A sealing structure for a cavity via actuation mechanism and a design method thereof

Abstract

The application relates to the field of aero-engine design, and discloses a sealing structure for an actuating mechanism at a cavity through hole and a design method thereof. The sealing structure is characterized in that a first mounting assembly on a bellows is used to fix a sealing element at the cavity and seal a sealing rod which can be actuated in multiple directions, so that the sealing rod can smoothly pass through and maintain close contact with the wall of the mounting hole, and fluid or gas leakage is effectively prevented. In addition, the elastic properties of the bellows can compensate for the axial and radial displacement of the sealing rod during movement, so that the sealing structure can still maintain stable sealing effect under complex action of the sealing rod, and the reliability and service life of the equipment are greatly improved. The design of the bellows comprehensively considers the influence of the structure thickness, deflection angle, height and number of corrugated pieces of a single corrugated piece on the deflection stress of the bellows, so that the pressure-bearing capacity and service life of the sealing structure are further ensured.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of aero-engine design, and discloses a sealing structure for an actuating mechanism at a cavity through hole and a design method thereof. BACKGROUND

[0002] The actuating rod of the actuating mechanism extends into the cavity through the through hole and is connected with the adjusting plate. Since the required displacement of the actuating rod not only has a longitudinal stretching and compression, but also has a certain degree of radial bending actuation, a certain gap needs to be left between the cavity through hole and the actuating rod to meet the actuating stroke of the actuating rod. This leads to leakage of high-temperature combustion gas in the cavity through the gap between the through hole and the actuating rod, resulting in loss of engine thrust, and even possible ablation of other cavity external structural components. Therefore, solving the sealing problem at this position is a key design point for ensuring the thrust and safety of the engine.

[0003] The key to the sealing design at the actuating rod through hole lies in ensuring the close fit between the sealing member and the actuating rod, while considering the radial and axial movement of the actuating rod, and requiring the sealing structure to be reliably sealed under complex motion conditions. However, the commonly used shaft rod type sealing methods such as metal sealing ring, labyrinth seal and other sealing structures cannot meet the radial movement requirement of the actuating rod. SUMMARY

[0004] The present application aims to provide a sealing structure for an actuating mechanism at a cavity through hole and a design method thereof, which can ensure that the sealing structure still maintains stable sealing effect under complex action of the actuating rod, greatly improving the reliability and service life of the equipment. In addition, the design of the bellows comprehensively considers the influence of the thickness of a single corrugated sheet structure, the deflection angle, the height of the bellows and the number of corrugations on the deflection stress of the bellows, further ensuring the pressure-bearing capacity and service life of the sealing structure.

[0005] In order to achieve the above technical effects, the technical scheme adopted by the present application is as follows:

[0006] A sealing structure for an actuating mechanism at a cavity through hole, comprising:

[0007] a bellows fixed at the cavity through hole, the through hole being used for penetrating an actuating rod of the actuating mechanism;

[0008] a first mounting assembly mounted on the bellows, and the first mounting assembly being located at a bellows end head away from the cavity; a mounting hole for the actuating rod to pass through is formed in the first mounting assembly, and the mounting hole is in sealing fit with the outer wall of the actuating rod.

[0009] Further, the first mounting assembly comprises an upper flange, the mounting hole is a lower concave ball head seat arranged in the middle of the upper flange, and the outer wall of the actuating rod is provided with a ball head structure matched with the ball head seat.

[0010] Further, the ball head structure is externally nested with a graphite packing seal ring, and the graphite packing seal ring and the ball head structure are fastened and connected in the ball head seat of the upper flange through the upper flange cover plate.

[0011] Further, the graphite packing seal ring comprises an upper hard graphite packing ring, a flexible graphite packing ring and a lower hard graphite packing ring, and the flexible graphite packing ring is located between the upper hard graphite packing ring and the lower hard graphite packing ring; the upper hard graphite packing ring, the flexible graphite packing ring and the lower hard graphite packing ring are all provided with through holes, which jointly form a spherical hole matched with the ball head structure.

[0012] Further, the bellows is fixedly connected with the cavity through the lower flange.

[0013] Further, the lower flange is provided with an elastic sealing assembly at the contact position with the edge of the through hole of the cavity.

[0014] To achieve the above technical effects, the application further provides a sealing structure design method for an actuating mechanism at a through hole of a cavity, comprising:

[0015] A three-dimensional simulation analysis model of the sealing structure is constructed, the sealing structure comprising a bellows fixed at the through hole of the cavity, the bellows being provided with a first mounting assembly at the end away from the cavity, the first mounting assembly being sealingly connected with the end of the bellows; an actuating rod of the actuating mechanism passes through the first mounting assembly, the bellows and the through hole, and the first mounting assembly is provided with a mounting hole sealingly matched with the actuating rod;

[0016] The thickness of a single corrugated sheet structure of the bellows, the number of corrugations and the total height of the bellows are taken as inputs, and the deflection stress data of the bellows under different deflection angles of the actuating rod are obtained through simulation analysis;

[0017] According to the deflection stress under the corresponding input condition and the corresponding deflection angle, a bellows deflection stress analysis model is constructed;

[0018] According to the total height design value of the bellows of the sealing structure to be designed, the bellows deflection stress analysis model is used to analyze and obtain the single corrugated sheet structure thickness and the corrugation combination parameter value of the bellows material that meets the allowable stress of the sealing structure to be designed.

[0019] Further, the constructed bellows deflection stress analysis model is , wherein is the deflection stress, is the single corrugated sheet structure thickness, is the deflection angle of the actuating rod, is the total height of the bellows. is the number of corrugations, is the coefficient, , , are the exponents, respectively, , , , obtained by data fitting.

[0020] Compared with the prior art, the present application has the beneficial effects of:

[0021] 1. The first mounting assembly on the corrugated pipe is used to fix the sealing element at the cavity and to seal the actuating rod, so that the actuating rod can smoothly pass through and maintain close contact with the wall of the mounting hole, effectively preventing fluid or gas leakage; in addition, the elastic properties of the corrugated pipe can compensate for the axial and radial displacement of the actuating rod during movement, ensuring that the sealing structure can still maintain stable sealing effect under complex action of the actuating rod, greatly improving the reliability and service life of the equipment.

[0022] 2. The present application comprehensively considers the influence of single corrugated sheet structure thickness, deflection angle, corrugated pipe height and corrugation number on the deflection stress of the corrugated pipe when designing the corrugated pipe, further ensuring the pressure-bearing capacity and service life of the sealing structure. BRIEF DESCRIPTION OF DRAWINGS

[0023] Fig. 1 is a structural schematic diagram of the sealing structure of the actuating mechanism at the cavity through hole in the embodiment;

[0024] Fig. 2 is a mounting schematic diagram of the ball head structure and the graphite packing seal ring in the embodiment;

[0025] Fig. 3 is a structural schematic diagram of the graphite packing seal ring in the embodiment;

[0026] 1. corrugated pipe; 2. actuating rod; 3. upper flange; 4. ball head seat; 5. ball head structure; 6. flange cover plate; 7. graphite packing seal ring; 701. upper hard graphite packing ring; 702. flexible graphite packing ring; 703. lower hard graphite packing ring; 8. lower flange; 9. elastic sealing assembly. DETAILED DESCRIPTION

[0027] The present application will be further described in detail below in conjunction with the embodiments and drawings. However, this should not be understood as limiting the scope of the above-mentioned subject matter of the present application to the following embodiments only, and any technology realized based on the content of the present application falls within the scope of the present application.

[0028] EMBODIMENT

[0029] Referring to Figs. 1 to 3A sealing structure for a cavity through-hole actuator mechanism, comprising:

[0030] A bellows 1 is fixed at the cavity through-hole for the actuator rod 2 of the actuator mechanism;

[0031] A first mounting assembly is mounted on the bellows 1, and the first mounting assembly is located at the end of the bellows 1 away from the cavity; the first mounting assembly is provided with a mounting hole for the actuator rod 2 to pass through, and the mounting hole is in sealing cooperation with the outer wall of the actuator rod 2.

[0032] In this embodiment, the first mounting assembly on the bellows 1 realizes the fixation of the sealing element at the cavity and the sealing of the actuator rod 2 with multi-directional movement, so that the actuator rod 2 can smoothly pass through and maintain close contact with the wall of the mounting hole, effectively preventing the leakage of fluid or gas; in addition, the elastic properties of the bellows 1 can compensate for the axial and radial displacement of the actuator rod 2 during movement, ensuring that the sealing structure can still maintain stable sealing effect under the complex action of the actuator rod 2, greatly improving the reliability and service life of the equipment.

[0033] In this embodiment, the bellows 1 is made of metal and has an S-shaped cross-section. The metal bellows structure with an S-shaped cross-section has excellent flexibility and elasticity, and has lower deflection stress at the same deflection angle compared to other types of bellows. The S-shaped metal bellows 1 can effectively absorb the vibration generated during equipment operation, reducing the impact on the sealing element, thereby prolonging the service life of the system.

[0034] In this embodiment, the first mounting assembly includes an upper flange 3, and the mounting hole is a lower concave ball seat 4 arranged in the middle of the upper flange 3; the outer wall of the actuator rod 2 is fixed with a ball head structure 5 matched with the ball seat 4. When the actuator rod 2 is actuated, the ball head structure 5 moves accordingly. If the actuator rod 2 bends radially, the ball head structure 5 can freely rotate due to the spherical contact between the ball seat 4 and the ball head structure 5. The bellows 1 structure moves accordingly under the transmission of the force of the actuator rod 2 and the ball head structure 5, and the graphite packing ring 7 always maintains contact with the ball head structure 5, changing the larger sealing gap at the through-hole into a smaller sealing problem at the upper flange 3, and without affecting the actuation stroke of the actuator rod 2.

[0035] In this embodiment, a graphite packing sealing ring 7 is nested outside the ball head structure 5. The graphite packing sealing ring 7 and the ball head structure 5 are fastened to the ball head seat 4 of the upper flange 3 by the upper flange cover plate 6. A threaded blind hole is opened at the upper end of the upper flange 3, and a screw hole is opened on the flange cover plate 6. The flange cover plate 6 is fixedly connected to the upper flange 3 by screws. This connection method facilitates the disassembly and maintenance of various components. A circular hole with the same outer diameter as the actuating rod 2 is provided inside the ball head structure 5. The actuating rod 2 can pass through the circular hole, with one end connected to the external actuation drive mechanism and the other end connected to the adjustment plate inside the cavity. In this embodiment, the installation position of the ball head structure 5 is slightly higher than that of the flange cover plate 6. Under the premise of ensuring the rotation stroke of the actuating rod 2, the lateral displacement of the actuating rod 2 is not affected, and the flange cover plate 6 is not subjected to significant compression. Especially during the process of the bellows 1 structure undergoing a certain degree of deformation as the actuating rod 2 and the ball head structure 5 move, the ball head structure 5 can always maintain close contact with the actuating rod 2, reducing the degree of compression between the actuating rod 2 and the upper flange 3, and further reducing the compressive force of the actuating rod 2 on the graphite packing sealing ring 7.

[0036] In this embodiment, the graphite packing sealing ring 7 is composed of an upper hard graphite packing ring 701, a flexible graphite packing ring 702, and a lower hard graphite packing ring 703. The flexible graphite packing ring 702 is located between the upper hard graphite packing ring 701 and the lower hard graphite packing ring 703. The upper hard graphite packing ring 701, the flexible graphite packing ring 702, and the lower hard graphite packing ring 703 are all provided with through holes, which together form a spherical hole that cooperates with the ball head structure 5. When the ball head structure 5 moves, the graphite packing sealing ring 7 will be subjected to a certain degree of compression. However, compared to when there is no ball head structure 5, the degree of compression on the graphite packing sealing ring 7 is smaller. Furthermore, the graphite packing sealing ring 7 adopts a split structure that combines a flexible graphite packing ring 702, an upper hard graphite packing ring 701, and a lower hard graphite packing ring 703. The three components of the graphite packing sealing ring 7 work together to ensure good sealing performance at the upper flange 3, while further increasing its pressure resistance. The risk of damage to the graphite packing sealing ring 7 is greatly reduced, and the sealing reliability is enhanced.

[0037] In this embodiment, the modification process of the graphite-filled sealing ring 7 is as follows: SiC powder and ADP solution are selected, and dimethyl sulfoxide (DMSO) is used as the dispersant for the two impregnation modification materials. The mass ratio of SiC powder, ADP solution and DMSO solution is 1:1:10. First, SiC powder and DMSO solution are mixed and ultrasonically dispersed uniformly at room temperature for 1 hour. Then, ADP solution is added and stirred in a water bath at 40°C for 1 hour. Then, the mixed solution is transferred to a pressure reactor containing the graphite-filled sealing ring 7. After the reactor lid is tightened, it is impregnated in an oven at 60°C for 4 hours. After the reactor cools to room temperature, the graphite-filled sealing ring 7 is taken out, dried to remove residual solvent from the surface, and then placed in a tube furnace for sintering at 600°C for 4 hours. During the sintering process, the DMSO solution inside the graphite-filled sealing ring 7 evaporates and dissipates at high temperature. After sintering, it is taken out and cooled to obtain the mixed ceramic coating impregnated graphite-filled sealing ring 7.

[0038] In this embodiment, a lower flange 8 is provided at the end of the bellows 1 furthest from the first mounting assembly, and the bellows 1 is fixedly connected to the cavity via the lower flange 8. An elastic sealing assembly 9 is provided at the contact point between the lower flange 8 and the edge of the cavity through hole. This ensures that the lower flange 8 always maintains a tight connection with the edge of the cavity through hole, preventing hot gas from leaking from the lower flange 8 and effectively solving the sealing problem between the actuating mechanism and the through hole.

[0039] Based on the same inventive concept, this embodiment also provides a sealing structure design method for an actuating mechanism at a cavity through-hole, including:

[0040] Step 1: Construct a three-dimensional simulation analysis model of the sealing structure. The sealing structure includes a bellows 1 fixed at the through hole of the cavity. A first mounting component is provided at the end of the bellows 1 away from the cavity. The first mounting component is sealed to the end of the bellows 1. The actuating rod 2 of the actuating mechanism passes through the first mounting component, the bellows 1 and the through hole. The first mounting component is provided with a mounting hole that seals with the actuating rod 2.

[0041] Step 2: Using the thickness of a single corrugated sheet structure, the number of corrugations, and the total height of the bellows 1 as inputs, obtain the deflection stress data of the bellows 1 under different deflection angles of the actuator 2 through simulation analysis;

[0042] In this embodiment, ABAQUS software was used to investigate and analyze the deflection stress data of bellows 1 with different sizes and configurations after applying different deflection angles. To accurately obtain the design configuration of the metal bellows 1, the simulation data of the bellows 1 in this embodiment covers a height of 26.92–29.52 mm, a number of corrugated plate pairs of 18–23, a single corrugated plate structural thickness of 0.1–0.3 mm, and a deflection angle of 2.5°–15°. Through simulation analysis, the deflection stress data of the bellows 1 under different deflection angles of the actuator 2 under the test conditions were obtained.

[0043] Step 3: Based on the corresponding input conditions and the deflection stress at the corresponding deflection angle, construct the deflection stress analysis model of bellows 1;

[0044] This embodiment establishes an explicit empirical model of deflection stress by performing multivariate nonlinear regression analysis on the obtained data. ,in For deflection stress, The thickness of a single corrugated sheet structure, The deflection angle of actuator 2. This represents the total height of bellows 1; The number of ripples. For coefficients, , , These are the exponents, and in the formula... , , , The deflection stress analysis model for bellows 1 was determined through least squares optimization. This model, for the first time, incorporates the core design parameters of individual bellows structure thickness, deflection angle, bellows 1 height, and number of bellows into a unified analytical framework. It can more accurately predict and analyze the influence of different design parameters on the deflection stress of bellows 1, thereby optimizing the design of the sealing structure and improving its pressure-bearing capacity and service life.

[0045] As shown in this embodiment, the result of the comprehensive fitting parameters is... .

[0046] Step 4: Based on the total height design value of the bellows 1 in the sealing structure to be designed, the deflection stress analysis model of the bellows 1 is used to analyze and obtain the combined parameter values ​​of the thickness of a single bellows structure and the number of bellows that satisfy the allowable stress of the bellows 1 material in the sealing structure to be designed.

[0047] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for designing a sealing structure for an actuating mechanism at a cavity through-hole, characterized in that, include: A three-dimensional simulation analysis model of the sealing structure is constructed. The sealing structure includes a bellows fixed at the through hole of the cavity. A first mounting component is provided at the end of the bellows away from the cavity. The first mounting component is sealed to the end of the bellows. The actuating rod of the actuating mechanism passes through the first mounting component, the bellows, and the through hole. The first mounting component is provided with a mounting hole that seals with the actuating rod. Using the thickness of a single corrugated sheet structure, the number of corrugations, and the total height of the corrugated pipe as inputs, simulation analysis is used to obtain the deflection stress data of the corrugated pipe under different deflection angles of the actuator. Based on the corresponding input conditions and the deflection stress at the corresponding deflection angle, a deflection stress analysis model for bellows is constructed. Based on the design value of the total height of the bellows in the sealing structure to be designed, the combined parameter values ​​of the thickness of a single bellows structure and the number of bellows are obtained by using the bellows deflection stress analysis model to satisfy the allowable stress of the bellows material in the sealing structure to be designed.

2. The sealing structure design method according to claim 1, characterized in that, The first mounting assembly includes an upper flange, the mounting hole is a recessed ball head seat located in the middle of the upper flange, and the outer wall of the actuating rod is provided with a ball head structure that mates with the ball head seat.

3. The sealing structure design method according to claim 2, characterized in that, The ball head structure is externally nested with a graphite packing sealing ring. The graphite packing sealing ring and the ball head structure are fastened to the ball head seat of the upper flange through the upper flange cover plate.

4. The sealing structure design method according to claim 3, characterized in that, The graphite packing sealing ring includes an upper hard graphite packing ring, a flexible graphite packing ring, and a lower hard graphite packing ring. The flexible graphite packing ring is located between the upper hard graphite packing ring and the lower hard graphite packing ring. The upper hard graphite packing ring, the flexible graphite packing ring, and the lower hard graphite packing ring all have through holes inside, which together form a spherical hole that matches the ball head structure.

5. The sealing structure design method according to claim 1, characterized in that, The bellows is provided with a lower flange at the end away from the first mounting component, and the bellows is fixedly connected to the cavity through the lower flange.

6. The sealing structure design method according to claim 5, characterized in that, An elastic sealing component is provided at the contact point between the lower flange and the edge of the cavity through hole.

7. The sealing structure design method according to claim 1, characterized in that, The constructed bellows deflection stress analysis model is as follows: ,in For deflection stress, The thickness of a single corrugated sheet structure, Let be the deflection angle of the actuator. This is the total height of the corrugated pipe; The number of ripples. For coefficients, , , They are indices, , , , Obtained through data fitting.

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