Non-contact dynamic and static sealing assembly and steam turbine

Abstract

The utility model discloses a non-contact dynamic and static sealing assembly and a steam turbine. The non-contact dynamic and static seal assembly comprises a steam seal body and a rotor, the steam seal body is arranged around the rotor, the central axis of the steam seal body and the central axis of the rotor are coaxial, a plurality of steam seal teeth are arranged on the inner side of the steam seal body and are arranged at intervals in the axial direction, an interstage seal cavity is defined between every two adjacent steam seal teeth, and the interstage seal cavity is communicated with the steam seal body. An annular containing groove is formed in the rotor, the containing groove corresponds to the interstage sealing cavity in the radial direction, and a plurality of turbulent flow blades are arranged in the containing groove and arranged at intervals in the circumferential direction. According to the non-contact type dynamic and static sealing assembly, the flow direction of steam entering the steam sealing body is forcibly disturbed through the turbulent flow blades arranged on the effective sealing portion of the rotor, flowing of the steam between teeth in the steam sealing body is blocked or reduced, and therefore the steam leakage amount is reduced, and the economic index of a unit is improved.

Description

A non-contact dynamic and static sealing assembly and a steam turbine Technical Field

[0001] This utility model relates to the field of thermal power generation technology, and in particular to a non-contact dynamic and static sealing assembly and a steam turbine. Background Technology

[0002] Steam seals are crucial components of large steam turbines in thermal power plants. Their function is to reduce and prevent steam leakage and air ingress into the cylinders at the gaps between the turbine's moving and stationary parts. The sealing performance of the steam seals affects not only the unit's economy but also its reliability. Steam leakage from the shaft seals not only wastes a large amount of high-quality steam but also allows leaked steam to enter the bearing housing, causing water to enter the oil, emulsifying the oil, deteriorating the quality of the lubricating oil film, disrupting dynamic lubrication, causing oil film oscillation, and potentially leading to unit vibration or even bearing failure and shutdown. Water ingress into the oil can also cause corrosion and jamming of regulating components, endangering unit safety.

[0003] To reduce steam leakage and improve unit safety and economy, various new steam seal structures have been developed. Based on different sealing principles, steam seals can be divided into non-contact and contact seals. Non-contact steam seals include curved diameter seals, side-tooth seals, Braidon seals, and honeycomb seals, etc. However, currently, all new non-contact steam seals are based on the study of expanding the labyrinth principle on a static seal body, resulting in very limited and passive improvements in economy. Summary of the Invention

[0004] This utility model aims to at least partially solve one of the technical problems in the related art.

[0005] Therefore, embodiments of this utility model propose a non-contact dynamic and static sealing assembly, which optimizes the design of the sealed part of the rotor to improve the economic performance of the turbine unit.

[0006] An embodiment of this utility model also proposes a steam turbine.

[0007] The non-contact dynamic and static sealing assembly of this utility model includes a steam seal body and a rotor. The steam seal body is arranged around the rotor and the central axes of the two are coaxial. The inner side of the steam seal body is provided with a plurality of steam seal teeth, which are arranged axially at intervals. An interstage sealing cavity is defined between two adjacent steam seal teeth. The rotor is provided with an annular receiving groove, which corresponds to the interstage sealing cavity radially. A plurality of turbulence-disrupting blades are provided in the receiving groove, which are arranged circumferentially at intervals.

[0008] The non-contact dynamic and static sealing assembly of this utility model uses turbulence blades set on the effective sealing part of the rotor to forcibly interfere with the steam flow direction entering the steam seal body, block or reduce the steam flow between the teeth in the steam seal body, thereby reducing steam leakage and improving the unit's economic indicators.

[0009] In some embodiments, the steam seal tooth is in the shape of an annular plate, and the central axis of the steam seal tooth is coaxial with the central axis of the rotor.

[0010] In some embodiments, the thickness of the steam seal teeth remains consistent from the root to the tip, and multiple steam seal teeth have the same thickness.

[0011] In some embodiments, the volume of the plurality of interstage sealing cavities decreases axially and gradually from the high-pressure side to the low-pressure side.

[0012] In some embodiments, the receiving groove corresponds radially to the interstage sealing cavity in the middle section of the steam seal body.

[0013] In some embodiments, the axial width of the accommodating cavity is defined as A, and the axial distance between two adjacent steam seal teeth is defined as a, satisfying the relationship: 3a≤A≤4a.

[0014] In some embodiments, the deflector blade is located in the middle of the receiving groove, and the axial width of the deflector blade is defined as B, satisfying the relationship: a≤B≤2a.

[0015] In some embodiments, the tip of the deflector blade is flush with the opening of the receiving groove, and the installation angle α of the deflector blade satisfies 25°≤α≤45°.

[0016] In some embodiments, the radial clearance between the steam seal and the rotor is 0.15-0.25 mm.

[0017] The steam turbine of this utility model embodiment includes the non-contact dynamic and static sealing assembly described in the above embodiment. Attached Figure Description

[0018] Figure 1 is a schematic diagram of a non-contact dynamic and static sealing assembly according to an embodiment of the present invention.

[0019] Figure 2 is a schematic diagram of the rotor in a stationary state according to an embodiment of the present invention.

[0020] Figure 3 is a schematic diagram of the rotor in a rotating state according to an embodiment of the present invention.

[0021] Figure label:

[0022] 1-Steam seal body, 2-Rotor, 3-Steam seal teeth, 4-Interstage sealing cavity, 5-Accommodation groove, 6-Breakthrough blade. Detailed Implementation

[0023] The embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0024] The following describes a non-contact dynamic and static sealing assembly according to an embodiment of the present invention, with reference to the accompanying drawings.

[0025] As shown in Figures 1 to 3, the non-contact dynamic and static sealing assembly of this utility model embodiment includes a steam seal body 1 and a rotor 2. The steam seal body 1 is arranged around the rotor 2 and the central axes of the two are coaxial. There is a radial gap between the steam seal body 1 and the rotor 2, for example, the radial gap between the two is 0.15-0.25mm.

[0026] The inner side of the steam seal body 1 is provided with multiple steam seal teeth 3, which are arranged at intervals along the axial direction, and an interstage sealing cavity 4 is defined between two adjacent steam seal teeth 3. In other words, multiple grooves are opened on the inner peripheral wall of the steam seal body 1, and the multiple grooves are arranged at intervals along the axial direction.

[0027] The rotor 2 is provided with an annular receiving groove 5, which corresponds to the interstage sealing cavity 4 radially upward. Multiple turbulence blades 6 are provided in the receiving groove 5, and the multiple turbulence blades 6 are arranged at intervals along the circumference.

[0028] It is understandable that, as shown in Figure 2, when the rotor 2 is stationary, the gas P0 (steam or other compressible gas; in this embodiment of the present invention, only steam is used as an example, and will not be repeated below) on the high-pressure side leaks to the low-pressure side P6 through the radial gap between the steam seal tooth 3 and the rotor 2, and is successively depressurized through the interstage sealing cavity 4. At this time, P0 > P1 > P2 > P3 > P4 > P5 > P6, and the turbulence blades 6 on the rotor 2 do not play a role.

[0029] As shown in Figure 3, when rotor 2 is rotating, the turbulence blades 6 on rotor 2 and the steam seal 1 generate relative circumferential motion. The steam leaking into P2 is driven into the tooth space of P3 under the action of centrifugal force and forms a backflow, so that P3≥P2. The backflowing steam of P3 interferes with the steam leaking into P2 and blocks the steam leaking into P2 from flowing into P4. At this time, P0>P1>P2≤P3=P4>P5>P6. The turbulence blades 6 on rotor 2 play the role of interfering with and blocking steam leakage.

[0030] Therefore, the non-contact dynamic and static sealing assembly of this utility model, by designing, processing or embedding turbulence blades 6 at the sealed part of the rotor 2, under the operation of the steam turbine, the high-speed rotating rotor 2 drives the turbulence blades 6 to generate forced disturbance to the steam leaking to the turbulence blades 6 of the rotor 2, actively interfering with the steam flow direction in the labyrinth teeth of the corresponding non-contact steam seal body 1, thereby preventing or reducing the flow of steam from the upper tooth to the lower tooth, thereby reducing the amount of steam leakage in the steam seal labyrinth teeth and improving the economic indicators of the unit.

[0031] This utility model is applicable to steam turbines, internal combustion engines, fans, water turbines, etc., and can be widely used in power, metallurgy, petroleum, chemical, shipbuilding and military industries.

[0032] Furthermore, based on the size, material, shape, effective length of the sealed section, structure of the steam seal 1, and effective number of teeth at the sealed section of rotor 2, mathematical modeling is used to rationally design the material, shape, size, angle, quantity, and placement of the turbulence blades 6. New units can be designed, processed, manufactured, and installed simultaneously according to the type of steam seal 1 used. For existing units requiring modification, on-site machining can be carried out during unit maintenance according to the maintenance plan. For units with an inlaid structure, the blades should be reinforced to rotor 2 using laser welding.

[0033] In some embodiments, as shown in Figures 1 to 3, the steam seal tooth 3 is in the shape of an annular plate, and the central axis of the steam seal tooth 3 is coaxial with the central axis of the rotor 2 to achieve a circumferentially uniform pressure field. The tooth body thickness is 8-12mm, the radial extension length is 50-80mm, and it is matched with the rotor 2 with a surface finish of ≤0.8μm to form a mirror-like contact interface.

[0034] The thickness of the steam seal tooth 3 remains consistent from the tooth root to the tooth tip, and multiple steam seal teeth 3 have the same thickness. The thickness tolerance of the entire tooth section is controlled within ±0.02mm. It is machined by five-axis linkage grinding, with a tooth tip chamfer R=0.3mm×45°, and is combined with a laser cladding reinforcement layer (thickness 0.1mm, hardness HRC58-62).

[0035] Furthermore, the volume of the multiple interstage sealing chambers 4 gradually decreases axially from the high-pressure side to the low-pressure side. Through the volume gradient design, the linear pressure decay of the traditional equal-volume design is broken, forming a nonlinear pressure balance zone (P0>P1>P2≤P3=P4>P5>P6). The large volume on the high-pressure side allows the steam to expand fully, while the small volume on the low-pressure side forces the steam to form a pressure plateau in the P2-P3 interval, blocking the leakage path.

[0036] In some embodiments, as shown in Figures 1 to 3, the receiving groove 5 corresponds radially to the interstage sealing cavity 4 in the middle section of the steam seal 1. That is, the axial position of the receiving groove 5 is located in the intermediate pressure section (P2-P5), which is the optimal turbulence operating condition zone, where the turbulence efficiency is greater than that of the front section of the steam seal 1.

[0037] Optionally, the axial width of the accommodating cavity is defined as A, and the axial distance between two adjacent steam seal teeth 3 is defined as a, satisfying the relationship: 3a≤A≤4a. The turbulence vane 6 is located in the middle of the accommodating groove 5, and the axial width of the turbulence vane 6 is defined as B, satisfying the relationship: a≤B≤2a. This ensures that the turbulence vane 6 covers at least two steam seal teeth 3, effectively achieving the turbulence effect.

[0038] Furthermore, as shown in Figures 1 to 3, the tip of the deflector blade 6 is flush with the opening of the receiving groove 5, and the installation angle α of the deflector blade 6 satisfies 25°≤α≤45°. Preferably, α=32°, ensuring that when the rotor 2 rotates, the requirement P3≥P2 is met.

[0039] The steam turbine of this utility model embodiment includes the non-contact dynamic and static sealing assembly described in the above embodiment.

[0040] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0041] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this utility model, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0042] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0043] In this utility model, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0044] In this utility model, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of this utility model. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Furthermore, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0045] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A non-contact dynamic and static sealing assembly, characterized in that, The device includes a steam seal body and a rotor. The steam seal body is arranged around the rotor and the central axes of the two are coaxial. The inner side of the steam seal body is provided with a plurality of steam seal teeth, which are arranged axially at intervals. An interstage sealing cavity is defined between two adjacent steam seal teeth. The rotor is provided with an annular receiving groove, which corresponds to the interstage sealing cavity radially. The receiving groove is provided with a plurality of turbulence-disrupting blades, which are arranged circumferentially at intervals.

2. The non-contact dynamic and static sealing assembly according to claim 1, characterized in that, The steam seal tooth is in the shape of an annular plate, and the central axis of the steam seal tooth is coaxial with the central axis of the rotor.

3. The non-contact dynamic and static sealing assembly according to claim 2, characterized in that, The thickness of the steam seal teeth remains consistent from the root to the tip, and multiple steam seal teeth have the same thickness.

4. The non-contact dynamic and static sealing assembly according to claim 3, characterized in that, The volume of the multiple interstage sealing cavities decreases axially from the high-pressure side to the low-pressure side.

5. The non-contact dynamic and static sealing assembly according to claim 1, characterized in that, The receiving groove corresponds radially to the interstage sealing cavity in the middle section of the steam seal body.

6. The non-contact dynamic and static sealing assembly according to claim 5, characterized in that, The axial width of the receiving groove is defined as A, and the axial distance between two adjacent steam seal teeth is defined as a, satisfying the relationship: 3a≤A≤4a.

7. The non-contact dynamic and static sealing assembly according to claim 6, characterized in that, The turbulence-disrupting blade is located in the middle of the receiving groove. The axial width of the turbulence-disrupting blade is defined as B, which satisfies the relationship: a≤B≤2a.

8. The non-contact dynamic and static sealing assembly according to claim 7, characterized in that, The tip of the deflector blade is flush with the opening of the receiving groove, and the installation angle α of the deflector blade satisfies 25°≤α≤45°.

9. The non-contact dynamic and static sealing assembly according to any one of claims 1-8, characterized in that, The radial clearance between the steam seal and the rotor is 0.15-0.25 mm.

10. A steam turbine, characterized in that, Includes the non-contact dynamic and static sealing assembly according to any one of claims 1-9.

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