WIND TURBINE ROTOR BLADE AND WIND TURBINE

Description

[0001] The present invention relates to a wind turbine rotor blade and a wind turbine.

[0002] Since the rotor blades of a wind turbine are exposed to all weather conditions without protection, they can ice up at certain temperatures. To prevent this, rotor blade heating can be used. This can be done either by installing a heater on the outside of the rotor blade or by providing heated air inside the rotor blade. This can be achieved, for example, by using a heating coil that generates warm air, which is then blown into the interior of the rotor blade.

[0003] WO 2017 / 021350 A1 shows a wind turbine rotor blade with a rotor blade root region and a rotor blade tip region, as well as a rotor blade heater. Furthermore, at least one web is provided along a longitudinal axis of the rotor blade. A deflection unit in the form of a web droplet can be provided on the web to reduce air turbulence during deflection.

[0004] WO 2018 / 211055 shows a wind turbine rotor blade with a rotor blade heater. The rotor blade has a web and a deflection unit in the area of ​​the rotor blade tip for deflecting heated air.

[0005] EP 3 048 296 A1 shows a rotor blade of a wind turbine with a rotor blade heater.

[0006] EP 3 048 297 A1 shows a rotor blade of a wind turbine with a rotor blade heater.

[0007] It is an object of the present invention to provide a wind turbine rotor blade which enables improved heating of the rotor blade.

[0008] This object is achieved by a wind turbine rotor blade according to claim 1.

[0009] Thus, a wind turbine rotor blade is provided with a rotor blade root, a rotor blade tip, a pressure side, a suction side, a leading edge, and a trailing edge. The rotor blade has a longitudinal direction. Warm air is generated by means of a rotor blade heater, which is then blown into the interior of the rotor blade. At least one passively controllable air control element is provided in the air duct within the rotor blade. The air control element ensures that the air flow in the air duct within the rotor blade can be influenced or controlled. This can, for example, ensure that air masses with different temperatures (warm air in the center of the air flow and colder air towards the outside of the rotor blade) mix better within the rotor blade.

[0010] The passively controllable air control element has a temperature-dependent section that changes its shape depending on the temperature. The air control element thus reacts automatically to a change in temperature, which leads to a change in the air flow. The temperature-dependent change in shape can be used to influence the air flow to increase efficiency. Optionally, at least one web is provided between the pressure side and the suction side along the longitudinal direction of the rotor blade. The air heated by the rotor blade heater can be blown along the web towards the rotor blade tip, where it is deflected so that the heated air can flow back on the other side of the web from the rotor blade tip area to the rotor blade root area. At least one passively controllable air control element can be provided along a web to influence the air flow.The passively controllable air control element has no active control elements, but only passively controllable elements. Therefore, there is no active intervention in the air control elements. The passively controllable air control element allows for temperature-dependent passive control. To achieve this, the air control element allows for at least partial temperature-dependent deformation.

[0011] According to one aspect, the passively controllable air control element can comprise a bimaterial section with a first and a second material section. The material of the first material section has a different thermal expansion coefficient than the material of the second material section. Thus, a temperature change can cause the first and second material sections to expand differently, thus resulting in deformation of the bimaterial section.

[0012] Preferably, the bimaterial section is provided as a bimetallic section with a first and second metal section with different coefficients of thermal expansion. As the temperature increases, the first and second metal sections, which are coupled to each other, expand differently, resulting in a bending of the bimetallic section toward the metal section with the lower coefficient of thermal expansion. This change in shape influences the airflow of the heated air inside the rotor blade.

[0013] The passively controllable air control element can be configured as a passively controlled static mixer. The mixer comprises a bimaterial section with a first and second material, which are coupled to one another and have different thermal expansion coefficients. Furthermore, an air guide element is coupled to the bimaterial section. The deformation of the bimaterial section, for example, leads to a change in the angle of the air guide element. Thus, an air flow in the air guide of the rotor blade heater within the rotor blade can be changed, for example, by the passively controlled static mixer. The bimaterial section deforms depending on the temperature, and thus the position of the air guide unit changes, which in turn leads to a change in the air flow.

[0014] The passively controlled air control element can be configured as a passively controlled vortex generator. The vortex generator can comprise a bimaterial section comprising a first and second material with different thermal expansion coefficients. Heating or cooling the bimaterial section results in a deformation of the bimaterial section. This causes a change in the shape of the vortex generator, which changes the air flow in the air duct of the rotor blade heater within the rotor blade. Thus, a passively controlled change in the air flow within the air duct of the rotor blade can be achieved.

[0015] The passively controllable air control element can comprise an element that exhibits a temperature-dependent change in length. This element can be coupled to a baffle, so that, for example, the angle of the baffle changes depending on the temperature. This can result in the air flow within the air duct being deflected by the baffle, which can cause turbulence in the different temperature layers. For example, the angle of the baffle can be increased as the temperature increases.

[0016] The passively controllable air flow elements can also be retrofitted to existing rotor blades.

[0017] The passively controlled air control elements are optionally used to locally improve the rotor blade heating by locally influencing the air flow of the rotor blade heating.

[0018] The passively controllable air control element has at least a first and a second operating position, wherein the air control element is active in the first operating position and inactive in the second operating position. Alternatively, the air control element can be inactive in the first operating position and active in the second operating position. The transition from the first to the second operating position or from the second to the first operating position occurs as a function of the temperature. In particular, a transition between the first and second operating positions occurs due to a non-linear linear expansion of a bimaterial element having a first and second material section with different thermal expansion coefficients.

[0019] The passively controlled air control elements can be active in the initial position (vortex generators VG, static mixer, flap (open)) and inactive in the end position (vortex generator VG inactive, static mixer inactive, flap (closed)), or vice versa. This can be achieved through targeted positioning or preloading by the bimaterial element.

[0020] The passively controllable air control element can be arranged on an inner wall of the rotor blade or on a web within the rotor blade. Alternatively, the passively controllable air control element can also be attached to other components inside the rotor blade. In particular, one end of the passive air control element can be attached to the web or the inner wall, so that the other end protrudes into the interior volume of the rotor blade and deforms depending on the temperature.

[0021] The passively controllable air control element with the temperature-dependent deformation can be designed as a vortex generator, static mixer and / or deflection vane.

[0022] The temperature-dependent variability (for example, by using two bimaterial elements) allows for the provision of a passively controllable air control element that only intervenes in the air flow when needed. This is advantageous because the passively controllable air control elements only intervene in the air flow when actually needed. This can prevent, for example, a permanent pressure loss due to the passively controllable air control elements interfering with the air flow of the rotor blade heater.

[0023] In particular, if the passively controllable air control elements do not cause any change in the air flow of the rotor blade heater in their normal operating mode, this does not lead to any impairment of the air flow in the normal state.

[0024] The passively controllable air control elements placed along the rotor blade allow for localized control of the rotor blade heating airflow. Thus, specific sections of the rotor blade can be heated more effectively thanks to the passively controllable air flow elements, preventing or reducing ice buildup.

[0025] This makes it possible that not all areas of the rotor blade are heated, but that a local change in the temperature distribution can be achieved.

[0026] Further embodiments of the invention are the subject of the subclaims.

[0027] Advantages and embodiments of the invention are explained in more detail below with reference to the drawing. Fig. 1 shows a schematic representation of a wind turbine according to the invention, Fig. 2 shows a schematic sectional representation of the rotor blade of the wind turbine of Fig. 1 according to a first embodiment, Fig. 3 shows a schematic sectional view of a rotor blade of a wind turbine of Fig. 1 according to a second embodiment, Fig. 4 shows a schematic representation of a passively controllable air control element, Fig. 5 shows a schematic representation of a passively controllable air control element, Fig. 6 shows a schematic representation of a passively controllable air control element, and Fig. 7 shows a schematic representation of a passively controllable air control element.

[0028] Fig. 1 shows a schematic representation of a wind turbine according to the invention. The wind turbine 100 has a tower 102 and a nacelle 104 on the tower 102. An aerodynamic rotor 106 with three rotor blades 200 and a spinner 110 is provided on the nacelle 104. During operation of the wind turbine, the aerodynamic rotor 106 is set into rotation by the wind and thus also rotates a rotor or rotor of a generator, which is directly or indirectly coupled to the aerodynamic rotor 106. The electrical generator is arranged in the nacelle and generates electrical energy. The pitch angles of the rotor blades 200 can be changed by pitch motors at the rotor blade roots 210 of the respective rotor blades 200.

[0029] Fig. 2 shows a schematic section of the rotor blade of the wind turbine from Fig. 1 according to a first exemplary embodiment. The rotor blade 200 has a length 201, a rotor blade wall 202, an internal volume 203, a rotor blade root 210, a rotor blade tip 220, a leading edge 230, a trailing edge 240, a pressure side 250, and a suction side 260. An air guide 400 is provided within the rotor blade 200, which can be configured, for example, as a web 410. A rotor blade heater 300 can be provided in the region of the rotor blade root 210. The rotor blade heater 300 can have a fan 320 and a heating unit 310 and can generate warm air that can be directed into the interior of the rotor blade 200, i.e., the internal volume 203.

[0030] At least one web 410, 411, 412 extends within the rotor blade along a longitudinal direction L of the rotor blade 200. This web is part of the air duct 400 or is already present for other reasons, and the air duct 400 merely represents a secondary function. Optionally, more than one web can be provided.

[0031] The air heated by the rotor blade heater 300 can be guided along the web 411—as part of the air guide 400—in the direction of the rotor blade tip 220 and then deflected in the region of the rotor blade tip 220. For this purpose, a deflection section 402 can be provided in the region of the rotor blade tip 220. Optionally, the rotor blade tip 220 can be at least partially hollow, so that a portion of the heated air can flow through the rotor blade tip 220 to also de-ice the rotor blade tip 220.

[0032] The heated air can be generated by means of the rotor blade heater 300 either in the rotor blade root area by heating the air by means of a heating unit 310, or the heated air is supplied to the rotor blade 200 in the area of ​​the rotor blade root 210.

[0033] At least one passively controllable air control element 800 can be provided along the length L of the rotor blade 200 in the air guide 400. The passively controllable air control element 800 serves to control or influence the air flow of the rotor blade heater within the rotor blade 200, e.g., through temperature-dependent deformation.

[0034] Fig. 3 shows a schematic representation of a rotor blade according to a second exemplary embodiment. The rotor blade 200 has a rotor blade root 210, a rotor blade tip 220, a leading edge 230, and a trailing edge 240. At least one web 410 is provided inside the rotor blade, extending from the region of the rotor blade root 210 into the region of the rotor blade tip 220. The rotor blade 200 has at least one passively controllable air control element 800. Such a passively controllable air control element can be arranged along the length of the webs 410.

[0035] According to one aspect of the present invention, the passively controllable air control element 800 may be provided at various locations along the length L of the rotor blade 200 and inside the rotor blade 200, for example between a web 411 and the rotor blade wall 202 or between a web 410 and a rotor blade trailing edge 230.

[0036] According to one aspect of the present invention, the passively controllable air control element 800 serves to (locally) influence an air flow within the air duct of the rotor blade, e.g., by temperature-dependent deformation.

[0037] Fig. 4 shows a schematic representation of a passively controllable air control element. The passively controllable air control element 800 can be configured as a passively controlled flow deflector 810. The flow deflector 810 comprises a bimaterial element 811 with a first material section and a second material section 812, 813, wherein the thermal expansion coefficients of the two material sections 812, 813 differ. Preferably, the flow deflector 810 comprises a bimetal element 811 with a first metal section and a second metal section 812, 813, wherein the thermal expansion coefficients of the two metal sections 812, 813 differ. This results in one of the two metal sections expanding greater than the other when the flow deflector 810 is heated, thus causing the flow deflector 810 to bend.This temperature-dependent change in shape results in a different influence on the air flow in the air duct 400. The air control element 800 can be attached to a rotor blade wall and / or to a web 410 and can protrude into the inner volume 203 of the rotor blade 200.

[0038] Fig. 5 shows a schematic representation of a passively controllable air control element. The air control element can be designed as a passively controlled static mixer 820. For this purpose, the mixer 820 has a bimaterial element 821 with a first and second material section 812, 813, each of which has a different coefficient of thermal expansion. Furthermore, an air guide element 824 is provided, which is coupled to the bimaterial section 821. When heated, the bimaterial element 821 bends, so that the position of the air guide element 824 attached to it also changes. In particular, an angle of the air guide element 824 can be adjusted, as shown, for example, in Fig. 5 shown. This temperature-dependent change in shape results in a different influence on the air flow in the air duct 400. The air control element 800 can be attached to a rotor blade wall and / or to a web 410 and can protrude into the interior volume 203 of the rotor blade 200.

[0039] Fig. 6 shows a schematic representation of a passively controllable air control element. The air control element can be configured, for example, as a passively controlled vortex generator 830. The passively controlled vortex generator 830 has a bimaterial element 831 with a first and second material section 832, 833, which have different thermal expansion coefficients, so that the bimaterial element 831 bends when heated. The bimaterial section can be configured as a bimetal section with two different metal sections with different thermal expansion coefficients. This can change the shape of the vortex generator 830. In particular, passive control of the shape of the vortex generator 830 can thus be achieved, for example, depending on a temperature. This is particularly advantageous because it eliminates the need for active actuators to change the shape of the vortex generators.The air control element 800 can be attached to a rotor blade wall and / or to a web 410 and can protrude into the interior volume 203 of the rotor blade 200.

[0040] Fig. 7 shows a schematic representation of a passively controllable air control element. The air control element 800 can, for example, be designed as a passively controlled flap unit 840. The passively controlled flap unit 840 can have a bimaterial section 841 with a first and second material section 842, 843. The bimaterial section 841 can, for example, be coupled to a flap 844, so that the flap 844 can be opened or closed due to the deformation of the bimaterial section 841. Such a flap 844 can, for example, be provided in or on a web 410 within the rotor blade. By opening and closing the flap 844, an opening 410a in the web can thus be opened or closed, thereby influencing an air flow. The air control element 800 can be attached to a rotor blade wall and / or to a web 410 and can protrude into the interior volume 203 of the rotor blade 200.

[0041] According to one aspect of the present invention, the passively controlled air control element can have a significant improvement on the air flow in the air duct for the rotor blade heater by an increased heat exchange at the surface to be heated (rotor blade wall).

[0042] According to one aspect of the present invention, already installed rotor blades can be retrofitted with passively controlled air control elements to increase the efficiency of rotor blade heating.

[0043] The passively controlled air control elements can be used particularly for rotor blades of a wind turbine, which are long and have a smaller internal cross-section.

[0044] According to one aspect of the present invention, the use of passively controlled air control elements allows the air flow temperature at the rotor blade shell to be significantly improved. While in the prior art, the air flow temperature at the shell can drop to as low as 50 °C, the aerodynamic mixers according to the invention can significantly increase the air flow temperature at the inner wall, in particular to 70-80 °C.

[0045] According to the invention, an improved heat transfer from the heated air to the material of the rotor blade casing can be achieved without significantly increasing the pressure losses.

[0046] According to the invention, a thermal exchange cooler with near-wall flow can be improved with warm far-wall flow without resulting in higher pressure losses.

[0047] With the passively controllable air control elements, the elements here can be activated (e.g. deformed) when they are needed.

[0048] The passively controllable air control element 800 may have at least a first and second operating position. As shown in Fig. 4 As shown, a first operating position can be provided in which the air control element is designed straight. In a second operating position (right in the Fig. 4 shown), the passive air control element may be deformed. Between the first and second operating positions, for example as shown in Fig. 4 shown, there may have been a change in temperature.

[0049] For example, in Fig. 5 As shown, the passive air control element can have a first operating position (left in Fig. 5 ) and a second operating position (right in Fig. 5 ). In the first operating position, the air control element can be straight and in the second operating position, the air control element can be deformed.

[0050] In Fig. 6 The air control element can have a first operating position (left) and a second operating position (right). In the first operating position, the air control element can be straight, and in the second operating position, the air control element can be deformed.

[0051] In Fig. 7 A first operating position (top) and a second operating position (bottom) are shown. In the first operating position, the air control element can be straight, and in the second operating position, the air control element can be deformed.

[0052] The passively controlled air control elements can be active or passive in the initial position. A change can occur by influencing the bimaterial section (i.e., temperature-dependent). When the air control elements are active, the vortex generators VG can be active, the static mixer can be active, and the damper can be open. The passively controlled air control elements can be inactive in their end position, i.e., the vortex generators VG are inactive, the static mixers are inactive, and the damper can be closed. Alternatively, the passively controlled air control elements can also be configured the other way around, i.e., the air guide elements are inactive in the initial position and active in the end position. Bezugszeichenliste

[0053] 100 Wind turbine 102 Tower 104 Nacelle 106 Rotor 110 Spinner 200 Rotor blades 201 Length 202 Rotor blade wall 203 Internal volume 210 Rotor blade root 220 Rotor blade tip 230 Leading edge 240 Trailing edge 250 Pressure side 260 Suction side 300 Rotor blade heater 310 Heating unit 320 Fan 400 Air duct 402 Deflection section 410 Web 410a Opening 411 Web 412 Web 800 Passive controllable air control element 810 Flow deflection element 811 Bimaterial element / bimetal element 812 First material section / metal section 813 Second material section / metal section 820 Passive controllable static mixer 821 Bimaterial element / bimetal element 822 First material section / metal section 823 Second material section / metal section 824 Air guide element 830 Passive-controlled vortex generator 831 Bimaterial element / bimetal element 832 First material section / metal section 833 Second material section / metal section 840 Passive-controlled flap unit 841 Bimaterial element / bimetal element 842 First material section / metal section843Second material section / metal section 844Flap LLongitudinal direction

Claims

1. A wind turbine rotor blade (200), with a length (201), a rotor blade root (210), a rotor blade tip (220), a pressure side (250), a suction side (260), a rotor blade wall (202), an inner volume (203), an air guide (400) for heated air to guide heated air inside of the rotor blade (200) and along a longitudinal direction (L) of the rotor blade (200) from the rotor blade root (210) in the direction of the rotor blade tip (220), and at least one passively controllable air control element (800) to control or influence an air flow in the area of the air guide (400) and in the inner volume (203), characterized in that the passively controllable air control element (800) has a temperature-dependent section (810, 820, 830, 840), which changes its shape depending on the temperature.

2. The wind turbine rotor blade (200) according to claim 1, wherein the air guide (400) has at least one web (410), which is arranged between the pressure side (250) and the suction side (260), and extends along the longitudinal direction (L) of the rotor blade (200), wherein the at least one passively controllable air control element (800) is arranged along the at least one web (410).

3. The wind turbine rotor blade (200) according to claim 1 or 2, wherein the passively controllable air control element (800) has a bimaterial element (811, 821, 831, 841), which has a first and second material section (812, 813) with different heat expansion coefficients.

4. The wind turbine rotor blade (200) according to one of claims 1 to 3, wherein the passively controllable air control element (800) is designed as a flow deflection element (810) with a bimetal element (811) with a first and second bimetal section (812, 813).

5. The wind turbine rotor blade (200) according to one of claims 1 to 4, wherein the passively controllable air control element (800) is designed as a passively controllable static mixer (820) with a bimaterial element (821), the shape of which depends on temperature.

6. The wind turbine rotor blade (200) according to one of claims 1 to 5, wherein the passively controllable air control element (800) has at least one passively controlled swirl generator (830), wherein the passively controlled swirl generator (830) has a bimaterial element (831) with a first and second bimaterial section (832, 833), the heat expansion coefficients of which differ.

7. The wind turbine rotor blade (200) according to one of claims 1 to 6, wherein the passively controllable air control element (800) has at least a first and second operating position, wherein the passively controllable air control element (800) actively influences the air controller in the first operating position, and the air flow is not influenced in the second operating position.

8. The wind turbine rotor blade (200) according to one of claims 1 to 7, wherein the passively controllable air control element (800) has at least a first and second operating position, wherein the control element does not influence the air flow in the first operating position, and the air control element actively influences the air flow in the second operating position.

9. The wind turbine rotor blade (200) according to one of claims 1 to 8, wherein the at least one passively controllable air control element (800) is arranged along an inner wall of the rotor blade.

10. A wind turbine with at least one wind turbine rotor blade (200) according to one of claims 1 to 9.