Magnus airfoil profile and vertical axis wind turbine

Abstract

The invention relates to the technical field of Magnus airfoils, and provides a Magnus airfoil and a vertical axis wind turbine, the Magnus airfoil comprises a frame body, and a rotating cylinder is rotatably arranged on the frame body; the number of the blocking pieces is two, the blocking pieces are both arranged on the frame body, the two blocking pieces are located at the positions close to the two ends of the rotating cylinder correspondingly, intervals are formed between the two blocking pieces and the outer wall of the rotating cylinder so that airflow can penetrate through the outer wall of the rotating cylinder, and the blocking pieces can block end vortexes at the two ends of the rotating cylinder. The technical problem that in the prior art, end vortexes generated by a rotating cylinder in airflow can generate resistance to the rotating cylinder is solved, so that the power loss of a driving device of the rotating cylinder is smaller, and the purpose of saving energy is achieved.

Description

Technical Field

[0001] Embodiments of the present invention relate to the technical field of Magnus airfoils, and more particularly, to Magnus airfoils and vertical axis wind turbines. Background Art

[0002] The combination of a transmission airfoil and a rotating cylinder is called a Magnus airfoil. The rotating cylinder will generate a co-flow side and a counter-flow side under the air flow. Since the air flow velocity on the co-flow side is greater than that on the counter-flow side, the rotating cylinder will generate a force along the radial direction of the rotating cylinder, pressing from the counter-flow side to the co-flow side. By controlling the rotation direction of the rotating cylinder so that the upper part of the rotating cylinder is the co-flow side and the lower part is the counter-flow side, not only will the rotating cylinder itself be subject to the lift generated by the Magnus effect, but also the flow velocity difference between the two sides of the airfoil can be further increased, enhancing the lift of the airfoil.

[0003] In the prior art, placing the airfoil at the tail of the traveling direction of the rotating cylinder can effectively reduce the wake resistance of the rotating cylinder. However, for a rotating cylinder with a finite length, at the end of the rotating cylinder, due to the sudden change in shape and the reduction of the pressure difference between the counter-flow side and the co-flow side at the end, a wind flowing along the axial direction of the rotating cylinder is formed, so an end vortex phenomenon will occur in the area near the end of the rotating cylinder. This phenomenon will increase the aerodynamic resistance of the rotating cylinder and the airfoil, thereby increasing the energy consumption of the rotating cylinder. Especially in the application of vertical axis wind turbines, increasing energy consumption is equivalent to reducing the power generation efficiency of vertical axis wind turbines. Summary of the Invention

[0004] To overcome the above defects, the present invention provides a Magnus airfoil and a vertical axis wind turbine, solving the technical problem that the end vortex generated by the rotating cylinder in the air flow will cause resistance to the rotating cylinder in the prior art.

[0005] According to one aspect, at least one embodiment of the present invention provides a Magnus airfoil, including: A frame; A rotating cylinder rotatably arranged on the frame; Blocking members are all arranged on the frame, and the blocking members are arranged at positions close to both ends of the rotating cylinder, and there is an interval between the blocking members and the outer wall of the rotating cylinder, so that the air flow can pass through along the outer wall of the rotating cylinder, and the blocking members can block the end vortices at both ends of the rotating cylinder.

[0006] For example, in the Magnus airfoil provided by at least one embodiment of the present invention, the shortest distance between the blocking member and the main axis of the rotating cylinder is 1.2 - 1.6R, where R is the radius of the rotating cylinder.

[0007] For example, in the Magnus airfoil provided by at least one embodiment of the present invention, the maximum perpendicular distance between the two blocking members and the two end faces of the rotating cylinder close to each other is not greater than 3R, where R is the radius of the rotating cylinder.

[0008] For example, in the Magnus airfoil provided by at least one embodiment of the present invention, the blocking member is a plate-like member having an airfoil curve.

[0009] For example, in the Magnus airfoil provided by at least one embodiment of the present invention, the projection of the blocking member along the main axis direction of the rotating cylinder is symmetric with respect to the shortest line connecting the blocking member and the main axis of the rotating cylinder.

[0010] For example, in the Magnus airfoil provided by at least one embodiment of the present invention, along the direction of the main axis of the rotating cylinder, the length of the blocking member is 0.2 - 1R, where R is the radius of the rotating cylinder.

[0011] For example, in the Magnus airfoil provided by at least one embodiment of the present invention, when projected along the main axis direction of the rotating cylinder, the coverage angle of the drag reduction ring on the rotating cylinder is 30° - 90°.

[0012] The vertical axis wind turbine further includes: A bracket; A rotating seat rotatably arranged on the bracket, the rotation axis of the rotating seat being parallel to the rotation axis of the rotating cylinder, for connecting the Magnus airfoil, and the frame body being arranged at one end of the rotating seat away from the main axis; An airfoil blade arranged on the frame body, along the rotation direction of the rotating seat, the airfoil blade and the rotating cylinder are arranged in sequence, the blocking member is arranged on the frame body through the airfoil blade, and there is a gap between the airfoil blade and the surface of the rotating cylinder, and the airfoil blade is used to reduce the wake of the rotating cylinder.

[0013] For example, in the vertical axis wind turbine provided by at least one embodiment of the present invention, at least two Magnus airfoils distributed in a circumferential array are connected to the rotating seat.

[0014] For example, in the vertical axis wind turbine provided by at least one embodiment of the present invention, the cross-sectional area of the airfoil blade gradually decreases along the direction away from the rotating cylinder.

[0015] The beneficial effects of the embodiments of the present invention are: In the present invention, by arranging blocking members at both ends of the rotating cylinder, the formation of end vortices is effectively blocked, and the aerodynamic drag of the rotating cylinder is reduced. In practical applications, due to the reduction of aerodynamic drag, the driving energy required for the rotating cylinder is reduced, thereby reducing the energy consumption of the Magnus airfoil. Description of the Drawings

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments of the present invention. Obviously, the drawings in the following description are only some exemplary embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained according to the content of the exemplary embodiments of the present invention and these drawings.

[0017] Figure 1 It is a schematic diagram of the air flow on both sides when the rotating cylinder rotates; Figure 2 It is a schematic diagram of the pressure distribution of the rotating cylinder in the plane perpendicular to the oncoming wind; Figure 3 It is a schematic diagram of the principle of the formation of the tip vortex; Figure 4 It is a simulation diagram of the tip vortex when the rotating cylinder rotates; Figure 5 It is a simulation diagram of the tip vortex of the rotating cylinder after adding a blocking member; Figure 6 It is a schematic diagram of the principle of the action of the blocking member; Figure 7 It is a test diagram of the blocking members with different widths; Figure 8 It is a simulation diagram of the tip vortex formed by the blocking members with different widths; Figure 9 It is a schematic diagram of the first form of the rotating cylinder, the blocking member and the airfoil blade; Figure 10 It is a schematic diagram of the first form of the rotating cylinder, the blocking member and the airfoil blade from another angle; Figure 11 It is a schematic diagram of the second form structure of the blocking member; Figure 12 It is a schematic diagram of the third form structure of the blocking member; Figure 13 It is a schematic diagram of the structure of the vertical axis wind turbine; Figure 14 It is a top view of the vertical axis wind turbine; Figure 15 It is a top view of the rotating cylinder, the blocking member and the airfoil blade; In the figure: 100, frame body; 200, rotating cylinder; 300, blocking member; 400, bracket; 500, rotating seat; 600, airfoil blade; 700, rotation direction of the rotating seat. Detailed implementation manners

[0018] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It can be understood that the specific embodiments described herein are only used to explain the present invention, rather than limiting the present invention.

[0019] To make the drawings concise, only the parts related to the invention are schematically shown in each figure, and they do not represent the actual structure of the product. In addition, to make the drawings concise and easy to understand, for components with the same structure or function in some figures, only one of them is schematically shown, or only one of them is marked. In this article, "one" not only means "only this one", but also means "more than one" situation, and "several" includes "two" and "more than two".

[0020] In this article, it should be noted that unless otherwise clearly specified and limited, the terms "installation", "connection", and "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0021] In the present invention, unless otherwise clearly specified and limited, the first feature being "above" or "below" the second feature may include the direct contact of the first and second features, or may include the situation where the first and second features are not in direct contact but in contact through other features between them. Moreover, the first feature being "above", "over", and "on" the second feature includes the first feature being directly above and obliquely above the second feature, or simply indicating that the horizontal height of the first feature is higher than that of the second feature. The first feature being "under", "below", and "beneath" the second feature includes the first feature being directly below and obliquely below the second feature, or simply indicating that the horizontal height of the first feature is less than that of the second feature.

[0022] In the description of this embodiment, the orientation or positional relationships such as "above", "below", "left", and "right" are based on the orientation or positional relationships shown in the accompanying drawings, and are only for the convenience of description and simplifying the operation, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation to the present invention.

[0023] In addition, in the description of this application, the terms "first", "second", etc. are only used for distinguishing descriptions, and cannot be understood as indicating or implying relative importance.

[0024] Such as Figures 9 to 15As shown in the figure, it shows a Magnus airfoil in an embodiment of the present invention, including a frame body 100. A special mounting seat is provided on the frame body 100 for mounting a rotating cylinder 200 and a blocking member 300. The frame body 100 serves as the support structure of the entire Magnus airfoil, providing a stable mounting foundation for the rotating cylinder 200 and the blocking member 300. It can withstand the centrifugal force generated during the rotation of the rotating cylinder 200 and various forces acting on the rotating cylinder 200 and the blocking member 300 by the airflow, ensuring the normal operation of the entire device in the airflow environment without deformation or damage. The rotating cylinder 200 can rotate on the frame body 100 through a driving device. By rotating in the airflow, one side of the rotating cylinder 200 is the co-flow side and the other side is the counter-flow side. Among them, the airflow direction on the counter-flow side is opposite to the rotation direction of the rotating cylinder 200, and it is the key component for the Magnus airfoil to generate lift. Under the action of the airflow, by controlling its rotation direction, the upper side is the co-flow side and the lower side is the counter-flow side, using the Magnus effect to generate lift, but end vortices will be generated at the position near the end on the leeward side, increasing the aerodynamic drag. The blocking member 300 is a plate-like structure and there are two of them. The two blocking members 300 are respectively located on the leeward side of the rotating cylinder 200 and near the end. The blocking member 300 can play a role in blocking the formation of end vortices.

[0025] There is a gap between the blocking member 300 and the rotating cylinder 200. This gap allows the end vortices to form on the leeward side of the rotating cylinder 200, so that the blocking member 300 can play a role in blocking the formation of end vortices. If there is no gap between the blocking member 300 and the rotating cylinder 200, it will cause the end vortices to form behind the blocking member 300, resulting in the blocking member 300 being unable to play a blocking role.

[0026] Working principle: When the Magnus airfoil is in an airflow environment, the rotating cylinder 200 starts to rotate under the action of a power device. The airflow flows through the rotating cylinder 200. Due to the rotation of the rotating cylinder 200, the flow velocity on the side where the tangential velocity of the airflow and the surface of the rotating cylinder 200 is the same increases and is called the co-flow side, and the flow velocity on the side where the tangential velocity of the airflow and the surface of the rotating cylinder 200 is opposite decreases and is called the counter-flow side. According to the Magnus effect, the rotating cylinder 200 itself will be subjected to a force pressing from the counter-flow side to the co-flow side, that is, the counter-flow side is in a positive pressure state and the co-flow side is in a negative pressure state. During this process, the frame body 100 stably supports the rotating cylinder 200 to ensure its normal rotation.

[0027] As Figures 1 to 4 shown, during the rotation of the rotating cylinder 200, the area near the end of the rotating cylinder 200 is prone to form wind flowing along the axis due to the sudden change in shape and the reduction of the pressure difference on both sides of the end. Since the wind directions flowing along the axis on the counter-flow side and the co-flow side are different, end vortices are generated.

[0028] AsFigure 5 As shown in the figure, after the blocking member 300 is installed, due to the different air pressures at the end and the middle of the rotating cylinder 200, when the oncoming wind is blocked by the blocking member 300, the wind on the convection side of the rotating cylinder 200 will flow towards the end, the wind on the co-flow side of the rotating cylinder 200 will flow towards the middle, and the wind on the leeward side will flow from the co-flow side to the convection side. At this time, the blocking member 300 changes the flow direction of the end airflow, causing the airflow that might originally form an end vortex to flow along the gap between the blocking member 300 and the outer wall of the rotating cylinder 200, avoiding the formation of the end vortex or weakening its intensity. In this way, the aerodynamic drag of the rotating cylinder 200 and the airfoil is effectively reduced, the energy consumption of the rotating cylinder 200 is reduced, and the efficiency of the entire Magnus airfoil is improved.

[0029] In some examples, the shortest distance between the blocking member 300 and the main axis of the rotating cylinder 200 is 1.2 - 1.6R, where R is the radius of the rotating cylinder 200. That is, the gap between the blocking member 300 and the surface of the rotating cylinder 200 is 0.2R - 0.6R. If the gap between the blocking member 300 and the surface of the rotating cylinder 200 is too small, an end vortex will form on the side of the blocking member 300 away from the rotating cylinder 200, so that the blocking member 300 cannot achieve the purpose of blocking the generation of the end vortex. If the gap between the blocking member 300 and the surface of the rotating cylinder 200 is too large, the end vortex will fully develop, and at this time, the end vortex has generated a relatively high aerodynamic drag on the rotating cylinder 200, resulting in the blocking member 300 being unable to play a role in reducing drag.

[0030] In some examples, the maximum vertical distance between the two blocking members 300 and the two end faces of the rotating cylinder 200 close to each other is not greater than 3R, where R is the radius of the rotating cylinder 200. As Figures 3 to 4 shown, according to the wind tunnel test and simulation research results of the rotating cylinder 200, it is proved that the generation position of the end vortex is within the range of not more than 3 times the diameter from the end of the rotating cylinder 200. Placing the blocking member 300 at the center of the end vortex can effectively block the generation of the end vortex.

[0031] In some examples, as Figures 9 to 13 shown, the blocking member 300 is a plate-shaped member, and its projection along the axial direction of the rotating cylinder 200 can be in the form of a notched ring, a straight line, etc. In the projection along the radial direction of the rotating cylinder 200, the blocking member 300 can be in the shape of a rectangle, a triangle, a trapezoid, etc.

[0032] In some examples, the projection of the blocking member 300 along the main axis direction of the rotating cylinder 200 is symmetric with respect to the shortest connection line between the blocking member 300 and the main axis of the rotating cylinder 200. The blocking member 300 has symmetry along a radius of the rotating cylinder 200, and the symmetric blocking member 300 can ensure that the axial wind on the convection side and the co-flow side is uniform.

[0033] In some examples, such as Figures 6 to 8 shown, along the direction of the main axis of the rotating cylinder 200, the length of the blocking member 300 is 0.2 - 1R, where R is the radius of the rotating cylinder 200. Through the research results of the rotating cylinder 200 equipped with the blocking member 300, when the width of the blocking member 300 does not exceed 0.5 times the diameter of the rotating cylinder 200, it can better destroy the generation of the tip vortex.

[0034] The specific principle is as follows: After the blocking member 300 blocks the oncoming wind, the blocked wind will flow in the circumferential direction around the cylinder. If the blocking member 300 is too wide, the amount of blocked wind will increase, and the acceleration effect of the co-flow side on the wind flow is not sufficient to make the wind on the co-flow side enter the counter-flow side along the blocking member 300, but diffuse along the axial direction of the rotating cylinder 200. As a result, the wind flowing along the axial direction of the rotating cylinder 200 on the counter-flow side flows in the opposite direction to the blocked wind, and the wind flowing along the axial direction of the rotating cylinder on the co-flow side flows in the same direction. Thus, the wind on the counter-flow side flows from the center of the rotating cylinder 200 to the blocking member 300, and then flows along the axis of the rotating cylinder 200 towards the position closer to the middle with the blocked wind, resulting in the generation of the tip vortex at a position closer to the middle of the blocking member 300. At this time, the blocking member 300 can no longer play the role of preventing the generation of the tip vortex.

[0035] When the width of the blocking member 300 does not exceed 0.5 times the diameter of the rotating cylinder 200, the oncoming wind will move in a circumferential flow around the rotating cylinder 200. Due to the faster wind speed on the co-flow side and the smaller amount of blocked wind, part of the wind passing through the counter-flow side will enter the counter-flow side along the blocking member 300, and then flow towards the end under the action of the pressure difference in the middle of the end of the rotating cylinder 200. Since part of the blocked wind on the co-flow side enters the counter-flow side, the pressure at the end of the co-flow side increases and the pressure on the co-flow side decreases, not only blocking the formation of the tip vortex at the end, but also enhancing the force pressing from the counter-flow side to the co-flow side.

[0036] In some examples, when projected along the main axis direction of the rotating cylinder 200, the length of the drag reduction ring is greater than the diameter of the rotating cylinder 200, and the coverage angle of the drag reduction ring on the rotating cylinder 200 is 30° - 90°, which can make the drag reduction ring play a role in blocking the oncoming wind.

[0037] Such as Figures 13 to 15 shown, the vertical axis wind turbine includes a bracket 400. The rotating seat 500, as a component connecting the bracket 400 and the Magnus airfoil, provides rotational support for the Magnus airfoil, enabling it to rotate around the central axis of the bracket 400, thereby generating electricity through rotation. After starting the driving device of the rotating cylinder 200, the rotating cylinder 200 can generate a force to rotate the rotating seat 500 by rotating in the air flow.

[0038] The airfoil blade 600 is arranged on the frame body 100. Along the rotation direction of the rotating seat 500, the airfoil blade 600 and the rotating cylinder 200 are distributed in sequence. After the rotating seat 500 starts to rotate, due to the relative movement between the rotating cylinder 200 and the air flow, the main wind source acting on the rotating cylinder 200 will become the wind generated by rotation. The airfoil blade 600 can make the air flowing over the rotating cylinder 200 on the co-flow side and the counter-flow side flow along the surface of the airfoil blade 600, so that the pressure generated on the co-flow side and the counter-flow side acts on the airfoil blade 600, providing power for the rotation of the rotating seat 500. Moreover, the airfoil blade 600 is placed at the tail of the advancing direction of the rotating cylinder 200. Referring to the principle of action of the Magnus airfoil aircraft, the airfoil blade 600 can effectively reduce the wake resistance of the rotating cylinder 200.

[0039] The airfoil blade 600 also provides an installation base for the blocking piece, and the blocking piece directly passes through the airfoil blade 600 and is fixed by means of a connecting piece or welding. Secondly, the airfoil blade 600 can also change the wind direction of the oncoming wind acting on the rotating cylinder 200, so that multiple Magnus airfoils can generate a tangential force on the rotating seat 500, thereby making the rotating seat 500 rotate.

[0040] Applying the Magnus airfoil to a vertical axis wind turbine, the resistance generated by the tip vortices can be reduced through the blocking member 300, and the efficiency of the vertical axis wind turbine can be increased.

[0041] In some examples, at least two Magnus airfoils distributed in a circumferential array are connected to the rotating seat 500. The two Magnus airfoils can make the force on the rotating seat 500 more uniform. When three Magnus airfoils with the same interval are arranged on the rotating seat 500, the efficiency of the vertical axis wind turbine can reach the highest.

[0042] In some examples, the cross-sectional area of the airfoil blade 600 gradually decreases along the direction away from the rotating cylinder 200. The conical airfoil blade 600 is more conducive to the air flow on the co-flow side and the counter-flow side sticking to the surface of the airfoil blade 600.

[0043] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present invention, and they should all be covered within the scope of the claims of the present invention.

Claims

1. A Magnus airfoil, characterized in that, Comprising: Frame body (100); Rotating cylinder (200), rotatably arranged on the frame body (100); Blocking members (300), all arranged on the frame body (100), the blocking members (300) are arranged at positions close to both ends of the rotating cylinder (200), and there is an interval between the blocking members (300) and the outer wall of the rotating cylinder (200) so that air flow can pass through along the outer wall of the rotating cylinder (200), and the blocking members (300) can block the end vortices at both ends of the rotating cylinder (200).

2. The Magnus airfoil according to claim 1, characterized in that, The shortest distance between the blocking member (300) and the main axis of the rotating cylinder (200) is 1.2 - 1.6R, where R is the radius of the rotating cylinder (200).

3. The Magnus airfoil according to claim 1, characterized in that, The maximum vertical distance between the two blocking members (300) and the two end faces of the rotating cylinder (200) close to each other is not greater than 3R, where R is the radius of the rotating cylinder (200).

4. The Magnus airfoil according to claim 1, characterized in that, The blocking member (300) is a plate-shaped member with an airfoil curve.

5. The Magnus airfoil according to claim 1, characterized in that, The projection of the blocking member (300) along the main axis direction of the rotating cylinder (200) is symmetric with respect to the shortest connection line between the blocking member (300) and the main axis of the rotating cylinder (200).

6. The Magnus airfoil according to claim 1, characterized in that, Along the main axis direction of the rotating cylinder (200), the length of the blocking member (300) is 0.2 - 1R, where R is the radius of the rotating cylinder (200).

7. The vertical axis wind turbine according to claim 1, characterized in that, When projected along the main axis direction of the rotating cylinder (200), the coverage angle of the drag reduction ring on the rotating cylinder (200) is 30° - 90°.

8. Vertical axis wind turbine, characterized in that, When using the Magnus airfoil according to any one of claims 1 - 7, further comprising: Bracket (400); Rotating seat (500), rotatably arranged on the bracket (400), the rotation axis of the rotating seat (500) is parallel to the rotation axis of the rotating cylinder (200) and is used to connect the Magnus airfoil, and the frame body (100) is arranged at one end of the rotating seat (500) away from the main axis; Airfoil blade (600), arranged on the frame body (100), along the rotation direction of the rotating seat (500), the airfoil blade (600) and the rotating cylinder (200) are distributed in sequence, the blocking member (300) is arranged on the frame body (100) through the airfoil blade (600), and the airfoil blade (600) is used to reduce the wake of the rotating cylinder (200).

9. The vertical-axis wind turbine according to claim 8, wherein, At least two Magnus airfoils distributed in a circumferential array are connected to the rotating seat (500).

10. The vertical axis wind turbine according to claim 8, characterized in that, The cross-sectional area of the airfoil blade (600) gradually decreases along the direction away from the rotating cylinder (200).

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