Novel floating ring sealing device with stability augmentation and leakage control functions

Abstract

The invention discloses a novel floating ring sealing device with stability augmentation and leakage control functions. The novel floating ring sealing device comprises a rotating main shaft, a floating ring, a rotating hemisphere, a shaft sleeve, a flat foil piece, a wave foil piece, a sealing cavity, a wave spring, a sealing end cover, a lifting lug, a shaft end labyrinth seal, an auxiliary sealing ring and the like. The rotating main shaft supports the cantilever on the mounting seat through an arranged bearing; a plurality of spiral groove structures are machined in the outer surface of the rotating hemisphere in the circumferential direction. A plurality of polygonal micron-sized grooves are machined in the outer surface of the shaft sleeve in the circumferential direction. The bump foil is attached to the flat foil and the inner side of the sealing cavity through the arc junction plates on the inner diameter side and the outer diameter side respectively. The gas film dynamic pressure effect of the floating ring seal can be improved, the pneumatic performance of the floating ring seal is improved, the stability augmentation and leakage control effects are high, the strict requirement of a main bearing cavity of an aero-engine for the sealing capacity of the floating ring seal is met, and the purposes of prolonging the service life of the floating ring seal and improving the overall performance of the aero-engine are achieved.

Description

Technical Field

[0001] This invention patent relates to the field of fluid dynamic sealing technology, and in particular to a novel floating ring sealing device with stabilization and leakage control functions. Background Technology

[0002] A floating ring seal is a non-contact sealing device whose sealing mechanism relies on the flow resistance generated when fluid flows through a tiny gap to suppress leakage. During operation, due to the eccentric motion of the rotor, the fluid within the gap generates a dynamic pressure buoyancy force on the floating ring. When this buoyancy force exceeds the combined force of the floating ring's weight, inertial force, and frictional resistance between the ring and the housing end face, the floating ring will float. Under normal operating conditions, a fluid film forms between the floating ring and the shaft surface, effectively preventing high-pressure gas from leaking to the low-pressure side; simultaneously, under the action of the wave spring and the pressure difference between the two sides, the floating ring end face is tightly pressed against the inner side of the housing, preventing gas from leaking radially.

[0003] However, the application of traditional floating ring seal structures in the main bearing cavity of modern aero-engines still has certain limitations, and the actual sealing effect has not reached the ideal state. First, during the start-up phase of an aero-engine, due to the low main shaft speed and low airflow pressure, the buoyancy generated by the floating ring seal with a smooth cylindrical surface structure is insufficient, causing the sealing ring to remain in a dry friction state for a certain period of time, which is prone to wear. Second, the rotational speed of the power turbine and gas turbine rotors in modern aero-engines has increased significantly, and the vibration and yaw generated when the main shaft rotates at high speed have increased, which can easily cause uneven flow and thus trigger vibration instability of the sealing system. Third, with the increasing demand for aero-engines to fly in various attitudes, the working conditions of the main bearing cavity seal have become more complex—rotational speed, temperature, and sealing pressure difference all change with the operating conditions, and traditional floating ring seals are difficult to adapt to such large parameter fluctuations. Finally, most existing aero-engine floating ring seals adopt a narrow ring structure, which has limited sealing capacity and cannot meet the stringent requirements of modern high-performance aero-engines for extremely low leakage rates.

[0004] In summary, the aforementioned problems severely restrict the further application and development of traditional floating ring sealing technology in the main bearing cavity of advanced aero-engines. Summary of the Invention

[0005] The present invention aims to address the aforementioned technical problems of existing floating ring seals by providing a novel floating ring seal device with stabilization and leakage control functions. This device can improve the gas film dynamic pressure effect and aerodynamic performance of the floating ring seal, and has strong stabilization and leakage control functions. It is suitable for sealing the main bearing cavity of aero-engines under all-variable operating conditions.

[0006] This invention is achieved using the following technical solution: A novel floating ring sealing device with stabilizing and leak-controlling functions includes a rotating spindle, a floating ring, a rotating hemisphere, a flat foil, a corrugated foil, a bushing, a sealing cavity, a wave spring, a sealing end cap, a lifting lug, a shaft end labyrinth seal, and auxiliary sealing rings, etc. The rotating spindle is cantilevered on a mounting base by a bearing. The rotating hemisphere has several helical grooves machined circumferentially on its surface. The bushing has several polygonal micron-level grooves machined circumferentially on its surface. The corrugated foil is bonded to the flat foil and the inner side of the sealing cavity by arc-shaped plates on its inner and outer diameter sides, respectively.

[0007] In this application, both the rotating main shaft and the auxiliary seal can adopt existing technologies of aero-engines, that is, the main shaft of the aero-engine is used as the rotor, and other auxiliary sealing forms are used in conjunction with the sealing system of this invention to achieve good stabilization and leakage control, thereby improving the sealing capability of traditional floating ring seals under all-variable operating conditions.

[0008] In this application, a rotating hemisphere is fixed to a rotating spindle and rotates with it. Simultaneously, a floating assembly is provided on the outer side of the rotating hemisphere, located radially outward, with a gap between the floating assembly and the rotating hemisphere.

[0009] In practical application, under the action of the eccentric motion of the rotating spindle and the hydrodynamic pressure, a highly rigid hydrodynamic pressure film is formed between the rotating hemisphere and the floating assembly, thereby enabling non-contact operation between the rotating ring and the floating assembly. Since the opposing surfaces of the rotating hemisphere and the floating assembly in this application are both arc-shaped structures, the floating ring sealing structure has a self-aligning function, which can effectively overcome the problem of poor stability caused by runout and yaw when the spindle rotates at high speed, thereby significantly reducing the risk of seal instability due to hard friction, and significantly improving the stability and reliability of the floating ring sealing technology in the main bearing cavity of aero-engines.

[0010] Preferably, the surface of the rotating hemisphere is a sphere. Of course, those skilled in the art should understand that the sphere in this solution cannot be a complete sphere, but rather a local area on the sphere.

[0011] Furthermore, several hydrodynamic microgrooves are provided on the surface of the rotating hemisphere.

[0012] As is common knowledge in this field, floating ring sealing technology has a low-pressure side on one side and a high-pressure side on the other along the axial direction. This solution incorporates several dynamic pressure grooves on the surface of the rotating hemisphere, significantly enhancing the dynamic pressure effect between the rotating hemisphere and the floating assembly. This results in a significant increase in the stiffness of the formed hydrodynamic film, ensuring relative axial and radial stability between the rotating ring and the floating assembly even under uneven flow conditions. This allows for more stable non-contact operation between the rotating ring and the floating assembly. During the aero-engine startup phase, the rotating hemisphere begins to rotate with the main shaft. The hemisphere with the dynamic pressure grooves can generate the necessary buoyancy force for the floating assembly at a lower speed, thus avoiding the hard friction caused by the relatively small buoyancy force in traditional floating ring seals during startup and extending service life. Furthermore, when the engine startup is complete and the main shaft rotates at high speed, the presence of the dynamic pressure grooves further enhances the hydrodynamic effect, increasing the buoyancy force and resulting in a fluid film with greater stiffness.

[0013] The hydrodynamic groove in this application can be any one or more of the existing fluid hydrodynamic groove types, such as spiral grooves, straight grooves, and arc grooves. Under varying operating conditions, groove type parameters with excellent overall sealing performance can be selected through groove type optimization design to meet the requirements of aero-engines operating under varying conditions.

[0014] In this application, the bushing surface is laser-processed with micron-sized grooves, which are connected polygons and exhibit a symmetrical distribution that first decreases and then increases along the axial direction.

[0015] In this application, the hydrodynamic fluid flows through the rotating hemispherical structure and then into the bushing. The micron-level grooves on its surface effectively enhance the hydrodynamic effect, significantly increasing the buoyancy force on the float ring and thus maintaining good floating performance during operation. Simultaneously, this structure also helps reduce rubbing between the rotor and the float ring caused by changes in operating conditions, improving the stability and service life of the seal.

[0016] Furthermore, the micron-sized grooves exhibit a symmetrical distribution that first decreases and then increases along the axial direction. As the texture density increases, the flow of the leaking fluid gradually becomes compressed from a rarefied state, further increasing the buoyancy of the floating ring.

[0017] The grooves in this application can be existing polygonal single, composite, or derived structures such as triangles, quadrilaterals, and pentagons.

[0018] In this specific implementation, the corrugated foil has arc-shaped structures on both its inner and outer diameter sides, which respectively fit against the inner wall of the flat foil and the sealing cavity. After the air film buoyancy force is formed, the floating ring is slightly lifted by it and tends to expand radially; at this time, the corrugated foil generates a corresponding rebound force due to elastic deformation, which, after reaching a balance with the air film force, further enhances the floating ability and centering stability of the floating ring. In addition, when the operating conditions change, the coordinated deformation between the corrugated foil and the flat foil can effectively buffer radial disturbances, enhance the adaptability and overall stability of the floating ring sealing system, and reduce the risk of instability.

[0019] In this application, the wave foil is a five-layer composite structure consisting of a base flat foil, two upper and lower warped flat plates, and an arc plate, and is uniformly distributed along the circumferential direction.

[0020] Furthermore, the components of the corrugated foil are connected by welding.

[0021] The arc plate in this application can be a single arc structure or a wave-shaped structure, etc., which can generate effective rebound force under the action of radial buoyancy force, thereby increasing the stability of the sealing system of this invention.

[0022] Furthermore, wave springs are used to provide elastic force to the floating assembly, ensuring that the low-pressure side of the floating assembly remains in close contact with the housing.

[0023] It should be noted that the application of this application is in the main bearing cavity of an aircraft engine. Due to the limited space in this area, conventional spring structures are not suitable. Therefore, this solution uses wave springs, which are beneficial for providing the required elastic force in a narrow space.

[0024] Compared with the prior art, the present invention has the following advantages and beneficial effects: 1. Under the action of the eccentric motion of the rotating spindle and the hydrodynamic pressure, a highly rigid hydrodynamic pressure film is formed between the rotating hemisphere and the floating assembly, thereby enabling non-contact operation between the rotating ring and the floating assembly. Since the opposing surfaces of the rotating hemisphere and the floating assembly in this application are both arc-shaped structures, the floating ring sealing structure has a self-aligning function, which can effectively overcome the problem of poor stability caused by runout and yaw when the spindle rotates at high speed, thereby significantly reducing the risk of seal instability due to hard friction, and significantly improving the stability and reliability of the floating ring sealing technology in the main bearing cavity of aero-engines.

[0025] 2. The hydrodynamic fluid flows through the rotating hemispherical structure and then into the bushing. The micron-level grooves on its surface effectively enhance the hydrodynamic effect, significantly increasing the buoyancy force on the float ring and thus maintaining good floating performance during operation. Simultaneously, this structure also helps reduce rubbing between the rotor and the float ring caused by changes in operating conditions, improving the stability and service life of the seal.

[0026] 3. The corrugated foil has arc-shaped structures on both its inner and outer diameter sides, which respectively fit against the inner wall of the flat foil and the sealing cavity. After the air film buoyancy force is formed, the floating ring floats slightly under its influence and tends to expand radially. At this time, the corrugated foil generates a corresponding rebound force due to elastic deformation. After reaching a balance with the air film force, it further enhances the floating ability and centering stability of the floating ring. In addition, when the operating conditions change, the coordinated deformation between the corrugated foil and the flat foil can effectively buffer radial disturbances, enhance the adaptability and overall stability of the floating ring sealing system, and reduce the risk of instability.

[0027] 4. The above-mentioned sealing system, in conjunction with other auxiliary sealing methods, can achieve better leakage control, significantly reduce shaft end leakage, and ensure the stable operation of the main bearing cavity of the aero-engine. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of a specific embodiment of the present invention; Figure 2 This is a schematic diagram of the rotating hemisphere in a specific embodiment of the present invention; Figure 3 This is a schematic diagram of the structure of the laser-processed microgroove in a specific embodiment of the present invention; Figure 4 This is a schematic diagram of the structure of the flat foil in a specific embodiment of the present invention; Figure 5 This is a schematic diagram of the structure of the corrugated foil in a specific embodiment of the present invention; Figure 6 This is a schematic diagram of the structure of the sealing end cap in a specific embodiment of the present invention; Figure 7 This is a schematic diagram of the structure of the sealed cavity in a specific embodiment of the present invention; Figure 8 This is a cross-sectional view of the floating ring in a specific embodiment of the present invention; Figure 9 This is a schematic diagram of the structure of the floating ring in a specific embodiment of the present invention; Figure 10 This is a schematic diagram of the rotating component in a specific embodiment of the present invention; Figure 11 This is a schematic diagram of the wave spring structure in a specific embodiment of the present invention; Figure 12This is a schematic diagram of the auxiliary seal structure in a specific embodiment of the present invention; The attached diagram shows the markings and corresponding component names: 1-Sealed cavity, 13-Threaded hole, 14-Air inlet, 15-Internal thread, 16-Auxiliary sealing ring groove, 111-Threaded hole, 122-Flat foil placement groove, 2-Wave foil, 21-Base flat foil, 22-Warped plate I, 23-Circular arc plate I, 24-Warped plate II, 25-Circular arc plate II, 3-Flat foil, 31-Flat foil fold, 4-Floating ring, 5-Rotating hemisphere, 51-Helical fluid microgroove, 52-Auxiliary sealing ring placement 6-Groove, 7-Wave spring, 8-Screw, 81-Shaft sleeve, 82-Micron-level groove, 9-Rotating spindle, 10-Shaft end labyrinth seal, 101-Labyrinth seal at floating ring, 102-Labyrinth seal at spindle, 11-Lifting lug, 111-Threaded hole, 112-Wave spring placement groove, 113-Flat foil folding edge placement groove, 12-Sealing end cap, 121-Threaded hole, 122-Shaft end labyrinth seal mounting groove, 123-Threaded hole, 13-Auxiliary sealing ring. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments and accompanying drawings. The illustrative embodiments and descriptions of this invention are for explanation only and are not intended to limit the invention. In the description of this application, it should be understood that terms such as "front," "rear," "left," "right," "up," "down," "vertical," "horizontal," "high," "low," "inner," and "outer" indicate orientations or positional relationships based on the accompanying drawings. The orientations or positional relationships shown are for the convenience of describing the invention 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 protecting this application. Scope limitations.

[0030] Example 1: See Figure 1 and Figure 7This invention discloses a novel floating ring sealing device with stabilizing and leak-controlling functions, including a rotating spindle (9), a floating ring (4), a rotating hemisphere (5), a flat foil (3), a corrugated foil (2), a bushing (8), a sealing cavity (1), a wave spring (7), a sealing end cap (12), a lifting lug (11), a shaft end labyrinth seal (10), and an auxiliary sealing ring (13), etc.; the rotating spindle (9) is supported by a bearing and cantilevered on the mounting base; the rotating hemisphere (5) has several spiral groove structures (51) processed along the circumference; the bushing has several polygonal micron-level grooves (81) processed along the circumference; the corrugated foil (3) is attached to the flat foil (3) and the inner side of the sealing cavity (1) through the arc-shaped plates (22) (24) on the inner and outer diameter sides, respectively.

[0031] In a more preferred embodiment, the rotating hemispherical surface is a sphere.

[0032] In this embodiment, each component is connected to the sealing end cap (12) and the sealing cavity (1) by a number of set screws (7).

[0033] Example 2: A novel floating ring sealing device with enhanced stability and leakage control function, based on Example 1, such as... Figure 2 As shown, several hydrodynamic microgrooves (51) are provided on the surface of the rotating hemisphere (5).

[0034] In a more preferred embodiment, the fluid dynamic pressure groove (51) can be any one or more groove types among existing fluid dynamic pressure grooves, such as spiral groove, straight groove, arc groove, etc.

[0035] In a more preferred embodiment, the depth of the fluid dynamic pressure groove (51) is 1 to 5 μm.

[0036] In a more preferred embodiment, the number of fluid dynamic pressure grooves (51) is 6 to 12.

[0037] Example 3: A novel floating ring sealing device with enhanced stability and leakage control function, based on Example 1, such as... Figure 3 As shown, the bushing (8) has micron-sized grooves (81) laser-processed on its surface.

[0038] In a more preferred embodiment, the groove (81) has a cross-sectional shape that is a connected polygon.

[0039] In a more preferred embodiment, the grooves (81) exhibit a symmetrical distribution that first decreases and then increases along the axial direction.

[0040] In a more preferred embodiment, the groove (81) has a depth of 1 to 5 μm.

[0041] In a more preferred embodiment, the number of grooves (81) is 6 to 12.

[0042] Example 4: A novel floating ring sealing device with enhanced stability and leakage control function, based on Example 1, such as... Figure 4 and Figure 5 As shown, the corrugated foil (2) has arc structures (25) (23) on both the inner and outer diameter sides, which are respectively attached to the inner wall of the flat foil (3) and the sealing cavity (1).

[0043] In a more preferred embodiment, the corrugated foil (2) is a five-layer composite structure consisting of a base flat foil (21), two upper and lower warped flat plates (22) (24) and an arc plate (23) (25), and is evenly distributed along the circumferential direction.

[0044] In a more preferred embodiment, the angle between the upper and lower warped plates and the axial direction is ±0.5 to 2°.

[0045] In a more preferred embodiment, the number of the upper and lower warped flat plates (22) (24) and the arc plates (23) (25) is 6 to 12.

[0046] In a more preferred embodiment, the components of the corrugated foil (2) are connected by welding.

[0047] Example 5: A novel floating ring sealing device with enhanced stability and leakage control function, based on Example 1, such as... Figure 7 and Figure 11 As shown, a wave spring placement groove (112) is provided on the inner surface of the sealed cavity (1) to prevent the wave spring (6) from moving radially, so as to effectively provide the spring force required for the system to maintain stability.

[0048] Example 6: A novel floating ring sealing device with enhanced stability and leakage control function, based on Example 1, such as... Figure 6 and Figure 7 As shown, the sealing end cap (12) and the sealing cavity (1) are provided with auxiliary sealing ring grooves (16) and shaft end labyrinth seal mounting grooves (122), which improves the overall leakage control capability of the present invention.

[0049] In summary, this invention can improve the gas film dynamic pressure effect of the floating ring seal, improve the aerodynamic performance of the floating ring seal, and has a strong stabilization and leakage control effect. It meets the stringent requirements of the main bearing cavity of aero-engine for the sealing capability of the floating ring seal, and achieves the goal of improving the service life of the floating ring seal and the overall performance of the aero-engine.

[0050] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the principles and scope of the present invention should be included within the scope of protection of the present invention.

Claims

1. A novel floating ring sealing device with stabilization and leakage control functions, characterized in that, It includes a rotating spindle (9), a floating ring (4), a rotating hemisphere (5), a flat foil (3), a corrugated foil (2), a bushing (8), a sealing cavity (1), a wave spring (6), a screw (7), a lifting lug (11), a sealing end cap (12), a shaft end labyrinth seal (10), and an auxiliary sealing ring (13).

2. The novel floating ring sealing device with stabilization and leakage control function according to claim 1, characterized in that, The rotating hemisphere (5) is hemispherical in shape.

3. A novel floating ring sealing device with stabilization and leakage control function according to claim 2, characterized in that, The outer surface of the rotating hemisphere (5) is provided with several spiral fluid micro-grooves (51) and auxiliary sealing ring placement grooves (52).

4. A novel floating ring sealing device with stabilization and leakage control function according to claim 1, characterized in that, The surface of the bushing (8) is laser-processed with micron-level grooves (81).

5. A novel floating ring sealing device with stabilization and leakage control function according to claim 4, characterized in that, The micron-level trenches (81) are polygonal in shape, and all trenches are connected.

6. A novel floating ring sealing device with stabilization and leakage control function according to claim 4, characterized in that, The micron-sized trenches (81) exhibit a symmetrical distribution along the axial direction, first decreasing and then increasing.

7. A novel floating ring sealing device with stabilization and leakage control function according to claim 1, characterized in that, The floating ring (4) is fitted to the sealing end cap (12) by the spring force of the wave spring (6).

8. A novel floating ring sealing device with stabilization and leakage control function according to claim 1, characterized in that, The corrugated foil (2) is a five-layer composite structure consisting of a base flat foil (21), a warped flat plate (22) (24), and an arc plate (23) (25).

9. A novel floating ring sealing device with stabilization and leakage control function according to claim 8, characterized in that, The substrate flat foil (21), warped flat plate (22) (24) and arc plate (23) (25) are connected by welding.

10. A novel floating ring sealing device with stabilization and leakage control function according to claim 8, characterized in that, The arc plates (23) and (25) on the inner and outer diameter sides of the corrugated foil (2) are respectively attached to the flat foil (3) and the inner side of the sealed cavity (1).

11. A novel floating ring sealing device with stabilization and leakage control function according to claim 1, characterized in that, The sealing end cap (12) has several threaded holes (121) through which it is threaded to the sealing cavity (1); the outer surface of the sealing end cap (12) has several threaded holes (123) through which it is threaded to the lifting lug (11); in addition, the inner diameter side of the sealing end cap (12) has a shaft end labyrinth seal mounting groove (122) for tight connection with the auxiliary sealing ring.

12. A novel floating ring sealing device with stabilization and leakage control function according to claim 1, characterized in that, The sealing cavity (1) has threaded holes (111) (114) for threaded connection; the cavity (1) has an auxiliary sealing ring groove (16); the cavity (1) has a flat foil placement groove (112) for fixing the folded edge (31) of the flat foil (3); the cavity (1) has an air inlet (15) with threads (14) on its outer surface for easy installation.

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