aerodynamic performance advantages. The symmetrical airfoil allows the fan blades to maintain relatively uniform airflow distribution during rotation, regardless of the angle, thereby reducing turbulence and resistance and improving wind energy conversion efficiency. In addition, the head and tail design of the symmetrical airfoil makes the fan blades more balanced under stress, enhancing the structural stability and service life of the fan blades. Real-time optimization of the airfoil through a curve equation can further match the current environmental wind conditions, ensuring that the fan maintains optimal operating conditions at different wind speeds.

[0022] 2、The precise value range of model parameters ensures the flexibility and adaptability of the airfoil design. By adjusting these parameters, the aerodynamic performance of the fan blades can be optimized for different wind speeds, wind directions, and terrain conditions. Parameterized design not only improves the manufacturing precision of the fan blades, but also makes the performance of the fan blades more stable and reliable in different environments.

[0023] 3、The wind turbine of the present application adopts an optimized fan blade, which significantly improves the power generation efficiency and stability. The optimized fan blade can better capture wind energy and convert it into electrical energy, thereby improving the output power of the entire power generation system. In addition, due to the improved aerodynamic performance of the fan blade, the operating noise and vibration of the generator are effectively controlled, improving the operating quality of the equipment.

[0024] 4、The uniform distribution of fan blades ensures that the wind turbine maintains balance and stability during rotation. This design reduces additional stress and vibration caused by uneven distribution of fan blades, prolonging the service life of the generator. At the same time, the uniformly distributed fan blades can also more effectively capture wind energy, improving power generation efficiency.

[0025] 5、The gear ratio of the gear set can be adjusted according to actual conditions to ensure that the generator operates at the best speed. In addition, the connection between the main shaft and the motor shaft is more stable and reliable, improving the stability and durability of the entire system.

[0026] 6、The fan blades made of glass fiber reinforced plastic or carbon fiber reinforced plastic have high strength, light weight, and corrosion resistance. These materials not only improve the load-bearing capacity of the fan blades, but also reduce the weight of the fan blades, making the wind turbine more energy-efficient during operation. At the same time, these materials also have excellent fatigue resistance, prolonging the service life of the fan blades.

[0027] 7、The real-time monitoring function of the anemometer provides important data support for the operation of the wind turbine. By monitoring wind speed changes, the operating state and output power of the generator can be adjusted in a timely manner to ensure that the generator operates under optimal conditions. This helps to improve power generation efficiency and reduce energy waste.

[0028] 8、The real-time monitoring function of the wind direction instrument enables the wind turbine to accurately capture changes in wind direction and adjust the orientation of the turbine blades as needed. This automatic adjustment function not only improves power generation efficiency but also reduces additional stress and vibration caused by changes in wind direction. At the same time, the monitoring data of the wind direction instrument can also provide important reference for the maintenance and management of the wind turbine.

[0029] 9、The design of the nacelle cover provides effective protection for the generator. It not only prevents damage to the generator caused by external harsh environments, but also reduces the spread of noise and vibration. In addition, the nacelle cover also facilitates maintenance and repair work, improving the operational reliability and maintenance efficiency of the wind turbine.

[0030] 10、The use of the coupling makes the connection between the output shaft of the gear set and the motor shaft more stable and reliable. It can withstand large torque and axial force, ensuring the stability of the generator during high-speed rotation. At the same time, the coupling also has certain buffering and damping functions, which can reduce additional stress caused by vibration and impact, prolonging the service life of the generator. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 It is a schematic diagram of the structure of the turbine blade in the application.

[0032] Figure 2 It is a schematic diagram of the structure of the wind turbine in the application.

[0033] Figure 3 It is a curve graph of the numerical simulation results of the turbine blade attack angle in the application.

[0034] Figure 4 It is a wind speed change curve in the application.

[0035] Figure 5 It is a comparison graph of the turbine blade airfoils before and after optimization in the application.

[0036] Figure 6 It is a pressure cloud chart when the turbine blade attack angle is 3° and the wind speed is 5m / s.

[0037] Figure 7 It is a pressure cloud chart when the turbine blade attack angle is 6° and the wind speed is 5m / s.

[0038] Figure 8 It is a velocity cloud chart when the turbine blade attack angle is 3° and the wind speed is 5m / s.

[0039] Figure 9 It is a velocity cloud chart when the turbine blade attack angle is 6° and the wind speed is 5m / s.

[0040] Figure 10 For the fan blade attack angle of the present application is 3°, the lift-drag ratio comparison chart before and after optimization.

[0041] Figure 11 For the fan blade attack angle of the present application is 6°, the lift-drag ratio comparison chart before and after optimization.

[0042] In the figure: 1, fan blade; 11, upper skeleton line; 12, lower skeleton line; 13, tail edge; 2, hub; 3, generator; 4, tower. DETAILED DESCRIPTION

[0043] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0044] Please refer to Figures 1-2 In the embodiments of the present application, a wind turbine includes a tower 4 that can stand on the ground, a machine cabin cover is installed at the top of the tower 4, and a generator 3 is installed in the machine cabin cover. A hub is fixedly installed on a main shaft, the main shaft is rotatably installed on the tower 4, and the main shaft and the motor shaft are transmissionally matched through a gear set. The output shaft of the gear set and the motor shaft are connected to each other through a shaft coupling. Each of the fan blades 1 is circumferentially and uniformly distributed on the outer circular surface of the hub 2 in sequence.

[0045] The generator 3 and a power control system are connected to each other, the power control system is the “brain” of the wind turbine, is responsible for monitoring the running state of the wind turbine, and adjusts the working parameters of each component as needed. The control system usually includes a computer that continuously monitors the state of the fan, and controls components such as yaw devices and brake devices.

[0046] Please refer to Figures 3-11 The optimization process of the symmetrical airfoil in the present application is as follows:

[0047] I. Obtain historical operation data.

[0048] The historical operation data of the fan blade includes basic parameters of the fan blade, original airfoil data of the fan blade, and wind speed in the environment where the fan blade is located. In this embodiment, the basic parameters of the fan blade of a small and medium-sized wind turbine with a rated power of 1 kW are shown in Table 1.

[0049] Table 1 Basic parameters

[0050]

[0051] The original airfoil data of the fan blade refers to a curve coordinate formed by the original airfoil of the fan blade in a coordinate system O-XY.

[0052] II. Constructing a model and determining model parameters.

[0053] An optimized airfoil upper bone line model is constructed, and the optimized airfoil upper bone line model is shown in formula (1):

[0054]

[0055] The optimized airfoil upper bone line model is a polynomial combination equation, and the starting point is the coordinate origin, and the terminal point is (0, 1). By controlling a1, a2, b1, b2 and b3 in the equation, the bone line geometry structure can be adjusted. In this way, a standard symmetrical airfoil can be obtained. When the standard symmetrical airfoil is used, only the chord length of the airfoil needs to be determined according to the design parameters of the fan, such as power, rotating speed, current, voltage, etc. After the chord length is determined, the fan airfoil geometry structure suitable for the design parameters can be obtained.

[0056] Each curve coordinate in the original airfoil data of the fan blade is sequentially input into the optimized airfoil upper bone line model, an equation group is established, and solving is performed; then the maximum value and the minimum value of the same model parameter are obtained, the value range of the model parameter is formed by the maximum value and the minimum value, and is stored in the initial population, so as to be used for subsequent genetic algorithm.

[0057] The value range of the model parameter of the embodiment is shown in Table 2.

[0058] Table 2 Model parameters

[0059]

[0060] III. Determining the value range of the attack angle.

[0061] Through the above basic parameters, the tip speed ratio λ = 3 can be obtained. The included angle between the relative velocity and the chord line of the fan blade is the attack angle of the fan blade

[0062]

[0063] Through the equation Derivation is performed on the fan blade leading edge angle θ, and the following is obtained:

[0064]

[0065] Let formula (4) be 0, and the following can be obtained:

[0066]

[0067] Substitute the tip speed ratio λ = 3 into equation (5), we can get θ ≈ 109.47°. Substitute equation (3), we can get: Therefore, the angle of attack of the fan blade should not exceed 19.47°.

[0068] Firstly, the original airfoil is selected to carry out numerical simulation at a wind speed of 5 m / s and different fan blade angles. The numerical simulation results are shown in Figure 3 As shown in the figure, when the fan blade angle is 0°-6°, the lift-drag ratio is rising, which has the greatest impact on the efficiency of the wind turbine in this range. When the fan blade angle is 6°-10°, the lift-drag ratio shows a significant downward trend, which has no obvious effect on the efficiency of the wind turbine. Therefore, 6° is selected as the reference angle. Under this angle condition, the original fan blade airfoil is simulated at different wind speeds. Figure 3 When the fan blade angle is 6°-10°, the lift-drag ratio shows a significant downward trend, which has no obvious effect on the efficiency of the wind turbine. Therefore, 6° is selected as the reference angle. Under this angle condition, the original fan blade airfoil is simulated at different wind speeds. When the fan blade angle is 6°-10°, the lift-drag ratio shows a significant downward trend, which has no obvious effect on the efficiency of the wind turbine. Therefore, 6° is selected as the reference angle. Under this angle condition, the original fan blade airfoil is simulated at different wind speeds.

[0069]

[0070]

[0071] Wherein, r1 is the lift-drag ratio corresponding to r2 is the lift-drag ratio corresponding to

[0072] Four, calculate the upper bone line equation of the optimized airfoil under each condition.

[0073] According to the area where the fan is located, determine the annual wind speed variation curve of the area, determine the wind speed variation range, as shown in Figure 4 According to the actual local wind speed, set different wind speed weighting coefficients.

[0074] The ratio of the time occupied by different wind speeds to 1 year is used as the wind speed weighting coefficient, and equation (7) is used for calculation.

[0075]

[0076] The calculation results are shown in Table 3.

[0077] Table 3 Wind speed weighting coefficient

[0078]

[0079] ​​The wind speed in this area has been preliminarily investigated above, and there may be some differences if the average wind speed is divided by day or hour. Therefore, the wind speed range is conservatively selected as 2-11 m / s. According to Table 3, the wind speed is divided into 2 m / s, 5 m / s, 8 m / s, and 11 m / s, and the corresponding wind speed weighting coefficients are D1, D2, D3, and D4, respectively. The wind speed weighting coefficient value range is as follows: 0.4≤D1≤0.5; 0.2≤D2≤0.5; 0.015≤D3≤0.02; 0.005≤D4≤0.01.

[0080] After determining the range of the fan blade attack angle and the wind speed, the genetic algorithm is used, the model parameters stored in the initial population are used, and the lift coefficient and the drag coefficient of each individual under different working conditions are simulated by numerical simulation to obtain the lift-drag ratio. The fitness of each individual is obtained by the verification method of the crossover operator, and the multiple regression coefficient R 2 is used as the fitness function to verify the credibility of the obtained model. The definition is shown in formula (8):

[0081]

[0082] When R 2 > 0.90, it can be considered that the model has high credibility, and can be replaced by the simulation program for further multi-objective optimization. When the fitness R 2 > 0.90, the optimal coefficient combination under this working condition is obtained, that is, the optimized airfoil camber line equation under this working condition is obtained. The specific calculation results are as follows:

[0083] When the fan blade attack angle is 2°:

[0084] When the wind speed v=2 m / s, the optimized airfoil camber line equation is:

[0085]

[0086] When the wind speed v=5 m / s, the optimized airfoil camber line equation is:

[0087]

[0088] When the wind speed v=8 m / s, the optimized airfoil camber line equation is:

[0089]

[0090] When the wind speed v=11 m / s, the optimized airfoil camber line equation is:

[0091]

[0092] When the attack angle is 5°:

[0093] Wind speed v = 2 m / s, the optimized airfoil upper skeleton line equation:

[0094]

[0095] Wind speed v = 5 m / s, the optimized airfoil upper skeleton line equation:

[0096]

[0097] Wind speed v = 8 m / s, the optimized airfoil upper skeleton line equation:

[0098]

[0099] Wind speed v = 11 m / s, the optimized airfoil upper skeleton line equation:

[0100]

[0101] Five, obtain the fan blade airfoil.

[0102] Each of the resulting optimized airfoil upper skeleton line equation is in accordance with the standard airfoil non-uniform segmentation, from beginning to end, in turn, select a number of curve coordinate points. For example, the first curve segmentation method is: (0, y 1,1 ), (0.05, y 1,2 ), (0.10, y 1,3 ), (0.15, y 1,4 ), (0.20, y 1,5 ), (0.25, y 1,6 ), (0.30, y 1,7 ), (0.40, y 1,8 ), (0.50, y 1,9 ), (0.60, y 1,10 ), (0.70, y 1,11 ), (0.75, y 1,12 ), (0.80, y 1,13 ), (0.85, y 1,14 ), (0.90, y 1,15 ), (0.95, y 1,16 ) and (1.00, y 1,17 ), a total of 17 curve coordinate points. The other curves are the same.

[0103] Based on the above obtained all curve coordinates, the longitudinal coordinate weighting formula as shown in formula (9) is used to calculate the weighted longitudinal coordinates corresponding to all longitudinal coordinates at the same horizontal coordinate value point.

[0104]

[0105] The various abscissa value points and their corresponding weighted ordinate are input into the optimized airfoil upper skeleton line model, an equation group is established, and the equation group is solved to obtain the specific values of each model parameter. The values are shown in Table 4.

[0106]

[0107] The specific values of each model parameter are brought into the optimized airfoil upper skeleton line model to obtain the optimized airfoil upper skeleton line equation as shown in formula (10).

[0108]

[0109] The optimized airfoil upper skeleton line equation is symmetrical along the chord line of the fan blade and connected to the trailing edge to obtain the optimized fan blade airfoil as shown in Figure 5 .

[0110] The original airfoil data and the optimized airfoil upper skeleton line equation are input into the simulation software for finite element simulation to obtain the finite element analysis result graph as shown in Figures 6-9 . Figure 6 is the pressure cloud graph of the fan blade at an attack angle of 3° and a wind speed of 5 m / s. Figure 7 is the pressure cloud graph of the fan blade at an attack angle of 6° and a wind speed of 5 m / s. Figure 8 is the velocity cloud graph of the fan blade at an attack angle of 3° and a wind speed of 5 m / s.

[0111] Figure 9 is the velocity cloud graph of the fan blade at an attack angle of 6° and a wind speed of 5 m / s. Figures 6-9 The right graph in is the simulation result graph corresponding to the optimization scheme, and the left graph is the simulation structure graph corresponding to the original scheme.

[0112] From the pressure cloud graphs of Figure 6 and Figure 7 , it can be observed that under different attack angles and wind speeds, the low-pressure area of the surface of the optimization scheme is more than that of the original scheme, and the high-pressure area of the upper surface of the optimization scheme is also more than that of the original scheme. Therefore, the pressure difference of the upper and lower surfaces of the optimization scheme is higher than that of the original scheme, which can provide more lift (taking the negative direction of the Y axis as positive). At the same time, the size of the high-pressure area of the leading edge of the optimization scheme is not significantly different from that of the original scheme, that is, the pressure difference resistance changes little. Therefore, the lift-drag ratio of the optimization scheme will be significantly improved compared with the original airfoil.

[0113] From the velocity cloud graphs of Figure 8 and Figure 9 , it can be observed that the high-speed area of the upper surface of the original scheme is larger than that of the optimization scheme, and according to Bernoulli's principle, the average pressure of the upper surface of the optimization scheme is higher than that of the original scheme. This is consistent with the pressure cloud graph.

[0114] The simulation data are integrated, and the lift-drag ratio curve of the optimization scheme and the original scheme is drawn as shown in .Figure 10 and Figure 11 . and by Figure 10 and Figure 11 It can be seen that the lift-drag ratio of the optimized airfoil is significantly improved compared with the original airfoil under different working conditions.

[0115] The above merely describes the preferred embodiments of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can make equivalent substitutions or changes within the technical scope disclosed by the present application and according to the technical solutions and inventive concept of the present application, which should be covered within the protection scope of the present application.

Claims

1. A wind turbine blade, characterised in that The airfoil of the wind turbine blade (1) is a symmetrical airfoil, which comprises an upper camber line (11) and a lower camber line (12) connected directly at the head and connected to each other through a tail edge (13) at the tail; the upper camber line (11) and the lower camber line (12) are arranged symmetrically with the chord line as the axis of symmetry, and the chord line intersects the midpoint of the tail edge (13) perpendicularly; The upper bone line model in the orthogonal coordinate system - is represented as follows: ； In the formula, the head intersection point of the upper bone line (11) and the lower bone line (12) is the origin , the straight line where the chord line is located is the axis, the straight line passing through the origin and perpendicular to the axis is the axis; ; represents the longitudinal coordinate of the upper bone line (11) and the unit is m; represents the transverse coordinate of the upper bone line (11) and the unit is m; , , , , and all represent the model parameters of the upper bone line (11); The value range of the model parameters is specifically: The value range of is ; The value range of is ; The value range of is ; The value range of is ; The value range of is .

2. A wind power generator using a wind turbine blade according to claim 1, characterized in that, The wind turbine comprises a tower (4) which can stand on the ground, a generator (3) connected with the power control system is fixedly installed at the top of the tower (4), a hub (2) is drivingly installed on the motor shaft of the generator (3), and a plurality of the wind turbine blades (1) are installed on the hub (2).

3. A wind driven electric power generator according to claim 2 wherein, Each of the wind turbine blades (1) is evenly distributed on the outer surface of the hub (2) in sequence in the circumferential direction.

4. A wind driven electric power generator according to claim 3 wherein, The hub is fixedly installed on a main shaft, the main shaft is rotatably installed on the tower (4), and the main shaft and the motor shaft are drivingly connected through a gear set.

5. A wind driven electric power generator as claimed in claim 4 wherein, The wind turbine blade (1) is made of glass fiber reinforced plastic or carbon fiber reinforced plastic.

6. A wind driven electric power generator according to claim 5 wherein, A wind speed meter is installed at the top of the tower (4).

7. A wind driven electric power generator according to claim 6 wherein, A wind direction meter is installed at the top of the tower (4).

8. A wind driven electric power generator according to claim 7 wherein, A machine cabin cover is installed at the top of the tower (4), and the generator (3) is installed in the machine cabin cover.

9. A wind driven electric power generator according to claim 8 wherein, The output shaft of the gear set and the motor shaft are connected with each other through a shaft coupling.

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