Fluid power system with eccentrically controlled, shape-changing airfoil profiles

Abstract

Fluid power system (100) comprising a base guide column (106), a base hub (112) rotatably arranged about the base guide column (106), at least one rotor blade (130) rotatable about the base guide column (106), wherein the at least one rotor blade (130) is connected to the base hub (112) via a base support arm (113), and an eccentric arrangement (141) connected to the at least one rotor blade (130) via an eccentric support arm (123), characterized in that the eccentric arrangement (141) is rotatable together with the at least one rotor blade (130), and the base support arm (113) and the eccentric support arm (123) are each connected to the at least one rotor blade via a different number of connection points (135, 136, 137, 138, 139, 140). (130) are interconnected.

Description

2. Technical field

[0001] The present invention relates to a fluid power system for converting the kinetic energy of a flowing medium into mechanical rotational energy or electrical energy. 3. State of the art

[0002] Common vertical-axis fluid power systems (e.g., H-rotors) typically use rigid airfoils. These airfoils are optimized for a specific angle of attack, but exhibit significant efficiency losses throughout the entire 360° rotation cycle because the local angle of attack changes continuously. Due to the approximately equal division of the angle of attack into positive and negative operating ranges, symmetrical airfoils are often employed. In large portions of the rotation, symmetrical airfoils operate in a suboptimal range, resulting in increased drag and reduced lift. Known solutions for improvement include pitch control. These either simply change the angle of the entire blade or require highly complex, maintenance-intensive sensors and actuators. 4. Object of the invention

[0003] The object of the present invention is therefore to create a fluid power system with improved efficiency for converting the kinetic energy of a flowing medium into mechanical energy. 5. Summary of the invention

[0004] This problem is solved according to the invention by a fluid power system comprising a base guide column, a base hub rotatably arranged about the base guide column, at least one rotor blade rotatable about the base guide column, wherein the at least one rotor blade is connected to the base hub via a base support arm, and an eccentric arrangement connected to the at least one rotor blade via an eccentric support arm. The eccentric arrangement is rotatable together with the at least one rotor blade, and the base support arm and the eccentric support arm are each operatively connected to the at least one rotor blade via a different number of connection points. The advantage of this solution is that the dynamic variation of a skeletal line between positive and negative camber generates an asymmetric profile which exhibits a significantly higher power coefficient C in each rotation phase. Pfeatures more symmetrical profiles than conventional ones.

[0005] In an advantageous embodiment of the invention, the base support arm has two base connection points and the eccentric support arm has one eccentric connection point on the at least one rotor blade. The double connection of the base support arm results in increased static stiffness of the rotor blade at the main hub. The advantage of this arrangement is that the blade is stabilized against undesired torsional forces, while the reduction to a single connection point on the eccentric support arm enables particularly sensitive and precise application of the deformation forces. This refines the control of the blade's skeletal structure without weakening its structural base.

[0006] In a further advantageous embodiment of the invention, the base support arm has one base connection point and the eccentric support arm has two eccentric connection points on the at least one rotor blade. This distributes the actuating forces over a larger area of ​​the airfoil surface via the two connection points of the eccentric support arm. The resulting advantage is maximized shape control of the airfoil profile, particularly under high wind loads. The area-wide force application prevents local material overstretching, ensuring that the asymmetric airfoil maintains its aerodynamically ideal shape and preventing camber collapse at the limits of performance.

[0007] In a further advantageous embodiment, at least one rotor blade has an elastic airfoil. The advantage of this elastic design is that the airfoil can be continuously modified. This allows for an aerodynamically smooth surface throughout the entire deformation process, thereby avoiding lossy turbulence and pressure fluctuations such as those that occur with conventional flap mechanisms. Furthermore, it reduces wear and increases resistance to environmental influences.

[0008] In a further advantageous embodiment, the connection points are arranged directly on an inner skeletal line of the rotor blade. The advantage of this central connection lies in a symmetrical and homogeneous force distribution from the airfoil center to the entire surface. Since the actuating forces act at the energetic center of the airfoil, undesirable local deformation of the outer skin is minimized. This results in a particularly stable and reproducible geometry of the skeletal line, which improves the aerodynamic predictability of the morphing effect under changing load conditions.

[0009] In a further advantageous embodiment, the connection points are arranged directly on the elastic profile skin. The resulting advantage lies in a significantly reduced design complexity, as additional internal support structures or a separate skeletal support can be dispensed with. Furthermore, this arrangement allows the aerodynamic forces to be transferred directly from their point of origin – the profile surface – into the support arm structure. This minimizes internal stresses in the component and leads to a weight-optimized, low-maintenance design for the entire rotor.

[0010] In a further advantageous embodiment, the eccentricity of the eccentric guide column relative to the base guide column is determined by shifting a first guide element to a second guide element. The resulting technical advantage lies in the dynamic adaptability of the morphing degree to the prevailing environmental conditions. Through manual or actuator-based control of the eccentricity, the intensity of the profile camber can be precisely adjusted to varying fluid velocities. This makes it possible to determine the optimal performance coefficient C. P to maintain stability over a significantly wider operating range than would be possible with a fixed eccentricity. The system can thus actively respond to gusts or changing flow conditions, increasing the overall efficiency of the system while simultaneously limiting mechanical stress at extreme speeds by reducing the camber.

[0011] Furthermore, it can be advantageous if the alignment of the eccentricity relative to the fluid flow direction is achieved passively via a guide surface and / or actively by an actuator. The resulting advantage lies in the precise orientation of the morphing mechanism to the main flow direction. This alignment ensures that the maximum airfoil camber is achieved during those rotational phases in which it contributes most to lift and thus to the power coefficient C. P The passive guide surface guarantees simple, energy-autonomous tracking in changing wind directions, while the use of an actuator enables highly dynamic adjustment that prevents misalignment even in turbulent flow conditions. This also protects the system from one-sided mechanical stresses and increases the overall service life of the elastic components.

[0012] In a further advantageous embodiment, the eccentric arrangement comprises an eccentric guide column, an eccentric hub, an eccentric support arm, a first guide element, a second guide element, and a guide surface. The advantage of this design flexibility lies in the ability to precisely influence not only the airfoil camber but also the pitch angle of the rotor blade relative to the circular path. By individually positioning the attachment points, the relationship between the morphing-induced camber and the effective angle of attack to the airflow can be structurally defined. This allows for precise adjustment of the angle of attack in different rotation phases, thereby further improving the aeroelastic response of the blade to the oncoming airflow.This allows the system to exhibit advantageous behavior over a wider operating range, as the mechanical coupling between the support arm and the blade can be individually designed to meet the desired aerodynamic characteristics.

[0013] In a further advantageous embodiment, the fluid is air, allowing the fluid power plant to be operated as a wind turbine, or the fluid is a liquid, enabling the fluid power plant to be operated as a current or tidal power plant. The advantage of this embodiment is that the plant can be specifically tailored to the site-specific energy sources. While current and tidal power plants utilize the high density of water to achieve high power outputs at comparatively low flow velocities, the advantage of wind turbines lies in the ubiquitous availability of air currents, which allows them to be used at a wide variety of locations.The morphing-based principle allows for precise adaptation of the profile geometry to the prevailing flow velocity in both application cases, thereby achieving a high performance coefficient (Cp value) across the entire spectrum of operating points.

[0014] The invention thus offers an adaptable technical concept that consistently utilizes the physical advantages of water currents (high energy density) and air currents (wide site availability) for maximum energy yield. 6. Description of the figures

[0015] Further advantages and advantageous embodiments of the invention are explained below with reference to exemplary embodiments and the figures. The accompanying drawings serve to illustrate the principle of the invention and show preferred embodiments of the fluid power system.

[0016] They show: Fig. 1: Perspective schematic view of a fluid power plant with two connection points of the base support arm and one connection point of the eccentric support arm, Fig. 2: Perspective schematic view of a fluid power plant with one connection point of the base support arm and two connection points of the eccentric support arm.

[0017] In the figures, identical reference numerals denote identical or functionally equivalent elements. The invention is not limited to the embodiments shown. The embodiments shown in the figures merely represent concrete examples of the invention. Within the scope of their expert knowledge, a person skilled in the art can recognize embodiments of the invention that are not explicitly shown. 7. Description of exemplary implementations

[0018] Fig. Figure 1 schematically shows a perspective view of a fluid power system 100 according to the invention. The fluid power system 100 has a base guide column 106 that is fixedly connected to a base housing 105. A base hub 112 is rotatably mounted around the base guide column 106. A base support arm 113 connects the rotor blade 130 to the base hub 112 at the first connection point (base support arm 135) and the second connection point (base support arm 136).

[0019] The eccentric arrangement 141 is also provided around the base guide column 106, wherein the eccentric arrangement 141 preferably comprises a first guide element 125, a second guide element 126, an eccentric guide column 121, an eccentric hub 122, an eccentric support arm 123, and a guide surface 127 rotating in this configuration. The eccentric support arm 123 connects the rotor blade 130 to the eccentric hub 122 at the first connection point eccentric support arm 137.

[0020] The guide surface 127 aligns the eccentric arrangement with the fluid flow direction. The translational relative movement between a first guide element 125 and a second guide element 126 enables stepless adjustment of the eccentricity of the base guide column 106 to the eccentric guide column 121. This adjusts the center-to-center distance between the base guide column 106 and the eccentric guide column 121, which influences the intensity of the profile deformation. The positioning of the connection points 135, 136, 137 influences the angle of attack to the circular path.

[0021] The morphological change of the rotor blade 130 results from the kinematic forced coupling of two different centers of rotation. While the base support arms 113 define a circular path around the base guide column 106, the eccentric support arms 123 describe an offset path around the eccentric guide column 121. Since both support arm groups attach at spatially separated connection points 135, 136, 137, 138, the eccentric offset induces a continuous change in the distance and angle between these points during each revolution. To generate the controlled deformation, the base support arm 113 has two distinct points with a first connection point base support arm 135 and a second connection point base support arm 136, while the eccentric support arm 123 has a first connection point eccentric support arm 137 which serves as the primary static basis.Depending on the positioning of the connection points on the rotor blade, in addition to controlled deformation, a change in the angle of attack relative to the circular path can also occur.

[0022] This mechanical difference prevents the profile from simply pivoting and forces elastic deformation of the airfoil 132 and the skeleton line 134. The connection can be made variably to the inner structure (skeletal line 134), directly to the outer membrane (airfoil 132), or via a hybrid connection. This superimposed pivoting and deformation movement enables precise alignment of the airfoil with the resulting flow vector. This achieves the smooth transition from a symmetrical initial airfoil to an asymmetrically cambered lift airfoil. Through this continuous transformation, the wing can assume a shape that, under the given environmental conditions, provides a better lift coefficient c. a to the resistance coefficient c woffers. This can lead to an improvement in the performance coefficient C. P lead.

[0023] Fig. Figure 2 schematically shows in perspective another embodiment of a fluid power system 100 according to the invention, similar to the one in Figure 2. Fig. Figure 1 shows a fluid power system 100. The base support arm 113 connects the rotor 130 to a first connection point, base support arm 138. The eccentric support arm 123 connects the rotor 130 to a first connection point, eccentric support arm 139, and a second connection point, eccentric support arm 140. This allows the actuating forces to be distributed over a larger area of ​​the airfoil surface via the two connection points 139 and 140 of the eccentric support arm.

[0024] In the examples shown, Fig. 1 and Fig. 2. The position of the connection points on the rotor blade can generally be chosen arbitrarily and can therefore be adapted to the respective requirements. 8. List of reference symbols 100 Fluid Power Plant 105 Base case 106 Basic guide column 112 Base hub 113 Base support arm 121 Eccentric guide column 122 eccentric hub 123 Eccentric support arm 125 First guiding element 126 Second guide element 127 Guide surface 130 rotor blades 132 Elastic profile sleeve 134 Skeletal line 135 First connection point base support arm 136 Second connection point base support arm 137 First connection point eccentric support arm 138 First connection point base support arm 139 First connection point eccentric support arm 140 Second connection point eccentric support arm 141 Eccentric arrangement

Claims

Fluid power system (100) comprising a base guide column (106), a base hub (112) rotatably arranged about the base guide column (106), at least one rotor blade (130) rotatable about the base guide column (106), wherein the at least one rotor blade (130) is connected to the base hub (112) via a base support arm (113), and an eccentric arrangement (141) connected to the at least one rotor blade (130) via an eccentric support arm (123), characterized in that the eccentric arrangement (141) is rotatable together with the at least one rotor blade (130), and the base support arm (113) and the eccentric support arm (123) are each connected to the at least one rotor blade (130) via a different number of connection points (135, 136, 137, 138, 139, 140) Rotor blade (130) are functionally connected. Fluid power plant (100) according to claim 1, characterized in that the base support arm (113) has two base connection points (135, 136) and the eccentric support arm (123) has an eccentric connection point (137) on the at least one rotor blade (130). Fluid power plant (100) according to claim 1, characterized in that the base support arm (113) has a base connection point (138) and the eccentric support arm (123) has two eccentric connection points (139, 140) on the at least one rotor blade (130). Fluid power plant (100) according to claim 1, characterized in that the at least one rotor blade (130) has an elastic profile shell (132). Fluid power plant (100) according to one of claims 1 to 4, characterized in that the connection points (135, 136, 137, 138, 139, 140) are arranged on an inner skeleton line (134) of the at least one rotor blade (130). Fluid power plant (100) according to one of claims 1 to 4, characterized in that the connection points (135, 136, 137, 138, 139, 140) are arranged directly on the elastic profile shell (132) of the at least one rotor blade (130). Fluid power system (100) according to one of claims 1 to 6, characterized in that the eccentricity of the eccentric guide column (121) to the base guide column (106) is determined by a manual or actuator-induced displacement of a first guide element (125) to a second guide element (126). Fluid power system (100) according to one of the preceding claims, characterized in that the orientation of the eccentric arrangement (141) relative to the flow direction of the fluid can be passively adjusted via fluid dynamic processes by means of a guide surface (127) and / or actively by means of an actuator. Fluid power system (100) according to one of the preceding claims, characterized in that the eccentric arrangement (141) comprises an eccentric guide column (121), an eccentric hub (122), an eccentric support arm (123), a first guide element (125), a second guide element (126) and a guide surface (127). Fluid power plant (100) according to one of the preceding claims, characterized in that the fluid is air and the fluid power plant (100) can be operated as a wind power plant, or that the fluid is a liquid and the fluid power plant (100) can be operated as a current or tidal power plant.

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