WIND TURBINE ROTOR BLADE

Description

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

[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 circulating heated air inside the rotor blade.

[0003] To prevent icing on rotor blades, rotor blade heating is often used. Typically, heated air is introduced into the interior of the rotor blade near the root of the rotor blade. This heated air, in turn, heats the rotor blade shell, for example, near the leading edge, thus de-icing the rotor blade.

[0004] WO 2017 / 021350 A1 shows a wind turbine rotor blade with a rotor blade root region and a rotor blade tip region. Furthermore, at least one web is provided along a longitudinal direction of the rotor blade. A deflection unit for deflecting the air can be provided on the web.

[0005] WO 2018 / 211055 shows a rotor blade of a wind turbine with a rotor blade that has a web and a deflection unit at the rotor blade tip for deflecting heated air. US 2017254316 shows a rotor blade of a wind turbine with a rotor blade heater.

[0006] Therefore, an object of the present invention is to provide a wind turbine rotor blade with an improved rotor blade heater.

[0007] This object is achieved by a wind turbine rotor blade according to claim 1.

[0008] Thus, a wind turbine rotor blade is provided with a rotor blade shell surrounding an internal volume and at least one cross-sectional constriction for narrowing the free cross-section of the internal volume. This constriction can increase the flow velocity, which leads to improved heat transfer and thus better heating of the rotor blades.

[0009] According to the invention, the rotor blade has at least a first and a second web along a longitudinal direction of the rotor blade. Furthermore, a first air duct is provided between a leading edge of the rotor blade and a first web, wherein at least one first cross-sectional constriction is provided in the first air duct.

[0010] According to a further aspect of the present invention, the rotor blade has a second air duct between a web and a rotor blade trailing edge. A second cross-sectional constriction is provided at least partially in the second air duct along the longitudinal direction of the rotor blade.

[0011] According to a further aspect of the present invention, the rotor blade has at least a third cross-sectional constriction in a third air channel between the first and second web.

[0012] According to the invention, the rotor blade has a rotor blade heating system in or at the root of the rotor blade. The rotor blade heating system generates warm air, which is conveyed into the interior volume of the rotor blade.

[0013] The invention also relates to a wind turbine with at least one wind turbine rotor blade as described above.

[0014] Thus, a wind turbine rotor blade is provided with a (two-part) blade shell surrounding an internal volume. The rotor blade further comprises a rotor blade root and a rotor blade tip. A first and second web are provided between the two blade shells along a longitudinal direction of the rotor blade.

[0015] The rotor blade further comprises a rotor blade heater located in the region of the rotor blade root, which conveys heated air into the interior volume of the rotor blade. To improve the effectiveness of the blade heater, at least one cross-sectional constriction is provided in the interior volume, reducing the remaining air volume within the interior volume. Furthermore, the cross-section available for air flow is also reduced. Reducing the free cross-section increases the flow velocity, as the rotor blade heater provides a substantially constant air volume flow. The increased flow velocity results in improved heat transfer to the rotor blade shells, enabling improved rotor blade heating to be achieved by providing the cross-sectional constrictions.

[0016] According to the invention, this results in a reduction of the free cross-sectional area through which the heated air can be transported.

[0017] According to the invention, a web is provided between the two blade shells (pressure side, suction side), creating an air channel in the area of ​​the leading edge of the rotor blade through which the air heated by the rotor blade heater can flow. At least one first cross-sectional constriction is provided in the area of ​​the first channel, at least partially along a longitudinal axis of the rotor blade.

[0018] According to the invention, a second web is provided between the two rotor blade shells, creating a second channel in the area of ​​the rotor blade trailing edge. An optional second cross-sectional constriction can be provided in this second channel, reducing the cross-section of the second channel free for airflow.

[0019] According to one aspect of the present invention, a third channel may be provided at least partially between the first and second webs. Optionally, third cross-sectional constrictions may be provided in the third channel to reduce the free cross-sectional area.

[0020] According to the invention, three first cross-sectional constrictions are provided in the first channel along a longitudinal axis of the rotor blade, wherein a first cross-sectional constriction is provided at a rotor blade length between 10 and 15 m, a second cross-sectional constriction is provided in the region of a rotor blade length of 20 to 25 m and / or a third cross-sectional constriction is provided in the region of a rotor blade length of 30 to 35 m.

[0021] According to the invention, by reducing the free cross-sectional area in a ventilation duct, the flow velocity (which results from the volume flow and the cross-section) is increased. As the flow velocity increases, the heat transfer coefficient α also increases.

[0022] According to the invention, the internal blade flow is changed to improve heat transfer of the heated air from the blade heater to the rotor blade shell.

[0023] The cross-sectional constrictions represent passive possibilities for increasing the flow velocity.

[0024] According to one aspect of the invention, the cross-sectional constrictions can be installed subsequently.

[0025] Further embodiments of the invention are the subject of the subclaims.

[0026] 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, Figs. 2A and 2B show a schematic cross-section and a schematic longitudinal section of a rotor blade according to the prior art, Fig. 3A shows a schematic cross-section of a rotor blade, Fig. 3B shows a schematic longitudinal section of a rotor blade according to Fig. 3A , Fig. 4A shows a schematic cross section of a first section of a rotor blade, Fig. 4B shows a schematic cross section of a section of the rotor blade and a schematic longitudinal section of a rotor blade, Fig. 4C shows a schematic cross section of a section of a rotor blade and a longitudinal section of a rotor blade according to an aspect of the present invention, Fig. 5A shows a graph illustrating a surface temperature of a rotor blade for the Fig. 4A, 4B und 4C shown embodiments, Fig. 5B shows a graph illustrating a heat transfer coefficient α as a function for the three embodiments of Fig. 4A, 4B und 4C , Fig. 5C shows a graph illustrating a heating power L for the embodiments of Fig. 4A, 4B und 4C , and Fig. 6 shows a graph illustrating a fluid temperature for the embodiments of Fig. 4A, 4B und 4C .

[0027] 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 104 and generates electrical energy. The pitch angles of the rotor blades 200 can be changed by pitch motors at the rotor blade roots of the respective rotor blades 200.

[0028] For rotor blade de-icing, a rotor blade heater 500 can be provided in the area of ​​a rotor blade root. Alternatively, the rotor blade heater 500 can be provided in the area of ​​a rotor hub or at a rotor blade connection. The rotor blade heater 500 generates warm air and then directs it into the interior of the rotor blade to de-ice the rotor blade or to prevent icing.

[0029] Fig. 2A shows a cross-section of a rotor blade and Fig. 2B shows a longitudinal section of a rotor blade. The rotor blade 200 has two blade shells 210, 220 surrounding an interior volume 203. The rotor blade 200 further has a rotor blade leading edge 230 and a rotor blade trailing edge 240. Webs 231, 232 can be provided between the blade shells 210, 220, so that the interior volume 203 can be divided into different sections or channels 250, 260, and 270 (first channel 250 between leading edge 230 and first web 231, second channel 260 between trailing edge 240 and second web 232, and third channel 270 between first and second webs 231, 232). The web 231 can, for example, be longer than the web 232.

[0030] Fig. 3A und 3B show a corresponding cross-section of a rotor blade and a longitudinal section of the rotor blade.

[0031] While in the rotor blade according to Fig. 2A und 2B Channels 250, 260 and 270 are shown unchanged, are in the channels according to Fig. 3A und 3B at least partially cross-sectional constrictions 310 in the first channel 250, second cross-sectional constrictions 320 in the second channel 260 and / or optionally third cross-sectional constrictions 330 in the third channel 270 are provided. In Fig. 3B the distribution of the cross-sectional constrictions 310, 320, 330 along a longitudinal axis of the rotor blade is shown.

[0032] Both the cross-sections of the cross-section constrictions and their distribution along the longitudinal axis of the rotor blade can be influenced by the Fig. 3A und 3B shown cross-sections and longitudinal distributions.

[0033] The cross-sectional constrictions result in a higher flow velocity of the air flowing through the rotor blade heater 500 into the interior (into the channels 250, 260, 270) of the rotor blade.

[0034] Fig. 4A shows a schematic cross section of a first channel of Fig. 3A . No cross-sectional constrictions are provided in the first channel 250.

[0035] In Fig. 4B Cross-sectional constrictions are provided in the first channel 250. The distribution of the cross-sectional constrictions is also in Fig. 4B shown in a schematic longitudinal section. The cross-sectional constrictions 310 can be provided, for example, between a rotor blade length or a radius of 20 to 30 m.

[0036] In Fig. 4C A schematic cross-section of a first channel and a schematic longitudinal section of the first channel are shown. The cross-sectional constrictions 310 are according to Fig. 4C at three locations along the rotor blade longitudinal axis, namely at a rotor blade radius of 10 to 15 m, 20 to 25 m and 30 to 35 m.

[0037] In Fig. 4A The case without cross-sectional constrictions is shown, in Fig. 4B is the case with a narrowing of the cross-section and in Fig. 4C An embodiment with three cross-sectional constrictions is shown.

[0038] In Fig. 5A A graph is shown which shows the dependence of the surface temperature on the radius R of the rotor blade for the embodiments of Fig. 4A (S1), Fig. 4B (S2) and Fig. 4C (S3). In the embodiment of Fig. 4A a linear decrease in the surface temperature along the radius R of the rotor blade can be observed. In the second and third embodiments of Fig. 4B und Fig. 4C There are increases in temperature in the area of ​​the cross-sectional constrictions.

[0039] In Fig. 5B The dependence of the heat transfer coefficient α on the radius R is shown. In the embodiment S1 of Fig. 4A No change is visible. In the embodiment S2 of Fig. 4B and S3 of Fig. 4C an increase in the heat transfer coefficient α can be seen in the area of ​​the cross-sectional constrictions.

[0040] In Fig. 5C A heating power L is shown for the above three embodiments S1, S2 and S3. From the Fig. 4 It can be seen that the heating output increases with increasing use of the cross-sectional constrictions.

[0041] In Fig. 6 A dependence of the fluid temperature on the radius R is shown. For the first embodiment S1 of Fig. 4A A linear decrease in fluid temperature is present. In the embodiments S2 and S3, a more pronounced decrease in fluid temperature is shown, with a greater reduction in fluid temperature still present, particularly in the area of ​​the cross-sectional constrictions.

[0042] According to one aspect of the present invention, the cross-sectional constrictions can be used, for example, in channel cross-sections with an area of ​​30,000 mm 2< to 100,000 mm 2<. Bezugszeichenliste

[0043] 100 Wind turbine 102 Tower 104 Nacelle 106 Rotor 110 Spinner 200 Rotor blades 203 Internal volume 210 Blade shells 220 Blade shells 230 Rotor blade leading edge 231 Webs 232 Webs 240 Rotor blade trailing edge 250 Channels 260 Channels 270 Channels 310 Cross-section constrictions 320 Cross-section constrictions 330 Cross-section constrictions 500 Rotor blade heating

Claims

1. A wind turbine rotor blade (200), with a rotor blade shell (210, 220), which envelops an internal volume (203), a rotor blade heating system (500) in or on a rotor blade root (201) of the wind turbine rotor blade (200), wherein the rotor blade heating system (500) generates heated air, and conveys it into the internal volume (203) of the rotor blade (200), a passive flow rate increasing unit in form of at least one cross sectional constriction (300, 310, 320, 330) for narrowing a free cross section of the internal volume (203), and at least one first and second web (231, 232) along a longitudinal axis (L) of the rotor blade (200), a first air channel (250) between a leading edge (230) of the rotor blade (200) and a first web (231), wherein at least one first cross sectional constriction (310) is provided in the first air channel (250), characterized in that the first cross sectional constriction is in three parts and arranged at a rotor blade length (L) of between 10 m to 15 m, of at between 20 m to 25 m and of between 30 m to 35 m.

2. The wind turbine rotor blade (200) according to claim 1, with a second air channel (260) between a web (231, 232) and a rotor blade trialing edge (240), wherein at least one second cross sectional constriction (320) is provided at least partially in the second air channel (260) along the longitudinal direction (L) of the rotor blade (200).

3. The wind turbine rotor blade (200) according to claim 2, with at least one third cross sectional constriction (330) in a third ventilation channel (270) between the first and second webs (231, 232).

4. A wind turbine (100) with at least one wind turbine rotor blade (200) according to one of claims 1 to 3.