Brush seal with rotatable disks

Abstract

This invention discloses a brush seal structure with a rotatable wheel, comprising: a brush seal element and a multi-stage wheel. The rear baffle of the brush seal element has multiple rings of axial pressure equalizing holes spaced radially apart. The front end of the rear baffle has multiple pressure balancing chambers arranged radially from the inside out. The wheel is sequentially fitted onto the rear end of the rear baffle. Each stage of the wheel has a corresponding ring of holes corresponding to the axial pressure equalizing holes. The outermost wheel can open / close the outermost axial pressure equalizing holes by rotation. The inner wheel can open / close its corresponding axial pressure equalizing holes under the action of the adjacent outer wheel and an electromagnet array. This brush seal structure can suppress hysteresis and blowdown effects to varying degrees, improving the dynamic sealing performance of the brush seal and extending its overall service life.

Description

Technical Field

[0001] This invention relates to a sealing structure for use in rotating machinery, and particularly provides a brush seal structure with a rotatable wheel. Background Technology

[0002] Brush seals are a key sealing technology widely used in turbine machinery such as aero-engines, steam turbines, and compressors. They consist of a front baffle, a brush bristle bundle, and a rear baffle. Because brush seals have a leakage rate only 10-20% of traditional labyrinth seals, they are widely used as a replacement for labyrinth seals. Brush seals are a flexible contact dynamic sealing technology; the flexible brush bristles can follow the eccentric rotor movement, improving rotor dynamic characteristics and providing good dynamic sealing performance. This is beneficial for ensuring the safe and stable operation of aero-engine sets. Therefore, brush seals play an important role in the sealing of turbine machinery in industries such as aerospace.

[0003] However, brush seals suffer from hysteresis and blowdown effects. The axial pressure difference creates friction between the brush filaments and the back baffle, reducing the dynamic following performance of the brush filaments and rotor. This causes the brush filaments to lag behind the rotor, creating an additional leakage gap between the brush tip and the rotor surface, negatively impacting the overall sealing performance. The radial pressure difference between the upper and lower end faces of the brush filaments leads to a blowdown effect, causing the brush filament tips to press tightly against the rotor surface. This increases the contact force between them, exacerbating frictional heat generation between the brush filament tips and the rotor surface. This can easily lead to high-temperature adhesion and melting of the brush filaments, fatigue fracture, and other failures, affecting the service life of the brush seal.

[0004] Therefore, developing a novel brush seal structure that can adjust the pressure distribution characteristics of the flow field in the brush filament bundle region under the action of external driving force, reduce the adverse effects of axial and radial pressure differences on the brush filament bundle, suppress hysteresis and blowdown effects, and improve the dynamic sealing performance and service life of the brush seal has become an urgent problem to be solved. Summary of the Invention

[0005] Therefore, the purpose of this invention is to provide a brush seal structure with a rotatable disc to solve the problem that the hysteresis effect and blowdown effect caused by the axial and radial pressure difference in the flow field of the existing brush seal structure affect the dynamic sealing performance and service life of the brush seal.

[0006] This invention provides a brush seal structure with a rotatable wheel, comprising: a brush seal, a first-stage wheel, a second-stage wheel, and a third-stage wheel. The brush seal includes a front baffle, a bristle bundle, and a rear baffle. The rear baffle has a first ring of axial pressure equalizing holes, a second ring of axial pressure equalizing holes, and a third ring of axial pressure equalizing holes spaced apart radially from the inside to the outside. The front end of the rear baffle has three annular pressure balancing chambers, each corresponding to one of the first, second, and third rings of axial pressure equalizing holes. The first-stage wheel, second-stage wheel, and third-stage wheel are sequentially fitted onto the rear end of the rear baffle from the inside to the outside. The first-stage wheel has a first ring of corresponding holes that mate with the first ring of axial pressure equalizing holes. The second-stage wheel has a second ring of corresponding holes that mate with the second ring of axial pressure equalizing holes. The third-stage wheel has corresponding holes that mate with the first ring of axial pressure equalizing holes. The third ring of axial equalizing holes corresponds to the third ring of holes. Electromagnetic arrays I and II are correspondingly arranged on the outer circumference of the first-stage wheel and the inner circumference of the second-stage wheel. Electromagnetic arrays III and IV are correspondingly arranged on the outer circumference of the second-stage wheel and the inner circumference of the third-stage wheel. In the initial state, the first-stage wheel, second-stage wheel, and third-stage wheel are respectively closed. The third-stage wheel can rotate under the control of an external drive structure, thereby opening / closing the third ring of axial equalizing holes. The second-stage wheel can rotate under the action of electromagnetic arrays III and IV, thereby opening / closing the second ring of axial equalizing holes. The first-stage wheel can rotate under the action of electromagnetic arrays I and II, thereby opening / closing the first ring of axial equalizing holes.

[0007] Preferably, the rear end face of the rear baffle is provided with three boss structures, and the first-stage wheel, the second-stage wheel and the third-stage wheel are respectively mounted on the three boss structures through the first bearing, the second bearing and the third bearing.

[0008] Further preferably, the brush-type sealing structure with a rotatable wheel also includes a magnetic induction wheel position sensor for detecting the position of the third-stage wheel.

[0009] Further preferably, the brush-type sealing structure with a rotatable wheel also includes an external drive structure, which is an electromagnetic drive device mounted on the stator. The electromagnetic drive device includes multiple winding magnetic poles evenly distributed along the outer circumference of the third-stage wheel, multiple protruding teeth evenly distributed along the inner circumference of the winding magnetic poles, and multiple mating teeth evenly distributed along the outer circumference of the third-stage wheel. A permanent magnet is disposed inside the wheel for rotating under the control of the electromagnetic drive device.

[0010] The brush seal structure with a rotatable disc provided by this invention has a reasonable structure. The three-stage disc can correspond to the opening / closing of the three rings of axial pressure equalizing holes on the rear baffle, thereby connecting the flow field in the corresponding pressure balance chamber with the downstream of the brush seal structure. This improves the pressure distribution characteristics of the flow field in the brush filament bundle region at different radial heights and the flow field in the pressure balance chamber. It weakens the adverse effects of axial and radial pressure differences on the brush filament bundle, thereby suppressing the hysteresis effect and the blowdown effect to varying degrees. It reduces the impact of axial pressure difference on the brush filament bundle, improves the dynamic following of the brush filament bundle and the rotor, enhances the dynamic sealing performance of the brush seal, reduces the blowdown effect of radial airflow on the brush filament bundle tip, reduces frictional heat generation at the brush filament bundle tip, avoids high-temperature adhesion and fatigue fracture of the brush filament bundle, and extends the overall service life of the brush seal. Attached Figure Description

[0011] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments:

[0012] Figure 1 A cross-sectional view of the brush seal structure with a rotatable disc provided by the present invention;

[0013] Figure 2 for Figure 1 AA cross-section view. Detailed Implementation

[0014] The present invention will be further explained below with reference to specific implementation schemes, but this explanation does not limit the scope of the invention.

[0015] like Figure 1 , Figure 2As shown, the present invention provides a brush seal structure with a rotatable wheel, comprising: a brush seal, a first-stage wheel 2, a second-stage wheel 3, and a third-stage wheel 4. The brush seal includes a front baffle 11, a brush filament bundle 12, and a rear baffle 13, which are fitted onto the outer side of the rotor 10. The rear baffle 13 has a first ring of axial pressure equalizing holes 131, a second ring of axial pressure equalizing holes 132, and a third ring of axial pressure equalizing holes 133 spaced apart radially from the inside out. The front end of the rear baffle 13 has three annular pressure balancing chambers 1. 34. The pressure balancing chamber 134 is connected to the first ring of axial pressure equalizing holes 131, the second ring of axial pressure equalizing holes 132, and the third ring of axial pressure equalizing holes 133 in a one-to-one correspondence. The first-stage wheel 2, the second-stage wheel 3, and the third-stage wheel 4 are sequentially fitted onto the rear end of the rear baffle 13 from the inside out. The first-stage wheel 2 is provided with a first ring corresponding hole 21 that mates with the first ring of axial pressure equalizing holes 131. The second-stage wheel 3 is provided with a second ring corresponding hole 31 that mates with the second ring of axial pressure equalizing holes 132. The third... The first-stage wheel 4 is provided with a corresponding hole 41 on the third ring that mates with the third ring axial equalization hole 133. Electromagnetic arrays I22 and II32 are provided on the outer periphery of the first-stage wheel 2 and the inner periphery of the second-stage wheel 3, respectively. Electromagnetic arrays III33 and IV42 are provided on the outer periphery of the second-stage wheel 3 and the inner periphery of the third-stage wheel 4, respectively. In the initial state, the first-stage wheel 2, the second-stage wheel 3, and the third-stage wheel 4 are respectively closed by the first ring axial equalization hole 131 and the second ring axial equalization hole 133. The third-stage wheel 4 can rotate under the control of an external drive structure to open / close the third-circle axial equalizing hole 133, which is directed towards the equalizing hole 132 and the third-circle axial equalizing hole 133. The second-stage wheel 3 can rotate under the action of the electromagnet array III33 and the electromagnet array IV42 to open / close the second-circle axial equalizing hole 132. The first-stage wheel 2 can rotate under the action of the electromagnet array I22 and the electromagnet array II32 to open / close the first-circle axial equalizing hole 131.

[0016] This brush seal structure with a rotatable disc can open / close the three rings of axial pressure equalizing holes on the rear baffle through a three-stage disc, thereby connecting the flow field in the corresponding pressure balance chamber with the downstream of the brush seal structure. This improves the pressure distribution characteristics of the flow field in the brush filament bundle region at different radial heights and the flow field in the pressure balance chamber, reduces the adverse effects of axial and radial pressure differences on the brush filament bundle, and thus produces varying degrees of suppression of hysteresis and blowdown effects, improving the dynamic sealing performance of the brush seal and extending its service life.

[0017] The working principle of the brush seal structure with a rotatable wheel is as follows: In the initial state, the first-stage wheel, the second-stage wheel, and the third-stage wheel are respectively closed in the first, second, and third rings of axial pressure equalization holes. During operation, when the axial and radial pressure differences in the upper region of the brush filament bundle are at a critical value, the third-stage wheel is rotated by an external drive structure to open the third ring of axial pressure equalization holes, thus opening the outer airflow channel. At this time, the flow field pressure in the upper region of the brush filament bundle is reduced, which suppresses the hysteresis and blowdown effects in the upper region of the brush filament bundle. When the axial and radial pressure differences in the upper region of the brush filament bundle are both large, the third ring of axial pressure equalization holes remains open. At the same time, the airflow is directed towards the electromagnet array III and... Current is input into electromagnet array IV, causing the electromagnets in electromagnet arrays III and IV to generate an attractive force. This causes the second-stage wheel to rotate to the same phase as the third-stage wheel, opening the second ring of axial equalizing holes and opening the intermediate airflow channel. At this time, the flow field pressure in the upper region of the brush filament bundle is reduced, which helps to suppress the hysteresis and blowdown effects in the upper region of the brush filament bundle. When the downstream surface of the brush filament bundle experiences both large axial and radial pressure differences, the third and second rings of axial equalizing holes are kept open. Simultaneously, current is input into electromagnet arrays I and II, causing the electromagnets in electromagnet arrays I and II to generate an attractive force, thus causing the first-stage wheel to rotate to the same phase as the second-stage wheel. With the same phase as the disk, open the first ring of axial equalizing holes to open the inner airflow channel. At this time, the flow field pressure in the entire downstream area of ​​the brush bundle will be reduced, which will suppress the hysteresis effect and the blowdown effect in the entire downstream area of ​​the brush bundle. When the hysteresis effect and the blowdown effect no longer occur significantly, more attention can be paid to the static sealing performance. In order to reduce leakage and improve the static sealing performance, the first ring of axial equalizing holes, the second ring of axial equalizing holes, and the third ring of axial equalizing holes can be closed in sequence as needed. The method for closing the first ring of axial equalizing holes is as follows: control the rotation of the third-stage disk through the external drive structure, and at the same time drive the second-stage disk and the first-stage disk to rotate synchronously, closing the three rings of axial equalizing holes. After that, stop supplying the electromagnet array I and electromagnet array II. When current is input into electromagnet arrays III and IV, the first and second stage wheel disks will not affect each other. At this time, the third stage wheel disk is rotated by an external drive structure, which simultaneously drives the second stage wheel disk to rotate synchronously, opening the two outer rings of axial equalization holes. This closes the first ring of axial equalization holes. Similarly, the method to close the second ring of axial equalization holes is as follows: the third stage wheel disk is rotated by an external drive structure, which simultaneously drives the second stage wheel disk to rotate synchronously, closing the two outer rings of axial equalization holes. After that, the current input into electromagnet arrays III and IV is stopped, and the second and third stage wheel disks will not affect each other. At this time, the third stage wheel disk is rotated by an external drive structure, opening the third ring of axial equalization holes. This closes the second ring of axial equalization holes.

[0018] As an improvement to the technical solution, such as Figure 1 As shown, the rear end face of the rear baffle 13 is provided with three boss structures. The first-stage wheel 2, the second-stage wheel 3 and the third-stage wheel 4 are respectively mounted on the three boss structures through the first bearing 5, the second bearing 6 and the third bearing 7.

[0019] As an improvement to the technical solution, such as Figure 2 As shown, the brush seal structure with a rotatable wheel also includes a magnetic induction wheel position sensor 9, which is used to detect the position of the third-stage wheel 4. Based on the detection result, the position of the third-stage wheel can be further adjusted to ensure the opening / closing of the third ring of axial pressure equalization holes.

[0020] The rotation and fixation of the third-stage wheel can be achieved through an external drive structure. This external drive structure can take various forms, as long as it can control the rotation and fixation of the third-stage wheel. As an improvement to the technical solution, such as... Figure 2 As shown, the brush seal structure with a rotatable wheel also includes an external drive structure, which is an electromagnetic drive device. The electromagnetic drive device is mounted on the stator 8 and includes multiple winding magnetic poles 81 evenly distributed along the outer circumference of the third-stage wheel 4. Multiple protruding teeth are evenly distributed along the inner circumference of the winding magnetic poles 81. Multiple mating teeth are evenly distributed along the outer circumference of the third-stage wheel 4. A permanent magnet 43 is provided inside for rotating under the control of the electromagnetic drive device. The principle is the same as the rotation drive principle of a hybrid stepper motor.

[0021] The specific embodiments of the present invention are written in a progressive manner, emphasizing the differences between the various implementation schemes, and the similar parts can be referred to each other.

[0022] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A brush-type sealing structure with a rotatable disc, characterized in that, include: The brush seal comprises a first-stage wheel (2), a second-stage wheel (3), and a third-stage wheel (4). The brush seal includes a front baffle (11), a brush filament bundle (12), and a rear baffle (13). The rear baffle (13) has a first ring of axial pressure equalizing holes (131), a second ring of axial pressure equalizing holes (132), and a third ring of axial pressure equalizing holes (133) spaced outwards along its radial direction. The front end of the rear baffle (13) has three annular pressure equalization chambers (134). The pressure equalization chambers (134) are connected to the first ring of axial pressure equalizing holes (131), the second ring of axial pressure equalizing holes (132), the third ring of axial pressure equalizing holes (133), and the third ring of axial pressure equalizing holes (133). The first-stage wheel (2), the second-stage wheel (3), and the third-stage wheel (4) are connected in a one-to-one correspondence. The first-stage wheel (2), the second-stage wheel (3), and the third-stage wheel (4) are sequentially fitted onto the rear end of the rear baffle (13) from the inside out. The first-stage wheel (2) is provided with a first-stage corresponding hole (21) that mates with the first-stage axial equalization hole (131). The second-stage wheel (3) is provided with a second-stage corresponding hole (31) that mates with the second-stage axial equalization hole (132). The third-stage wheel (4) is provided with a corresponding hole that mates with the third-stage axial equalization hole. The third ring of the hole (41) is fitted with the hole (133). The outer circumference of the first-stage wheel (2) and the inner circumference of the second-stage wheel (3) are respectively provided with electromagnet array I (22) and electromagnet array II (32). The outer circumference of the second-stage wheel (3) and the inner circumference of the third-stage wheel (4) are respectively provided with electromagnet array III (33) and electromagnet array IV (42). In the initial state, the first-stage wheel (2), the second-stage wheel (3), and the third-stage wheel (4) are respectively closed by the first ring axial pressure equalizing hole (131) and the second ring axial pressure equalizing hole (132). The third-stage wheel (4) can rotate under the control of the external drive structure, thereby opening / closing the third-stage axial equalizing hole (133). The second-stage wheel (3) can rotate under the action of the electromagnet array III (33) and the electromagnet array IV (42), thereby opening / closing the second-stage axial equalizing hole (132). The first-stage wheel (2) can rotate under the action of the electromagnet array I (22) and the electromagnet array II (32), thereby opening / closing the first-stage axial equalizing hole (131).

2. The brush-type sealing structure with a rotatable disc according to claim 1, characterized in that: The rear end face of the rear baffle (13) is provided with three boss structures. The first stage wheel (2), the second stage wheel (3) and the third stage wheel (4) are respectively installed on the three boss structures through the first bearing (5), the second bearing (6) and the third bearing (7).

3. The brush-type sealing structure with a rotatable disc according to claim 1, characterized in that: It also includes a magnetic induction wheel position sensor (9) for detecting the position of the third-level wheel (4).

4. The brush seal structure with a rotatable disc according to claim 1, characterized in that: It also includes an external drive structure, which is an electromagnetic drive device. The electromagnetic drive device is mounted on the stator (8) and includes multiple winding magnetic poles (81) evenly distributed along the outer periphery of the third-stage wheel (4). Multiple protruding teeth are evenly distributed along the inner periphery of the winding magnetic poles (81). Multiple mating teeth are evenly distributed along the outer periphery of the third-stage wheel (4). A permanent magnet (43) is provided inside for rotating under the control of the electromagnetic drive device.

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