Non-contact fingertip sealing device with high-stability sealing performance

Abstract

The invention discloses a non-contact fingertip sealing device with high-stability sealing performance, and belongs to the technical field of mechanical sealing. The fingertip sealing device comprises a rotor and a fingertip sealing mechanism matched with the rotor, the fingertip sealing mechanism comprises a high-pressure fingertip piece and a low-pressure fingertip piece, the low-pressure fingertip piece comprises a sealing boot, a surface texture is arranged on the rotor, and the position of the surface texture corresponds to the position of the end of the sealing boot and the position of the end of the high-pressure fingertip piece. According to the non-contact fingertip sealing device, the surface texture is arranged on the rotor, so that a more stable and uniform dynamic pressure gas film is formed in the high-speed running process of the rotor, the bearing capacity of the dynamic pressure gas film is improved, and the non-contact fingertip sealing device has more excellent sealing performance.

Description

Technical Field

[0001] The invention belongs to the technical field of mechanical seals and relates to a non-contact fingertip seal device with high stable sealing performance. Background Art

[0002] Sealing devices are an important part of turbomachinery and its accessory systems, and are often used to control the leakage and flow of fluids. With the continuous development of the aerospace industry, sealing devices have received extensive attention as important components of aerospace engines.

[0003] The evaluation criteria for sealing performance are seal leakage and service life. Sealing devices with excellent sealing performance usually have lower leakage and longer service life. Excellent sealing performance is particularly important for improving engine performance, and can effectively improve the performance and service life of various engine components.

[0004] Finger tip seal is a new type of sealing technology developed after comb seal and brush seal, and is known as a revolutionary sealing technology. Finger tip seal is used in the static and dynamic gas path sealing between the high pressure chamber and the low pressure chamber in the engine and the bearing chamber sealing of the engine main shaft. It has many outstanding advantages, such as small leakage and low manufacturing cost. The sealing effect of finger tip seal is similar to that of brush seal, but the manufacturing cost of finger tip seal is only about half of that of brush seal; compared with comb seal, the leakage factor of finger tip seal can be reduced by 20%-70%.

[0005] At present, fingertip seals are mainly divided into contact fingertip seals and non-contact fingertip seals. The principle of contact fingertip seals is that along the circumference of the baffle, several fingertip sheets (high-pressure fingertip sheets and low-pressure fingertip sheets) are staggered and overlapped, so that the fingertip of one fingertip sheet covers the gap between the fingertips of adjacent fingertip sheets, and then several fingertip sheets are clamped by front and rear baffles and fixed by rivets to form a sealing structure, in which the sealing boot and the rotor are interference-fitted to form a contact and a sealing structure to prevent fluid leakage along the axial direction of the rotor. Non-contact fingertip seals are developed based on the contact fingertip seal as a prototype. The sealing boot and the rotor of the non-contact fingertip seal are not interference-fitted, but have an installation gap. When working, a layer of dynamic pressure gas film is formed between the sealing boot and the rotor through the high-speed operation of the rotor to achieve non-contact sealing, and the fluid lift generated by the dynamic pressure gas film is used to provide radial lift for the sealing boot (radial is the radial direction of the rotor), so that the sealing boot and the rotor remain in a non-contact state, and the generation of contact wear is reduced on the basis of achieving the sealing effect.

[0006] As an advanced technology of contact fingertip sealing, non-contact fingertip sealing has become a research hotspot. At present, the research on non-contact fingertip sealing devices focuses on solving the "hysteresis effect" of non-contact fingertip sealing devices. The "hysteresis effect" is mainly due to the radial displacement of the rotor, which pushes the fingertip sheet away from the initial position. When the radial displacement of the rotor decreases or disappears, the friction between the fingertip sheet and the baffle prevents the fingertip sheet from returning to the initial position, thereby generating a large gap between the sealing boot and the rotor surface, resulting in a decrease in sealing performance. For example, the patent with application number 201510156112.0 discloses a non-contact fingertip sealing device with a microporous texture on the rear baffle. The device reduces the friction coefficient between the low-pressure fingertip sheet and the rear baffle by means of a pressure balance chamber of the rear baffle and a textured area on the end face of the rear baffle, thereby reducing the "hysteresis effect". However, the "hysteresis effect" is a factor that affects the sealing performance of the non-contact fingertip sealing device. The non-contact fingertip sealing device mainly realizes sealing and maintains the non-contact state of the sealing boot, high-pressure fingertip piece and the rotor by high-speed operation of the rotor to form a dynamic pressure air film between the rotor and the sealing boot and the end of the high-pressure fingertip piece. Therefore, the stability of the dynamic pressure air film also has a direct impact on the sealing performance of the non-contact fingertip sealing device.

[0007] Therefore, it is necessary to provide a non-contact fingertip sealing device with highly stable sealing performance, so that a more stable dynamic pressure air film can be formed during the operation of the rotor, thereby improving the sealing stability of the non-contact fingertip sealing device, and at the same time improving the stability of the radial lift provided by the dynamic air film to the sealing boot and the end of the high-pressure fingertip piece, which is equivalent to improving the bearing stability of the dynamic air film, making the gap between the sealing boot, the end of the high-pressure fingertip piece and the rotor more stable, and enabling the non-contact fingertip sealing device to maintain a relatively excellent sealing performance. Summary of the invention

[0008] In order to overcome the problems in the background technology, the present invention sets a surface texture on the rotor (surface texture refers to the use of appropriate processing technology to prepare a microstructure array of specific shape, arrangement and size on its surface without changing the material itself, so as to obtain special surface properties). The surface texture and the gas in the sealing gap produce a shearing effect to form a local fluid dynamic pressure effect. The surface texture "pumps" the gas into the sealing interface, increases the pressure distribution of the dynamic pressure gas film, and improves the bearing capacity of the gas film. In addition, the operation of the rotor causes the surface texture to move with it, plays a guiding role, controls the flow direction of the gas in the sealing gap, avoids the disordered turbulence caused by high-speed airflow, reduces pressure pulsation, maintains the uniformity and stability of the gas film, reduces the probability of rupture of the dynamic pressure gas film, and thus keeps the dynamic pressure gas film in a relatively excellent stable state, thereby improving the sealing performance of the non-contact fingertip sealing device.

[0009] In order to achieve the above object, the present invention is implemented by the following technical solutions:

[0010] The non-contact fingertip sealing device includes a rotor 1 and a fingertip sealing mechanism 2 cooperating with the rotor 1, the fingertip sealing mechanism 2 includes a high-pressure fingertip sheet 203 and a low-pressure fingertip sheet 204, the low-pressure fingertip sheet 204 includes a sealing boot 2042, and a surface texture 3 is provided on the rotor 1, and the position of the surface texture 3 corresponds to the end position of the sealing boot 2042 and the high-pressure fingertip sheet 203.

[0011] Preferably, the surface texture is a teardrop-shaped groove.

[0012] Preferably, the fingertip sealing mechanism 2 also includes a front baffle plate 201, a distance ring 202, and a rear baffle plate 205. From the high-pressure side to the low-pressure side of the fingertip sealing mechanism 2, they are the front baffle plate 201, the distance ring 202, the high-pressure fingertip sheet 203, the low-pressure fingertip sheet 204, and the rear baffle plate 205. The front baffle plate 201, the distance ring 202, the high-pressure fingertip sheet 203, the low-pressure fingertip sheet 204, and the rear baffle plate 205 are connected by rivets. There are several high-pressure fingertip sheets 203 and low-pressure fingertip sheets 204, which are arranged circumferentially along the front baffle plate 201 to form a high-pressure fingertip ring and a low-pressure fingertip ring, respectively.

[0013] Preferably, the low-pressure fingertip sheet 204 also includes a fingertip beam 2041, which is located between the high-pressure fingertip sheet 203 and the rear baffle 205, and the fingertip beam 2041 is connected to the high-pressure fingertip sheet 203 and the rear baffle 205 by rivets, and the sealing boot 2042 is fixedly connected to the fingertip beam 2041 near one end of the rotor, and the sealing boot 2042 is radially perpendicular to the rotor 1 and extends toward the low-pressure side.

[0014] Beneficial effects of the present invention:

[0015] 1. The present invention can effectively reduce the probability of dynamic pressure air film rupture, increase the pressure distribution of the dynamic pressure air film, and reduce the probability of disordered turbulence by arranging surface texture on the rotor, thereby improving the uniformity and stability of the dynamic pressure air film, and maintaining a relatively stable gap between the sealing boot, the end of the high-pressure fingertip sheet and the rotor, so that the non-contact fingertip sealing device has stable, long-lasting and excellent sealing performance.

[0016] 2. The present invention arranges a surface texture on the rotor. Since the rotor has a large surface area and is a continuous surface, the processing difficulty is small. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the cross-sectional structure of the device of the present invention;

[0018] Figure 2 It is a schematic diagram of the rotor surface texture structure of the present invention;

[0019] In the figure, 1-rotor, 2-finger sealing mechanism, 201-front baffle, 202-distance ring, 203-high-pressure fingertip plate, 204-low-pressure fingertip plate, 2041-fingertip beam, 2042-sealing boot, 205-rear baffle, 3-surface texture, 4-dynamic pressure air film. DETAILED DESCRIPTION

[0020] The present invention is further described in detail below in conjunction with the accompanying drawings, but the protection scope of the present invention is not limited to the described contents.

[0021] like Figure 1-2 As shown, the non-contact fingertip sealing device includes a rotor 1 and a fingertip sealing mechanism 2 cooperating with the rotor 1, the fingertip sealing mechanism 2 includes a high-pressure fingertip sheet 203 and a low-pressure fingertip sheet 204, the low-pressure fingertip sheet 204 includes a sealing boot 2042, and a surface texture 3 is provided on the rotor 1, and the position of the surface texture 3 corresponds to the end position of the sealing boot 2042 and the high-pressure fingertip sheet 203.

[0022] The surface texture is a water drop-shaped groove.

[0023] When the non-contact fingertip sealing device is working normally, the rotor 1 rotates at high speed, and a dynamic pressure air film is formed between the rotor 1 and the ends of the sealing boot 2042 and the high-pressure fingertip sheet 203 to achieve a sealing effect. The dynamic pressure air film provides lift to the ends of the sealing boot 2042 and the high-pressure fingertip sheet 203, so that the dynamic pressure air film forms a supporting and bearing effect on the sealing boot 2042 and the high-pressure fingertip sheet 203, so that the ends of the sealing boot 2042 and the high-pressure fingertip sheet 203 maintain a non-contact state with the rotor 1. By arranging a surface texture 3 on the rotor 1, the dynamic pressure air film formed during the high-speed operation of the rotor 1 has better uniformity, stability and load-bearing capacity, so that the dynamic pressure air film has more stable and excellent sealing performance and load-bearing capacity, and thus the non-contact fingertip sealing device has better sealing performance.

[0024] The fingertip sealing mechanism 2 also includes a front baffle plate 201, a distance ring 202, and a rear baffle plate 205. From the high-pressure side to the low-pressure side of the fingertip sealing mechanism 2, they are the front baffle plate 201, the distance ring 202, the high-pressure fingertip sheet 203, the low-pressure fingertip sheet 204, and the rear baffle plate 205. The front baffle plate 201, the distance ring 202, the high-pressure fingertip sheet 203, the low-pressure fingertip sheet 204, and the rear baffle plate 205 are connected by rivets. There are multiple high-pressure fingertip sheets 203 and low-pressure fingertip sheets 204, which are arranged circumferentially along the front baffle plate 201 to form a high-pressure fingertip ring and a low-pressure fingertip ring, respectively.

[0025] The low-pressure fingertip sheet 204 also includes a fingertip beam 2041, which is located between the high-pressure fingertip sheet 203 and the rear baffle 205. The fingertip beam 2041 is connected to the high-pressure fingertip sheet 203 and the rear baffle 205 through rivets. The sealing boot 2042 is fixedly connected to one end of the fingertip beam 2041 close to the rotor. The sealing boot 2042 is radially perpendicular to the rotor 1 and extends toward the low-pressure side.

[0026] The installation method and working principle of each component of the fingertip sealing mechanism 2 are the same as those of the corresponding components of the existing non-contact fingertip sealing device.

[0027] Finally, it should be noted that the above preferred embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail through the above preferred embodiments, those skilled in the art should understand that various changes can be made in form and details without departing from the scope defined by the claims of the present invention.

Claims

1. A non-contact fingertip sealing device with high stable sealing performance, characterized in that: The non-contact fingertip sealing device comprises a rotor (1) and a fingertip sealing mechanism (2) matched with the rotor (1); the fingertip sealing mechanism (2) comprises a high-pressure fingertip sheet (203) and a low-pressure fingertip sheet (204); the low-pressure fingertip sheet (204) comprises a sealing boot (2042); a surface texture (3) is arranged on the rotor (1); the position of the surface texture (3) corresponds to the end position of the sealing boot (2042) and the high-pressure fingertip sheet (203).

2. A non-contact fingertip sealing device with high stable sealing performance according to claim 1, characterized in that: The surface texture is a water drop-shaped groove.

3. A non-contact fingertip sealing device with high stable sealing performance according to claim 1, characterized in that: The fingertip sealing mechanism (2) further comprises a front baffle plate (201), a distance ring (202), and a rear baffle plate (205), wherein from the high-pressure side to the low-pressure side of the fingertip sealing mechanism (2), the front baffle plate (201), the distance ring (202), the high-pressure fingertip sheet (203), the low-pressure fingertip sheet (204), and the rear baffle plate (205) are arranged in sequence; the front baffle plate (201), the distance ring (202), the high-pressure fingertip sheet (203), the low-pressure fingertip sheet (204), and the rear baffle plate (205) are connected by rivets; there are a plurality of high-pressure fingertip sheets (203) and low-pressure fingertip sheets (204), which are arranged circumferentially along the front baffle plate (201) to form a high-pressure fingertip ring and a low-pressure fingertip ring, respectively.

4. A non-contact fingertip sealing device with high stable sealing performance according to claim 3, characterized in that: The low-pressure fingertip sheet (204) further comprises a fingertip beam (2041), wherein the fingertip beam (2041) is located between the high-pressure fingertip sheet (203) and the rear baffle (205), and the fingertip beam (2041) is connected to the high-pressure fingertip sheet (203) and the rear baffle (205) via rivets, and the sealing boot (2042) is fixedly connected to one end of the fingertip beam (2041) close to the rotor, and the sealing boot (2042) is radially perpendicular to the rotor (1) and extends toward the low-pressure side.

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