CN114562427A

CN114562427A - Offshore wind turbine

Info

Publication number: CN114562427A
Application number: CN202210157955.2A
Authority: CN
Inventors: 周腾; 秦志文; 蔡畅; 孙香宇; 李庆安; 张一楠
Original assignee: Institute of Engineering Thermophysics of CAS
Current assignee: Institute of Engineering Thermophysics of CAS
Priority date: 2022-02-21
Filing date: 2022-02-21
Publication date: 2022-05-31

Abstract

The invention provides an offshore wind turbine, which comprises an offshore wind turbine tower, a cabin and a sound absorption coating, wherein the offshore wind turbine tower is partially arranged at the lower part of the sea level, the sound absorption coating is coated on the periphery of the offshore wind turbine tower arranged at the lower part of the sea level, and the sound absorption coating can absorb noise transmitted to the sea water by the offshore wind turbine tower. By arranging the sound absorption coating, the noise transmitted to the water by the offshore wind turbine can be reduced, so that the noise energy entering the water is reduced, and the noise amplitude in the water is reduced.

Description

Offshore wind turbine

Technical Field

The specification relates to the technical field of wind turbines, in particular to an offshore wind turbine.

Background

In order to reduce carbon emission and environmental pollution and realize sustainable development, the proportion of renewable energy in energy structures of various countries is increased year by year. Wind energy is a renewable energy form, has the advantages of low development cost, mature technology, wide energy distribution and the like, and is a key development direction of renewable energy. In recent years, offshore wind power gradually becomes the research focus of the wind power generation industry due to the characteristics of abundant wind resources, high wind resource quality, proximity to high power utilization areas and the like in offshore areas.

The existing research shows that the construction and operation of the offshore wind turbine can also cause certain influence on the surrounding environment. Whether the offshore wind turbine is a fixed type or a floating type, because a part of the tower drum is submerged below the sea level, noise generated in the operation process of the wind turbine can be transmitted into water through the tower drum, and therefore the survival of marine organisms is adversely affected. Previous researches show that the offshore wind turbine generates strong noise in the piling construction and operation processes, and the noise can cause abnormal phenomena of unsmooth communication, avoidance behaviors, anorexia, hearing impairment and the like of peripheral marine organisms. In some areas, it has been found that wind turbine underwater noise can lead to reduced production of surrounding economic fish. Therefore, the underwater noise control method has important significance for the vigorous development of offshore wind power generation.

In the past, the research on the noise of the wind turbine is mostly started from the aspect of aerodynamic noise of a wind turbine blade, and the generation mechanism and the control method of the aerodynamic noise are mainly studied. However, previous researches show that the aerodynamic noise of the blade is hardly transmitted into water due to the abrupt change of the medium density between the air and the sea level, the underwater noise generated by an offshore wind turbine mainly comes from impact noise during piling or mechanical noise in a cabin during running, and the control effect of reducing the aerodynamic noise of the blade on the noise is very limited. In order to reduce the transmission of underwater noise of the wind turbine, measures need to be taken in two aspects of reducing cabin noise or blocking the transmission of the noise from the tower to the water.

Disclosure of Invention

In view of this, the embodiments of the present specification provide an offshore wind turbine. The purpose of reducing noise energy entering water and reducing noise amplitude in water is achieved by reducing the absorption effect of the offshore wind turbine on the noise propagating to water.

The embodiment of the specification provides the following technical scheme:

the utility model provides an offshore wind turbine, includes offshore wind turbine tower section of thick bamboo and sound absorption coating, and the lower part at sea level is arranged in to offshore wind turbine tower section of thick bamboo part, and the sound absorption coating cladding is in the periphery of the offshore wind turbine tower section of thick bamboo of arranging the lower part at sea level in, and the sound absorption coating can absorb the noise that the offshore wind turbine tower section of thick bamboo propagated to sea water.

Furthermore, a plurality of cavity-shaped cellular units are arranged inside the sound absorption cladding.

Further, a plurality of cell units are uniformly distributed inside the sound absorption cover.

Further, the cavity of unit cell has big footpath end and path end, and the big footpath end orientation is kept away from tower section of thick bamboo direction and is set up, and the path end is towards the marine wind turbine tower section of thick bamboo setting.

Further, the shape of the cavity of the unit cell includes a cone shape, a truncated cone shape, or a trumpet shape.

Further, the sound absorbing cladding is greater than 12 centimeters thick; the radius of the large-diameter end is 1.5cm-3 cm; the radius of the small-diameter end is 1cm-1.5 cm; the length of the cellular unit is 5cm to 10 cm; the distance between two adjacent unit cells is less than 3 times of the length of the unit cell.

Further, the cavity shape of the unit cell includes a cylindrical shape, a circular shape, or a spiral shape.

Further, the sound absorption coating is made of one or more of nitrile rubber, hydrogenated nitrile rubber and carboxyl nitrile rubber.

Further, the density of the nitrile rubber was 1200kg/m³-1300kg/m³The Young modulus of the nitrile rubber is 28MPa-32 MPa.

Further, the material for the sound-absorbing covering includes polyurethane.

Compared with the prior art, the embodiment of the specification adopts at least one technical scheme which can achieve the beneficial effects that at least:

in the case of a substantially low frequency of noise generated by an offshore wind turbine, the sound pressure level drops significantly after passing through the underwater noise reduction coating. After the underwater noise reduction coating is installed, the far-field sound pressure level in water is 5-12dB lower than that without the sound absorption coating. The invention has simple structure and simple installation mode. The sound absorption effect only depends on the design of the cavity, and the sound absorption effect is independent of the size of the offshore wind turbine and has wide application range.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

FIG. 1 is a schematic view of the installation of the acoustical layer of the present invention on an offshore wind turbine;

FIG. 2 is a diagram of the position of the sound absorbing layer of the present invention in relation to the tower of a wind turbine;

FIG. 3 is a cross-sectional view of a portion of a radial plane of the first embodiment of the present invention;

FIG. 4 is a cross-sectional view of a portion of a radial plane of the first embodiment of the present invention;

FIG. 5 is a graph of sound absorption coefficient and wavelength for a first embodiment of the present invention;

FIG. 6 is a graph of the variation of the underwater far field noise sound pressure level along the depth of water for the first embodiment of the present invention;

FIG. 7 is a cross-sectional view of a portion of a radial face of a second embodiment of the present invention;

FIG. 8 is a cross-sectional view of a portion of a radial plane of a third embodiment of the present invention;

FIG. 9 is a cross-sectional view of a portion of a radial plane of a fourth embodiment of the present invention;

FIG. 10 is a cross-sectional view of a portion of a radial plane of a fifth embodiment of the present invention;

fig. 11 is a cross-sectional view of a portion of a radial plane of a sixth embodiment of the present invention.

Description of reference numerals: 1. a nacelle; 2. a tower drum; 3. sea level; 401. a sound absorbing cladding; 402. a unit of cells.

Detailed Description

The embodiments of the present application will be described in detail below with reference to the accompanying drawings.

The following embodiments of the present application are described by specific examples, and other advantages and effects of the present application will be readily apparent to those skilled in the art from the disclosure of the present application. It is to be understood that the embodiments described are only a few embodiments of the present application and not all embodiments. The present application is capable of other and different embodiments and its several details are capable of modifications and/or changes in various respects, all without departing from the spirit of the present application. It is to be noted that the features in the following embodiments and examples may be combined with each other without conflict. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

It is noted that various aspects of the embodiments are described below within the scope of the appended claims. It should be apparent that the aspects described herein may be embodied in a wide variety of forms and that any specific structure and/or function described herein is merely illustrative. Based on the present application, one skilled in the art should appreciate that one aspect described herein may be implemented independently of any other aspects and that two or more of these aspects may be combined in various ways. For example, an apparatus may be implemented and/or a method practiced using any number and aspects set forth herein. Additionally, such an apparatus may be implemented and/or such a method may be practiced using other structure and/or functionality in addition to one or more of the aspects set forth herein.

It should be noted that the drawings provided in the following embodiments are only for illustrating the basic idea of the present application, and the drawings only show the components related to the present application rather than the number, shape and size of the components in actual implementation, and the type, amount and ratio of the components in actual implementation may be changed arbitrarily, and the layout of the components may be more complicated.

In addition, in the following description, specific details are provided to facilitate a thorough understanding of the examples. However, it will be understood by those skilled in the art that the aspects may be practiced without these specific details.

The technical solutions provided by the embodiments of the present application are described below with reference to the accompanying drawings.

Referring to fig. 1, a schematic diagram of an application scenario of the present invention is shown.

As shown in fig. 1, for an offshore wind turbine, noise is generated from the nacelle 1, travels down the tower 2, and after reaching below the sea level 3, the noise travels from the surface of the tower 2 into the water. The sound absorption coating 401 is wrapped on the underwater part of the wind turbine tower 2, and can absorb the noise transmitted to the water, so that the noise energy entering the water is reduced, and the noise amplitude in the water is reduced.

The sound absorption coating 401 uses rubber or polyurethane with characteristic impedance close to that of water to realize impedance matching, so that sound waves can enter the interior of the sound absorption material to the maximum extent and then be absorbed.

Fig. 3 and 4 illustrate an embodiment of a cell unit 402 according to the present invention.

The sound absorption coating 401 is made of nitrile rubber with impedance matched with water, the density is 1250kg/m3, the Young modulus is 30MPa, and the sound absorption coating has good water resistance and corrosion resistance.

The cellular units 402 inside the sound absorption coating 401 are air cavities, and the cellular units 402 are configured in the shape of a combination of a cylinder and a circular truncated cone. The section with the smaller radius of the circular truncated cone faces the noise incidence direction, namely the direction of the tower barrel 2. The cylinder faces the noise exit direction, i.e. away from the direction of the tower 2 (the direction of the seawater). The unit cells 402 are uniformly arranged in the circumferential direction and the vertical direction inside the sound absorption cover 401.

Fig. 5 and 6 show the sound absorption effect which can be achieved when the following parameters are adopted for the sound absorption coating 401.

1. The sound absorption coating 401 has a thickness of 12 cm or more;

2. the major radius of the air cavity of the unit cell 402 is 1.5cm-3cm, the minor radius is 1cm-1.5cm, and the length of the air cavity of the unit cell 402 is 5 cm-10 cm;

3. the air cavities of the cellular units 402 are uniformly distributed along the circumferential direction, and the number of the cavities is more than 12 around the tower 2;

4. the air cavities of the cellular units 402 are uniformly distributed along the water depth direction, and the axle distance between two adjacent cavities is less than 3 times of the cavity length.

The sound absorption coefficient curve of the sound absorption cladding 401 is shown in fig. 5. The vertical axis of figure 5 is sound absorption coefficient and the horizontal axis is frequency of audio in hertz. Compared with most underwater sound absorption materials, the cellular unit 402 of the embodiment has better low-frequency sound absorption characteristics, the maximum value of the sound absorption coefficient is 3000Hz, and the sound absorption coefficient can be kept above 0.8 in the range of 600Hz-5800 Hz.

The underwater far-field sound absorption effect is shown in fig. 6, and a schematic diagram of the change of the sound pressure level with the water depth is obtained through a scaling model. dB means decibel, and one grid on the abscissa represents 10 decibels. The m of the ordinate is the water depth, the unit is meter, the 0m position is the water surface, and the total four grids of the water depth directions of the chart indicate the water depth of 4 meters. The solid line indicates the absence of the acoustic coating and the dotted line indicates the presence of the acoustic coating 401.

FIG. 6 is a graph showing the variation of sound pressure level with water depth at a distance of 6 m from the tower of a wind turbine by a scaling model. After the sound absorption coating is used, the sound pressure level of underwater far-field noise changes along the water depth direction. Taking the results in the two low frequency ranges of 500Hz and 1100Hz as an example, the sound pressure level drops significantly after passing through the sound-absorbing coating. The far field sound pressure level in the water after installation of the acoustic cladding 401 is 5-12dB lower than without the acoustic cladding 401.

Fig. 7 is a horizontal sectional view of the sound absorbing coating 401 when the unit cell 402 is shaped as a sphere.

Fig. 8 is a horizontal sectional view of the sound absorbing coating 401 when the unit cell 402 is configured as a cone. Wherein the apex of the cone is directed towards the direction of incidence of the noise, i.e. the direction in which the tower 2 is located. The bottom of the cone faces the noise emergence direction, namely the direction of the seawater.

Fig. 9 is a horizontal sectional view of the sound absorbing coating 401 when the unit cells 402 are configured in a cylindrical shape.

Fig. 10 is a horizontal sectional view of the sound absorbing coating 401 when the cell unit 402 is configured as a circular truncated cone. Wherein, the minor diameter end of round platform is towards the noise incident direction, the tower section of thick bamboo 2 is in the direction. The big diameter end of the round table faces the noise emergent direction, namely the direction of the seawater.

Fig. 11 is a horizontal cross-sectional view of the sound absorbing coating when the cell unit 402 is configured as a circular truncated cone. Wherein, the minor diameter end of round platform is towards the noise incident direction, the tower section of thick bamboo 2 is in the direction. The big diameter end of the round table faces the noise emergent direction, namely the direction of the seawater.

In other embodiments, the configuration of the cell unit 402 is a double trumpet. In other embodiments, cellular unit 402 is in the shape of a vase. In other embodiments, the configuration of the unit cell 402 is a spiral. Compared with a pure cylindrical cavity, the sound wave can be better absorbed by adopting a double-horn or vase or spiral cavity structure.

In other embodiments, the polymer is made of rubber or polyurethane with a characteristic impedance close to that of water to achieve impedance matching, so that sound waves can enter the interior of the sound absorption material to the maximum extent and then be absorbed.

Since the air cavities of the unit cells 402 exist inside nitrile rubber or polyurethane, the sound-absorbing cover 401 can be manufactured using a method of manufacturing in sections and then bonding. For example, the upper layer cavity is in a round table shape, the lower layer is in a cylindrical shape, and after the two layers are bonded, an integral cavity is formed.

The embodiments in the present specification are described in a progressive manner, and the same and similar parts among the embodiments can be referred to each other, and each embodiment focuses on the differences from the other embodiments. In particular, for the method embodiments described later, since they correspond to the system, the description is simple, and for the relevant points, reference may be made to the partial description of the system embodiments.

The above description is only for the specific embodiments of the present application, but the scope of the present application is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present application should be covered within the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. The offshore wind turbine is characterized by comprising an offshore wind turbine tower (2), a cabin (1) and a sound absorption coating (401), wherein the part of the offshore wind turbine tower (2) is arranged at the lower part of a sea level (3), the sound absorption coating (401) is coated on the periphery of the offshore wind turbine tower (2) arranged at the lower part of the sea level (3), and the sound absorption coating (401) can absorb noise transmitted from the offshore wind turbine tower (2) to sea water.

2. Offshore wind turbine according to claim 1, characterized in that the sound absorption coating (401) is internally provided with a plurality of cavity-like cellular units (402).

3. Offshore wind turbine according to claim 2, characterized in that a plurality of cell units (402) are evenly distributed inside the sound absorption cladding (401).

4. Offshore wind turbine according to claim 1, characterized in that the cavities of the cell units (402) have a large diameter end, which is arranged away from the tower (2), and a small diameter end, which is arranged towards the offshore wind turbine tower (2).

5. The offshore wind turbine of claim 4, wherein the cavity shape of the cell unit (402) comprises a cone shape, a truncated cone shape or a trumpet shape.

6. The offshore wind turbine of claim 4, characterized in that the sound absorbing coating (401) has a thickness greater than 12 centimeters; the radius of the large-diameter end is 1.5cm-3 cm; the radius of the small-diameter end is 1cm-1.5 cm; the length of the cellular unit (402) is 5cm to 10 cm; the distance between two adjacent cellular units (402) is less than 3 times of the length of the cellular unit (402).

7. An offshore wind turbine according to claim 1, wherein the cavity shape of the cell unit (402) comprises a cylindrical, circular or spiral shape.

8. Offshore wind turbine according to claim 1, characterized in that the sound absorbing coating (401) is made of one or more combinations of nitrile rubber, hydrogenated nitrile rubber, carboxylated nitrile rubber.

9. An offshore wind turbine according to claim 8, wherein said nitrile rubber has a density of 1200kg/m³-1300kg/m³The Young modulus of the nitrile rubber is 28-32 MPa.

10. An offshore wind turbine according to claim 1, characterized in that the sound absorbing coating (401) is made of a material comprising polyurethane.