A seal structure for a gas turbine turbine guide vane diaphragm

Abstract

The application aims to provide a seal structure for a gas turbine turbine guide vane diaphragm, which comprises a diaphragm assembled between a guide vane and a rotor, the diaphragm comprising a seal cover, a seal ring and a seal insert, the seal ring being connected with two diaphragm half rings and forming a hollow structure, the connecting part of the two diaphragm half rings being a solid structure, the upper part of the seal ring being provided with support spokes in a circumferential direction, the support spokes being provided with pin holes, a positioning pin being installed in the pin holes of the support spokes in an interference fit, the lower part of the seal ring being a thin-walled and arc-shaped structure, the seal ring being provided with an upper sliding ring track and a lower sliding ring track, the seal cover sliding into the upper sliding ring track, and the seal insert sliding into the lower sliding ring track. The application is suitable for a half-split turbine guide vane, has the characteristics of high strength, small deformation, compact structure and simple assembly, and can improve the sealing effect and operation reliability of the gas turbine.

Description

Technical Field

[0001] The present invention relates to a gas turbine, specifically a turbine guide vane. Background Technology

[0002] Gas turbines, due to their high power density and rapid response, are widely favored in mechanical drives and industrial power generation worldwide, especially in marine and industrial power generation where long operating times, high reliability requirements, and long overhaul cycles are essential. The turbine, as a high-temperature component of the gas turbine, endures long-term high-temperature and high-pressure operating environments, and its complex structural design affects the reliability of the unit. The diaphragm, as a crucial component for sealing the turbine rotor and stator, divides the turbine stages into multiple relatively independent regions; its strength and deformation at high temperatures directly affect the reliability and efficiency of the gas turbine. For a long time, diaphragm designs have employed multi-component welding and screw or rivet connections for fastening. This not only results in cumbersome assembly but also makes disassembly of diaphragm screws or rivets extremely difficult after the high temperatures of unit operation. The significant pressure difference across the diaphragm and its substantial load-bearing capacity make it prone to weld cracking, posing a safety hazard to the unit. Excessive deformation of the baffle at high temperatures will cause the rotor-stator clearance to deviate from the design value. Too small a clearance will cause the rotor-stator to scrape, while too large a clearance will increase gas leakage, affecting the flow distribution of cooling and sealing gas in the front and rear disk cavities (cavity 1 and cavity 2) of the guide vane and reducing unit efficiency. Summary of the Invention

[0003] The purpose of this invention is to provide a sealing structure for a gas turbine guide vane that can improve the sealing effect and operational reliability of a gas turbine.

[0004] The objective of this invention is achieved as follows:

[0005] This invention discloses a diaphragm sealing structure for a gas turbine guide vane, characterized in that: it includes a diaphragm assembled between the guide vane and the rotor; the diaphragm includes a sealing cover, a sealing ring, and a sealing insert; the sealing ring is formed by two diaphragm half-rings connected together to form a hollow structure; the cross-section at the connection of the two diaphragm half-rings is a solid structure; the upper part of the sealing ring has circumferentially distributed support spokes; the support spokes are provided with pin holes; positioning pins are installed in the pin holes of the spokes with an interference fit; the lower part of the sealing ring is a thin-walled, arc-shaped structure; the sealing ring is provided with an upper sliding ring track and a lower sliding ring track; the sealing cover slides into the upper sliding ring track, and the sealing insert slides into the lower sliding ring track.

[0006] The present invention may also include:

[0007] 1. A square hole is provided on the sealing cover. Two partition half-rings are connected by a connecting assembly. The connecting assembly includes an internal hexagonal locating nut, a sleeve, and a double-ended stud. When connecting the two partition half-rings, the double-ended stud and the sleeve are first installed on one of the partition half-rings, and then the other partition half-ring is connected to the sleeve. The sleeve and the two partition half-rings are interference fit. The internal hexagonal locating nut extends through the square hole to tighten the double-ended stud.

[0008] 2. The positioning pin adopts a square head structure, which corresponds to the positioning groove of the guide vane to achieve circumferential positioning of the partition.

[0009] 3. The pin holes supporting the spokes include two beveled pins with an inclination angle of 45°.

[0010] 4. The hollow structure is filled with cooling air.

[0011] 5. The square hole includes two square holes, each 45mm long and 30mm wide, with four 10mm rounded corners. The center-to-center angle between the two square holes is 15° to 18°.

[0012] 6. The thickness of the arc at the bottom of the sealing ring is 3mm.

[0013] 7. The circumferential thickness of the spokes is 8mm, the radial width is 22mm, and the angle between adjacent auxiliary plates is 36°.

[0014] The advantages of this invention are: the partition sealing assembly is self-contained, has low dependence on other parts during assembly, and improves disassembly and assembly efficiency.

[0015] The diaphragm is made of hollow casting, and the design combines the spokes and the arc-shaped thin-walled structure, which reduces its own weight, increases the strength requirements, reduces the deformation of the diaphragm, meets the design requirements of the stator-rotor clearance during unit operation, and ensures the distribution requirements of cooling air flow. The arc-shaped cross-section structure reduces the axial distance of the cavities (cavity 1 and cavity 2), improves the rotating pressurization effect of the cooling sealing gas, and is beneficial to the sealing of the main gas flow. The hollow structure inside the diaphragm is filled with cooling air during operation, which can effectively block the heat conduction of the guide vane assembly to the diaphragm, reduce thermal deformation, and reduce the requirements for the diaphragm material.

[0016] The locating pins feature a square head structure that mates with the guide vane locating groove, circumferentially fixing the partition. Two symmetrically distributed beveled pins ensure that, regardless of the installation direction, the pin heads easily slide into the guide vane groove along the beveled edges on both sides.

[0017] The sealing ring consists of two half-rings assembled into a complete ring. Two square holes are designed at each end of the sealing cover, and the connecting structure is arranged in the hollow structure of the partition plate under the sealing cover. This avoids direct contact between the connecting structure and the high-temperature gas, effectively preventing the problem of difficult disassembly of bolts due to high-temperature deformation. The sleeve and the partition plate have an interference fit, and the separate tensioning structure of the internal hexagonal locating nut and double-ended stud ensures the structural stability and firmness of the partition plate, reduces the assembly space, and at the same time, the locking hole structure of the locating nut prevents the nut from loosening and falling off, which could damage the gas turbine. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the installation of the present invention;

[0019] Figure 2a For AA view, Figure 2b for Figure 2a A magnified view of a portion of the image. Figure 2c Schematic diagram for supporting the spokes;

[0020] Figure 3 This is a cross-sectional view of the present invention;

[0021] Figure 4 A schematic diagram of an internal hexagonal locating nut and a square hole;

[0022] Figure 5 This is a schematic diagram of the guide vane positioning groove. Detailed Implementation

[0023] The invention will now be described in more detail with reference to the accompanying drawings:

[0024] Combination Figure 1-5This invention provides a sealing structure for a gas turbine guide vane diaphragm. The diaphragm 3 is assembled between the guide vane 1 and the rotor 2, and consists of a sealing cover 4, a sealing ring 5, a sealing insert 6, and a positioning pin 7. The sealing ring 5 is manufactured using a blank precision casting process, with a split and hollow structure. The cross-section at the connection between the two halves is a solid structure. The upper part of the sealing ring cross-section has circumferentially distributed support spokes, while the lower part adopts a thin-walled, arc-shaped structure design with an arc wall thickness of approximately 3 mm. Three support spokes are evenly distributed in the middle of the upper half of the ring, and sufficient installation space is provided for connecting bolts on both sides of the lower half of the ring. Five support spokes are evenly distributed in the lower half of the ring. The circumferential thickness of the spokes is approximately 8 mm, the radial width is approximately 22 mm, the angle between adjacent spokes is 36°, and the spokes have positioning holes in the radial direction. The sealing ring 5 has upper and lower sliding ring tracks. The sealing cover 4 and the sealing insert 6 slide into the upper and lower tracks of the two half-rings of the sealing ring 5, respectively, allowing for quick assembly and disassembly. Positioning pins 7 are installed with an interference fit into the eight pin holes located on the spokes, two of which are angled pins with an inclination angle of 45°. Positioning pins 7 not only provide circumferential positioning for the sealing cover 4 to prevent slippage, but also serve to provide circumferential positioning for the partition and guide vane group 1. After the half-ring assembly is completed, the connecting assembly fastens the two half-rings into a complete ring. The connecting assembly consists of an internal hexagonal locating nut 8, a sleeve 9, and a double-ended stud 10. First, the double-ended stud 10 and the sleeve 9 are installed on one of the partition half-rings. Then, the other partition half-ring is mated with the sleeve 9. The sleeve 9 has an interference fit with the two half-ring partitions to ensure accurate alignment of the two half-rings and prevent deformation of the connected complete ring. The internal hexagonal locating nut 8 and a wrench are inserted into the two square holes on the sealing cover 4 to tighten the double-ended stud 10, locking the screws to prevent loosening. The sealing cover has a square hole 45mm long and 30mm wide, with four 10mm rounded corners and a center-to-center angle of 15° to 18°. After installation, the partition assembly is inserted into the guide semi-ring, and the head of the locating pin 7 is circumferentially slid into the guide vane locating groove 11 to complete the installation of the guide partition seal.

[0025] The diaphragm 3 is made of hollow casting, and the design combines the spoke plate and the arc-shaped thin-walled structure to reduce the deformation of the diaphragm, meet the stator clearance design requirements during unit operation, and ensure the distribution requirements of cooling air flow. The arc-shaped cross-section structure reduces the axial distance between the front and rear cavities of the diaphragm 3, improves the rotating pressurization effect of the cooling sealing gas, and is beneficial to the sealing of the mainstream gas. The hollow structure inside the diaphragm 3 is filled with cooling air, which can effectively block the heat conduction of the guide vane assembly to the diaphragm 3, reduce thermal deformation, and at the same time reduce the requirements for the material of the diaphragm 3.

[0026] The positioning pin 7 adopts a square head structure, which corresponds to and cooperates with the guide vane positioning groove 11 to achieve circumferential positioning of the partition 3. The symmetrical arrangement of the angled pins allows the partition 3 to easily slide into the guide vane groove regardless of the installation direction.

[0027] Square holes are opened at both ends of the sealing cover 4. The connecting structure is arranged in the hollow structure of the partition plate under the sealing cover 4, avoiding direct contact between the connecting structure and the high-temperature gas, and effectively preventing the problem of difficult disassembly of bolts due to high temperature deformation. The tensioning structure of the positioning nut 8, sleeve 9 and double-ended stud 10 ensures the structural stability and firmness of the partition plate 3, and makes assembly simple and convenient.

[0028] This type of baffle structure is suitable for split-type turbine guide vanes. Its unique structural design has a significant effect on improving the reliability and sealing performance of gas turbines.

Claims

1. A sealing structure for a gas turbine guide vane, characterized in that: The system includes a diaphragm, which is assembled between the guide vane and the rotor. The diaphragm includes a sealing cover, a sealing ring, and a sealing insert. The sealing ring is formed by two diaphragm half-rings connected together to form a hollow structure. The cross-section of the connection between the two diaphragm half-rings is a solid structure. The upper part of the sealing ring has circumferentially spaced support spokes. The support spokes are provided with pin holes. The positioning pins are installed in the pin holes of the spokes with an interference fit. The lower part of the sealing ring is a thin-walled, arc-shaped structure. The sealing ring is provided with an upper sliding ring track and a lower sliding ring track. The sealing cover slides into the upper sliding ring track, and the sealing insert slides into the lower sliding ring track. The locating pin adopts a square head structure, which corresponds to the locating groove of the guide vane to achieve circumferential positioning of the partition. The arc-shaped cross-section structure reduces the axial distance between the front and rear cavities of the partition, improving the cooling and sealing gas rotation and pressurization effect.

2. The sealing structure for a gas turbine guide vane according to claim 1, characterized in that: A square hole is provided on the sealing cap. Two partition half-rings are connected by a connecting assembly, which includes an internal hexagonal locating nut, a sleeve, and a double-ended stud. When connecting the two partition half-rings, the double-ended stud and the sleeve are first installed on one of the partition half-rings, and then the other partition half-ring is connected to the sleeve. The sleeve is interference-fitted with the two partition half-rings. The internal hexagonal locating nut extends through the square hole to tighten the double-ended stud.

3. The sealing structure for a gas turbine guide vane according to claim 1, characterized in that: The pin holes supporting the spokes include two beveled pins with an inclination angle of 45°.

4. The sealing structure for a gas turbine guide vane according to claim 1, characterized in that: The hollow structure is filled with cooling air.

5. A sealing structure for a gas turbine guide vane according to claim 2, characterized in that: The square hole includes two holes, each 45mm long and 30mm wide, with four 10mm rounded corners. The center-to-center angle between the two square holes is 15° to 18°.

6. A sealing structure for a gas turbine guide vane according to claim 1, characterized in that: The thickness of the arc at the bottom of the sealing ring is 3mm.

7. A sealing structure for a gas turbine guide vane according to claim 1, characterized in that: The spokes have a circumferential thickness of 8 mm, a radial width of 22 mm, and an angle of 36° between adjacent spokes.

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