A high-damping integrated vibration reduction foundation suitable for nuclear power plant wind turbines

Abstract

This invention belongs to the field of vibration reduction technology for nuclear power plant fans, specifically relating to a high-damping integrated vibration reduction foundation suitable for nuclear power fan fans. It consists of a steel frame connected to a height-adjustable vibration damper. The steel frame is welded from high-damping composite channel steel, which is composed of conventional channel steel and particulate dampers. The height-adjustable vibration damper uses the housing as the installation reference. An upper annular metal rubber is inserted into its inner cavity, followed by the upper end of the mandrel being inserted into the inner hole of the upper annular metal rubber. Then, a lower annular metal rubber is inserted into the inner cavity of the housing, with its upper end face against the mandrel. A base is then placed on top, and rivets are used to connect the base and housing through four mounting holes. Finally, the internal thread of the mounting block is screwed into the external thread at the upper end of the mandrel. This invention effectively reduces the vibration level of the fan, ensuring safe operation of the fan.

Description

Technical Field

[0001] This invention belongs to the field of vibration reduction technology for nuclear power plant fans, specifically relating to a high-damping integrated vibration reduction foundation suitable for nuclear power fans. Background Technology

[0002] Centrifugal fans are widely used in nuclear power systems. Based on the transmission method between the impeller and the motor, they can be divided into two types: direct-drive and belt-driven. During operation, both the motor and the impeller rotate at high speed. Due to manufacturing or assembly factors, the fan can easily generate periodically changing disturbances (such as centrifugal force). These disturbances manifest externally as fan vibration. If the vibration level is too high, it poses a risk to the normal operation of the nuclear power unit, requiring shutdown for inspection and maintenance.

[0003] The foundations of existing nuclear power plant wind turbines mainly consist of steel frames and rubber / wire rope vibration dampers. The steel frames are typically made of channel steel, angle steel, square tubing, etc., cut and welded according to the installation conditions of the wind turbine at the project site. They primarily meet the installation requirements of the wind turbine, without considering the structure's vibration damping performance. Materials science research has shown that the structural loss factor of commonly used steel is only 0.0001–0.0006; therefore, the vibration damping performance of the steel frames used in wind turbine foundations is negligible. The vibration energy generated during wind turbine operation cannot be dissipated by the steel frame, meaning it cannot provide vibration damping.

[0004] On the other hand, nuclear power plant construction often employs concrete pouring techniques, and the same process is used in the turbine installation area. This results in poor levelness of the turbine installation platform. Rubber or wire rope vibration dampers are typically installed between the steel frame and the ground to provide elastic support for the turbine. However, due to the poor levelness of the installation platform, it is impossible to ensure that all vibration dampers are installed at the same level; some dampers bear heavy loads while others bear light loads. This makes it difficult to maintain the levelness of the steel frame during operation, thereby exacerbating turbine vibration. Summary of the Invention

[0005] The purpose of this invention is to provide a high-damping integrated vibration reduction foundation suitable for nuclear power plant fans, which meets the usage requirements of nuclear power plant fans in extreme environments, effectively reduces the vibration level of the fans, and ensures the safe operation of the fans.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A high-damping integrated vibration reduction foundation suitable for nuclear power plant fans is composed of a steel frame connected to a height-adjustable vibration damper. The steel frame is welded from high-damping composite channel steel, which is composed of conventional channel steel and particle dampers.

[0008] High-damping composite channel steel utilizes the existing cavity of the channel steel to weld partitions to form several cavities, and then fills the cavities with metal particles before welding the plugs.

[0009] The height-adjustable vibration damper uses the housing as the installation reference. The upper ring-shaped metal rubber is installed into its inner cavity, and then the upper end of the spindle is installed into the inner hole of the upper ring-shaped metal rubber. Next, the lower ring-shaped metal rubber is installed into the inner cavity of the housing, with the upper end face of the lower ring-shaped metal rubber attached to the spindle. The base is then covered, and rivets are used to rivet the base and the housing through the four mounting holes. Finally, the internal thread of the mounting block is screwed into the external thread at the upper end of the spindle.

[0010] The spindle is a stepped spindle.

[0011] Both the upper and lower ring-shaped metal rubber are made of 304 stainless steel.

[0012] Both the upper and lower annular metal rubber rings are manufactured through a process of winding dense spiral coils, stretching with a fixed pitch, winding blanks, and molding.

[0013] The upper ring-shaped metal rubber and the lower ring-shaped metal rubber are in parallel.

[0014] Under vertical vibration loads, vertical stiffness and damping are provided by the vertical elastic deformation of the upper and lower annular metal rubbers. Under horizontal loads, horizontal stiffness and damping are provided by the radial deformation of the upper and lower annular metal rubbers.

[0015] During the pouring of the installation platform, anchor bolts are pre-embedded. The mounting holes of the height-adjustable vibration damper are secured with anchor bolts and anchor nuts. The mounting holes of the steel frame are aligned with the center threaded holes of the height-adjustable vibration damper, and the fastening bolts are tightened to achieve a reliable connection between the steel frame and the height-adjustable vibration damper.

[0016] The design process of the steel frame is as follows: ① Create a 3D model of the wind turbine, including the motor and impeller, using 3D modeling software; ② Based on the location and size of the wind turbine mounting holes, use channel steel as the raw material to initially construct the steel frame to meet the installation requirements of the wind turbine; ③ Perform modal analysis on the wind turbine and the initial steel frame using finite element analysis software to obtain the modal frequencies, mode shapes, and modal displacements of each order; ④ During the design process, resonance between the wind turbine and the steel frame should be avoided, and the mode shapes at the operating speed should be analyzed in detail. Local reinforcement should be carried out in areas of large deformation of the steel frame, including increasing the number of channel steels and shortening the spacing between the channel steels; ⑤ Perform modal analysis on the locally reinforced steel frame to verify the results. The improvement effect of the enhanced part; ⑥ Install particle dampers in the area of ​​the wind turbine foot mounting point in the frame. Utilize the groove structure of the channel steel, arrange partitions in the channel steel to form a particle damping installation cavity, and fill it with metal particles to form a particle damping composite steel frame; ⑦ Analyze the energy consumption level of the composite steel frame using particle damping analysis software or open-source particle damping analysis software, and change the particle diameter, material, and filling rate to obtain better particle damping parameters; ⑧ Through the above design and analysis, the final particle damping composite steel frame can be obtained. The particle dampers are arranged in the area of ​​large modal displacement of the steel frame, and the area near the wind turbine foot hole is also the installation area of ​​the particle dampers.

[0017] The beneficial effects achieved by this invention are as follows:

[0018] This invention proposes a comprehensive vibration reduction foundation for nuclear power plant fans, consisting of a particle-damped composite steel frame and height-adjustable metal rubber vibration isolators. Compared to existing technologies, its advantages include: an all-metal structure with excellent environmental adaptability, meeting the requirements of extreme environments such as irradiation, high temperature, low temperature, and oil mist; and applicability for fan foundation vibration reduction in nuclear power plants, thermal power plants, etc. The spatial structure of the channel steel is utilized to combine the particle dampers with the channel steel to form a high-damping composite channel steel, thereby increasing the structural loss factor of the channel steel. This is then welded into a high-damping composite steel frame, which enhances the energy dissipation capacity of the steel frame and reduces the vibration level of the fan. Adjusting the height of the metal rubber vibration isolators ensures good levelness of the steel frame, improving the operating conditions of the fan. Attached Figure Description

[0019] Figure 1 A schematic diagram of a comprehensive vibration reduction foundation suitable for nuclear power plant fans;

[0020] Figure 2 The diagram shows the implementation scheme of high-damping composite channel steel, (a) channel steel welded partition, (b) filling metal particles, and (c) seam welded plug.

[0021] Figure 3 Schematic diagram of the installation of a height-adjustable metal-rubber vibration damper;

[0022] Figure 4The diagram shows a height-adjustable metal-rubber vibration damper, including (a) a cross-sectional view, (b) a top view, and (c) an exploded view.

[0023] Figure 5 This is a schematic diagram illustrating the height adjustment of a height-adjustable metal-rubber vibration damper.

[0024] Figure 6 This is a flowchart for the design and analysis of a composite damping steel frame.

[0025] In the diagram: 1-1 is channel steel; 1-2 is partition plate; 1-3 is metal granules; 1-4 is blocking plate; 1 is steel frame (channel steel); 2 is height-adjustable vibration damper; 3 is installation platform (cast foundation); 4 is anchor nut; 5 is anchor bolt; 6 is fastening bolt; 2-1 is mandrel; 2-2 is mounting block; 2-3 is shell; 2-4 is upper annular metal rubber; 2-5 is lower annular metal rubber; 2-6 is rivet; 2-7 is base. Detailed Implementation

[0026] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0027] This is a comprehensive vibration damping foundation for nuclear power plant wind turbines, consisting of a particle-damped composite steel frame 1 and height-adjustable metal-rubber vibration isolators 2. The particle-damped composite steel frame 1 is welded from high-damping composite channel steel. The high-damping composite channel steel is composed of conventional channel steel and particle dampers. The particle-damped composite steel frame 1 and the height-adjustable metal-rubber vibration isolators 2 are connected by bolts, and the height-adjustable metal-rubber vibration isolators are secured using bolts pre-embedded in the mounting platform.

[0028] The high-damping composite channel steel utilizes the existing cavity of the channel steel 1-1 to weld partition plates 1-2 to form several cavities. Metal particles 1-3 are then filled into these cavities, and plug plates 1-4 are welded in to ensure the particles are sealed. Vibration energy is dissipated through collisions between the metal particles and between the metal particles and the structural steel, thereby increasing the structural loss factor of the channel steel, which in turn increases the structural loss factor of the particle-damped composite steel frame 1, ultimately reducing the vibration level of the wind turbine.

[0029] The height-adjustable metal-rubber vibration damper 2 is composed of a spindle 2-1, a mounting block 2-2, a housing 2-3, an upper annular metal rubber 2-4, a lower annular metal rubber 2-5, a rivet 2-6, and a base 2-7. The upper annular metal rubber 2-4 and the lower annular metal rubber 2-5 serve as elastic damping elements of the damper, acting together as elastic supports. Under external excitation loads, sliding friction occurs between the metal wires in contact between the upper and lower annular metal rubber 2-4 and 2-5, thereby dissipating vibration energy. The upper end of the spindle 2-1 is machined with external threads and an internally threaded through hole. The mounting block 2-2 is machined with internal threads, which mate with the external threads at the upper end of the spindle 2-1.

[0030] The installation of each component of the height-adjustable metal-rubber vibration damper 2 is as follows: Figure 4 As shown in (c), with the housing 2-3 as the installation reference, the upper annular metal rubber 2-4 is installed into its inner cavity. Then, the upper end of the mandrel 2-1 is installed into the inner hole of the upper annular metal rubber 2-4. Next, the lower annular metal rubber 2-5 is installed into the inner cavity of the housing. The upper end face of the lower annular metal rubber 2-5 is attached to the mandrel 2-1. The base 2-7 is covered, and the base 2-7 and the housing 2-3 are riveted by using rivets 2-6 through the four mounting holes of the base 2-7 and the housing 2-3. Finally, the internal thread of the mounting block 2-2 is screwed into the external thread at the upper end of the mandrel 2-1.

[0031] By adjusting the thread engagement length between the mounting block 2-1 and the spindle 2-2, the height of the metal rubber damper 2 can be adjusted, thereby enabling the particle damping composite steel frame 1 to maintain a good level.

[0032] The key points and intended protection points of this invention are: by increasing the structural loss factor of the steel frame (increasing particle damping), the vibration level of the wind turbine can be effectively reduced. By increasing the energy dissipation level of the damper through dry friction energy dissipation of the internal metal wires of the metal rubber damper, the vibration energy of the wind turbine can be effectively dissipated. Regarding the issue of wind turbine installation levelness, the height adjustment of the metal rubber damper can ensure the wind turbine's installation levelness.

[0033] The high-damping integrated vibration reduction foundation for nuclear power wind turbines proposed in this invention is composed of a particle-damped composite steel frame 1 and a height-adjustable metal rubber vibration damper 2.

[0034] The design process of particle-damped composite steel frames is as follows: Figure 6As shown. ① A 3D model of the wind turbine (including the motor and impeller) is created using 3D modeling software; ② Based on the location and size of the wind turbine mounting holes, an initial steel frame is constructed using channel steel to initially meet the wind turbine's installation requirements; ③ Modal analysis of the wind turbine and the initial steel frame is performed using commercial finite element analysis software to obtain the modal frequencies, mode shapes, and modal displacements of each order; ④ During the design process, resonance between the wind turbine and the steel frame must be avoided, and the mode shape analysis should focus on the operating speed (operating frequency). Local reinforcement should be carried out in areas of large deformation of the steel frame (e.g., increasing the number of channel steels or shortening the spacing between channel steels); ⑤ Modal analysis was performed on the locally reinforced steel frame to verify the improvement effect of the local reinforcement; ⑥ Particle dampers were installed in the area of ​​the frame near the wind turbine mounting points. Utilizing the unique groove structure of the channel steel, partitions were arranged in the channel steel to form particle damping installation cavities, which were then filled with metal particles to form a particle-damped composite steel frame; ⑦ The energy consumption level of the composite steel frame was analyzed using commercial or open-source particle damping analysis software. By changing the particle diameter, material, and filling rate, optimal particle damping parameters were obtained; ⑧ The final particle-damped composite steel frame was obtained through the above design and analysis. Particle dampers are mainly arranged in areas of large modal displacement of the steel frame. Simultaneously, the area near the wind turbine mounting holes is also an installation area for particle dampers.

[0035] After determining the scheme of the particle damping composite steel frame 1, it can be decomposed into several high-damping composite channel steels. The partition plate 1-2 and the channel steel 1-1 can be welded together. After the metal particles 1-3 are filled, the blocking plate 1-4 is welded to the particle damping area by welding together to achieve the sealing of particle damping and form a high-damping composite channel steel. Finally, the high-damping composite channel steel is welded into a particle damping composite steel frame.

[0036] The height-adjustable metal-rubber vibration damper 2 consists of a spindle 2-1, a mounting block 2-2, a housing 2-3, an upper annular metal rubber 2-4, a lower annular metal rubber 2-5, a rivet 2-6, and a base 2-7. The spindle 2-1 is a stepped shaft with external threads machined at the upper end and a threaded through hole in the middle. The mounting block 2-2 has an internally threaded hole. The internal thread of the mounting block 2-2 mates with the external thread of the spindle 2-1, and the height of the vibration damper can be adjusted by adjusting the length of the thread engagement. Both the upper annular metal rubber 2-4 and the lower annular metal rubber 2-5 are all-metal elastic damping elements made of 304 stainless steel through processes such as spiral winding with dense turns -> fixed pitch stretching -> winding blank -> molding. The outer diameters of both the upper annular metal rubber 2-4 and the lower annular metal rubber 2-5 are the same as the inner diameter of the housing 2-3 of the vibration damper.

[0037] Both the housing 2-3 and the base 2-7 have six through holes machined in them. The housing 2-3 and the base 2-7 are connected and fastened with four rivets 2-6. The remaining two sets of through holes are used for the height-adjustable metal rubber vibration damper 2 to pass through the anchor bolts 5 pre-embedded on the mounting platform 6 to achieve the installation of the height-adjustable metal rubber vibration damper 2.

[0038] In the vibration damper, the upper annular metal rubber 2-4 and the lower annular metal rubber 2-5 are connected in parallel. Under vertical vibration loads, the vertical elastic deformation of the upper annular metal rubber 2-4 and the lower annular metal rubber 2-5 provides vertical stiffness and damping for the vibration damper. Under horizontal loads, the radial deformation of the upper annular metal rubber 2-4 and the lower annular metal rubber 2-5 provides horizontal stiffness and damping for the height-adjustable metal rubber vibration damper 2.

[0039] The installation diagram of the height-adjustable metal-rubber vibration damper 2 is as follows: Figure 3 As shown. During the pouring of the installation platform 3, anchor bolts 5 are pre-embedded. The mounting holes of the height-adjustable metal rubber vibration damper 2 are passed through the anchor bolts 5, and the anchor nuts 4 are used to tighten them, thus achieving the installation of the height-adjustable metal rubber vibration damper 2 on the installation platform 3. Align the mounting holes of the steel frame 2 with the center threaded holes of the height-adjustable metal rubber vibration damper 2, and tighten the fixing bolts 6 to achieve a reliable connection between the steel frame 1 and the height-adjustable metal rubber vibration damper 2.

Claims

1. A high-damping integrated vibration reduction foundation suitable for nuclear power fan, characterized in that: The steel frame is connected with the height-adjustable damper, the steel frame is welded by high-damping composite channel steel, and the high-damping composite channel steel is composed of a conventional channel steel and a particle damper. The high-damping composite channel steel utilizes the existing cavity of the channel steel to weld a plurality of cavities by a partition plate, and metal particles are filled into the cavities and then a blocking plate is welded. The height-adjustable damper takes a shell as a mounting reference, an upper annular metal rubber is mounted in the inner cavity of the shell, the upper end of a mandrel is mounted into the inner hole of the upper annular metal rubber, a lower annular metal rubber is mounted in the inner cavity of the shell, the upper end surface of the lower annular metal rubber is mounted against the mandrel, a base is covered, rivets are passed through four mounting holes of the base and the shell to realize riveting, and finally the internal thread of a mounting block is screwed into the external thread of the upper end of the mandrel. Under the action of vertical vibration load, vertical stiffness and damping are provided by vertical elastic deformation of the upper annular metal rubber and the lower annular metal rubber, and under the action of horizontal load, horizontal stiffness and damping are provided by radial deformation of the upper annular metal rubber and the lower annular metal rubber.

2. The high-damping integrated vibration isolation foundation suitable for nuclear power fan according to claim 1, characterized in that: The mandrel is a stepped shaft.

3. The high damping composite vibration isolation mount suitable for nuclear power plant service of claim 1, wherein: The upper annular metal rubber and the lower annular metal rubber are made of 304 stainless steel.

4. The high damping composite vibration isolation mount suitable for nuclear power plant service of claim 1, wherein: The upper annular metal rubber and the lower annular metal rubber are made by the process of winding a dense spiral, constant-pitch stretching, winding a blank and die forming.

5. The high damping composite vibration isolation mount suitable for nuclear power plant service of claim 1, wherein: The upper annular metal rubber and the lower annular metal rubber are in a parallel state.

6. The high damping composite vibration isolation mount suitable for nuclear power plant service of claim 1, wherein: During pouring of the mounting platform, foundation bolts are embedded in advance, the mounting through hole of the height-adjustable damper is fastened by the foundation bolts with foundation nuts, the mounting hole of the steel frame is aligned with the center threaded hole of the height-adjustable damper, and the fastening bolts are tightened to realize reliable connection of the steel frame and the height-adjustable damper.

7. The high damping composite vibration isolation mount suitable for nuclear power plant service of claim 1, wherein: The design process of the steel frame is as follows: ① a three-dimensional model of the fan including a motor and a wind wheel is established by using a three-dimensional modeling software; ② according to the position and size of the fan mounting hole, an initial steel frame is made of channel steel to preliminarily meet the installation requirements of the fan; ③ modal analysis is performed on the fan and the initial steel frame by using a finite element analysis software to obtain modal frequencies, modal shapes and modal displacements of each order; ④ resonance of the fan and the steel frame is avoided during the design process, and the vibration mode under the working speed is analyzed, and local reinforcement is performed in the area where the deformation of the steel frame is large, including increasing the number of channel steels and shortening the spacing of the channel steels; ⑤ modal analysis is performed on the locally reinforced steel frame to verify the improvement effect of the local reinforcement; ⑥ particle dampers are arranged in the area of the fan foot mounting point in the frame, the recess structure of the channel steel is utilized to arrange a partition plate to form a particle damper installation cavity, and metal particles are filled to form a particle damping composite steel frame; ⑦ the energy dissipation level of the composite steel frame is analyzed by using a particle damper analysis software, the particle diameter, material and filling rate are changed to obtain optimal particle damper parameters; and ⑧ the final particle damping composite steel frame is obtained through the above design and analysis, the particle dampers are arranged in the area where the modal displacement of the steel frame is large, and the area near the fan foot hole is also the installation area of the particle dampers.

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