Horizontal shaft willow leaf type wind power generation device

Abstract

A horizontal-axis willow-leaf-shaped wind power generation device is characterized in that the cross section structure of a blade tip section of a willow-leaf-shaped counter-power blade is of a willow-leaf shape, namely, the left arc face and the right arc face are completely symmetrical, and an efficient working method of the blade comprises the steps that working state parameters of a pitch angle, a zero lift angle and a relative attack angle are kept to be equal to 0 degree, and a natural attack angle is equal to 90 degrees. As a result, the direction of rotating resistance is consistent with the chord length direction, so that the rotating resistance is extremely small, a laminar flow boundary layer is relatively stable, and the efficiency of reaction power is relatively high; the cross section structure of the blade root section of the salix leaf type reverse power blade is asymmetric, the front edge width is equal and is always larger than the blade tail deviation degree b, the natural attack angle is smaller than 90 degrees, and the blade tail deflection angle is smaller than 30 degrees, so that the natural wind energy utilization rate can be increased, and rotation resistance is not increased. The tail fin is additionally arranged at the blade tail of the salix leaf type reverse power blade, and the tail fin is mainly used for separating wake flow, avoiding turbulent flow loss and reducing noise.

Description

[0001] Technical Field: This invention relates to the field of wind power generation technology.

[0002] Background Technology: (Instruction manual attached) Figure 1 The working principle diagram of an existing horizontal airfoil-type lifting wind turbine is given, and the instruction manual is attached. Figure 2 The following was given Figure 1 Sectional view along line AA, attached to the instruction manual Figure 3 The following was given Figure 1 A cross-sectional view along the BB direction, as shown below. Figure 2 As shown, when the pitch angle β of the airfoil-shaped lifting blade is greater than 0°, the blade will inevitably generate rotational drag. Furthermore, this rotational drag is directly proportional to the product of blade length and rotational speed, and it is a major cause of low wind turbine efficiency and blade breakage. In addition, lift... It must be converted into thrust. Only then can the blades rotate, which inevitably reduces the lift effect. For example, this... Figure 3 As shown, the cross-section of the blade tip is approximately flat, with almost zero lift, but high rotational drag. Larger eddies. In addition, eddies can form at the tip and leading edge or tail of the blade, and these eddies not only reduce power but are also a major source of noise.

[0003] Of course, the advantages of horizontal axis wind turbines are also obvious. Since the rotation plane of a horizontal axis wind turbine is perpendicular to the natural wind direction, the angle of attack of its blades remains unchanged at any position. Therefore, each blade can maintain synchronous power output, resulting in a higher utilization rate of natural wind energy.

[0004] Summary of the Invention: During wind tunnel tests of various blade structures, the inventors accidentally discovered that a vertical-axis willow-leaf blade exhibits counter-wind rotation. (Instructions attached) Figure 4 A schematic diagram of a vertically oriented willow-leaf blade rotating against the wind is provided. As shown in the diagram, the willow-leaf blade (1) rotates against the wind around a vertical axis (2). (Instruction manual attached) Figure 5 The above is given Figure 4 The cross-sectional view along the AA direction is shown in the figure. The cross-sectional structure of the willow-leaf blade (1) is willow-leaf shaped, that is, the upper and lower arc surfaces are completely symmetrical. The curvature h and thickness b are within a suitable range. The normal working state of the blade is: maintaining a completely horizontal working state, that is, zero lift angle and zero angle of attack.

[0005] Instruction manual attached Figure 6 The cross-sectional structure and lift working principle diagram of a typical airfoil lift blade are given. As shown in the figure, the cross-sectional structure of a typical airfoil blade is airfoil-shaped, meaning the upper and lower curved surfaces are asymmetrical, with the camber h and thickness b within a suitable range, and a zero lift angle. Both the angle of attack α and the angle of attack α must be greater than zero; only in this way can the airfoil blade generate lift. The cross-sectional structure of the aforementioned willow-leaf-shaped blade (1) is willow-leaf shaped, meaning the upper and lower arc surfaces are completely symmetrical. This blade maintains a completely horizontal working state, meaning both the lift angle and angle of attack are zero. Therefore, lift cannot be generated on the upper surface of the willow-leaf-shaped blade (1). Thus, the force propelling the willow-leaf-shaped blade (1) to rotate against the wind is not lift. So, where does the force propelling the willow-leaf-shaped blade (1) to rotate against the wind come from?

[0006] The inventors believe that the laminar boundary layer is the medium for fluid-structure interaction. Therefore, the fluid and the solid surface interact through the laminar boundary layer. When the curvature h and thickness b of the solid surface are within a suitable range, this arc surface has a rectifying and accelerating effect on the fluid. When the fluid is in a laminar state, it has a velocity gradient in its longitudinal direction. According to Bernoulli's theorem, the velocity gradient equals the pressure gradient, and this pressure gradient is the lift. Simultaneously, when the fluid maintains a laminar state, the fluid's kinetic energy acts on the solid surface through the laminar boundary layer. According to Newton's third law, for every action, there is an equal and opposite reaction; the action force is the driving force, and the reaction force is the reaction force. In fact, the reaction force of a rocket nozzle or the turbine blades comes from the fluid's driving force. Therefore, both the reaction force and the lift are inevitable results of the fluid maintaining a laminar state.

[0007] The inventors believe that the structure and laminar flow state of the willow-shaped blade (1) are extremely similar to the structure and laminar flow state of the converging nozzle formed by the turbine blades or the rocket tail nozzle. Based on the principle of similarity, the hydrodynamics on the upper and lower surfaces of the willow-shaped blade (1) are similar. Able to form a reaction force This causes the blade to rotate against the wind. Therefore, the only driving force that causes the willow-shaped blade (1) to rotate against the wind is the reaction force of the fluid dynamics.

[0008] According to Newton's third law, action and reaction forces are equal in magnitude and opposite in direction. That is to say, the theoretical reaction force of a fluid is equal in magnitude and opposite in direction to its theoretical force. However, in reality, even the drag coefficient of a standard streamline is 0.04 (see "My Understanding of Fluid Mechanics" by Wang Hongwei, published by National Defense Industry Press, December 2014, 1st edition, page 177). Therefore, the reaction force efficiency of a standard streamline is equal to 0.96. Thus, the reaction force efficiency of the aforementioned willow-shaped blade (1) is no more than 0.96, and the limiting efficiency value is equal to 1.

[0009] So, are willow-leaf-shaped counter-force blades suitable for horizontal axis wind turbines? Wind tunnel test results show that willow-leaf-shaped counter-force blades are indeed suitable for horizontal axis wind turbines, and with extremely high efficiency.

[0010] Instruction manual attached Figure 7An assembly drawing of a horizontal-axis willow-leaf shaped wind (reverse) power generation device is provided, as shown in the figure.

[0011] The blade root section (3) of the willow-leaf-shaped reactive blade (1) deviates from the chord line at a certain angle, thus reducing the natural wind force. When acting on the blade root section (3), the wind speed remains high, thus generating a large thrust, which drives the willow-shaped reaction blade (1) to rotate the hub (2), the hub (2) to rotate the main shaft (7), the main shaft (7) to rotate the generator (9) through the coupling (8), and the generator (9) to convert the kinetic energy of the willow-shaped reaction blade (1) into electrical energy.

[0012] Instruction manual attached Figure 8 The above is given Figure 7 A cross-sectional view along line AA, as shown below. Figure 7 and 8 As shown, the cross-sectional structure of the root section (3) of the willow-leaf-shaped reaction blade (1) is asymmetrical, the pitch angle is equal to 0°, the chord is perpendicular, the blade tail deviates from the chord at a certain angle, the leading edge width a is equal and a is always greater than the blade tail deviation b, the natural angle of attack α < 90°, the blade tail sway Ƴ < 30°, and a tail fin (4) is added at the blade tail. Thus, on the windward side (A), the natural wind speed is... It can maintain a relatively high wind speed. Due to thrust With natural wind speed It is proportional to the square of the number of winds, therefore, natural wind power It can generate a large thrust This causes the willow-leaf-shaped reaction blade (1) to rotate, while at the same time, natural wind power... Hydrodynamics was also formed on the windward side (A). And fluid dynamics This will inevitably create a counterforce. This, in turn, drives the willow-leaf-shaped blade (1) to rotate. When the willow-leaf-shaped reaction blade (1) starts to rotate, rotational resistance will inevitably form on the leeward side (B). Since the blade tip sway angle Ƴ < 30°, the blade tip deviation angle b is always less than the leading edge width a. Therefore, the rotational drag formed on the leeward side (B) is... Smaller. The main function of the tail fin (4) is to separate the fluid at the tail of the blade, thereby eliminating the conditions for the formation of turbulence and keeping the fluid at the tail of the blade in a laminar state, thus greatly reducing the power loss and noise of the wake.

[0013] While airfoil-shaped lift blades can generate significant wind speeds on their frontal surfaces, the blade pitch angle is greater than 0°, resulting in greater rotational drag on the leeward side and consequently lower blade efficiency.

[0014] Instruction manual attached Figure 9The above is given Figure 7 The cross-sectional view along the BB direction is shown in the figure. The cross-sectional structure of the tip section (5) of the willow-leaf-shaped reaction blade (1) is completely symmetrical. The efficient working method of this blade is: the natural angle of attack α is equal to 90°, the pitch angle ˎ zero lift angle and the relative angle of attack are both zero degrees (the so-called natural angle of attack is the angle between the natural wind direction and the chord line, and the so-called relative angle of attack is the angle between the relative wind direction and the chord line). As a result, the rotational drag is reduced. The direction is consistent with the blade chord direction, therefore the rotational resistance Extremely small, with very high reaction efficiency. The tail fin (6) is added to the tail of the willow-shaped reaction blade (1). The main function of the tail fin (6) is to separate the fluid at the tail of the blade, thereby eliminating the conditions for the formation of turbulence and keeping the fluid at the tail of the blade in a laminar state, thereby greatly reducing the power loss and noise of the wake. Wind tunnel test results show that the reaction effect is significantly different with or without the tail fin.

[0015] Main advantages:

[0016] 1. The rotational drag at the tip of the willow-leaf-shaped reaction blade is aligned with the chordal direction, resulting in a very small drag coefficient and a more stable laminar flow, thus leading to higher reaction efficiency. 2. Because the reaction force of the willow-leaf-shaped reaction blade primarily acts along the chordal direction, and the blade has high strength in this direction, the risk of blade breakage is lower.

[0017] 3. The willow-leaf-shaped reactive blade has an added tail fin, which eliminates the conditions for turbulence formation at the blade tail and reduces dynamic loss and noise at the blade tail. 4. The asymmetrical cross-sectional structure of the blade root section and the blade tail offset from the chord line at a certain angle improve the utilization rate of natural wind energy on the windward side. Attached Figure Description

[0018] Figure 1 -----A working principle diagram of an existing horizontal-axis airfoil-shaped lifting wind turbine is given.

[0019] Figure 2 ---This gives the Figure 1 Sectional view along line AA.

[0020] Figure 3 ---This gives the Figure 1 Sectional view along the BB direction.

[0021] Figure 4 ---A schematic diagram of a vertical axis willow-shaped blade rotating against the wind is given.

[0022] Figure 5 The above is given. Figure 4 Sectional view along line AA.

[0023] Figure 6 ------This diagram shows the cross-sectional structure of a typical airfoil-shaped lift blade and its lift operation principle.

[0024] Figure 7 ------This presents an assembly drawing of a horizontal axis willow-leaf shaped wind (reverse power) generator.

[0025] Figure 8 The above is given. Figure 7 Sectional view along line AA.

[0026] Figure 9 The above is given. Figure 7 Sectional view along the BB direction.

[0027] Figure 10 -----This provides a schematic diagram of wind tunnel tests for horizontal axis willow-shaped reaction blades and airfoil-shaped blades.

[0028] Figure 11 The above is given. Figure 10 The actual size of the willow-shaped reaction blade (3).

[0029] Specific implementation method: As shown in the attached drawings (7), (8) and (9) of the specification, the willow-shaped reaction blade (1) is connected to the hub (2), the hub (2) is connected to the main shaft (7), the main shaft (7) is connected to the generator (11) through the bearing (8) and the coupling (9), the generator (11) is fixed in the chassis (10) through the platform (12), and the chassis (10) is connected to the tower (13). The cross-sectional structure of the tip section (5) of the willow-shaped reaction blade (1) is completely symmetrical, the pitch angle ˎ zero lift angle and the relative angle of attack are both 0°, the natural angle of attack is equal to 90°, and a tail fin (6) is added to the tail of the blade; the cross-sectional structure of the root section (3) of the willow-shaped reaction blade (1) is asymmetrical and the leading edge width is greater than the tail deviation, the natural angle of attack is less than 90°, the tail sway is less than 30°, and a tail fin (4) is added to the tail of the blade.

[0030] Appendix: Comparative wind test reports of willow-leaf shaped reaction blades and airfoil-shaped lift blades:

[0031] I. Date: June 17, 2025

[0032] II. Location: Ulan Buh May 1st Base

[0033] III. Test Results:

[0034] 1. Willow-leaf shaped reaction blade: rotational speed n=44rpm, power =8w.

[0035] 2. Airfoil-shaped lift blades: rotational speed n=55rpm, power

[0036] IV. Schematic diagram of wind tunnel test:

[0037] Instruction manual attached Figure 10 A wind tunnel test diagram of the willow-leaf-shaped reaction blade (3) is given. As shown in the figure, the outlet diameter of the wind turbine (1) is 1000 mm, the diameter of the impeller (9) is Φ=1950 mm, and the distance between the impeller and the wind turbine (1) is 3230 mm. The maximum wind speed measured within 1 meter of the diameter of the impeller (9) is 7.8 m / s. As shown in the figure, after the wind turbine (1) is started, the impeller (9) under test rotates slowly. When the speed of the impeller (9) reaches 44 rpm, the controller of the generator (7) displays a power value of 8 W. Then, an airfoil blade of the same size is installed. When the speed reaches 55 rpm, the controller of the generator (7) displays a power value of 8 W.

[0038] V. Test blade dimensions:

[0039] Instruction manual attached Figure 11 The above is given Figure 10 The actual dimensions of the willow-shaped reaction blade (3) are shown in the figure. The surface of the blade is divided into 8 approximate trapezoids, plus the approximate triangle at the blade tip. The area of ​​each of the 8 approximate trapezoids is calculated, multiplied by 2, and then multiplied by 3 to get the total surface area of ​​the three blades in each segment. Adding the area of ​​the approximate triangle at the blade tip, the result is obtained through calculation: =0.09m²; =0.11m²; =0.11m²; =0.1m² =0.09m²; =0.08m²; =0.07m²; =0.06m²; =0.01m². The radius of the surface area of ​​each segment. Take the median values, respectively: =270mm; =370mm; =470mm; =570mm; =670mm; =770mm; =870mm; =957mm; =975mm.

[0040] VI. Applicable Formulas and Calculation Results:

[0041] We know that the theoretical power of a wind turbine •ω, in the formula Let ω be the torque and ω be the angular velocity. In other words, when the angular velocity ω of the wind turbine is constant, the theoretical power of the wind turbine... With torque Proportional, while torque Equal to torque With leaf length The product of these two forces means that the longer the blade, the greater the torque and the greater the theoretical power. This is the unique lever effect of a wind turbine. We know that torque... = • In the formula, ρ is the air density. This refers to the working area of ​​the blade. Relative velocity, i.e., linear velocity. =2π And angular velocity ω= Therefore, we have: •ω= • • •ω = • •• = • The working efficiency of the wind turbine η = / In the formula To measure the actual power, substitute the linear velocity and surface area values ​​of each segment into the theoretical power equation of the wind turbine to obtain the theoretical power fraction of the blade at each segment. Then, add up the theoretical power fractions to obtain the theoretical power of the wind turbine at different speeds. And the efficiency η, the results are as follows:

[0042] 1. When the blade tip angle and relative angle of attack of the willow-leaf type reaction blade are both equal to 0°, while the blade root angle Ƴ is less than 20° and the natural angle of attack α is less than 90°:

[0043] Measured power at 44 rpm =8W, theoretical power =11.38w, efficiency η=0.7.

[0044] 2. When the pitch angle β and natural angle of attack α of the airfoil lifting blades are both equal to 15°:

[0045] Measured power at 55 rpm 8W, theoretical power 23W, efficiency 0.34.

[0046] VII. Conclusion: Analysis of the above data shows that the efficiency of the wind turbine with the willow-leaf-shaped anti-power blade proposed for the first time in this invention is twice as high as that of the existing airfoil-shaped lift blade wind turbine.

Claims

1. A horizontal axis wind turbine comprising a blade (1)  hub (2)  main shaft (7)  bearing (8)  coupling (9)  machine case (10)  generator (11)  base plate (12) and tower (13), characterized in that The reaction force blade (1) is connected with the wheel hub (2), the wheel hub (2) is connected with the main shaft (7), the main shaft (7) is connected with the generator (11) through the bearing (8) and the shaft coupling (9), and the generator (11) is fixed in the machine box (10) through the table plate (12).

2. The willow-leaf-shaped reaction blade (1) according to claim 1 above, characterized in that... The efficient working method of the tip section (5) is that the pitch angle, the relative attack angle and the natural attack angle are all equal to 0°.

3. The willow-leaf-shaped reaction blade (1) according to claim 1 above, characterized in that... The front edge width a of the root section (3) is equal and always greater than the tail deviation b, and the tail angle Ƴ is less than 30°.

4. The willow-leaf-shaped reaction blade (1) according to claim 1 above, characterized in that... The tail fins (4) and (6) are additionally arranged at the tail of the blade.

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