Design method of magnetic suspension thrust bearing of hydro-generator

Abstract

The application relates to the technical field of water-turbine generators and discloses a design method of a magnetic suspension thrust bearing of a water-turbine generator, which comprises the following steps: step 1, determining the design of a self-contained magnetic suspension ring; step 2, optimizing the structure of the magnetic suspension ring by using analysis software; step 3, adding a heat dissipation system and part structure elements to the optimized main structure; and step 4, checking whether the main structure can meet the mechanical performance requirements. The overall rigidity of the magnetic suspension thrust bearing of the water-turbine generator is improved.

Description

Technical Field

[0001] This invention relates to the field of hydro-generator technology, and specifically to a design method for a magnetic levitation thrust bearing for a hydro-generator. Background Technology

[0002] The thrust bearing of a hydro-generator mainly bears the axial load. Generally speaking, the larger the unit capacity, the greater the axial load. For conventional oil-lubricated thrust bearings, as the axial load increases, the thrust bearing will face many problems such as weakened structural support stiffness, reduced strength, increased friction loss, and reduced unit operating efficiency. Therefore, magnetic levitation thrust bearings for hydro-generators are currently used to solve the above problems. Although magnetic levitation thrust bearings for hydro-generators are more efficient and have lower losses than traditional lubricated thrust bearings, they have high requirements for overall stiffness. How to improve the overall stiffness of magnetic levitation thrust bearings is a technological gap. Summary of the Invention

[0003] To address the technical problem of improving the overall stiffness of magnetic levitation thrust bearings in hydro-generators, this invention provides a design method for magnetic levitation thrust bearings in hydro-generators, characterized by the following steps: Step 1: Determine the design of the independent magnetic levitation dynamic ring; Step 2: Optimize the magnetic levitation moving ring structure using analysis software; Step 3: Add a heat dissipation system and component structural elements to the optimized main structure; Step 4: Verify whether the main structure can meet the mechanical performance requirements.

[0004] To ensure the flatness of the magnetic levitation moving ring, in step 1, the magnetic levitation moving ring adopts a double-layer ring plate structure. The two ring plates are supported by radially arranged vertical ribs, and a bushing is set at the center of rotation.

[0005] Furthermore, in step 1, a magnetically levitated moving ring and a stationary ring are fitted onto the main shaft. Between the magnetically levitated moving ring and the stationary ring, there are staggered moving magnetic rings and stationary magnetic rings. The moving magnetic ring is fixed on the magnetically levitated moving ring, and the magnetically levitated moving ring drives the magnetic ring to rotate.

[0006] Preferably, in step 2, the main structure is subjected to stiffness and strength analysis using finite element analysis software. After the structural model is established using 3D modeling software, it is imported into the finite element analysis software to set material properties and generate a mesh. When setting boundary conditions, only compressive support is applied to the mating surface between the magnetic levitation moving ring and the main shaft. Thrust load is applied to the contact surface between the magnetic levitation moving ring and the moving magnetic ring. A rotational speed is applied to the magnetic levitation moving ring. During the calculation, the weak spring set in the finite element analysis software is turned on to stabilize the model, and the strength and displacement distribution diagram of the magnetic levitation moving ring are obtained.

[0007] To dissipate heat from the system, in step 3, the double-layer ring plate structure includes an upper ring plate and a lower ring plate. The lower ring plate has small holes between each magnetic ring, and the upper ring plate has larger holes at positions away from the rotation center. Then, the outer side of the magnetic levitation moving ring is completely sealed with a vertical wall.

[0008] Preferably, in step 4, the part where the main shaft and the magnetically levitated moving ring are connected is modeled, contact relationship and constraint conditions are set, and the stress and displacement distribution diagram of the magnetically levitated moving ring is calculated to determine whether the magnetically levitated moving ring meets the design specifications.

[0009] The present invention has the following beneficial effects: 1. This invention adopts an independent magnetic levitation dynamic ring design structure, and optimizes and analyzes the stiffness of the magnetic levitation dynamic ring structure and heat dissipation system respectively, thereby improving the stiffness of the bearing ring, reducing costs, and meeting the requirements for improving the overall stiffness of the magnetic levitation thrust bearing. Attached Figure Description

[0010] Figure 1 A schematic diagram of the overall layout of the magnetic levitation thrust bearing of a hydro-generator. Figure 2 This is a schematic diagram of the magnetically levitated moving ring. Detailed Implementation

[0011] The following detailed description illustrates the specific implementation method: 1. The reference numerals in the attached drawings of the instruction manual include: main shaft 1, magnetic levitation moving ring 2, stationary ring 3, moving magnetic ring 4, stationary magnetic ring 5, bushing 6, upper ring plate 7, lower ring plate 8, vertical rib 9, vertical wall 10.

[0012] Example 1 like Figure 1 and 2 As shown, a design method for a magnetic levitation thrust bearing of a hydro-generator includes the following steps: Step 1: Determine the overall layout scheme of the independent magnetic levitation moving ring 2. The magnetic levitation moving ring 2 directly cooperates with the main shaft 1. The magnetic levitation moving ring 2 adopts a double-layer ring plate structure, with radially arranged vertical ribs 9 supporting the two ring plates. A bushing 6 is set at the rotation center. The magnetic levitation moving ring 2 and the stationary ring 3 are sleeved on the main shaft 1. Between the magnetic levitation moving ring 2 and the stationary ring 3, there are staggered moving magnetic rings 4 and stationary magnetic rings 5. The moving magnetic rings 4 are fixed on the magnetic levitation moving ring 2, and the magnetic levitation moving ring 2 drives the magnetic rings 4 to rotate. Several moving magnetic rings 4 are arranged on the lower surface of the magnetic levitation moving ring 2. During operation, it is mainly subjected to the action of the moving magnetic rings 4 and the thrust of 590t from the lower surface of the magnetic levitation moving ring 2, as well as the centrifugal force at a rotation speed of 841 RPM. Step 2: Perform stiffness and strength analysis on the magnetic levitation ring 2 structure using finite element analysis software: After establishing the structural model using 3D modeling software, import it into the finite element analysis software, set material properties, and mesh. When setting boundary conditions, apply only compressive support to the mating surface between the magnetic levitation ring 2 and the main shaft 1; apply a thrust load of 590t to the contact surface between the magnetic levitation ring 2 and the moving magnetic ring 4; apply a rotational speed of 841RPM to the magnetic levitation ring 2; during calculation, enable the weak spring setting in the finite element analysis software to stabilize the model, and obtain the strength and displacement distribution diagrams of the magnetic levitation ring 2. According to the analysis results, it can be seen that under the action of thrust load and rotational centrifugal load, the stress of the magnetic levitation ring 2 is concentrated near the rotation center on the thrust load surface. Based on this, the model is reasonably modified, and structural reinforcement is carried out at this position to improve the stress condition of the model. Then, the overall height and material thickness of the magnetic levitation ring 2 are optimized and adjusted to reduce the maximum stress of the magnetic levitation ring 2 to below 200MPa and the warpage of the magnetic ring surface to below 1mm, thus obtaining the optimized magnetic levitation ring 2 model. Step 3: Add a heat dissipation system and component structure elements to the optimized magnetic levitation ring 2 model: The double-layer ring plate structure includes an upper ring plate 7 and a lower ring plate 8. When designing the ventilation system, consider using the rotation of the magnetic levitation ring 2 itself to form airflow for wind cooling. Small holes are opened between each magnetic ring in the lower ring plate 8, and larger holes are set in the upper ring plate 7 at positions away from the rotation center. Then, the outer side of the magnetic levitation ring 2 is completely sealed with a vertical wall 10 to obtain the structure diagram of the magnetic levitation ring 2. When the magnetic levitation ring 2 rotates, air flows in from the small holes in the lower ring plate 8 and flows out from the openings in the upper ring plate 7 to dissipate heat from the system. Step 4: Analyze the magnetic levitation moving ring 2 model using finite element analysis software to verify whether its stiffness and strength meet the design specifications. Ignoring the minor features of the magnetic levitation moving ring 2, model the magnetic levitation moving ring 2 and part of the main shaft 1. Then, in the finite element analysis software, set the contact relationship to frictionless support. When setting the boundary conditions, use radial free displacement support for the cross-section of the main shaft 1. Apply standard Earth gravity to the entire model. Apply a thrust load of 590t to the contact surface between the magnetic levitation moving ring 2 and the moving magnetic ring 4. Apply a rotational speed of 841RPM to the magnetic levitation moving ring 2 and the main shaft 1. Run the calculation example to obtain the strength and displacement distribution diagram of the magnetic levitation moving ring 2. It can be seen that the maximum stress of the magnetic levitation moving ring 2 is 177.13MPa, and the warpage of the magnetic ring contact area is 0.974mm, which meets the design requirements.

[0013] The above descriptions are merely embodiments of the present invention. Commonly known structures and characteristics are not described in detail here. Those skilled in the art are aware of all common technical knowledge in the field prior to the application date or priority date, are aware of all existing technologies in that field, and have the ability to apply conventional experimental methods prior to that date. Those skilled in the art can, under the guidance of this application, improve and implement this solution in combination with their own capabilities. Some typical known structures or methods should not be obstacles for those skilled in the art to implement this application. It should be noted that those skilled in the art can make several modifications and improvements without departing from the structure of the present invention. These should also be considered within the scope of protection of the present invention, and will not affect the effectiveness of the implementation of the present invention or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A design method for a magnetic levitation thrust bearing of a hydro-generator, characterized in that, Includes the following steps: Step 1: Determine the design of the independent magnetic levitation moving ring (2). The magnetic levitation moving ring (2) is directly connected to the main shaft (1). The magnetic levitation moving ring (2) adopts a double-layer ring plate structure. The two layers of ring plates are supported by radially arranged vertical ribs (9). A bushing (6) is set at the rotation center. The magnetic levitation moving ring (2) and the stationary ring (3) are sleeved on the main shaft (1). There are staggered moving magnetic rings (4) and stationary magnetic rings (5) between the magnetic levitation moving ring (2) and the stationary ring (3). The moving magnetic ring (4) is fixed on the magnetic levitation moving ring (2). The magnetic levitation moving ring (2) drives the magnetic ring (4) to rotate. Several moving magnetic rings (4) are arranged on the lower surface of the magnetic levitation moving ring (2). Step 2: Optimize the structure of the magnetic levitation moving ring (2) using analysis software; Step 3: Add a heat dissipation system and component structural elements to the optimized main structure; Step 4: Verify whether the main structure can meet the mechanical performance requirements.

2. The design method for magnetic levitation thrust bearing of a hydro-generator according to claim 1, characterized in that: In step 2, the main structure is subjected to stiffness and strength analysis using finite element analysis software. After the structural model is established using 3D modeling software, it is imported into the finite element analysis software to set material properties and generate a mesh. When setting boundary conditions, apply only compressive support to the mating surface of the magnetic levitation moving ring (2) and the main shaft (1); apply thrust load to the contact surface of the magnetic levitation moving ring (2) and the moving magnetic ring (4); A rotational speed is applied to the magnetically levitated moving ring (2). During the calculation, the weak spring setting in the finite element analysis software is turned on to stabilize the model, and the strength and displacement distribution diagram of the magnetically levitated moving ring (2) are obtained.

3. The design method for magnetic levitation thrust bearing of a hydro-generator according to any one of claims 1 and 2, characterized in that: In step 3, the double-layer ring plate structure includes an upper ring plate (7) and a lower ring plate (8). The lower ring plate (8) has small holes between each magnetic ring, and the upper ring plate (7) has larger holes at positions away from the rotation center. Then, the outer side of the magnetic levitation moving ring (2) is completely sealed with a vertical wall (10).

4. The design method for magnetic levitation thrust bearing of a hydro-generator according to claim 3, characterized in that: In step 4, the part of the main shaft (1) and the magnetic levitation moving ring (2) that are connected is modeled, the contact relationship and constraint conditions are set, the stress and displacement distribution diagram of the magnetic levitation moving ring (2) is calculated, and it is determined whether the magnetic levitation moving ring (2) meets the design specifications.

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