WO2013004156A1

WO2013004156A1 - Blade with constant cross section, forming method thereof, and horizontal axis wind turbine impeller comprised of the same

Info

Publication number: WO2013004156A1
Application number: PCT/CN2012/077981
Authority: WO
Inventors: 张向增
Original assignee: Zhang Xiangzeng
Priority date: 2011-07-04
Filing date: 2012-06-30
Publication date: 2013-01-10
Also published as: CN102305174A; CN102305174B

Abstract

Disclosed in the present invention are a fiber reinforced resin matrix composite blade with a constant cross section, a forming method thereof and a wind turbine impeller comprised of the blade, wherein the blade is mainly comprised of resin, fiber and core material, and can be a combined structure of multiple blade fragments (1). Each of the blade fragments has a constant cross section with a special chord length, and the chord lengths of various blade fragments are different with each other. The blade is fixed on a hub (8) of the impeller by means of a tensioned-cable structure, so as to form the impeller with fixed or variable pitch. The blade formed by pultrusion has very high quality stability and a high-precision exterior geometrical profile. The impeller with a large diameter, which is needed in a horizontal axis wind turbine, can be realized with the blade above, so that the impeller can have high aerodynamic profile precision, small stress deformation deflection and large sweeping area of a long blade, so as to realize an ideal wind catching effect.

Description

Constant cross-section blade, forming method, and horizontal axis wind turbine impeller

The present invention relates to a fiber reinforced resin composite blade having a constant cross section formed by a continuous pultrusion process, which is fixed by a truss structure or a cable structure, and can easily realize a large horizontal axis wind turbine The large diameter impeller required, the impeller of this construction greatly reduces the cost of the wind turbine impeller.

The invention belongs to the field of composite blade manufacturing, or to the field of horizontal axis wind turbine manufacturing. Background technique

Modern horizontal-axis wind turbine impeller, whether it is a single-blade, two-bladed or three-bladed impeller, since each blade is a cantilever-mounted load-bearing structure with independent pitch control, each blade from the tip to the blade The roots are subjected to a sharp increase in the bending moment, so the geometrical thickness of the blade profile from the tip to the blade root is increased, and the wall thickness of the blade is also rapidly increased. Because of the strength and modulus of the material, the blade is difficult to achieve. Even with carbon fiber materials with higher specific strength and specific modulus, it is very cumbersome to achieve large-diameter impeller blades, which consumes a large amount of material.

In order to improve the wind energy utilization rate of wind turbines, modern wind turbine blades adopt variable-section structure. From the tip of the blade to the blade root, the chord length of the blade is continuously increased, and the thickness of the blade is also increasing, which is in line with the maximum aerodynamic efficiency and structure. A design principle that maximizes efficiency.

This is a design idea that maximizes performance and, for this reason, the cost of the cost will be high. Although it has been proposed to add an extension between the hub and the blade to increase the diameter of the impeller in a phased manner. The problem described above has not been solved in essence.

There are a number of designers who use fewer blades (for example, 2 pieces) and higher tip speed ratios to reduce the cost of the impeller. The effect is not very satisfactory. The reason is that the tip speed ratio is too high, which will inevitably lead to a significant increase in the thrust of the impeller, the bending moment of the blade itself will increase, and the bending moment of the wind tower will also increase. Pay extra reinforcement costs.

It is better to change the idea that the equivalent power is achieved at a lower cost, which can be explained as: If an inexpensive process is used to manufacture the blades of equal section, and the blade is used with the lightweight structure to manufacture the impeller, although the blades are pneumatic The efficiency may be reduced a little, but the large-diameter impeller can be easily achieved, and the increase in the swept area contributes to the power loss to the power loss caused by the decrease in efficiency. In addition, the current blade molding is statically intermittently formed one by one in a specific mold. This process is usually: preformed main beam system, preformed pneumatic pressure surface, preformed pneumatic suction surface, and then bonded together with structural adhesive. Finally, the adhesive parts are re-reinforced. The most disadvantages of the blades formed by this process are: unreliable bonding + poor resin infiltration defects + ply fiber direction deviation + ply wrinkle defects + insufficient curing defects. The existence of these defects leads to the failure of the blade operation and the reliability is not high. Composite blades formed by continuous pultrusion processes are bound to overcome all of these shortcomings. Summary of the invention

It is an object of the present invention to achieve an inexpensive, reliable, horizontal axis wind turbine large diameter impeller manufacturing technique.

The so-called large diameter impeller can be understood as an impeller with a diameter of 80 m or more.

The idea of the invention is to manufacture a blade with a constant cross section by a continuous pultrusion process of a fiber reinforced resin composite material, which is not sufficiently resistant to large bending moments and torques due to its light weight and thinness, so on the impeller A truss structure or a cable structure must be provided to secure the blade and maintain stability in operation.

The cheap blades and the cheap cable structure make the cost of the impeller greatly reduced.

However, each blade must be capable of independent pitch control, which is a must for modern horizontal axis fans. To achieve this, the blade and the joint structure must be connected by bearings.

First, the blade structure and its forming method will be explained.

The pultrusion process to form a continuous composite profile is a mature process. A fiber-reinforced resin composite blade having a typical aerodynamic structural profile, consisting of resin and fiber, can be completely achieved by a pultrusion process, with the result that a blade segment having a constant cross section is of course produced.

A full-size blade, from the tip to the root of the blade, can be composed of several segments of chord lengths, each of which is a pultrusion of a segment having a constant cross section. Of course, one of the most compact combinations is that the chord length from the tip to the blade root is constant and has a constant cross section. In the case of a plurality of segments that are butt-joined, the blade segments are preferably joined by a joint flange and bolt structure, which facilitates replacement.

Because the blades are subject to torque, only the blades of the longitudinal continuous fibers cannot meet the strength requirements. It is desirable to introduce a cloth or felt having a transverse fiber distribution in the pultrusion process. The result is a composite structure in which the blades are composed of a combination of longitudinal fibers and transverse fibers. Of course, the transverse fibers comprise diagonal fibers that are placed at an angle to the longitudinal direction. These can be achieved by multi-axial fiber cloth.

In order to improve the longitudinal compression stability of the blade, a solid foam sandwich material can be introduced into the wall of the blade.

High-speed moving wind turbine blades must be blades with a specific geometric airfoil for efficient lift-to-drag ratio aerodynamic performance. Moreover, due to the difference in linear velocity from the tip to the root of the blade, to achieve an ideal aerodynamic angle of attack for all leaf elements (leaf micro-element segments) of the blade length, it is necessary that the constant cross-section of the blade segment is along the length of the blade. The ideal twist angle. This torsion is a type of torsion in which the blade cross section surrounds the central axis of the blade pitch. This torsional angle is solidified in the geometry of the blade.

The fibers of such composite blades may be carbon fibers, glass fibers, organic fibers, etc., or a combination thereof. The resin may be a polyester resin, an epoxy resin, an epoxy-based epoxy resin or the like.

Thus, a fiber reinforced resin composite blade having a specific cross section and a specific twist angle is achieved by the process described below:

The continuous fibers are immersed in the resin and collected into a heated mold cavity. Under the continuous stretching force of the traction mechanism, the fibers of the impregnated resin continue to walk in the mold and are hardened by chemical reaction and then removed from the mold cavity. After cooling, a composite blade segment having a constant cross section of a particular chord length is obtained. This is the pultrusion composite blade.

When the resin-impregnated longitudinal continuous fibers are brought together, they are supplemented with a transversely oriented fiber cloth (multi-axial cloth, woven cloth, etc.) or fiber mat, continuously passed through the heated mold cavity, and the reaction is solidified and removed from the mold. After cooling, A composite blade segment having a constant cross section of a particular chord length is obtained. The introduction of transverse fibers enhances the shear strength of the blade shell.

The resin-impregnated longitudinal continuous fibers are brought together by continuous laying of the solid foam core material, continuously passing through the heated mold cavity, reacting and solidifying out of the mold, and cooling to obtain a composite blade having a constant cross section with a specific chord length. Fragment. Thus, the introduction of the sandwich material greatly increases the buckling resistance of the blade against compression forces.

When the cavity of the mold has a sufficient length and the cross section of the mold cavity is continuously twisted in one direction, a torsional shaping of a constant cross section is obtained after the resin undergoes a reaction history of moving hardening in the cavity. In this way, for each segment of the constant cross-section of the blade, from the blade root to the tip of the blade, each differential cross-section is continuously twisted at an angle about the central axis of the pitch. Since the blade is a hollow structure, there are necessarily two parts of the cavity outer mold and the inner cavity mold of the mold during pultrusion, and the two portions define the shape of the drawn hollow blade. Moreover, due to the existence of transverse fibers in the skin structure of large blades, the conventional pultrusion equipment cannot be used in the inside of the cavity and the internal mold part is supported by the outer mold. The invention adopts a cantilever support structure extending outside the mold cavity at the inlet of the mold to support the cavity inner mold, so that the cavity inner mold can be suspended in the outer cavity of the cavity.

When the blade segment of the cavity is removed after hardening and setting, and the traveling speed of the traction mechanism is synchronized, a synchronous surface roughening mechanism and a synchronous coating coating mechanism are provided, and the automatic continuous construction of the outer protective coating of the blade can be completed. .

Since there are longitudinal and transverse continuous fibers at the leading and trailing edges of the blade airfoil and between the spar cap and the web, there is no glue joint between the two half shells in the conventional process. In conventional blades, such bonded joints are usually the most prone to defects and cause the blades to be broken. In addition, since each fiber is pre-impregnated and aggregated, the good wettability of the fiber and the resin content of the hook are fully ensured, and the serious defects such as the formation of leukoplakia existing in the current vacuum guiding process forming blade are avoided. Also, since each of the fibers is always strictly stretched in the longitudinal direction, there is no loss of modulus and strength due to the fiber bending of the multiaxial woven fabric.

For a complete blade, the root of the blade naturally has a transitional structure connected to the hub, and the tip of the blade naturally has a sharp structure that reduces tip eddy current loss and lightning protection. All of these tip and root profiled structures, as well as transitional structures between different chord-length blade segments, do not affect the essential features of the pultrusion constant cross-section blade set forth herein.

The constant cross-sectional vane of the present invention can also be formed by a conventional vacuum infusion process, or by hand lay-up. However, the most suitable one is continuous pultrusion molding.

The structural features of the blade and its forming process characteristics have been described above. Next, a technical feature of the impeller composed of such a blade will be described.

The impellers of the two operating modes can be assembled with the blades of the invention. One is the early fixed pitch fan impeller, and the other is the contemporary variable pitch impeller. The stator blade of the fixed-blade fan is defined as the main part of the blade is fixedly connected to the hub, and only a small section of the tip can be rotated, and the part is turned to adjust the power and the pneumatic brake when parking. The variable pitch fan impeller cylinder is explained by the fact that the entire blade can be adjusted at the blade root to achieve the blade windward angle adjustment, which can realize the brake feathering when parking.

No matter which type of impeller, because the structure of the blade is too thin, it is impossible to achieve independent cantilever installation. Support the bending of the body itself. Therefore, truss support or cable structure fastening support is required. With the introduction of these connecting structures, the blades are changed from the original bending stress to the state where the bending and axial compressive forces coexist. Of course, for blades with a certain thickness and blades with multiple supports, the longitudinal compression stability of the blades is sufficient. The centrifugal force generated by the rotation of the impeller counteracts a portion of the axial compression force. The amount of bending stress experienced by the blade segments is naturally related to the span between the blade support points. This span can usually be designed in the range of 10m to 30m.

So far, we can summarize an impeller, an impeller of a horizontal-axis wind turbine consisting of constant-section composite blades, consisting of a blade, a blade fixing mechanism, a blade pitching mechanism, and a hub, characterized in that: the impeller is at least Containing 3 blades; a segment containing at least one constant cross section along the longitudinal length of each blade; the blade has a front end axial connection structure connected by a common support point at the front end of the impeller, although it is a diagonally pulled structure, The axial force of the bearing blade restrains the deformation deflection of the blade, and the lateral connection structure between the blades is located in the rotation surface of the blade, and is used for carrying the lateral force transmitted between the blades; the connection between the connecting structure and the blade The point is located at the aerodynamic working section between the blade root and the tip of the blade, which is different from the prior art truss structure constructed between the blade root and the hub.

This structure is fully capable of withstanding the wind force from the front of the impeller, and the present invention respects the use of the cable structure, which makes the impeller very lightweight. However, the biggest problem is that it cannot withstand the wind force from the rear under certain conditions. To this end, a conductivity-conducting structure can be designed, that is, an impeller structure in which the blades are mounted at a certain inclination angle. Each blade pitch axis and the impeller rotation axis form an angle greater than 90 degrees, the blade is swept back, and the blades have a rear end axial connection structure connected by a common support point at the rear end of the impeller.

So far, a fixed pitch structure impeller has been summarized. The transverse joint structure and the blade, the front end axial joint structure and the blade, the rear end axial joint structure and the blade are fixedly connected. More than 80% of the length of the blade, a portion of the blade segment located at the tip end of the blade, which is less than 20% of the blade length, is cantilevered, and the mounting point has a slewing mechanism that supports the rotation of the blade tip segment.

So far, a variable pitch structure impeller has been summarized, and the transverse joint structure and the blade, the front end axial joint structure and the blade, the rear end axial joint structure and the blade are all connected by a bearing.

For the bearing joint structure, the most ideal bearing is a non-metallic full-sealed bearing that is dust-proof, corrosion-resistant, and resistant to aging, and should also be a thrust bearing. Since the bearing force is not very large, a self-lubricating wear-resistant bearing like PTFE can meet the requirements. From the elaboration of this paper, it can be found that the constant cross-section composite blade is manufactured by the pultrusion process, and the blade itself has the advantages of low cost and high reliability. There are two disadvantages: one is too light and thin, the ability to independently resist bending loads is limited, and the full-size blade cantilever is not installed, which can compensate the truss structure or cable structure on the blade; the second is due to the constant section, low aerodynamic efficiency In the current complex shape of the variable-section blade, this can easily compensate for the lack of power by increasing the blade length (increasing the diameter of the impeller).

In the traditional model design, in order to reduce the cost of the impeller, a two-blade impeller is used. In order to obtain a certain impeller solidity, a very high tip-to-speed ratio is inevitable, and a too high tip-to-speed ratio necessarily brings about a significant increase in the axial thrust of the impeller. The bending moments experienced by the blades themselves are significantly increased, and the bending moments experienced by the wind towers are also significantly increased, resulting in additional reinforcement costs. With the method set forth in the present invention, it is in fact possible to use more light and thin blades (e.g., 3-bladed or 4-bladed impellers) and a relatively low tip speed ratio λ, such as a range of 6 < λ < 10.

The impeller of the invention has great advantages in suppressing the vibration of the fan, balancing the load caused by the wind shear, smoothing the load, and prolonging the fatigue life of the blade and the spindle bearing.

The impeller composed of such a blade structure is characterized by the fact that the blades are abnormally thin and light, and each blade is a combined state of the blade segments, which is of great significance especially for the offshore wind turbine. On the one hand, the reliability of the wind wheel is improved, and on the other hand, even if the blade is replaced. It is necessary to hoist the entire impeller and replace it with a single blade or a single blade.

A specific embodiment of a 3 MW wind turbine of the present invention having 50 m long blades and impellers will now be described with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS:

Figure 1 is a schematic diagram of a constant cross-sectional blade structure divided into three sections;

Figure 2 is a side elevational view showing the mounting state of a blade of an impeller;

Figure 3 is a schematic axial view of the mounting state of three blades of an impeller;

Figure 4 is a schematic perspective view of a three-blade impeller;

Figure 5 is a schematic illustration of a method of pultrusion of a blade segment.

In Figure 1, 1 - constant cross section, 2 - joint, 3 - leaf tip, 4 - leaf root

In Figure 2, 1 - constant cross section, 2 - joint, 3 - tip, 4 - root, 5 - front end To the joint structure, 6 - front common support point, 7 - front strut, 8 _ hub, 9 _ rear common support point, 10 - rear axial joint structure, 11 - hub flange.

In Fig. 3, 1 - constant cross section, 2 - joint point, 3 - leaf tip, 4 - blade root, 8 - hub, 12 - transverse joint structure.

In Fig. 4, 1 - constant cross section, 2 - joint point, 3 - blade tip, 4 - blade root, 5 - front end axial joint structure, 6 - front end common support point, 7 - front strut, 8 _ hub , 9 _ rear common support point, 10 - rear axial joint structure, 11 - hub flange, 12 - lateral joint structure, 13 - nacelle, 14 tower.

In Fig. 5, 511 - cavity outer mold, 512 - cavity inner mold, 513 - cantilever support, 51 - fiber, 52 - resin tank, 53 - fiber cloth, 54 - solid foam, 55 - cavity, 56 - Heat curing device, 57 - traction mechanism, 58 - synchronous roughing device, 59 - synchronous spraying device, 60 - cutting device, 1 constant cross section. Specific implementation plan:

In this embodiment, the blade has a length of 50 m and a blade impeller structure.

Figure 1 shows a blade consisting of three segments of constant cross-section, with increasing chord length from tip to root. And each segment has a moderate twist angle. In the figure, the length of L1 is 20m, L2 is 20m, and L3 is 10m. In the figure, a three-section constant cross-section segment 1 is combined into one blade. The joint point 2 is a joint point for fixing the blade, the tip 3 is a structure that combines rectification and lightning protection, and the blade root 4 is a structure in which the blade and the hub are connected. The view on the right side of Figure 1 is a cross-sectional view. It shows a hollow structure with a good lift-to-drag ratio and aerodynamic shape.

In Fig. 2, a schematic view of the axially mounted connection state of one blade on the impeller is shown, and the circumferential connection between the blades is omitted. The other blades in the impeller are installed in the same way. In the figure, there is a front strut 7 in front of the hub 8, and the front end axial joint structure 5 is connected together through the front common support point 6 to balance and balance the pulling force. The front end axial joint structure 5 may be a truss structure or a cable structure. The rear end axial joint structures 10 are joined together by a common support point 9 at the rear end. The rear axial joint structure 10 can be a truss structure or a cable structure. The blade is coupled to the front end axial joint structure 5 through the joint point 2 and the front end axial joint structure 5. In Figure 2, Wind indicates the direction of the wind when the impeller is in operation, and the impeller is in the windward state. The blade is connected by the blade root 4 and the hub 8. The impeller is connected to the nacelle spindle by means of a hub flange 11 .

The most cylindrical type of blade installation is that there is no rear end axial joint structure 10, only the front end axial direction The joint structure 5 is also a cable structure. This kind of impeller requires that the impeller should always be kept in the wind direction from the beginning of the installation of the fan, and it can not withstand the wind blowing force in the opposite direction.

Of course, the mounting angle a between the blade and the horizontal axis of rotation of the impeller can be 90° or greater than 90°. Since the space between the blade and the tower column is limited, the angle a is greater than 90°. The blade thus mounted has a swept posture. It is completely different from the current conventional blade installation with a forward tilting posture. This type of impeller naturally does not require the blade to have a pre-bent shape.

In Fig. 3, an axial view of the installation state of three blades of an impeller is shown, which is a schematic view; the purpose is to indicate the lateral connection state between the blades. This lateral connection is located in the plane of revolution of the blade. The longitudinal connection between the blades is omitted in the figure. The three blades are joined together as a whole by a transverse joint structure 12. The lateral joint structure 12 may be a truss structure or a cable structure. The most simple one is the structure of the cable. This joint structure realizes the transmission and bearing of the impeller torque composed of thin and thin blades.

In Fig. 4, a three-dimensional structure diagram of a complete impeller is shown; a case of a wind turbine impeller formed by a cable structure by a cable structure is fully illustrated.

In Fig. 4, the assembly relationship between the nacelle 13, the tower 14, and the impeller is illustrated. This is an up-and-down operational design. Of course, such an impeller can also be installed in a downwind running assembly relationship.

In Fig. 4, the constant cross-section section 1 is connected by the blade root 4 and the hub 8, and the front end axial joint structure 5 and the rear end axial joint structure 10 are fixed by the joint point and the blade. The distance between the common support point 6 at the front end and the blade root 4 affects the force applied to the blade and the front end axial joint structure. Similarly, the distance between the back end common support point 9 and the blade root 4 affects the force applied to the blade and the rear axial joint structure. The axial joint structure, the transverse joint structure and the joint point 2 secure the blade. The axially connected structure carries the windward force of the blade, and the transverse joint structure carries the torsional force of the blade. The specific axial and lateral joining structures are not limited to the illustrated connecting lines.

Although a three-bladed impeller is illustrated in Figure 4, the impeller of the present invention may also be a multi-blade impeller with the same joining characteristics. Moreover, the blade may be a single chord blade from the tip to the root of the blade, or a combination of multiple segments of the chord with different chord lengths. The location of the common junction 2 is arranged as desired, not necessarily at the junction between the two segments, and the location of the junction 2 is within the range of the pneumatic working segment of the blade.

In the case of a combination of multi-segment blade segments, the segments are connected by a connecting flange and a bolt structure, which can facilitate future maintenance and replacement.

This kind of impeller structure, due to the constraint of the joint structure, the deformation deflection of the blade is more than that of the conventional cantilever The blade is greatly reduced, which always guarantees the ideal aerodynamic angle of attack of the entire blade, so the efficiency of the wind is relatively high.

The joint point 2 in Fig. 4, which is a fixed joint structure in the fixed-blade fan impeller, is a dead joint. It appears as a bearing connection structure in the pitch fan fan.

When bearing joints are used, since the applied stress is not very large, it is possible to use non-metallic bearings with low corrosion resistance and light weight. Polytetrafluoroethylene bearings with self-lubricating properties are ideal.

Figure 5 illustrates a method of forming such composite blades by a pultrusion process.

The continuous fiber 51 is continuously impregnated by the resin groove 52, and the fiber cloth 53 is continuously assisted, and if necessary, the solid foam material 54 is introduced. These materials are combined into the cavity 55, and the resin is rapidly reacted and solidified by the heat curing device 56, and is solidified after curing. A constant cross-section segment 1 having the required geometry.

The pultrusion power is derived from the directional walking traction of the traction mechanism 57.

Of course, the cavity 55 needs to be long enough, and the cross-section of the cavity profile requires continuous torsion to produce a composite blade having a specific twist angle. The shaping of the torsion angle of the blade requires adaptation of the curing reaction speed and the traction speed of the resin. The cavity length also depends on the curing reaction rate and the pulling speed. Through the ply design, the asymmetry of the blade shell laminate structure is introduced, which can also cause the natural deformation of the cured blade.

In Fig. 5, a cross-sectional view of the constant cross-section section 1 is shown in the A-A view, which is a hollow structure, so that the cavity 55 is composed of a cavity outer mold 511 and a cavity inner mold 512. Due to the presence of the transverse fibers of the blade skin, it is necessary to have a cantilever support 513 located outside the cavity 55 to fix the cavity inner mold 512 so that the cavity inner mold 512 is suspended in the cavity outer mold 511. The fibers, resin, and sandwich material enter the cavity 55 together and are solidified to form a constant cross-sectional segment 1 .

Of course, the configuration of the synchronous roughening device 58 and the synchronous spraying device 59, as well as the subsequent auxiliary devices such as the cutting device 60, form a continuous production line. This process has revolutionized the current unfavorable situation in which blade manufacturing is labor intensive. At the same time, the consumption of auxiliary molding materials such as vacuum bag film of traditional process and environmental pollution are greatly reduced.

The blades formed by this pultrusion process have a precise geometry and therefore exhibit ideal aerodynamic characteristics.

By using different equipment to draw constant cross-section blade profiles of different chord lengths, and then cutting into segments of the required length, further combinations can be obtained to obtain the blades we require.

The invention realizes a low-cost, high-reliability, lightweight large-diameter horizontal-axis wind turbine set

01

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Claims

Rights request

1. A constant-section fiber-reinforced resin composite blade for a horizontal-axis wind turbine, having a typical aerodynamic structural profile, mainly composed of a resin, a fiber, and a sandwich material, characterized by: a blade segment having at least one constant cross section in the longitudinal length of the blade, a blade composed of a plurality of blade segments, each blade segment having a constant cross section of a specific chord length, for each segment of the constant cross section of the blade segment, from the blade The blade roots are oriented in the direction of the tip of the blade, and each differential cross section is continuously twisted by a certain angle around the central axis of the pitch.

The constant cross-section fiber reinforced resin composite blade according to claim 1, wherein the segments of each blade are connected by a joint flange and a bolt structure.

The constant cross-section fiber reinforced resin composite blade according to claim 1, wherein the blade is composed of a combination of longitudinal fibers and transverse fibers, and a composite structure of the introduced solid foam sandwich material.

4. An impeller of a horizontal-axis wind turbine consisting of constant cross-section composite blades, comprising a blade, a blade fixing structure, a blade pitching mechanism, and a hub, wherein: the impeller contains at least three blades; The longitudinal length of the blade comprises at least one constant cross-section segment (1); the blade has a front end axial connection structure (5) connected by a common support point (6) at the front end of the impeller, and the blade is located between the blade rotation surface The transverse joint structure (12); the joint point (2) formed between the joint structure and the blade is located at a pneumatic working section between the blade root and the tip of the blade.

5. The impeller of a horizontal axis wind turbine consisting of constant cross-section composite blades according to claim 4, wherein: each blade pitch axis and the impeller rotation axis form an angle greater than 90 degrees, the blade Installed in a swept-back attitude, there is a rear-end axial joint structure (10) between the blades that is connected by a common support point (9) at the rear end of the impeller.

6. The impeller of a horizontal-axis wind power generator comprising constant cross-section composite blades according to claim 4, wherein: the impeller is a fixed pitch impeller, and the transverse joint structure

(12) and the blade, the front end axial joint structure (5) and the blade, the rear end axial joint structure (10) and the blade are fixedly connected, the fixed structure constrains the blade length by more than 80% The portion of the blade segment located at the tip end of the blade, which is less than 20% of the blade length, is cantilevered, and the mounting point has a slewing mechanism for supporting the rotation of the blade tip segment.

7. The impeller of a horizontal axis wind turbine consisting of constant cross-section composite blades according to claim 4, wherein: the impeller is a pitch impeller, the transverse joint structure (12) and the blade, the front end axial joint structure (5) and the blade, the rear end axial joint structure (10) and the blade are connected by a bearing at the joint point (2).

8. An impeller for a horizontal axis wind turbine consisting of constant cross-section composite blades according to claims 4 and 7, characterized in that the bearing at the point of the joint (2) is a non-metallic bearing.

9. A method for forming a constant cross-section fiber reinforced resin composite blade segment comprising a resin-infiltrated fiber and a resin curing process to form a constant cross-sectional blade segment having a specific geometric profile, characterized in that: continuous fiber passes After the resin is infiltrated, it is collected into a heated mold cavity. The cavity of the mold has a sufficient length, and the cross section of the mold cavity is continuously twisted in one direction. Under the continuous tensile force of the traction mechanism, the resin impregnated with the resin After continuous walking in the mold and hardening by chemical reaction, the mold cavity is removed, and after cooling, a composite blade segment of a constant cross-section with a constant cross section of a specific chord length is obtained.

10. A method of forming a constant cross-section fiber reinforced resin composite blade segment according to claim 9, wherein: the resin-impregnated longitudinal continuous fibers are brought together to provide a transversely oriented fiber cloth or felt. Continuously passing through the heated mold cavity, the reaction solidifies and moves out of the mold, and after cooling, a composite blade segment having a constant cross section of a specific chord length is obtained.

11. A method of forming a constant cross-section fiber reinforced resin composite blade segment according to claim 9, wherein: the resin-impregnated longitudinal continuous fibers are brought together and continuously coated with a solid foam core material continuously. Through the heated mold cavity, the reaction solidifies and moves out of the mold, and after cooling, a composite blade segment having a constant cross-section of a particular chord length is obtained.

12. A method of forming a constant cross-section fiber reinforced resin composite blade segment according to claim 9, wherein: when the hollow constant cross-sectional segment (1) is pultrusion, the mold must have a cavity of the mold. The outer mold (511) and the inner cavity mold (512) have a cantilever support structure (513) extending outside the mold cavity at the inlet of the mold to support the cavity inner mold (512). In the cavity outer mold (511).

13. A method of forming a constant cross-section fiber reinforced resin composite blade segment according to claim 9, wherein: a synchronous roughening device (58), a synchronous spraying device

( 59 ) , in synchronization with the walking speed of the traction mechanism (57), complete the continuous construction of the outer protective coating of the constant cross-section of the cavity (1) after hardening and setting.