AERODYNAMIC STRUCTURE

Description

[0001] The invention relates to an aerodynamic structure comprising at least one wing-like shape with upper and lower surfaces, which has an axis of rotation in which a bearing is inserted and which is connected to an axis via a shaft, wherein a flat surface extends from the root of the wing-like shape to the tip and a thickening is present in the area of ​​the profile leading edge on the upper surface facing away from the wind, wherein the flat surface has the geometry of a general quadrilateral from the root of the shape and a triangular geometry adjoins one of the sides towards the tip of the shape.

[0002] The design of rotor blades has found a wide range of applications in recent years, from power generation in wind turbines to helicopters and turbochargers. These designs share the common feature of rotor blades that convert the flow energy of a gas mixture into mechanical energy.

[0003] Wind turbines have been used to generate electricity for quite some time, and the shape and design of components such as the nacelle, rotor blades, and tower have been the subject of much research. According to current technology, the rotor blades are profiled in such a way that a pressure difference is created between the upper and lower surfaces of the blades, which in turn sets the wind turbine in rotation.

[0004] In helicopter wings, rotation is generated by a motor, and there is also a pressure difference between the upper and lower surfaces of the wings, which ultimately causes the helicopter to be "lifted" or, more accurately, "pushed" upwards.

[0005] The design of rotor blades has already been extensively described in the prior art and is increasingly based on natural models. The prior art describes numerous flow-modifying measures for generating lift and further controlling the resulting flow. For example, a bionic approach based on a whale's fin is disclosed in DE 10 2011 056 342 A1.

[0006] AT 137 005 B describes a drive screw construction consisting of spoon-shaped wings mimicking bird wings, wherein the wing front part extending from the leading edge to at least the longitudinal center line is formed as a flat wedge towards the outer end and wherein the adjoining wing rear part is formed in the form of a longitudinally and transversely curved spoon half with a longitudinal rim forming the trailing edge.

[0007] DE 103 00 284 A1 discloses a rotor blade for a wind turbine, with an aerodynamic profile having a leading edge and a trailing edge, wherein the blade tip is bent or angled in its end region towards the pressure side of the blade. Furthermore, DE 103 002 84 describes features of various curvatures and directions in the longitudinal direction of a rotor blade, as well as different geometric designs of the blade tip.

[0008] Furthermore, CN 28 188 34 Y describes a wind turbine generator designed with a wind cylinder and a reinforcing rod in the turbine blades. The reinforcing rod of the wind turbine generator is a circular or square hollow tube element made of non-magnetic material, in which metal blocks act as centering elements. The reinforcing rod is located on each leeward surface of a turbine blade. However, it should be noted that the turbine blades are not flat but have a fold on one side of the surface, and the circular or square hollow element is positioned leeward of the direction of rotation. Therefore, no wind edge is present, and no vortex is generated on the surface of the turbine blades.

[0009] US patent 2008 / 0253896 A1 discloses lateral deflectors for fan blades designed to minimize backflow and prevent the formation of peak vortices and turbulent flow conditions. Without deflectors, vortices are generated during the rotation of fan blades, reducing the volume flow. Vortices generated by rotating fan blades without deflectors disrupt the axial volume flow, thus reducing the efficiency of a conventional fan without deflectors.

[0010] US patent 4,693,673 B1 discloses a blower or fan that draws air upwards or downwards into a room and disperses the air radially outwards to create greater air circulation. The blower or fan has fan blades arranged at a specific angle to the axis of rotation. As the blades rotate to generate an axial airflow, they also cause a radial airflow that moves laterally and outwards from the upper surfaces of the blades.

[0011] MX 2011 013 994 A discloses a wind turbine with a rotor configuration on a vertical axis consisting of three blades with a flat airfoil profile. These blades are connected by a rotor disk and are curved, enabling a nominally increased angular velocity at low wind speeds. The design of the rotor blades is such that, despite a possible flow separation, the torque of the configuration is sufficient to maintain rotation.

[0012] US 2017 / 174318 A1 describes noise reduction devices for aircraft propellers during operation. These devices can be arranged on the propellers and modify the airflow along them. By altering the airflow at and between the propellers, the airflow along the propeller is reduced, consequently lowering the noise level in the surrounding area. In particular, inflatable air chambers can be arranged laterally on the propeller blades to modify the airflow.

[0013] Finally, WO2018 / 046061 A1 discloses a structural unit for a wind turbine that is arranged on / at the hub or the axis of rotation of the turbine blades and ensures that air striking the area of ​​the axis of rotation is directed outwards towards the turbine blades. To optimally utilize wind power, wind-permeable thickenings are provided in the central area at the edges of the turbine blades, in which the wind can be trapped and used as an additional impulse for the rotational movement.

[0014] The problem with the current state of the art in rotor blade design is that, in addition to the manufacturing costs, existing systems only achieve an efficiency of 40-50%. This is primarily due to aerodynamic losses such as air friction on the blades, vortices at the blade tips, and rotor wake. Therefore, to improve the efficiency of wind turbines, turbochargers, and helicopters by modifying the rotor geometry, the design must be optimized to either increase the lift generated by the rotors or reduce aerodynamic losses.

[0015] The object of the invention is therefore to provide rotor blades for turbines, exhaust gas turbochargers and helicopters that are more cost-effective to manufacture and enable a higher efficiency of the systems than with the already known designs, whereby the designs should be compatible with existing systems.

[0016] The problem is solved according to the invention by an aerodynamic structure with the features of independent claim 1.

[0017] According to the invention, it is provided that an aerodynamic structure is provided which has at least one wing-like shape with upper and lower sides and an axis of rotation, wherein a bearing is embedded in the axis of rotation which is connected to an axis via a shaft, wherein a flat surface extends from the root of the wing-like shape to the tip.

[0018] In this context, aerodynamic structure is understood to mean a geometric form that is used as a wing-like shape in gas- and air-based constructions as part of a rotor, whereby the flow energy of a gas medium can be used for energy generation in the almost optimal range of the Betz coefficient.

[0019] The design according to the invention provides that the wing-like shape has a leading edge with a thickening on the upper surface facing away from the gas and / or wind and comprises a general quadrilateral geometry extending from the root of the shape, with a triangular geometry adjoining one of the sides of the quadrilateral towards the apex of the shape. It is generally provided that the triangular geometry adjoins the side of the quadrilateral opposite the root of the shape. However, it is also possible for the triangular geometry to adjoin the side directly adjacent to the root of the shape. It has been shown, however, that choosing the type in which the triangular geometry adjoins the side opposite the root of the shape generates the greatest permanent negative pressure on the upper surface of the wing-like shape when the structure is rotated about the axis of rotation.Therefore, the inventive form is generally based on this design, unless special designs of the structure are intended to result in reduced buoyancy.

[0020] When the structure is set into rotation by wind, a vortex or vortex-like movement of gas or air is created on the top of the form, i.e., on the flat surface. The vortex then spreads across the flat surface, drawing in air. It has been observed that the more completely the vortex or vortex-like movement of gas or air spreads across the surface of the flat area, the greater the generated negative pressure and the resulting lift.

[0021] According to the invention, a thickening is provided on the upper surface of the mold facing away from the wind. This thickening has sharp edges and is particularly rectangular or triangular. In this context, a sharp-edged design means that the transition from the sharp-edged thickening to the surface of the flat area is selected such that flow separation is generated on the side facing away from the wind, i.e., a wind edge is created. The height of the thickening relative to the flat area is at least twice the thickness of the flat area. In a particularly advantageous embodiment, it is provided that the geometry of the thickening follows the entire contour of the side of the mold facing away from the wind, i.e., that the contour of the thickening extends over the entire span of the mold, thus generating flow separation along the entire contour of the general quadrilateral and triangular geometry.The resulting flow separation therefore occurs completely along the entire length of the thickening.

[0022] For optimizing lift, it has proven particularly advantageous to choose the geometry of the wing-like shape such that at least 50% of the total wingspan of the shape is encompassed by the geometry of the general quadrilateral, which is oriented in nature towards an elliptical, maple seed-like surface. It has been shown that lift is greatest when the side of the quadrilateral is longer at the leading edge than at the trailing edge. This is done to create a geometry that approximates the shape of a maple seed.However, producing a completely maple seed-shaped structure is difficult and costly due to the elliptical curvature, so the aerodynamic structure has a geometry that is easier and more cost-effective to produce than the shape completely modeled on nature, the geometry being chosen to combine the advantages of the simpler production of the shape according to the invention with the advantages of the shape from nature.

[0023] In a further advantageous embodiment, the geometry of the general quadrilateral shape is replaced by a trapezoidal geometry. The advantage of the trapezoidal shape for part of the total span of the shape is that a parallel arrangement of two sides ensures simpler manufacturing of the shape according to the invention. The ratio of the short side of the trapezoidal geometry to the long side should be 2:3.

[0024] Furthermore, it has proven particularly advantageous that the angles of the wing-like shape can change with respect to the axis of rotation and / or the wind direction depending on the wind speed. Such an alignment is particularly important at the start of operation, as the shape must align itself with the direction of the air and / or gas flow so that flow separation occurs at the thickening on the edge of the shape facing the wind or gas mixture. Depending on the flow energy, the shape must align itself so that the torque generated by the induced flow separation is not too high at the start of operation, in order to prevent rotor wobble. The shape is slowly rotated into the gas flow. This is done analogously to the pitch control principle of known rotor blades according to the prior art.

[0025] The compatibility of the inventive form with forms according to the prior art is ensured by flat mountings on the hub for the rotor or turbine blade. In this context, flat mounting means a fastening option, for example via flanges with screws, for the rotor blades to the hub of the structure.

[0026] Since strong forces can act on the shape depending on the airflow, the flat surface extending from the root of the wing-like shape to the tip must be elastically designed. In this context, elasticity means that the surface changes its shape under the influence of a force, but returns to its original shape when the force is removed. This is particularly important so that the rotor blades can bend, but yield to the applied forces in such a way that a vortex or vortex-like gas or air movement on the shape, especially on the flat surface, is maintained throughout operation, even under high forces.

[0027] The flat surface is attached to the profile nose of the mold in such a way that it is connected to at least a portion of it by a force-fit and / or form-fit connection. Force-fit and / or form-fit connection means that the flat surface is attached in the area of ​​the thickening, whether by clamping, gluing, screwing, tongue-and-groove fastening, or being held in place with cotter pins.

[0028] The material of the flat surface and / or the form, as well as the overall structure in general, includes plastics, metals, wood, or composites, as well as mixtures of these materials. Plastics encompass all plastically deformable materials, such as PE, PVC, PEEK, etc., or carbon fibers. Metals include compounds of iron, chromium, nickel, manganese, aluminum, and alloys such as brass, bronze, etc. Wood includes woods such as maple, poplar, spruce, beech, or composites such as carbon fiber reinforced composites, especially those made from so-called pre-prags. All of the aforementioned materials exhibit elasticity that allows for deflection of the flat surface due to linear or non-linear elastic deformation.

[0029] It has been found in particular that roughening the surface of the flat area or arranging fiber lines allows rotation- and wind-edge-induced vortices or vortex-like gas and / or air movements to spread more effectively across the surface, thereby promoting their propagation or enabling a more uniform movement and distribution of the vortices. It is assumed that roughening or arranging the fiber lines results in improved lift compared to a shape without fiber lines. The manufacturing process specifically includes the case where the elastic surface is attached to the leading edge of the airfoil using a tongue-and-groove joint or cotter pins.

[0030] The structure according to the invention and the method for its manufacture are used particularly in application areas that include wind turbines, exhaust gas turbochargers or helicopters. Flow energy can be converted into mechanical energy and / or, with the aid of a generator, into electrical energy.

[0031] The invention is described in detail again with reference to the following figures.

[0032] Figure 1 The aerodynamic structure 1, with upper surface 3 and lower surface 4, is shown in a vertical cross-section to the axis of rotation 5. At one end of the cross-section, the leading edge 10, which has a thickening 9, can be seen. At the other end of the cross-section, the trailing edge 14 is visible, which has a smaller circumference than the thickening 9 at the leading edge 10.

[0033] In Figure 2The aerodynamic structure 1 is shown in a perspective top view. The wing-like shape 2 of the aerodynamic structure 1 has an upper surface 3 and a lower surface 4 with a leading edge 10 and a thickening 9, the thickening 9 being located on the upper surface 3 facing away from gas and / or wind. The wing-like shape 2 has a general quadrilateral geometry 11 extending from the root 6, to which a triangular geometry 12 is attached on the side of the general quadrilateral 11 opposite the root 6, the triangular geometry 12 pointing towards the apex 7 of the wing-like shape 2. A sharp-edged thickening 9 is arranged on the upper surface 3 of the wing-like shape 2 facing away from the wind. The transition from the sharp-edged thickening 9 to the upper surface 3 of the flat surface 8 is designed to create a wind edge.In the present illustration, the geometry of the thickening 9 follows the entire contour of the leeward side of the wing-like shape 2, i.e., the contour of the thickening 9 extends over the entire span of the wing-like shape 2. The flow separation generated by this thickening during rotation thus occurs completely along the entire length of the thickening 9 of the wing-like shape 2. If the aerodynamic structure 1 is set into rotation about the rotation axis 5, which is mounted in a receptacle 13, by a wind movement, a vortex or a vortex-like gas or air movement is created on the upper surface 3 of the wing-like shape 2, which moves in the direction of the trailing edge 14 of the profile.

[0034] In Figure 3The movement or direction of movement of the vortices on the wing-like shape 2 of the aerodynamic structure 1 is shown. If the aerodynamic structure 1 is set into rotation around the axis of rotation 5 by a wind movement, a vortex or vortex-like gas or air movement is created on the upper surface 3 of the flat surface 8. The vortex spreads out on the flat surface 8 and entrains air on the upper surface 3 of the wing-like shape 2. During the rotation, the vortices move in the direction of the trailing edge 14 of the profile and leave the flat surface 8 in the region of the trailing edge 14 of the triangular structure 12. The more completely the vortex or vortex-like gas or air movement spreads out on the upper surface 3 of the flat surface 8, the greater the generated negative pressure and the greater the lift generated. REFERENCE MARK LIST

[0035] 1 Aerodynamic structure 2 Wing-like shape 3 Top surface 4 Bottom surface 5 Rotation axis 6 Root 7 Tip 8 Plane 9 Thickening 10 Profile leading edge 11 General quadrilateral geometry 12 Triangular geometry 13 Intake 14 Profile trailing edge

Claims

1. Aerodynamic structure (1), comprising at least one wing-like shape (2) with a top (3) and bottom (4), which has an axis of rotation (5), in which a bearing is embedded and which is connected to an axis via a shaft, wherein a flat surface (8) extends from the root (6) of the wing-like shape (2) to the tip (7) and a thickening (9) is present in the region of the profile nose (10) on the upper side (3) facing away from the wind, wherein the flat surface (8) has the geometry of a general quadrilateral (11) from the root (6) of the shape (2) and a triangular geometry (12) adjoins one of the sides to the tip (7) of the shape (2), characterised in that the orientation of the thickening (9) changes at the transition of the general quadrilateral (11) to the triangular geometry (12) and the thickening (9) is quadrangular or triangular and sharp-edged.

2. Aerodynamic structure (1) according to claim 1, characterised in that the geometry of the general quadrilateral (11) occupies at least 50% of the total span of the shape (2).

3. Aerodynamic structure (1) according to one of claims 1 or 2, characterised in that the thickening (9) follows the geometry of the general quadrilateral (11) and the triangular geometry (12) of the entire span of the shape (2) in the contour.

4. Aerodynamic structure (1) according to any one of claims 1 to 3, characterised in that the geometry of the shape (2) of a general quadrilateral (11) is replaced by a trapezoidal geometry.

5. Aerodynamic structure (1) according to claim 4, characterised in that the ratio of the short side of the trapezoidal geometry to the long side has a value of 2:3.

6. Aerodynamic structure (1) according to any one of claims 1 to 5, characterised in that the angles of the wing-like shape (2) in relation to the axis of rotation (5) and / or the direction of the gaseous flow change as a function of the flow velocity.

7. Aerodynamic structure (1) according to any one of claims 1 to 6, characterised in that the shape (2) has receptacles (13) for attachment as a rotor or turbine blade.

8. Aerodynamic structure (1) according to any one of claims 1 to 7, characterised in that the flat surface (8) is elastic.

9. Aerodynamic structure (1) according to any one of claims 1 to 8, characterised in that the flat surface (8) is connected to at least part of the profile nose (10) in a force-fit and / or form-fit manner.

10. Aerodynamic structure (1) according to any one of claims 1 to 9, characterised in that the material for the shape (2) comprises plastics, metals, wood or composite materials.

11. Aerodynamic structure (1) according to any one of claims 1 to 10 characterised in that fibre lines are present on the flat surface (8).

12. Use of an aerodynamic structure (1) according to any one of claims 1 to 11, as part of a rotor, wherein the flow energy of a gas medium can be utilised to generate energy in the near-optimal range of the Betz coefficient.

13. Use of an aerodynamic structure (1) according to any one of claims 1 to 12, for use in wind turbines, exhaust gas turbochargers or helicopters.