Circular steel tube concrete composite wind turbine tower structure

Abstract

The present invention provides a circular steel tube concrete combined wind turbine tower structure, the tower structure includes an upper steel tower and a lower steel tube concrete tower, the steel tube concrete tower is composed of multiple circular steel tube concrete tower sections; the steel tube concrete tower section includes an inner and outer double-layer steel tube, the inner and outer steel tubes are connected at the upper and lower ends of the tower section, a grouting space is formed between the two, and concrete is poured and filled. The present invention meets the requirements of high-altitude and large-scale wind turbines, the total height of the upper steel tower and the lower steel tube concrete tower can reach no less than 150m, and it is easy to manufacture, transport and install, can be reused, and reduces costs.

Description

Technical Field

[0001] The invention belongs to the technical field of high towers of wind turbine generator sets in low wind speed areas. Background Art

[0002] At present, most of the traditional wind turbine support structures in my country use steel conical towers. However, with the rapid development of my country's wind power industry, the capacity of wind turbines is getting larger and larger. In order to effectively utilize the wind energy resources in low wind speed areas, wind turbines are gradually developing towards large-scale and high-altitude, and the requirements for the hub height and stiffness are increasing. When the hub height exceeds 100m, the diameter of the bottom section of the traditional conical steel tower will exceed the size limit of conventional road transportation, and as the height of the steel cylinder increases, its overall stiffness decreases, which will induce the adverse vibration characteristics of the wind turbine, thereby limiting the development of high-tower wind turbine technology. At present, prestressed steel-concrete towers and flexible towers have received certain attention and promotion and application in the field of high-tower wind power technology because both can meet the requirements of hub height and stiffness of large wind turbines. However, factors such as the long construction period of prestressed steel-concrete tower structures, the high cost of prestressed steel strands, and the complex tensioning and operation and maintenance procedures restrict the development of steel-concrete towers. As the hub height of the flexible tower increases, the overall flexibility of the tower increases, resulting in excessive displacement of the tower top, prominent fatigue damage problems, and serious impact on the normal operation of the wind turbine. In addition, the first-order natural frequency of the flexible tower is low and has entered the range of the impeller rotation frequency, so it will resonate at a certain speed of the impeller. Although the wind turbine can quickly skip this speed by adjusting the control strategy, it will lose about 3% to 5% of the power generation. It can be seen that the existing high tower technology solution still has obvious limitations. Summary of the invention

[0003] The purpose of the present invention is to provide a circular steel tube concrete combined wind turbine tower structure to solve the above problems, which meets the requirements of high altitude and large-scale wind turbines, and is easy to manufacture, transport and install, can be reused, and reduces costs. To this end, the present invention adopts the following technical solutions:

[0004] The circular steel tube concrete combined wind turbine tower structure is characterized in that: the tower structure includes an upper steel tower and a lower steel tube concrete tower, and the steel tube concrete tower is composed of multiple circular steel tube concrete tower sections; the steel tube concrete tower section includes an inner and outer double-layer steel tube, and the inner and outer steel tubes are connected at the upper and lower ends of the tower section to form a grouting space between the two, and concrete is poured and filled.

[0005] The total height of the upper steel tower and the lower steel tube concrete tower of the present invention can reach no less than 150m.

[0006] On the basis of adopting the above technical solution, the present invention can also adopt the following further technical solutions or use these further technical solutions in combination:

[0007] Horizontal and vertical shear keys are welded on the inner wall of the double-layer steel cylinder to enhance the shear resistance of the concrete.

[0008] The double-layer steel tube of the steel tube concrete tower section is prefabricated in batches in the factory, and its diameter does not exceed 4.3m, which can meet the requirements of road transportation; a number of grouting holes and grouting holes are opened in the inner steel tube corresponding to the grouting space, and each steel tube concrete tower section is connected section by section by pouring concrete on site and then hoisting.

[0009] The concrete grouting material is added with a micro-expansion agent to solve the shrinkage problem during the concrete setting process.

[0010] The bottom of the bottom section of the concrete-filled steel tube tower is connected to the wind turbine foundation, and the top of the top section of the concrete-filled steel tube tower is connected to the steel tower.

[0011] A T-shaped flange is arranged at the bottom of the bottom section of the steel tube concrete tower, which is connected to the wind turbine foundation through foundation anchor bolts; a door opening is opened in the bottom section of the steel tube concrete tower, and a door frame is arranged inside the door opening; the upper and lower adjacent steel tube concrete tower sections are connected through L-shaped flanges and bolt assemblies; an L-shaped flange is arranged at the top of the top section of the steel tube concrete tower section, and is connected to the steel tower through a bolt assembly.

[0012] The outer diameter of the steel tube concrete tower remains consistent, and the steel plate wall thickness of the inner and outer steel tubes is controlled between 16mm and 20mm according to the overall stress characteristics; the steel plate of the inner steel tube is welded with upper and lower sealing plates at the top and bottom respectively, so that the inner steel tube gradually transitions to the intersection with the outer steel tube. The intersection position is still some distance away from the end of the steel tube concrete tower, and the overall steel plate thickness after the intersection is ensured to be the sum of the thickness of the inner and outer steel tubes, so as to reserve installation space for the bolt assembly for connecting the steel tube concrete tower sections while ensuring the tower strength requirements.

[0013] Furthermore, the height of the lower steel tube concrete tower is greater than that of the upper steel tower.

[0014] The beneficial effects of the present invention are:

[0015] (1) The circular steel tube concrete composite wind turbine tower structure proposed in the present invention has a reasonable design, reliable structure, firm connection, convenient transportation, batch process construction, modular installation, and can be recycled and reused in the post-wind power era. It can greatly shorten the on-site construction period and has significant economic and environmental benefits.

[0016] (2) The lower part adopts several steel tube concrete tower structures, and the upper part is connected to the traditional steel tower. On the basis of ensuring the safe and stable operation of the wind turbine, the hub height of the wind turbine can be greatly increased to more than 150m, which can meet the development requirements of large-scale and high-altitude wind turbines and effectively utilize the wind resources in low wind speed areas. At the same time, the diameter of the tower can be reduced to meet the needs of road transportation, and there is no need to prefabricate and transport it in pieces like the previous concrete tower. On-site splicing and maintenance can greatly facilitate transportation, reduce the difficulty of on-site construction, and significantly shorten the construction period and reduce costs.

[0017] (3) The use of high-strength concrete poured into double-layer steel pipes can enhance the overall stiffness of the tower and reduce the amplitude. On the one hand, it can effectively avoid the structural fatigue problem caused by the periodic large swing of the tower. On the other hand, the natural frequency of the tower is increased, which can effectively avoid the rotation frequency of the fan impeller to avoid resonance.

[0018] (4) It can fundamentally change the limitations of prestressed steel-concrete towers, such as long construction period, expensive prestressed steel strands, small stiffness of flexible towers, large amplitude, severe fatigue damage problems, and frequency crossing. It can break through the bottleneck of existing high-tower solutions and provide a new type of ultra-high tower solution for future low wind speed areas. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is an overall elevation view of an embodiment of the circular steel tube concrete combined wind turbine tower structure of the present invention.

[0020] Figure 2 It is an elevation view of a circular steel tube concrete tower segment in an embodiment of the present invention.

[0021] Figure 3 It is a partial schematic diagram of the connection between the bottom section of the circular steel tube concrete tower and the foundation in an embodiment of the present invention.

[0022] Figure 4 It is a partial schematic diagram of the connection between the circular steel tube concrete tower segments in an embodiment of the present invention.

[0023] Figure 5 It is a horizontal cross-sectional view of a circular steel tube concrete tower in an embodiment of the present invention. DETAILED DESCRIPTION

[0024] The present embodiment is an ultra-high tower with a hub height of 150m, wherein the upper part is a 50m traditional steel tower 2, and the lower part is a steel tube concrete tower composed of four sections of circular steel tube concrete tower sections 3, each of which is 25m high. The present invention is further described in detail below in conjunction with the accompanying drawings.

[0025] like Figure 1~Figure 5As shown, the circular steel tube concrete composite wind turbine tower structure in this embodiment includes four 25m high circular steel tube concrete tower sections 3. The super high tower wind turbine unit comprises a wind turbine head 1, a steel tower 2, a steel tube concrete tower section 3 and a wind turbine foundation 4 from top to bottom.

[0026] The steel tower 2 is composed of a plurality of steel tower sections connected together.

[0027] The steel tube concrete tower section 3 is provided with inner and outer double-layer steel cylinders 6 and 7, and the wall thickness of the inner and outer double-layer steel cylinders is 18mm; steel bars with a diameter of 25mm are welded on the inner wall of the double-layer steel cylinder to serve as horizontal shear keys 19 and vertical shear keys 20 to enhance the shear resistance of concrete. The double-layer steel cylinder part of the steel tube concrete tower structure is prefabricated in batches in the factory, and the outer diameter of the tower is 4.3m, which can meet the requirements of highway transportation; the main wall thickness of the steel tube concrete tower section 3 is 300mm, and a grouting space is formed between the inner and outer steel cylinders; corresponding to the grouting space, two grouting holes 12 are opened at the bottom and middle positions of the inner steel plate of each section of the steel cylinder, and two grouting holes 13 are opened at the top position of the inner steel plate. The grouting space in the double-layer steel cylinder adopts high-pressure grouting to pour high-strength concrete 8 to increase the overall rigidity of the tower.

[0028] The high-strength concrete grouting material has micro-expansion, self-compactness, low bubbles and high fluidity, so as to solve the shrinkage problem in the concrete setting process and ensure that the concrete grouting material can meet the design requirements in a self-compacting state without vibration.

[0029] As a preferred solution, C50 concrete grouting material is used in this embodiment. Considering that each section of the steel tube concrete tower section 3 is 25m high, the first-level pumping scheme starts from the bottom of the tower section and directly transports and lifts the concrete to the top. Continuous pouring is difficult and the compactness of the concrete is difficult to ensure. Taking comprehensive consideration, the second-level pumping grouting is adopted. The specific pouring scheme is as follows: (1) Before pouring concrete, pump clean water once to keep the inner wall of the grouting space of the double-layer steel pipes 6 and 7 clean and moist to reduce the effect of pumping resistance. Remove the accumulated water 1 hour before grouting; (2) Place the first-level pump and the second-level pump near the grouting holes 12 near the bottom and the middle of the steel tube concrete tower section 3 respectively; (3) Keep the two grouting holes 12 in the middle and the two grouting holes 13 at the top open, and use the first-level pump to synchronously pour high-strength concrete grouting material through the two grouting holes 12 near the bottom until the two grouting holes in the middle are (4) Close the two grouting holes 12 near the bottom, keep the two outlet holes 13 near the top open, and use a two-stage pump to grout through the two middle grouting holes simultaneously until the two outlet holes 13 at the top both slurry spurt out; (5) Concrete does not need to be vibrated during the jacking process, and only relies on the pumping pressure and the vibration-free self-compactness of concrete to achieve compactness; the concrete jacking height can be determined by the hammering method during the pumping process, and the pumping pressure and flow rate can be controlled to ensure that the concrete pumping progress difference at the same tower elevation does not exceed 1m; (6) Concrete pouring in the steel pipe should be carried out continuously; (7) After the outlet holes slurry spurt out, use an inserted vibrator to vibrate several times. When the concrete in the pipe no longer sinks and bubbles, stop pumping grouting and seal the grouting holes 12 and outlet holes 13. If the on-site construction equipment and site permit, the grouting of each segment of the steel tube concrete tower section 3 can be carried out synchronously or continuously.

[0030] The steel tube concrete tower section 3 is installed by hoisting from bottom to top, and each section of the steel tube concrete tower section 3 can be hoisted only after the grouting is completed and the concrete 8 solidifies to the designed strength.

[0031] like Figure 3 As shown, a T-shaped bottom flange 16 is arranged at the bottom of the bottom steel tube concrete tower section 3 , the flange thickness is 100 mm, and both sides of the T-shaped flange 16 are connected to the wind turbine foundation 4 through foundation anchor bolts 17 .

[0032] like Figure 1 As shown, the bottom section of the steel tube concrete tower section 3 is provided with a door opening 5, the center of which is located 3m above the upper surface of the foundation. An elliptical door frame 18 is installed inside the door opening 5. The door frame is 40mm thick and is welded from two semi-elliptical steel plates.

[0033] Each section of the steel tube concrete tower section 3 is connected by an L-shaped flange 9 and a bolt assembly 15. Figure 4As shown, the flange thickness is 100mm. In order to reserve installation space for bolt assembly 15 between the steel tube concrete tower segments, the steel plate 7 inside the steel tube concrete tower is welded with upper sealing plate 11 and lower sealing plate 10 at a distance of 1m from the upper and lower flanges, so that the inner steel cylinder 7 gradually transitions to intersect with the outer steel cylinder 6. The thickness of the steel plate 14 after the intersection is 36mm, which is the sum of the thickness of the inner and outer steel cylinders, so as to ensure the overall strength and rigidity requirements of the tower.

[0034] An L-shaped flange 9 with a thickness of 100 mm is arranged on the top of the top steel tube concrete tower section 3 , and is connected to the upper conventional steel tower section 2 via a bolt assembly 15 .

[0035] Furthermore, in the embodiment, all welds need to be polished to eliminate residual stress, all bolt assemblies 15 and foundation anchor bolts 17 need to be treated with anti-corrosion, and waterproof sealant needs to be applied to the connection between each segment tower.

[0036] The above embodiment is only a preferred technical solution of the present invention. Those skilled in the art should understand that the technical solutions or parameters in the embodiments can be modified or replaced without departing from the principle and essence of the present invention, and all should be covered within the protection scope of the present invention.

Claims

1. The circular steel tube concrete combined wind turbine tower structure is characterized by: The tower structure includes an upper steel tower and a lower steel tube concrete tower, wherein the steel tube concrete tower is formed by connecting multiple sections of circular steel tube concrete tower sections; the steel tube concrete tower section includes an inner and outer double-layer steel tube, which are connected at the upper and lower ends of the tower section, and a grouting space is formed between the inner and outer layers of the steel tube, and concrete is poured to increase the overall stiffness of the tower, increase the natural frequency of the tower, and effectively avoid the rotation frequency of the fan impeller to avoid resonance; The outer diameter of the steel tube concrete tower is kept consistent, and the wall thickness of the steel plate of the inner and outer steel tubes is controlled between 16mm and 20mm according to the overall stress characteristics; the steel plate of the inner steel tube is welded with an upper sealing plate and a lower sealing plate at the upper and lower parts respectively, so that the inner steel tube gradually transitions to the intersection with the outer steel tube, and the intersection position is still a distance away from the end of the steel tube concrete tower, and the overall steel plate thickness after the intersection is ensured to be the sum of the thickness of the inner and outer steel tubes, so as to reserve the installation space for the bolt assembly for connecting the steel tube concrete tower sections under the premise of ensuring the tower strength requirements; The total height of the upper steel tower and the lower steel tube concrete tower is no less than 150m.

2. The circular steel tube concrete composite wind turbine tower structure according to claim 1 is characterized in that: Horizontal and vertical shear keys are welded on the inner wall of the double-layer steel cylinder to enhance the shear resistance of the concrete.

3. The circular steel tube concrete composite wind turbine tower structure according to claim 1 is characterized in that: The double-layer steel tube of the steel tube concrete tower section is prefabricated in batches in the factory, and its diameter does not exceed 4.3m, which can meet the requirements of road transportation; a number of grouting holes and grouting holes are opened in the inner steel tube corresponding to the grouting space, and each steel tube concrete tower section is connected section by section by pouring concrete on site and then hoisting.

4. The circular steel tube concrete composite wind turbine tower structure according to claim 1 is characterized in that: Micro-expansion agent is added to concrete grouting material to solve the shrinkage problem during the concrete setting process.

5. The circular steel tube concrete composite wind turbine tower structure according to claim 1 is characterized in that: The bottom of the bottom section of the concrete-filled steel tube tower is connected to the wind turbine foundation, and the top of the top section of the concrete-filled steel tube tower is connected to the steel tower.

6. The circular steel tube concrete composite wind turbine tower structure according to claim 1 is characterized by: A T-shaped flange is arranged at the bottom of the bottom section of the steel tube concrete tower, which is connected to the wind turbine foundation through foundation anchor bolts; a door opening is opened in the bottom section of the steel tube concrete tower, and a door frame is arranged inside the door opening; the upper and lower adjacent steel tube concrete tower sections are connected through L-shaped flanges and bolt assemblies; an L-shaped flange is arranged at the top of the top section of the steel tube concrete tower section, and is connected to the steel tower through a bolt assembly.

7. The circular steel tube concrete composite wind turbine tower structure according to claim 1 is characterized by: The lower concrete-filled steel tube tower has a height greater than that of the upper steel tower.

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