Wind power blade tip test section connecting structure

Abstract

The utility model relates to a wind power blade tip test section connecting structure which comprises a structural layer and a pouring layer, the structural layer comprises a bolt sleeve, a glass fiber reinforced plastic wedge-shaped strip, a PVC bevel angle, glass fiber cloth and a blade tip shell, and the pouring layer comprises a glue injection pipeline, a glue injection opening and a composite flow guide net. Glass fabric located on the inner side is laid on the outer side of the blade tip shell, and a core material, a bolt sleeve and a glass fiber reinforced plastic wedge-shaped strip are arranged on the outer side of the glass fabric located on the inner side. Vacuum infusion forming is adopted, the resin wettability is good, the cloth layer infusion quality of the connecting position is high, bolt sleeves are evenly arranged, and even stress is guaranteed.

Description

Technical Field

[0001] The utility model belongs to the field of wind turbine blade test devices, relates to a wind turbine blade tip test device, and in particular to a wind turbine blade tip test section connection structure. Background Art

[0002] As an important component of wind turbines, wind turbine blades are subjected to constantly changing wind loads during the actual operation of wind farms. The harsh climate and the continuous operation of blades over the years have made the fatigue life of wind turbine blades a focus of attention. Blades are usually divided into three parts: the root, the body and the tip. The tip is the part that produces the most power to drive the wind turbine to rotate, so the load-bearing capacity of the tip is relatively important. It is unknown how well the blades can resist fatigue loads when they are in operation with defects and after defect repair. Often, a section of the blade tip is taken from a certain blade type as a test object for verification and data collection to test whether the fatigue service life of wind turbine blades after defect repair can meet the design requirements. There are relatively few studies and tests in this area in China. In order to ensure a better connection between the blade tip and the test bench, high-strength connectors and connection solutions are required to support it. The existing technology often uses hand lay-up forming to add bolt sleeves, which causes large-area hand lay-up bubbles to form when the cloth layer is infiltrated. The quality of hand lay-up cannot be effectively guaranteed. The number of bolt sleeves is small, the gap between the sleeves is large, and the force is uneven, which cannot ensure the smooth completion of the blade tip test. Therefore, the blade tip connection position needs to be made of reinforced fiber, resin, embedded metal bolt sleeves, fiberglass preforms and other materials through vacuum injection and curing. Conventional pre-embedding methods will cause problems such as loosening and displacement of embedded parts.

[0003] The patent document "A perfusion system and perfusion molding process for pre-embedded wind turbine blade roots" (CN109968689B) discloses a perfusion system for pre-embedded wind turbine blade roots. Specifically, a vacuum bag film is provided on the surface of the guide net above the root cloth layer, and intersecting and vertically arranged spanwise injection ohmic tubes and chordwise injection ohmic tubes are provided between the guide net and the vacuum bag film. A glue injection port is provided at the intersection of the spanwise injection ohmic tube and the chordwise injection ohmic tube. The utility model provides a detailed description of the perfusion system for the blade root, and solves the risk of perfusion of multiple glue injection holes at the blade root. However, this perfusion process is only applicable to the production of blades with pre-embedded blade roots. It cannot meet the connection position molding requirements for the blade tip section used for blade testing, which is not conducive to the connection of the large blade tip test section with the test bench.

[0004] For vacuum infusion technology, at room temperature, the flow rate of the resin in the guide net is too fast, which exceeds the speed of the resin penetrating into the fiber. Therefore, during the infusion process, the ratio of the flow rate of the resin on the fiber surface to the flow rate inside the fiber increases, resulting in white spots or dry fibers after infusion. The current solutions to the above problems mainly include: laying multiple layers of the same guide net, starting mold preheating according to environmental conditions, preparing some injection tubes to form an enclosure, and then starting to evacuate or inject. However, the speed of resin injection will gradually decrease. If the multiple layers of guide nets are evenly distributed, although the flow rate of the resin will be reduced, the infusion resin will stay too long at the rear end of the material, resulting in problems such as very high viscosity and low fluidity in the later stage. Utility Model Content

[0005] (I) Purpose of the utility model

[0006] In view of the defects and shortcomings existing in the connection structure between the blade tip test section and the test bench in the prior art, the utility model proposes a connection structure for the blade tip test section of a wind turbine blade, which provides a reliable connection structure for the blade tip test section of the wind turbine blade and the test bench by arranging bolt sleeves, glass fiber reinforced plastic wedge strips, PVC bevels, and glass fiber cloth on the outer side of the blade tip shell using vacuum infusion technology; the glass fiber reinforced plastic wedge strips and the core material are filled between the bolt sleeves to ensure the connection strength and support strength of the bolt sleeves; the guide net is set as a composite guide net, and the grid distribution directions between the inner guide net and the outer guide net are different, so as to achieve faster and more uniform guide for the resin; the grid of the outer guide net is set to change from dense to sparse along the length direction of the blade tip shell, which can avoid white spots or dry fibers caused by too fast flow speed of the resin in the initial stage of injection, and can also avoid problems such as low fluidity and resin accumulation in the later stage; in addition, an S-shaped groove with an S-shaped path is provided on the core material, and the S-shaped groove of the S-shaped path changes from dense to sparse through this flow channel design, so that the resin can be gradually stabilized and evenly distributed during the flow process, so as to improve the glue filling effect.

[0007] (II) Technical solution

[0008] In order to achieve the purpose of this utility model, the utility model adopts the following technical solutions:

[0009] A wind turbine blade tip test section connection structure, the wind turbine blade tip test section connection structure comprises a structural layer and a perfusion layer, wherein:

[0010] The structural layer includes bolt sleeves, glass fiber reinforced plastic wedge strips, PVC bevels, glass fiber cloth, and blade tip shells. The infusion layer includes glue injection pipes, glue injection ports, and composite guide nets. The glass fiber cloth located on the inner side is laid on the outer side of the blade tip shell. The core material, bolt sleeves, and glass fiber reinforced plastic wedge strips are arranged on the outer side of the inner glass fiber cloth. The bolt sleeves are evenly arranged at the cutting position of the blade tip shell, and the glass fiber reinforced plastic wedge strips are arranged between two adjacent bolt sleeves. The core material is laid along the cutting position of the blade tip shell.

[0011] PVC bevels are respectively arranged at the trailing edge and the leading edge of the blade tip shell, and the PVC bevels are respectively fitted with the trailing edge and the leading edge of the blade tip shell;

[0012] The glass fiber cloth located on the outside is laid on the outside of the glass fiber reinforced plastic wedge strip, the bolt sleeve and the core material, and the composite guide net is laid on the outside of the outer glass fiber cloth. The glue injection pipeline and the glue injection port are arranged on the outside of the composite guide net, and a vacuum bag is arranged on the outside of the injection layer; the laying length of the core material is the same as the laying length of the inner glass fiber cloth and the outer glass fiber cloth;

[0013] The composite guide net includes an outer guide net and an inner guide net stacked together, the inner guide net is closer to the blade tip shell than the outer guide net, the grids between the inner guide net and the outer guide net are distributed in different directions, the grids of the inner guide net are evenly distributed, and the density of the grids of the outer guide net gradually decreases in the horizontal direction;

[0014] A groove is formed in the length direction of one end of the core material at the cutting position of the blade tip shell, the bolt sleeve is arranged in the groove, and a part of the core material at one end of the blade tip shell cutting position is cut off in the thickness direction, the fiberglass wedge strip is arranged at the cut off part of the core material, the fiberglass wedge strip is arranged on the outside of the core material, and the gap between two adjacent bolt sleeves is filled with the fiberglass wedge strip and the core material.

[0015] Preferably, the core material includes an upper surface and a lower surface in the thickness direction, and a plurality of shallow grooves extending along the length direction are respectively opened on the upper surface and the lower surface of the core material, and the shallow grooves are all linear grooves. S-shaped grooves of S-shaped paths are also provided in the upper surface and the lower surface, and the number of S-shaped grooves of the S-shaped path within unit length along the length direction changes from more to less.

[0016] Preferably, the glass fiber cloth located on the inner side is laid on the outer side of the blade tip shell within 2 m from the cutting position of the blade tip shell.

[0017] Preferably, the inner fiberglass cloth and the outer fiberglass cloth each have 25 layers.

[0018] Preferably, the grid distribution directions of the inner guide net and the outer guide net are different, the extension directions of the longitude and latitude lines forming the inner guide net are both at an angle of 45 degrees to the horizontal direction, and the latitude lines of the outer guide net are along the horizontal direction.

[0019] Preferably, the spacing distances between adjacent longitudes and adjacent latitudes of the inner guide net are the same; the spacing distances between adjacent latitudes of the outer guide net are the same, and the spacing distances between adjacent longitudes of the outer guide net gradually increase along the length direction of the blade tip shell.

[0020] Preferably, three glue injection pipelines are provided, the glue injection pipelines exist independently, and each of the glue injection pipelines is provided with a glue injection port.

[0021] (III) Technical Effect

[0022] Compared with the prior art, the wind turbine blade tip test section connection structure of the utility model has the following beneficial and significant technical effects:

[0023] (1) The utility model proposes a wind turbine blade tip test section connection structure, which requires vacuum infusion molding, good resin impregnation, high quality of infusion of the connection position layer, uniform arrangement of the bolt sleeves, sufficient number, and uniform force; the utility model is simple to operate, easy to control, and low in cost.

[0024] (2) The utility model provides an S-shaped groove with an S-shaped path on the core material. The S-shaped groove of the S-shaped path changes from dense to sparse through this flow channel design. The resin can be gradually stabilized and evenly distributed during the flow process, which helps to improve the glue filling effect.

[0025] (3) The guide net is set as a composite guide net. The grid distribution directions of the inner guide net and the outer guide net are different, which can achieve faster and more uniform guide for the resin without increasing the grid density and processing cost of a single guide net. The grid of the outer guide net is set to change from dense to sparse along the length direction of the blade tip shell, which can avoid white spots or dry fibers caused by excessive flow speed in the early stage of resin injection, and can also avoid problems such as low fluidity and resin accumulation in the later stage.

[0026] (4) The utility model fills the fiberglass wedge strips and the core material between the bolt sleeves, thereby ensuring the connection strength and support strength of the bolt sleeves. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of the end face of the wind turbine blade tip test section connection structure at the cutting position of the blade tip shell of the utility model;

[0028] Figure 2 It is a side view schematic diagram of the connection structure of the tip test section of a wind turbine blade;

[0029] Figure 3 is a schematic diagram of the perfusion layer. DETAILED DESCRIPTION

[0030] In order to better understand the present utility model, the content of the present utility model is further explained in conjunction with the embodiments below. In the accompanying drawings, the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The described embodiments are part of the embodiments of the present utility model, not all of them. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present utility model, and should not be understood as limitations on the present utility model. Based on the embodiments in the present utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present utility model. The structure and technical solution of the present utility model are further described in detail below in conjunction with the accompanying drawings, and an embodiment of the present utility model is given.

[0031] like Figures 1 to 3 As shown, in order to solve the connection problem between the existing blade tip test section and the test bench, the utility model proposes a wind turbine blade tip test section connection structure, which includes a structural layer and a perfusion layer, wherein the structural layer includes a bolt sleeve 1, a glass fiber reinforced plastic wedge strip 2, a glass fiber cloth 3, a blade tip shell 4, and a PVC bevel 5, and the perfusion layer includes a glue injection pipeline 9, a glue injection port 10, a composite guide net 11, and a vacuum bag 17, and 25 layers of glass fiber cloth 3 located on the inner side are laid on the outer side of the blade tip shell 4 within a range of 2m from the blade tip shell cutting position, and the glass fiber reinforced plastic wedge strip 2, a bolt sleeve 1, and a core material 12 are placed on the outer side of the glass fiber cloth located on the inner side, wherein the bolt sleeve 1 is evenly arranged at the blade tip shell cutting position, and the glass fiber reinforced plastic wedge strip 2 is arranged between two adjacent bolt sleeves 1; the core material 12 is laid along the blade tip shell cutting position, and the laying length of the core material 12 The laying length is the same as that of the glass fiber cloth 3 on the inner side. At the same time, PVC bevels 5 are respectively arranged at the trailing edge 7 and the leading edge 8 of the blade tip. The PVC bevels are respectively fitted with the trailing edge and the leading edge of the blade tip, and the outer surface of the PVC bevel forms the same streamline shape as the trailing edge 7 and the leading edge 8 of the blade tip at the trailing edge and the leading edge of the blade tip. 25 layers of glass fiber cloth 3 are laid on the outside of the glass fiber reinforced plastic wedge strip 2, the bolt sleeve 1, the core material 12, and the PVC bevel 5. A composite guide net 11 is laid on the outside of the outer glass fiber cloth 3. A glue injection pipeline 9 and a glue injection port 10 are arranged on the outside of the composite guide net 11. The mounting flange 15 is positioned and spliced ​​with the blade tip and the root side. A vacuum bag is arranged on the outside of the connecting structure. A vacuum bag 17 is used for vacuum sealing and vacuum pressure maintenance to complete vacuum infusion. The mounting flange 15 is connected to the bolt sleeve 1 through the mounting bolts 16 to install the blade tip shell to the test bench.

[0032] The composite guide net 11 includes a stacked outer guide net ( Figure 3 Medium dark mesh) and inner guide mesh ( Figure 3The inner guide mesh is closer to the blade tip shell than the outer guide mesh. The mesh distribution directions of the inner and outer guide meshes are different. Figure 3 As shown, the extension directions of the warp and weft lines forming the inner guide net are both at an angle of 45 degrees to the horizontal direction, the weft lines of the outer guide net extend in the horizontal direction, and the warp lines of the outer guide net are distributed perpendicular to the horizontal direction. The grids between the inner guide net and the outer guide net are distributed in different directions, which can achieve faster and more uniform guide for the resin without increasing the grid density and processing cost of a single guide net.

[0033] The grid of the inner guide net is evenly distributed, that is, the spacing distances between adjacent longitudes and latitudes of the inner guide net are the same; the density of the grid of the outer guide net gradually decreases in the horizontal direction, wherein the latitudes of the outer guide net are evenly distributed, that is, the spacing distances between adjacent latitudes of the outer guide net are the same, and the distribution of the warps of the outer guide net along the length direction of the blade tip shell gradually changes from dense to sparse, that is, the spacing distances between adjacent warps of the outer guide net along the length direction of the blade tip shell gradually increases.

[0034] The grid of the outer guide net is set to change from dense to sparse along the length direction of the blade tip shell. Since the grid is denser in the initial stage, white spots or dry fibers caused by too fast flow speed in the initial stage of resin injection can be avoided. Since the grid is set to gradually become sparse along the length direction of the blade tip shell, the flow resistance is also continuously reduced, so that the flow speed loss is maintained at a small level, avoiding problems such as low fluidity and resin accumulation in the later stage.

[0035] A groove is formed in the length direction at one end of the core material 12 at the cutting position of the blade tip shell, and the bolt sleeve 1 is arranged in the groove, and a part of the core material 12 at one end of the blade tip shell cutting position is cut off in the thickness direction. The glass fiber reinforced plastic wedge strip 2 is arranged at the part of the core material cut off, and the glass fiber reinforced plastic wedge strip 2 is arranged on the outside of the core material, that is, the gap between two adjacent bolt sleeves 1 is filled with the glass fiber reinforced plastic wedge strip 2 and the core material. Filling the glass fiber reinforced plastic wedge strip between the bolt sleeves can provide good support for the bolt sleeves, avoiding the problems of the bolt sleeves being damaged or displaced when subjected to a large external force, and extending the core material to fill between the bolt sleeves, so that the bolt sleeves are better combined and fixed with the core material, glass fiber cloth and other connecting parts at the rear end, avoiding the problems of the bolt sleeves loosening during operation. The utility model fills the glass fiber reinforced plastic wedge strip and the core material together between the bolt sleeves, thereby ensuring the connection strength and support strength of the bolt sleeves.

[0036] The core material 12 includes an upper surface and a lower surface in the thickness direction. A plurality of shallow grooves extending along the length direction are respectively provided on the upper surface and the lower surface of the core material. S-shaped grooves with S-shaped paths are also provided on the upper surface and the lower surface. The width of the S-shaped groove 3 is 1 mm, and the vertices of the S-shaped groove coincide with the edges of the upper surface and the lower surface.

[0037] Along the length direction of the core material strip 1 , the S-shaped grooves of the S-shaped path change from dense to sparse, that is, the number of the S-shaped grooves of the S-shaped path per unit length along the length direction changes from many to few.

[0038] The resin flows along the length direction of the core material, and the S-shaped grooves of the S-shaped path change from dense to sparse, that is, the number of S-shaped grooves in the S-shaped path per unit length along the length direction changes from many to few. The resin first enters the densely designed flow channel part, where the resin will encounter a certain amount of resistance, but because the flow channel is dense, the resin flow will be relatively stable. Subsequently, the resin will gradually transition to the loosely designed flow channel part. At this stage, the resin will undergo adjustments in speed and flow direction to adapt to changes in the flow channel structure. As the resin flows upstream, the flow rate of the resin will decrease, and in the loose flow channel part, the flow resistance of the resin will decrease. Through this flow channel design method, the resin can be gradually stabilized and evenly distributed during the flow process, which helps to improve the glue filling effect.

[0039] Through the above embodiments, the purpose of the utility model is fully and effectively achieved. Those skilled in the art can understand that the utility model includes but is not limited to the contents described in the drawings and the above specific embodiments. Although the utility model has been described with respect to the most practical and preferred embodiments currently considered, it should be understood that the utility model is not limited to the disclosed embodiments, and any modification that does not deviate from the functional and structural principles of the utility model will be included in the scope of the claims.

Claims

1. A wind turbine blade tip test section connection structure, the wind turbine blade tip test section connection structure comprising a structural layer and a perfusion layer, characterized in that: The structural layer includes bolt sleeves, glass fiber reinforced plastic wedge strips, PVC bevels, glass fiber cloth, and blade tip shells. The infusion layer includes glue injection pipes, glue injection ports, and composite guide nets. The glass fiber cloth located on the inner side is laid on the outer side of the blade tip shell. The core material, bolt sleeves, and glass fiber reinforced plastic wedge strips are arranged on the outer side of the inner glass fiber cloth. The bolt sleeves are evenly arranged at the cutting position of the blade tip shell, and the glass fiber reinforced plastic wedge strips are arranged between two adjacent bolt sleeves. The core material is laid along the cutting position of the blade tip shell. PVC bevels are respectively provided at the trailing edge and the leading edge of the blade tip shell, and the PVC bevels are respectively fitted with the trailing edge and the leading edge of the blade tip shell; Laying glass fiber cloth on the outside of the glass fiber reinforced plastic wedge strip, bolt sleeve and core material, laying a composite guide net on the outside of the glass fiber cloth, arranging glue injection pipes and glue injection ports on the outside of the composite guide net, and setting a vacuum bag on the outside of the injection layer; The laying length of the core material is the same as that of the inner fiberglass cloth and the outer fiberglass cloth; The composite guide net includes an outer guide net and an inner guide net stacked together, the inner guide net is closer to the blade tip shell than the outer guide net, the grids between the inner guide net and the outer guide net are distributed in different directions, the grids of the inner guide net are evenly distributed, and the density of the grids of the outer guide net gradually decreases in the horizontal direction; A groove is formed in the length direction of one end of the core material at the cutting position of the blade tip shell, the bolt sleeve is arranged in the groove, and a part of the core material at one end of the blade tip shell cutting position is cut off in the thickness direction, the fiberglass wedge strip is arranged at the cut off part of the core material, the fiberglass wedge strip is arranged on the outside of the core material, and the gap between two adjacent bolt sleeves is filled with the fiberglass wedge strip and the core material.

2. The wind turbine blade tip test section connection structure according to claim 1, characterized in that: The core material includes an upper surface and a lower surface in the thickness direction. A plurality of shallow grooves extending along the length direction are respectively provided on the upper surface and the lower surface of the core material. The shallow grooves are all linear grooves. S-shaped grooves of S-shaped paths are also provided on the upper surface and the lower surface. The number of S-shaped grooves of the S-shaped path within a unit length along the length direction changes from more to less.

3. The wind turbine blade tip test section connection structure according to claim 1, characterized in that: The glass fiber cloth located on the inner side is laid within 2m of the cutting position of the blade tip shell on the outer side of the blade tip shell.

4. The wind turbine blade tip test section connection structure according to claim 1, characterized in that: The inner fiberglass cloth and the outer fiberglass cloth each have 25 layers.

5. The wind turbine blade tip test section connection structure according to claim 1, characterized in that: The grid distribution directions of the inner guide net and the outer guide net are different. The extension directions of the longitude and latitude lines forming the inner guide net are both at an angle of 45 degrees to the horizontal direction, and the latitude lines of the outer guide net are along the horizontal direction.

6. The wind turbine blade tip test section connection structure according to claim 5, characterized in that: The spacing distances between adjacent longitudes and latitudes of the inner guide net are the same; the spacing distances between adjacent latitudes of the outer guide net are the same, and the spacing distances between adjacent longitudes of the outer guide net gradually increase along the length direction of the blade tip shell.

7. The wind turbine blade tip test section connection structure according to claim 6, characterized in that: There are three glue injection pipelines, each of which exists independently and has a glue injection port.

Images