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. Prior art solutions can also be found in documents DE 10 2010 051295 A1, US 2015 / 056074 A1, WO 2020 / 165663 A1, and CN 101705921 A.

[0005] It is an object of the present invention to provide a wind turbine rotor blade which enables improved heating of the rotor blade.

[0006] This object is achieved by a wind turbine rotor blade according to claim 1 and by a wind turbine according to claim 6.

[0007] Thus, a wind turbine rotor blade is provided with a rotor blade root, a rotor blade tip, a pressure side and 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 and is then blown into the interior of the rotor blade. An air duct is provided inside the rotor blade. The air duct can have at least two air duct sections, e.g. in the form of air ducts, which are designed at least partially separate from one another. At least one heat exchanger with a first and a second end is provided. The first end of the heat exchanger extends into a first air duct section, while the second end of the heat exchanger projects into a second air duct section. Heat is transferred from one of the air duct sections to the other air duct section by means of the heat exchanger.

[0008] The heat exchanger can be a passive heat exchanger that is able to transfer heat without external energy supply.

[0009] The heat exchanger can be designed as a heat pipe, as a two-phase thermosiphon or as a thermal bridge.

[0010] At least one web or other attachment of the rotor blade can be 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 through an air guide section towards the rotor blade tip, where it is deflected so that the heated air can flow on the other side of the web through another air guide section back from the rotor blade tip area to the rotor blade root area. At least one heat exchanger can be arranged in or on the web or the attachment such that a first end of the heat exchanger protrudes into an air guide section and a second end of the heat exchanger protrudes into an air guide section on the other side of the web. This allows heat to be transferred from the warmer end to the cooler end of the heat exchanger.

[0011] Warm air in one of the air duct sections flows past the first or second end of the heat exchanger and heats the first or second end. The heat in the first or second end is transferred to the second or first end via the heat exchanger (which is designed as a passive heat exchanger). The air flowing past the second or first end of the heat exchanger in the further air duct section then absorbs the heat in the second or first end. This cools the second or first end. Since heat is again supplied from the first or second end of the heat exchanger, the second or first end is heated again and can release this heat back into the air flowing past.

[0012] The heat exchanger can be provided with a web between a first and a second air guide section and can be coupled on one side to the rotor blade inner wall or to a web, so that heat is transferred transversely to the web.

[0013] To improve temperature distribution on the outside of a rotor blade, particularly at low outside temperatures or when ice builds up, a rotor blade heating system is provided, which can be an air heating system. (Several) air duct sections, such as air ducts, can be provided inside the rotor blade. Warm air from the rotor blade heater is blown into one of the air duct sections. The air can have a temperature of ≥ 70° C. The heated air is guided along the first air duct section from the rotor blade root to the rotor blade tip. The at least partially cooled air can then be directed back towards the rotor blade root via a second air duct section.To improve heat distribution, particularly along the rotor blade wall, at least one heat exchanger is provided, allowing heat transfer from one air duct section to another. This preferably occurs without mass transfer. Heat transfer can occur through thermal bridges.

[0014] The rotor blade may have at least one bypass in the web to allow air flow from one air guide section through the web to another air guide section.

[0015] The heat exchanger, as a passive heat exchanger, can be designed as a heat pipe or as a thermal bridge, for example, in the form of highly thermally conductive materials. Such materials can be copper or aluminum, for example. The heat exchangers have a first and a second end, with one end extending into the first air guide section and the second end extending into the second air guide section.

[0016] The advantage of heat exchangers is that they have a small cross-sectional area, and the provision of such a heat exchanger in a rotor blade web only results in a slight reduction in the web's mechanical stability. In contrast, bypasses can compromise the web's mechanical stability, as several holes in the web are required to create a bypass.

[0017] Thus, a heat exchanger with a small cross-sectional area is provided.

[0018] By locating the heat exchangers inside the rotor blade, the efficiency of the rotor blade heating can be significantly improved. In particular, local control of heat distribution can be improved.

[0019] According to one aspect of the present invention, in addition to the heat exchangers, at least one bypass can also be provided in or on the web.

[0020] Optionally, the heat exchanger can have a surface enlargement (for example, in the form of a ribbed structure). The surface enlargement can be provided at the first and / or second end. The surface enlargement can improve heat transfer.

[0021] The heat exchanger can be designed as a passive heat transport unit for heat transport from one end to the other end.

[0022] Further embodiments of the invention are the subject of the subclaims.

[0023] 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, and Fig. 3 shows a schematic sectional view of a rotor blade of a wind turbine of Fig. 1 according to a second embodiment.

[0024] Fig. 1shows 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.

[0025] Fig. 2 shows a schematic section of the rotor blade of the wind turbine from Fig. 1According to a first exemplary embodiment, the rotor blade 200 has a length 201, 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 first, second, and / or third air guide section 420, 430, 440. The air guide sections 420, 430, 440 can be separated from one another by elements of the rotor blade (e.g., webs 410), at least partially along the length 201 of the rotor blade 200. A rotor blade heater 300 can be provided in the region of the rotor blade root 210. The rotor blade heater 300 may include a fan 320 and a heater 310 and generate warm air that may be directed into the interior 203 of the rotor blade 200.

[0026] The rotor blade heater 300 can be integrated into the rotor blade or provided outside the rotor blade.

[0027] 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 guide 400 or is already present for other reasons, and the air guide 400 merely represents a secondary function. Optionally, more than one web can be provided. The webs 411, 412 can at least partially separate the first, second, and / or third air guide sections 420, 430, 440 from one another.

[0028] The air heated by the rotor blade heater 300 can be guided in the third air guide section 440 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. The heated air can then be guided along the first or second air guide section 420, 430 to the rotor blade root. For this purpose, a deflection section 221 can be present 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.

[0029] 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 heater 210, or the heated air is supplied to the rotor blade 200 in the area of ​​the rotor blade root 210.

[0030] At least one heat exchanger 500 can be provided along the length L of the rotor blade 200 in the air duct 400. The heat exchanger 500 has a first and a second end 510, 520. The first and second ends 510, 520 of the heat exchanger 500 are provided in different air duct sections 420, 430, 440 and can thus transfer heat from one air duct section to another. This is advantageous because it can lead to improved mixing of the air flow.

[0031] Fig. 3shows 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, which extends 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 heat exchanger 500 with a first and second end 510, 520.

[0032] The heat exchanger 500 can be configured as a heat pipe or as a rod made of a highly thermally conductive material (e.g., copper or aluminum). The heat exchanger 500 is characterized by its small cross-sectional area and the fact that it does not require an opening in the web. The heat exchanger 500 can be integrated during the manufacture of the web 410. Alternatively, a bore or opening can be provided in the web 410, and the heat exchanger 500 can be subsequently inserted after the web has been manufactured, and, for example, after the rotor blade has been manufactured with the web.

[0033] The heat exchanger 500 has a first and second end 510, 520. A first end 510 extends into a first air guide section, and a second end 520 extends into a further air guide section separated from the air guide section with the first end by a web 410 or another attachment. The heat exchanger 500 serves to transfer heat from one end to its other end. Warm air heated by the rotor blade heater 300 flows past the first or second end 510, 520 of the heat exchanger 500 and heats the heat exchanger 500. The heat then spreads to the other (second or first) end 520, 510 and heats the second or first end 520, 510 accordingly. Air flowing past the second (or first) end 520, 510 can absorb heat from the second end 520.The second end 520 of the heat exchanger 500 thus leads to a heating of the air which passes through the further air guide section.

[0034] Air heated by the rotor blade heater 300 flows along a first air guide section from the rotor blade root to the rotor blade tip, is deflected there, and then flows into another (second) air guide section back toward the rotor blade. In the first air guide section, the air heats the outer wall of the rotor blade, at least in those areas where the air flows past an outer wall of the rotor blade. This leads to a cooling of the heated air. In other words, air arriving in the area of ​​the rotor blade tip will thus be colder than the air heated directly by the rotor blade heater. The air flowing from the rotor blade tip along the first air guide section to the rotor blade tip continuously decreases in temperature and thus heats the wall of the rotor blade.The air, which then flows from the rotor blade tip through a further air guide section towards the rotor blade root, has a low temperature. To increase the temperature in the further air guide section, the heat exchanger can be provided in or on the web such that its first end extends into a first air guide section and its second end into the second air guide section. The air heated by the rotor blade heater flows past the first end and heats the first end. The heat in the first end then spreads towards the second end. Thus, the air flowing back along the further air flow section can be further heated, at least locally, by the heat exchanger. This makes it possible to achieve a more even temperature distribution between the air guide sections.

[0035] A heat exchanger can be deployed at specific locations to reduce a local temperature increase in an area. A heat exchanger can also be provided to compensate for a local temperature drop.

[0036] The heat exchanger can be designed as a heat pipe, a two-phase thermosyphon, or a thermal bridge. A thermal bridge can, for example, be a rod made of a highly thermally conductive material (e.g., copper or aluminum). Other non-metallic, highly thermally conductive materials are also possible. This is advantageous because, due to lightning protection issues, it makes sense to avoid metal in the rotor blade as much as possible.

[0037] In addition to the heat exchangers 500, at least one bypass 600 can be provided in or on one of the webs.

[0038] The solution according to the invention can be applied in particular to rotor blades of a wind turbine which have a great length and a smaller internal cross-section. List of reference symbols

[0039] 100 Wind turbine 102 Tower 104 Nacelle 106 Rotor 110 Spinner 200 Rotor blades 201 Length 202 Wall 203 Inside of the rotor blade 210 Rotor blade root 220 Rotor blade tip 221 Deflection section 230 Leading edge 240 Trailing edge 250 Pressure side 260 Suction side 300 Rotor blade heater 310 Heater 320 Fan 400 Air duct 410 Web 411 Web 412 Web 420 First air duct section 430 Second air duct section 440 Third air duct section 500 Heat exchanger 510 First end 520 Second end 600 Bypass L Longitudinal 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), an air guide (400) for heated air to guide heated air inside of the rotor blade (200) and at least partially 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 wherein the air guide (400) has at least one first and a second air guide section (420, 430, 440) separated from each other, at least one heat exchanger (500) with a first and second end (510, 520), wherein the first end (510) of the heat exchanger (500) protrudes into the first air guide section (420, 430, 440), and the second end (520) protrudes into the second air guide section (420, 430,4 40), so as to convey heat from one of the air guide sections (420, 430, 440) to another air guide section (420, 430, 440), wherein the heat exchanger (500) is configured as a passive heat exchanger, which is capable of conveying heat from one end (510) to the other end (520) without any energy being supplied from outside, wherein the heat exchanger (500) is configured as a heat pipe or as a two-phase thermosyphon.

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 at least partially between the pressure side (250) and the suction side (260), and extends at least partially along the longitudinal direction (L) of the rotor blade (200) and separates at least two air guide sections (420, 430, 440) from each other, wherein at least one heat exchanger (500) is arranged in or on the at least one web (410), in particular essentially perpendicularly.

3. The wind turbine rotor blade (200) according to one of claims 1 to 2, further with at least one bypass (600) in a web (410, 411) for coupling the first with the second air guide section (420, 430, 440), wherein the at least one bypass (600) allows air to flow from one air guide section through the bypass (600) in the web (410, 411) to another air guide section (420, 430, 440).

4. The wind turbine rotor blade (200) according claim 3, wherein the heat exchanger (500) is made out of a thermally conductive material, in particular metal.

5. The wind turbine rotor blade (200) according to one of claims 1 to 4, further with a rotor blade heater (300) in the area of the rotor blade root (210), which is configured to guide heated air into an interior (203) of the rotor blade (200).

6. A wind turbine, with at least one wind turbine rotor blade (200) according to one of claims 1 to 5.