A support structure for improving the dynamic performance and anti-deformation performance of the low-pressure outer cylinder of a high-power steam turbine

Abstract

The present invention discloses a support structure for improving the dynamic performance and anti-deformation performance of the low-pressure outer cylinder of a high-power steam turbine. There is an exhaust passage between the first inner support plate and the outer end plate of the low-pressure outer cylinder, and multiple original support pipes are fixedly connected between the first inner support plate and the outer end plate; a chamber is formed by the first inner support plate, the second inner support plate, the side rib plates and the side end plates of the low-pressure outer cylinder; the support structure includes a first support structure arranged in the chamber and a second support structure arranged in the exhaust passage; the first support structure includes an axial support plate fixedly connected to the first inner support plate and the second inner support plate, and multiple transverse support plates fixedly connected to the axial support plate and the side rib plates; the second support structure is fixedly connected to the first inner support plate and the outer end plate, and the second support structure is composed of multiple flow channel support pipes, and the flow channel support pipes are in the same plane as the axial support plate in the axial direction. The support structure of the present invention is simple in structure and convenient for on-site reinforcement, and can significantly improve the dynamic performance and anti-deformation performance of the low-pressure cylinder.

Description

Technical Field

[0001] The invention belongs to the technical field of steam turbine power generation, and particularly relates to a support structure for the dynamic performance and anti-deformation performance of a low-pressure outer cylinder. Background Art

[0002] Different from medium and small power steam turbines, the general structure of the low-pressure outer cylinder of large power steam turbines is complex, the overall size is large, and the vibration state is extremely susceptible to the influence of rotor unbalance and vacuum change. Therefore, during the operation of the unit, there is generally a problem of excessive vibration, which seriously affects the stable operation of the unit and often leads to the situation where the vibration amplitude exceeds the standard.

[0003] Limited by the existing conditions of the power plant (such as the layout of pipelines, workshops, etc.), the scope of transformation is usually the moving and static related components such as the flow-through blades, diaphragms, and inner cylinders. To ensure a feasible on-site reinforcement scheme for the low-pressure outer cylinder without replacing the low-pressure outer cylinder and without affecting the assembly relationship between the low-pressure inner and outer cylinders. Implementing the reinforcement scheme to significantly improve the dynamic performance and anti-deformation ability of the low-pressure outer cylinder and reduce the vibration amplitude of the low-pressure cylinder bearing seat is a major difficulty in the transformation of the low-pressure outer cylinder of large power steam turbines. Summary of the Invention

[0004] The technical problem to be solved by the present invention is: aiming at the above problems, a support structure for improving the dynamic performance and anti-deformation performance of the low-pressure outer cylinder of a large power steam turbine is provided, which has a simple structure, is convenient for on-site reinforcement, can improve the dynamic performance and anti-deformation ability of the low-pressure outer cylinder, and reduce the vibration amplitude of the low-pressure cylinder bearing seat.

[0005] The technical object of the present invention is achieved by the following technical solutions:

[0006] A support structure for improving the dynamic performance and anti-deformation performance of the low-pressure outer cylinder of a large power steam turbine. There is an exhaust passage between the first inner support plate and the outer end plate of the low-pressure outer cylinder, and multiple original support pipes are fixedly connected between the first inner support plate and the outer end plate; a chamber is formed by the first inner support plate, the second inner support plate, the side rib plates, and the side end plates of the low-pressure outer cylinder; the support structure includes a first support structure arranged in the chamber and a second support structure arranged in the exhaust passage; the first support structure includes an axial support plate fixedly connected to the first inner support plate and the second inner support plate, and multiple transverse support plates fixedly connected to the axial support plate and the side rib plates; the second support structure is fixedly connected to the first inner support plate and the outer end plate, and the second support structure is composed of multiple flow channel support pipes, and the flow channel support pipes are in the same plane as the axial support plate in the axial direction.

[0007] The overall height of the axial support plate of the first support structure is less than the height of the side rib plate, and the lower end of the axial support plate is in a suspended state; the transverse support plate is trapezoidal as a whole, and the height of the end connected to the side rib plate is the same as the height of the side rib plate, and the height of the end connected to the axial support plate is the same as the height of the axial support plate.

[0008] The axial support plate is inclined downward at a certain angle.

[0009] There are two transverse support plates, which are respectively located at the one-third points in the axial direction of the side rib plate.

[0010] There are two flow channel support pipes in the second support structure, and they are arranged in a "Z" shape in the axial space with the two original support pipes.

[0011] The thickness of the axial support plate and the transverse support plate is 30 mm to 50 mm.

[0012] The diameter of the flow channel support pipe is 120 mm to 160 mm, and the thickness of its pipe wall is 16 mm to 22 mm.

[0013] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0014] 1. The first support structure of the present invention adopts a combined structure of multiple support plates, which has a simple structure and is convenient for on-site reinforcement. The thickness of the axial support plate and the transverse support plate together play a role in reinforcing the surrounding side rib plates and change the vibration characteristics of the original side rib plates. Adopting this technical measure can significantly change the anti-vibration and anti-deformation performance of the low-pressure outer cylinder and the bearing pedestal. The second support structure is composed of multiple flow channel support pipes, and the flow channel support pipes are in the same plane as the axial support plate in the axial direction. The second support structure has a simple structure and is convenient for on-site reinforcement. The second support structure and the axial support plate form an axial support structure group, which further improves the axial anti-deformation ability of the low-pressure outer cylinder; the second support structure can effectively reduce the influence of the vacuum load on the bearing pedestal, and at the same time reduce the influence of the welding deformation of the first support structure on the inner cylinder positioning surface. This support structure can significantly change the vibration frequency of the low-pressure cylinder, reduce the influence of the vacuum load and the rotor unbalance on the low-pressure cylinder bearing pedestal, reduce the vibration amplitude of the low-pressure cylinder, and improve the dynamic performance and anti-deformation performance of the low-pressure cylinder. Therefore, through the first support structure and the second support structure, the natural frequency of the low-pressure outer cylinder can be effectively changed, so that the dynamic stiffness level of the bearing pedestal of the low-pressure outer cylinder near the rotor resonance frequency of 50 Hz is 13 to 20 times that before the transformation, reducing the sensitivity of the vibration characteristics of the low-pressure outer cylinder to changes in conditions such as load and working conditions, and significantly changing the anti-vibration and anti-deformation performance of the low-pressure outer cylinder and the bearing pedestal. It effectively reduces the influence of the rotor unbalance on the bearing pedestal, improves the dynamic performance and anti-deformation ability of the low-pressure cylinder, and ensures the safe and reliable operation of the unit.

[0015] 2. The overall height of the axial support plate of the first support structure of the present invention is less than the height of the side rib plate, and the lower end of the axial support plate is in a suspended state; the transverse support plate is trapezoidal as a whole, and the height of the end connected to the side rib plate is the same as the height of the side rib plate, and the height of the end connected to the axial support plate is the same as the height of the axial support plate. By adopting this technical measure, it is convenient for welding the first support structure and facilitating on-site reinforcement; at the same time, it will not have an unnecessary impact on the overall structure of the low-pressure outer cylinder.

[0016] 3. The axial support plate of the present invention is inclined downward at a certain angle. It is convenient for welding and on-site reinforcement.

[0017] 4. There are two transverse support plates in the present invention, which are respectively located at the one-third points in the axial direction of the side rib plate. By adopting this structure, the two transverse support plates and the axial support plate and the side rib plate form three square-shaped chambers. By adopting this technical measure, the structure is simple and it is convenient for on-site reinforcement. At the same time, when welding or assembling the first support structure, a certain distance should be left to avoid the outer cylinder support lugs and the inner cylinder cat claws. The first support structure can also significantly improve the dynamic stiffness level of the bearing seat.

[0018] 5. There are two flow channel support pipes in the second support structure of the present invention, and they are arranged in a "Z" shape in the axial space with the two original support pipes. By adopting this technical measure, it has a simple structure and is convenient for on-site reinforcement. At the same time, it does not interfere with the existing guide ring in terms of spatial position, occupies a small area of the exhaust passage, and will not cause additional aerodynamic losses to the low-pressure outer cylinder. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a schematic structural diagram of the present invention;

[0020] Figure 2 is Figure 1 a side view of the first support structure 31 and the second support structure 22 in

[0021] Figure 3 is Figure 1 a schematic structural diagram of part A in

[0022] Figure 4 is Figure 1 a view taken along line B-B in

[0023] Figure 5 is Figure 1 a view taken along line C-C in

[0024] Reference numerals: 11 - first inner support plate; 12 - outer end plate; 13 - second inner support plate; 14 - side rib plate; 15 - side end plate; 16 - outer cylinder support lug; 17 - inner cylinder cat claw; 18 - bearing seat;

[0025] 2 - Exhaust passage; 21 - Original support pipe; 22 - Second support structure; 221 - Flow passage support pipe;

[0026] 3 - Chamber; 31 - First support structure; 311 - Axial support plate; 312 - Transverse support plate. Detailed implementation mode

[0027] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. Generally, the components of the embodiments of the present invention described and illustrated in the drawings here can be arranged and designed in various different configurations.

[0028] Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed present invention, but merely represents selected embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0029] It should be noted that: Similar reference numerals and letters indicate similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings. In addition, the terms "first", "second", etc. are only used for distinguishing descriptions and cannot be understood as indicating or implying relative importance.

[0030] In the description of the embodiments of the present invention, it should be noted that the meaning of "a plurality" is two or more; the orientation or positional relationships indicated by the terms "upper", "lower", "left", "right", "inner", "outer", "front end", "rear end", "head", "tail", etc. are based on the orientation or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be understood as a limitation to the present invention.

[0031] Such as Figure 1 — Figure 5As shown in the figure, a support structure for improving the dynamic performance and anti-deformation performance of the low-pressure outer cylinder of a high-power steam turbine. There is an exhaust passage 2 between the first inner support plate 11 and the outer end plate 12 of the low-pressure outer cylinder, and multiple original support pipes 21 are fixedly connected between the first inner support plate 11 and the outer end plate 12; the first inner support plate 11, the second inner support plate 13, the side rib plates 14 and the side end plates 15 of the low-pressure outer cylinder form a chamber 3; the support structure includes a first support structure 31 arranged in the chamber 3 and a second support structure 22 arranged in the exhaust passage 2; the first support structure 31 includes an axial support plate 311 fixedly connected to the first inner support plate 11 and the second inner support plate 13, and multiple transverse support plates 312 fixedly connected to the axial support plate 311 and the side rib plates 14; the second support structure 22 is fixedly connected to the first inner support plate 11 and the outer end plate 12, and the second support structure 22 is composed of multiple flow channel support pipes 221, and the flow channel support pipes 221 are in the same plane as the axial support plate 311 in the axial direction.

[0032] As Figure 1 , Figure 2 , Figure 4 shown, Figure 1 is the top view of the 1 / 4 area of the low-pressure outer cylinder, which is a schematic structural diagram of the support structure installed in the low-pressure outer cylinder. In actual use, the 4 areas of the low-pressure outer cylinder have the same structure, so the same support structure is correspondingly arranged in the 4 areas; that is, the low-pressure outer cylinder includes 4 exhaust passages 2 and chambers 3 with the same structure.

[0033] Specifically, the first support structure 31 is composed of an axial support plate 311 and two transverse support plates 312, and the support plates are connected by assembly or welding. During actual use, the thickness of the axial support plate 311 and the transverse support plates 312 is 30 mm to 50 mm. The axial support plate 311 is vertically arranged and fixedly connected to the first inner support plate 11 and the second inner support plate 13 by welding; the transverse support plates 312 are also vertically arranged, one end of which is fixedly connected to the axial support plate 311, and the other end is fixedly connected to the side rib plate 14. The first support structure 31 adopts a combined structure of multiple support plates, which has a simple structure and is convenient for on-site reinforcement. The thickness of the axial support plate 311 and the transverse support plates 312 together play a role in strengthening the surrounding side rib plate 14 and changing the vibration characteristics of the original side rib plate 14. Adopting this technical measure can significantly change the anti-vibration and anti-deformation performance of the low-pressure outer cylinder and the bearing pedestal 18. The second support structure 22 is composed of multiple flow channel support pipes 221, and the flow channel support pipes 221 are in the same plane as the axial support plate 311 in the axial direction. The two ends of the flow channel support pipes 221 are respectively fixedly connected to the first inner support plate 11 and the outer end plate 12. The diameter of the flow channel support pipes 221 is 120 mm to 160 mm, and the wall thickness of the pipes is 16 mm to 22 mm. During actual use, solid support rods can also be used. The second support structure 22 has a simple structure and is convenient for on-site reinforcement. At the same time, the second support structure 22 and the axial support plate 311 form an axial support structure group, further improving the axial anti-deformation ability of the low-pressure outer cylinder; the second support structure 22 can effectively reduce the influence of the vacuum load on the bearing pedestal 18 and at the same time reduce the influence of the welding deformation of the first support structure 31 on the inner cylinder positioning surface. This support structure can significantly change the vibration frequency of the low-pressure cylinder, reduce the influence of the vacuum load and the rotor unbalance on the low-pressure cylinder bearing pedestal 18, reduce the vibration amplitude of the low-pressure cylinder, and improve the dynamic performance and anti-deformation performance of the low-pressure cylinder. Therefore, through the first support structure 31 and the second support structure 22, the natural frequency of the low-pressure outer cylinder can be effectively changed, so that the dynamic stiffness level of the bearing pedestal 18 of the low-pressure outer cylinder near the rotor resonance frequency of 50 Hz is 13 to 20 times that before the transformation, reducing the sensitivity of the vibration characteristics of the low-pressure outer cylinder to changes in conditions such as load and working conditions, and significantly changing the anti-vibration and anti-deformation performance of the low-pressure outer cylinder and the bearing pedestal 18. It effectively reduces the influence of the rotor unbalance on the bearing pedestal 18, improves the dynamic performance and anti-deformation ability of the low-pressure cylinder, and ensures the safe and reliable operation of the unit.

[0034] Such as Figure 2 , Figure 4As shown in the figure, the overall height of the axial support plate 311 of the first support structure 31 is less than the height of the side rib plate 14, and the lower end of the axial support plate 311 is in a suspended state; the transverse support plate 312 is trapezoidal as a whole, and the height of the end connected to the side rib plate 14 is the same as the height of the side rib plate 14, and the height of the end connected to the axial support plate 311 is the same as the height of the axial support plate 311. During actual use, the first support structure 31 is only fixedly connected to the first inner support plate 11, the second inner support plate 13 and the side rib plate 14, its upper end does not exceed the height of the first inner support plate 11, the second inner support plate 13 and the side rib plate 14, and its lower end is in a suspended state and is not connected to the low-pressure outer cylinder. By adopting this technical measure, it is convenient for welding the first support structure 31 and facilitating on-site reinforcement; at the same time, it will not have an unnecessary impact on the overall structure of the low-pressure outer cylinder.

[0035] During actual use, as Figure 4 shown, in order to facilitate welding and on-site reinforcement, the axial support plate 311 is inclined downward at a certain angle.

[0036] During actual use, as Figure 1 、 Figure 2 shown, there are two transverse support plates 312, which are respectively located at the three equal parts in the axial direction of the side rib plate 14. With this structure, the two transverse support plates 312 and the axial support plate 311 and the side rib plate 14 form three square-shaped chambers. By adopting this technical measure, the structure is simple and convenient for on-site reinforcement. At the same time, when the first support structure 31 is welded or assembled, a certain distance should be left to avoid the outer cylinder support lug 16 and the inner cylinder cat's paw 17. The first support structure 31 can also significantly improve the dynamic stiffness level of the bearing seat 18.

[0037] As Figure 1 、 Figure 2 、 Figure 5 shown, there are two flow channel support pipes 221 of the second support structure 22, and they are arranged in a "Z" shape in the axial space with the two original support pipes 21. By adopting this technical measure, it has a simple structure and is convenient for on-site reinforcement. At the same time, it does not interfere with the existing guide ring in terms of spatial position, occupies a small area of the exhaust passage 2, and will not cause additional aerodynamic losses to the low-pressure outer cylinder.

[0038] For the support structure for improving the dynamic performance and anti-deformation performance of the low-pressure outer cylinder of a high-power steam turbine described in the present invention, the first support structure 31 and the second support structure 22 are arranged on both the steam turbine side and the motor side of the low-pressure outer cylinder on the left and right sides. By arranging the support structure in this way, the vibration frequency of the low-pressure outer cylinder can be significantly changed, the influence of the vacuum load and the rotor unbalance on the bearing seat 18 can be reduced, the vibration amplitude of the low-pressure outer cylinder can be reduced, and the dynamic performance and anti-deformation performance of the low-pressure outer cylinder can be improved.

[0039] The above has introduced in detail the technical solutions provided by the embodiments of the present invention. Specific examples are used herein to elaborate on the principles and implementation manners of the embodiments of the present invention. The descriptions of the above embodiments are only applicable to helping understand the principles of the embodiments of the present invention. At the same time, for those of ordinary skill in the art, according to the embodiments of the present invention, there will be changes in the specific implementation manners and application scopes. In summary, the content of this specification should not be construed as a limitation on the present invention.

Claims

1. A support structure for improving the dynamic performance and anti-deformation performance of the low-pressure outer cylinder of a high-power steam turbine. There is an exhaust passage (2) between the first inner support plate (11) and the outer end plate (12) of the low-pressure outer cylinder, and multiple original support pipes (21) are fixedly connected between the first inner support plate (11) and the outer end plate (12); a chamber (3) is formed by the first inner support plate (11), the second inner support plate (13), the side rib plate (14), and the side end plate (15) of the low-pressure outer cylinder; Characterized in that: The support structure includes a first support structure (31) arranged in the chamber (3) and a second support structure (22) arranged in the exhaust passage (2); The first support structure (31) includes an axial support plate (311) fixedly connected to the first inner support plate (11) and the second inner support plate (13), and multiple transverse support plates (312) fixedly connected to the axial support plate (311) and the side rib plate (14); The second support structure (22) is fixedly connected to the first inner support plate (11) and the outer end plate (12). The second support structure (22) is composed of multiple flow channel support pipes (221), and the flow channel support pipes (221) are in the same plane as the axial support plate (311) in the axial direction.

2. The support structure for improving the dynamic performance and anti-deformation performance of the low-pressure outer cylinder of a high-power steam turbine according to claim 1, Characterized in that: The overall height of the axial support plate (311) of the first support structure (31) is less than the height of the side rib plate (14), and the lower end of the axial support plate (311) is in a suspended state; the transverse support plate (312) is integrally trapezoidal, the height of the end connected to the side rib plate (14) is the same as the height of the side rib plate (14), and the height of the end connected to the axial support plate (311) is the same as the height of the axial support plate (311).

3. The support structure for improving the dynamic performance and anti-deformation performance of the low-pressure outer cylinder of a high-power steam turbine according to claim 1 or 2, Characterized in that: The axial support plate (311) is inclined downward at a certain angle.

4. The support structure for improving the dynamic performance and anti-deformation performance of the low-pressure outer cylinder of a high-power steam turbine according to claim 1 or 2, Characterized in that: There are two transverse support plates (312), which are respectively located at the one-third points in the axial direction of the side rib plate (14).

5. The support structure for improving the dynamic performance and anti-deformation performance of the low-pressure outer cylinder of a high-power steam turbine according to claim 1, Characterized in that: There are two flow channel support pipes (221) in the second support structure (22), and they are arranged in a "Z" shape in the axial space with the two original support pipes (21).

6. The support structure for improving the dynamic performance and anti-deformation performance of the low-pressure outer cylinder of a high-power steam turbine according to claim 1, Characterized in that: The thickness of the axial support plate (311) and the transverse support plate (312) is 30 mm to 50 mm.

7. The support structure for improving the dynamic performance and anti-deformation performance of the low-pressure outer cylinder of a high-power steam turbine according to claim 1 or 5, Characterized in that: The diameter of the flow channel support pipe (221) is 120 mm to 160 mm, and the thickness of its pipe wall is 16 mm to 22 mm.

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