Method for arranging wind turbine blades during offshore wind turbine assembly

Abstract

The application discloses a method for arranging wind turbine blades during the transportation of a complete wind turbine at sea, the wind turbine blades comprising a first blade, a second blade and a third blade, characterized by the following steps: S1: rotating the first blade to a horizontal position and setting the pitch angle of the first blade to a feathered or near feathered state; S2: setting the geometric angle of attack of the second blade to a small positive angle of attack, about 1°, and the geometric angle of attack of the third blade to a small negative angle of attack, about -1°; S3: fine-tuning the third blade by using CFD simulation and / or wind tunnel test, so that the total torque of the first blade, the second blade and the third blade is zero. The application rotates the wind turbine rotor, arranges one of the blades to a horizontal position, and adjusts the pitch angle of each blade to eliminate the large torque generated by high wind pressure, thereby greatly reducing the load of the locking device and realizing the safe transportation of the complete wind turbine under high speed and high wind conditions.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of offshore wind turbine whole machine transportation wind turbine blade, and provides a wind turbine whole machine transportation wind turbine blade arrangement method. BACKGROUND

[0002] Compared with land, offshore wind resources are more abundant, but offshore wind power is limited by the installation and transportation of wind turbines. The development of offshore wind power is affected by complex construction, sea conditions, short operation window period and other unfavorable factors, so that efficient and safe construction methods have always been concerned by the industry. In the traditional offshore wind turbine blade transportation, the blades are usually placed horizontally in single layer or stacked in multiple layers, and then installed on the sea after reaching the installation site, which is low in installation efficiency and has great safety hazards.

[0003] Another is to use the whole machine transportation and installation method of the wind turbine. The assembly and testing of the wind turbine are first completed on land, and then the whole machine is transported and installed on the whole machine transportation and installation ship, which directly sails to the wind farm for installation. This method not only makes the offshore wind turbine installation more efficient, but also reduces the sea operation time, thereby reducing the operation risk. Due to its high efficiency and safety, the whole machine transportation and installation has gradually attracted attention in the industry and related technologies have been developed. Among them, high-speed offshore transportation of the whole machine will be an important part of efficient offshore installation of the whole machine.

[0004] Based on the transportation safety consideration, the wind turbine blades will be locked during the whole machine transportation process. However, under high speed and high wind conditions, the wind turbine blades will bear high wind pressure and generate large torque. Once the blade load exceeds the limit of the locking device, the blade will rotate and cannot be locked, which is not conducive to the safety of navigation. SUMMARY

[0005] The present application aims to overcome at least one of the above-mentioned defects of the prior art, and provides a wind turbine whole machine transportation wind turbine blade arrangement method, which can eliminate the large torque generated by high wind pressure and improve the transportation efficiency and safety.

[0006] Specifically, the present application provides a wind turbine whole machine transportation wind turbine blade arrangement method, wherein the wind turbine blade includes a first blade, a second blade and a third blade. The method comprises the following steps: S1: rotating the first blade to a horizontal position and setting the pitch angle of the first blade to a feathering or near feathering state; S2: setting the geometric angle of attack of the second blade to a small positive angle of attack, about 1°, and the initial geometric angle of attack of the third blade to a small negative angle of attack, about -1°; the absolute value of the positive angle of attack is equal to the absolute value of the negative angle of attack;

[0007] S3: fine-tuning the initial geometric angle of attack of the third blade by using CFD simulation and / or wind tunnel test, so that the total torque of the first blade, the second blade and the third blade is zero.

[0008] The wind turbine blade is generally three pieces at present; it is installed on land first and transported as a whole. The first blade, the second blade and the third blade are not the fixed definition of each wind turbine blade, but only represent the naming of the blade in the specified position, which cannot limit the protection scope of the application.

[0009] The operation details of the wind turbine blade arrangement are as follows: firstly, one of the three blades of the wind turbine waiting for transportation and standing vertically on the deck is rotated to the horizontal position. The blade is defined as the first blade; the pitch angle of the first blade arranged in the horizontal position is set to the feathering state or close to the feathering state. The other two blades are the second blade above and the third blade below, both of which are not in the horizontal position. The geometric angle of attack of the second blade and the third blade is set to be mirror-symmetric to the first blade arranged horizontally, and the geometric angle of attack of the third blade is finely adjusted, so that the torque of each blade of the wind turbine can be mutually cancelled. The actual setting of the geometric angle of attack of the second blade and the third blade is further determined by CFD simulation and / or wind tunnel test. Generally, the second blade is maintained at a geometric angle of attack of ±1°, and the final geometric angle of attack of the third blade is set to be in the range of ±5°.

[0010] When the pitch angle is finely adjusted by using CFD simulation and / or wind tunnel test, the blade arranged in the lower position is finely adjusted under the condition that the highest speed is in the wind at the highest wind speed, and the pitch angle is finally adjusted to make the total torque of the wind turbine zero by changing the pitch angle around the radial axis. In principle, the fine adjustment can be made for the second blade above or the first blade in the horizontal position, but the blade above the position is in a high wind speed environment, and the torque offset is more sensitive to the pitch angle, which makes the fine adjustment of the pitch angle more accurate and difficult. The third blade below is closer to the sea surface and has a lower wind speed, and the torque offset is relatively less sensitive to the pitch angle, so a greater change of the pitch angle is needed to generate the corresponding torque offset, which makes it easier to fine-tune the pitch angle of the third blade. Therefore, the third blade is preferably finely adjusted by using CFD simulation and / or wind tunnel test.

[0011] More specifically, the feathering state in step S1 is a state in which the pitch angle of the first blade reaches zero lift and the torque is very small.

[0012] The feathering setting is related to the three-dimensional geometric structure of the wind blade. Different products have different settings. Generally, it needs to be found from the product technical documents of the wind turbine manufacturer. Therefore, through the technical documents, the feathering setting can be made for the first blade of the wind turbine to maintain a state with very small torque.

[0013] If the fan manufacturer lacks the method of setting the precise pitch angle of the feathering, the step S1 can be replaced by setting the chord line of the section of the first blade parallel to the wind direction, i.e. the geometric angle of attack of the first blade is zero.

[0014] For the blade whose pitch angle is not uniformly distributed along the radial direction of the blade, the zero geometric angle of attack setting can be set according to the average geometric angle of attack along the radial direction of the blade being zero.

[0015] Preferably, in the step S2, the second blade and the third blade are mirror-symmetrically set with the first blade as the central axis.

[0016] Since the second blade and the third blade are not in the horizontal position, the present application adopts an upper and lower fan blade placement design, and more preferably, the pitch angle of the second blade and the third blade is set by mirror-symmetry with the first blade placed in the horizontal position, wherein the upper blade, i.e. the second blade, is a positive angle of attack, and the lower blade, i.e. the third blade, is a negative angle of attack, and a small attack angle of about 1° is generally sufficient; the attack angles of the upper and lower blades can also be set in opposite directions, which is basically effective for any wind speed.

[0017] Further, the fine-tuning process of the step S3 is mainly for adjusting the third blade; the CFD simulation and / or wind tunnel test fine-tuning includes the following steps:

[0018] A1: simulate and / or measure the total torque of the fan under the condition of the highest cruising speed and the highest wind speed; A2: if the total torque is zero, the fine-tuning is completed; if not, proceed to step A3; A3: if the total torque is the clockwise torque, fine-tune the negative angle of attack of the third blade to -1°-δ°; if the total torque is the counterclockwise torque, fine-tune the negative angle of attack of the third blade to -1°+δ°. Repeat the trial and error until the δ° that makes the total torque of the fan zero is obtained.

[0019] Further, in the step A3, the fine-tuning method of the third blade is to change the pitch angle by rotating around the radial axis to adjust the δ° that makes the total torque of the fan zero.

[0020] In summary, the whole fan blade setting operation includes: firstly, setting the three-blade fan into the initial setting state, i.e. the first blade is in the horizontal position, and the second blade and the third blade are not in the horizontal position, the second blade and the third blade are symmetrically set in the horizontal position blade, and the pitch angle of the blade is set. Then, the total torque of the fan under the condition of the highest sailing speed and the highest wind speed is simulated by using CFD or wind tunnel test; if the total torque is detected to be zero, the fine adjustment is completed, if the total torque does not reach the requirement of zero torque, the complementary adjustment in the opposite direction is made according to the direction of the total torque. That is, if the total torque is the clockwise torque, the negative attack angle of the lower blade is increased to -1°-δ°, if the total torque is the counterclockwise torque, the negative attack angle of the lower blade is decreased to -1°+δ°. Through repeated trial and error, δ° is obtained, and the pitch angle of the third blade is set accordingly.

[0021] Compared with the prior art, the present application has the following beneficial effects:

[0022] By rotating the fan rotor, setting one blade to the horizontal position, and adjusting the pitch angle of each blade, the large torque generated by high wind pressure can be eliminated, the load of the locking device can be greatly reduced, and the safe transportation of the whole fan under high sailing speed and high wind condition can be realized.

[0023] Meanwhile, the method of the present application can be applied to transportation under different wind conditions, i.e. it is suitable for any direction and wind speed, and has high practical value.

[0024] When the wind direction is oblique, the oblique wind speed can be decomposed into two components, i.e. a vertical rotor speed and a parallel rotor speed. The mechanism of torque cancellation for the vertical rotor speed is as described above; for the parallel rotor speed, the setting of the wind blade is symmetric about the parallel speed, so that the approximately cancelled torque can still be generated.

[0025] Moreover, the adjustment of the pitch angle of the present application combines the possible highest sailing speed and the highest wind speed during transportation; the setting of the wind blade can ensure the safe transportation of the whole fan under the most severe working condition. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 Figure 1 is a setting diagram of the fan blade for the whole fan transportation.

[0027] Figure 2 Figure 2 is another display diagram of the setting of the fan blade for the whole fan transportation.

[0028] Figure 3 Figure 3 is another display diagram of the A-A cross-section definition of the setting of the fan blade for the whole fan transportation.

[0029] Figure 4 Figure 4 is a schematic diagram of the setting of the fan blade for the whole fan transportation. Figure 3Cross-sectional geometry definition of middle blade A-A.

[0030] Figure 5 Explanation diagram of torque cancellation mechanism for headwind condition.

[0031] Figure 6 Wind speed decomposition diagram for crosswind condition.

[0032] Figure 7 Explanation diagram of torque cancellation mechanism for parallel wind turbine wind speed component.

[0033] Figure 8 Lift of blades at different angles of attack for different blade geometries. DETAILED DESCRIPTION

[0034] The accompanying drawings, which are included to provide a further understanding of the embodiments of the application and are incorporated in and constitute a part of this application, illustrate embodiments of the application and together with the description serve to explain the principles of the application. In the drawings:

[0035] It should be noted that, if the application embodiments have directionality indication (such as up, down, left, right, front, back, etc.), the directionality indication is only used to explain the relative position relationship, movement condition, etc. between components in a certain posture (as shown in the drawings), if the certain posture changes, the directionality indication also changes accordingly.

[0036] In addition, if the application embodiments have descriptions of "first", "second", etc., the descriptions of "first", "second", etc. are only for description purposes, and cannot be understood as indicating or implying the relative importance of the indicated technical features or implicitly indicating the number of the indicated technical features. Therefore, the features limited by "first", "second" can explicitly or implicitly include at least one of the features. In addition, the technical solutions of each embodiment can be combined with each other, but it must be based on the realization of ordinary skilled in the art, when the combination of technical solutions appears contradictory or unachievable, it should be considered that the combination of technical solutions does not exist, nor within the protection scope required by the application.

[0037] EMBODIMENT

[0038] The embodiment provides a method for arranging wind turbine blades in the transportation of a whole offshore wind turbine. As shown in Figure 1As shown, the wind turbine includes a first blade 1, a second blade 2, a third blade 3, and a tower 4; the rotation of the wind turbine generates a circular impeller 5; combined with... Figures 2-4 As shown, each blade has a radial axis 6, a blade section 7, and a blade section chord 8. The pitch angle θ1 is the angle between the blade section chord 8 and the geometric baseline of the blade section at radius r. The geometric angle of attack θ2 is the angle between the incoming wind direction and the blade section chord 8. Figure 5 As shown, the upward resultant force generated by the wind pressure of the second blade 2 in the windward direction under a small positive angle of attack setting is F1; the downward resultant force generated by the wind pressure of the third blade 3 in the windward direction under a small negative angle of attack setting is F2; ​​the minute resultant force generated by the wind pressure of the first blade 1 in the windward direction under a feathering setting is F3; the torque Tau1 generated by the upward resultant force of the second blade 2 in the windward direction under a small positive angle of attack setting; the torque Tau2 generated by the downward resultant force of the third blade 3 in the windward direction under a small negative angle of attack setting; the torque Tau3 generated by the minute resultant force of the first blade 1 in the windward direction under a feathering setting; as... Figure 6 As shown, the wind speed in the diagonal wind direction is V1; the wind speed component perpendicular to the wind rotor 5 in the diagonal wind direction is V11, and the wind speed component parallel to the wind rotor 5 in the diagonal wind direction is V12; as... Figure 7 As shown, the downward resultant force generated by the wind speed component parallel to the wind turbine 5 on the second blade 2 is F4; the upward resultant force generated by the wind speed component parallel to the wind turbine 5 on the third blade 3 is F5; the torque generated by the wind speed component parallel to the wind turbine 5 on the second blade 2 is Tau4; and the torque generated by the wind speed component parallel to the wind turbine 5 on the third blade 3 is Tau5.

[0039] The process of setting up the display is as follows:

[0040] like Figure 1 As shown, one of the blades of the three-bladed wind turbine, namely the first blade 1, is rotated to a horizontal position first.

[0041] The first blade 1 is then set to feathering configuration: The pitch angle of the first blade 1, which is placed in a horizontal position, is then set to feathering. The feathering state of the wind turbine of this invention refers to the state where the pitch angle of the first blade 1 reaches zero lift and the torque is very small.

[0042] It should be noted that the feathering setting described in this invention is related to the three-dimensional geometry of the wind turbine blades. Different products will have different settings. The setting of the feathering pitch angle can be found in the product technical documents of the wind turbine manufacturer. Figure 8 The figure shows the lift of the blades at different angles of attack for different blade geometries. The zero-lift setting of the blades can be directly obtained from the figure.

[0043] In the absence of accurate pitch angle setting method for the fan manufacturer, the setting of the pitch angle can be approximately set to the chord line 8 of the blade section 7 parallel to the wind direction, i.e. the geometric angle of attack θ2 is zero. However, since the pitch angle is generally not uniformly distributed along the radial direction of the blade, the setting of the pitch angle of the present application is to set the average geometric angle of attack θ2 along the radial direction of the blade to zero. The setting of the pitch angle is basically in the range of the geometric angle of attack θ2 near zero, as shown in Figure 8 To accurately find the pitch angle of the zero-lift blade, numerical simulation or experimental debugging in the range near the zero geometric angle of attack is generally required to determine.

[0044] Pitch angle setting of the second blade 2 and the third blade 3: the other two blades not in the horizontal position, one above and one below, are the second blade 2 and the third blade 3; the first blade 1 is used as a mirror image to set the geometric angle of attack θ2 of the second blade 2 to a positive angle of attack of 1°; and the geometric angle of attack θ2 of the third blade 3 to a negative angle of attack of -1°.

[0045] Fine adjustment of the angle of attack of the third blade 3: further use CFD simulation or wind tunnel test simulation and / or measurement of the total torque of the fan under the condition of the highest speed and the highest wind speed; check whether the total torque has been eliminated; if yes, the fine adjustment is completed; if not, further fine adjustment of the angle of attack θ2 of the third blade 3 according to the direction and size of the total torque; if the total torque is a clockwise torque, fine adjustment of the negative angle of attack θ2 of the third blade to -1°-δ°; if the total torque is a counterclockwise torque, fine adjustment of the negative angle of attack θ2 of the third blade to -1°+δ°. Repeat the trial and error until the δ° that makes the total torque of the fan zero is obtained. Here, the actual operation of adjusting the angle of attack θ2 of the third blade 3 is achieved by changing the pitch angle θ1 of the blade around the radial axis 6.

[0046] To illustrate the effectiveness of the present application, the mechanism thereof is described as follows:

[0047] The first blade 1 of the three-blade fan wheel 5 is rotated to the horizontal position, and the blade angles are placed in order, i.e. the first blade 1 placed in the horizontal position is set to the approximate feathering state, and the other two blades not in the horizontal position, one above and one below, are the second blade 2 and the third blade 3, the second blade 2 is a positive angle of attack, and the third blade 3 is a negative angle of attack.

[0048] After setting the pitch angle of each blade according to the above steps, under the action of the incoming wind, the forces F1, F2, F3 and torques Tau1, Tau2, Tau3 on each blade will be approximately as shown in Figure 5The distribution of the blades. Fine-tuning of the third blade 3 using CFD simulation (or wind tunnel testing) aims to give it a force capable of counteracting the torques of the first blade 1 and the second blade 2. While fine-tuning could theoretically be done on either the second blade 2 or the first blade 1, the third blade 3, being closer to the sea surface and operating at lower wind speeds, is less sensitive to pitch angle interference. Therefore, a larger adjustment to the pitch angle is needed to generate the corresponding torque, making fine-tuning easier. Conversely, the second blade 2, operating at high wind speeds, is more sensitive to pitch angle interference, requiring more precise and complex adjustments. Therefore, it is preferable to adjust the lower third blade 3.

[0049] The above-described method for arranging wind turbine blades is applicable to winds coming from any direction. In principle, for a given wind direction and speed, the optimal pitch angle setting to counteract the torque can be found. However, the final pitch angle setting will be based on the condition of maximum wind speed and maximum wind speed facing the wind, i.e., when the relative wind speed experienced by the wind turbine is at its maximum, to ensure the optimal setting under the worst-case scenario.

[0050] The mechanism by which this method remains approximately effective even when the wind direction is oblique can be explained by... Figure 6 Please explain. For example... Figure 6 As shown, the wind speed in the oblique direction can be decomposed into two components: the wind speed of a vertical wind turbine 5 and the wind speed of a parallel wind turbine 5. For the wind speed of the vertical wind turbine 5, the mechanism for canceling the torque generation is as described above. For the wind speed of the parallel wind turbine 5, because the arrangement of the blades in this invention is symmetrical about the parallel wind turbine wind speed, approximately canceling torque can still be generated, and the mechanism is as follows... Figure 7 As shown, the forces of the second blade 2 and the third blade 3 are opposite and their torques cancel each other out.

[0051] The above embodiments are merely illustrative of the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to the preferred embodiments above, those skilled in the art should understand that modifications or equivalent substitutions to the technical solutions of the present invention should not depart from the spirit and scope of the present invention. Those skilled in the art can also make other changes within the spirit of the present invention and use them in the design of the present invention, as long as they do not deviate from the technical effects of the present invention. These changes made according to the spirit of the present invention should all be included within the scope of protection claimed by the present invention.

Claims

1. A method of arranging the transport of a wind turbine blade for an offshore wind turbine, the wind turbine blade comprising a first blade (1), a second blade (2) and a third blade (3); characterized in that, Comprising the following steps: S1: rotate the first blade (1) to a horizontal position, and set the pitch angle of the first blade (1) to feather or near feather state; The feather state is the state that the pitch angle of the first blade (1) reaches zero lift, the torque tends to zero, and the chord line of the cross section of the first blade (1) is parallel to the wind direction; S2: set the geometric angle of attack of the second blade (2) to positive attack angle, and the geometric angle of attack of the third blade (3) to negative attack angle, the absolute value of the positive attack angle and the absolute value of the negative attack angle are equal; The second blade (2) and the third blade (3) are mirror symmetric with the first blade (1) as the central axis; the geometric angle of attack of the second blade (2) is 1°; the geometric angle of attack of the third blade (3) is -1°±δ°; wherein, δ° is determined by CFD simulation and / or wind tunnel test; S3: fine-tune the third blade (3) by CFD simulation and / or wind tunnel test, so that the total torque of the first blade (1), the second blade (2) and the third blade (3) is zero; CFD simulation and / or wind tunnel test fine-tuning Comprising the following steps: A1: simulate and / or measure the total torque of the wind turbine under the condition of the highest cruising speed and the highest wind speed against the wind; check whether the total torque is zero; A2: if yes, the fine-tuning is completed; if no, go to step A3; A3: if the total torque is clockwise torque, fine-tune the negative attack angle of the third blade (3) to -1°-δ°; if the total torque is counterclockwise torque, fine-tune the negative attack angle of the third blade (3) to -1°+δ°; the fine-tuning mode of the third blade (3) is to change the pitch angle by rotating around the radial axis, and finally adjust δ° to make the total torque of the wind turbine zero.

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