A dry gas sealing structure with an anti-spindle-shaped dynamic pressure groove

Abstract

This invention discloses a dry gas sealing structure with an inverted spindle-shaped dynamic pressure groove, including a rotating ring and a corresponding stationary ring. Several inverted spindle-shaped dynamic pressure grooves are evenly distributed circumferentially on the sealing end face of the rotating ring. The left and right walls of the inverted spindle-shaped dynamic pressure grooves bulge inwards in opposite directions, forming symmetrical arc-shaped groove walls. The curve at the inlet of the inverted spindle-shaped dynamic pressure groove coincides with the outer edge of the rotating ring, and the outlet is located in the middle of the end face of the rotating ring. This invention employs an inverted spindle-shaped design for the dynamic pressure groove. Due to the symmetry of the groove structure, bidirectional rotation is possible, and the sealing ring has no rotational direction requirement during installation, making it widely applicable. The inverted spindle design is based on the biomimetic principle of fish, making the windward side of the dynamic pressure groove spindle-shaped, which has excellent characteristics of low flow resistance. This reduces the obstruction of gas flowing into the groove area, and the efficiency of converting the kinetic energy of the gas flow into pressure potential energy is high, which is beneficial for increasing the opening force and thus improving the stability of the flow field.

Description

Technical Field

[0001] This invention belongs to the field of end-face sealing technology for rotating machinery shafts, specifically relating to a dry gas sealing structure with a reverse spindle-shaped dynamic pressure groove. Background Technology

[0002] Dry gas seals are a type of non-contact seal. Utilizing fluid dynamics principles, they achieve non-contact operation of the sealing end face by creating dynamic pressure grooves. Dry gas seals are widely used in high-speed, high-pressure fluid machinery such as centrifugal compressors, gas turbines, and pumps due to their excellent performance, including low wear, low leakage, and good stability. Based on the symmetry of the groove shape, dry gas seals can be divided into unidirectional and bidirectional rotary types. Unidirectional rotary dry gas seals have a better opening effect when rotating forward, but may fail when rotating in reverse. Bidirectional rotary dry gas seals have good dynamic pressure effects in both forward and reverse directions. Bidirectional rotary dry gas seals are more adaptable, but from a practical engineering application perspective, the dynamic pressure effect of the grooves in bidirectional rotary dry gas seals is slightly weaker than that of unidirectional rotary dry gas seals. To improve flow field stability and sealing performance, a new type of bidirectional rotary dry gas seal structure with better performance is needed. Summary of the Invention

[0003] The purpose of this invention is to provide a dry gas sealing structure for a reverse spindle-shaped dynamic pressure groove, so as to improve the problem of weak air film bearing capacity at the end face of the existing bidirectional rotary dry gas sealing groove.

[0004] The objective of this invention is achieved as follows: It includes a rotating ring and a corresponding stationary ring. A plurality of reverse spindle-shaped dynamic pressure grooves are evenly distributed circumferentially on the sealing end face of the rotating ring, with the axis of symmetry of each groove passing through the center of the rotating ring's end face. The left and right walls of the reverse spindle-shaped dynamic pressure grooves bulge inward in opposite directions to form symmetrical arc-shaped groove walls. The curve at the inlet of the reverse spindle-shaped dynamic pressure groove coincides with the outer edge of the rotating ring, and the outlet is located in the middle of the rotating ring's end face.

[0005] The external profile of deep-sea high-speed fish is generally spindle-shaped, such as tuna. They have excellent water diversion and drag reduction capabilities during swimming. The inverted spindle-shaped dynamic pressure channel refers to the channel wall profiles on both sides of the dynamic pressure channel being taken from the back and belly profiles of deep-sea high-speed fish, respectively. By reversing their positions, the convex side becomes the windward side of the dynamic pressure channel, forming an inverted spindle-shaped geometric structure with opposite convex surfaces.

[0006] Preferably, the inner wall of the outlet has an inwardly convex arc surface.

[0007] Preferably, the number of the anti-spindle-shaped dynamic pressure grooves is 4 to 30.

[0008] Preferably, the ratio of the inlet to the outlet arc length is 0.8 to 3:1.

[0009] Preferably, the ratio of the inlet circumferential length to the radial slot width L1 of the anti-spindle-shaped dynamic pressure groove is 0.5~3:1.

[0010] Preferably, the depth of the reverse spindle-shaped dynamic pressure groove is 0.1–20 μm.

[0011] Preferably, the radial slot width L1 (r) of the anti-spindle-shaped dynamic pressure groove is... o -r g ) and the width L2 (r) of the dynamic ring sealing end face o -r i The ratio is 0.45 to 0.75:1.

[0012] Preferably, the bottom of the inverted spindle-shaped dynamic pressure groove bulges upward in the middle to form an inverted spindle-shaped arc surface; more preferably, the shape of the bottom of the arc surface groove is the same as the shape of the side groove wall, forming a three-dimensional curved dynamic pressure groove, where the gas is acted upon by the three surfaces together, further improving performance.

[0013] Preferably, along the direction of lubricating gas flow, the anti-spindle dynamic pressure groove has an anti-spindle structure that first gradually converges and then gradually expands. This can improve the conversion of gas flow kinetic energy into pressure potential energy within the groove, which is beneficial to increasing the end face sealing opening capacity.

[0014] Preferably, along the flow direction of the lubricating gas, the anti-spindle-shaped dynamic pressure groove has a gradually converging anti-spindle structure, which can reduce the flow resistance of the dynamic pressure groove sidewall to the lubricating gas, improve the pumping capacity of the lubricating gas, and thus enhance the gas film stability of the dry gas seal.

[0015] The beneficial effects of this invention are:

[0016] 1. The dynamic pressure groove of this invention adopts an inverted spindle-shaped design. Due to the symmetry of the groove structure, it can achieve bidirectional rotation. The sealing ring also has no rotation direction requirement during installation, making it widely applicable.

[0017] 2. The reverse spindle design is based on the principle of fish bionics, which makes the windward side of the dynamic pressure groove spindle-shaped. It has the excellent characteristics of low flow resistance, which can reduce the obstruction of gas flowing into the groove area. The efficiency of converting the kinetic energy of gas flow into pressure potential energy is high, which is conducive to increasing the opening force, thereby improving the flow field stability and improving the problem of weak air film bearing capacity at the end face of the dry gas sealing groove.

[0018] 3. The arc surface at the bottom of the dynamic pressure groove also adopts an inverted spindle shape, and the depth of the groove area changes, forming a three-dimensional curved dynamic pressure groove together with the two side walls of the groove area, resulting in better performance. Attached Figure Description

[0019] Figure 1 This is a three-dimensional structural diagram of the present invention;

[0020] Figure 2 for Figure 1A schematic diagram of the outline structure of the inverted spindle-shaped dynamic pressure groove;

[0021] Figure 3 for Figure 1 A schematic diagram of the radial groove width and sealing end face width of the moving ring;

[0022] Figure 4 for Figure 3 A schematic diagram of the structure of the inverted spindle-shaped dynamic pressure groove with an upwardly convex arc surface at the bottom in the AA cross-sectional view;

[0023] Figure 5 A schematic diagram of a dynamic ring structure with a gradually converging inverted spindle-shaped dynamic pressure groove;

[0024] Figure 6 This is a schematic diagram of the dynamic ring structure in Example 5;

[0025] In the diagram: 1-Dynamic ring, 2-Static ring, 3-Reverse spindle-shaped dynamic pressure groove, 301-Inlet, 302-Left side groove wall, 303-Outlet, 304-Right side groove wall, 4-Sealing weir, 5-Sealing dam. Detailed Implementation

[0026] The present invention will be further described below with reference to the embodiments and accompanying drawings, but this does not limit the present invention in any way. Any changes or substitutions made based on the teachings of the present invention shall fall within the protection scope of the present invention.

[0027] Example 1

[0028] As attached Figures 1-2 As shown, the dry gas sealing structure of the reverse spindle-shaped dynamic pressure groove in this embodiment includes a moving ring 1 and a stationary ring 2 corresponding to the moving ring 1. Sixteen reverse spindle-shaped dynamic pressure grooves 3 are evenly distributed circumferentially on the sealing end face of the moving ring 1, and the axis of symmetry of the reverse spindle-shaped dynamic pressure grooves 3 passes through the center of the end face of the moving ring 1. The left side wall 302 and the right side wall 304 of the reverse spindle-shaped dynamic pressure groove 3 bulge inward in opposite directions to form symmetrical arc-shaped groove walls. The curve at the inlet 301 of the reverse spindle-shaped dynamic pressure groove 3 is parallel to... The outer edges of the moving ring 1 coincide, and the outlet 303 is located in the middle of the end face of the moving ring 1; the inner wall of the outlet 303 is an inwardly convex arc surface, and both the inlet 301 and the outlet 303 are arcs with the same center as the moving ring 1. The ratio of the arc length of the inlet 301 to that of the outlet 303 is 1.39:1. The ratio of the circumferential length W of the inlet 301 to the radial slot width L1 of the inverted spindle-shaped dynamic pressure groove 3 is 1.04:1. The groove depth of the inverted spindle-shaped dynamic pressure groove 3 is 5μm, and the radial slot width L1 (r) of the inverted spindle-shaped dynamic pressure groove 3 is... o -r g ) and the sealing end face width L2 (r) of the rotating ring 1 o -r iThe ratio of ) is 0.61:1; along the direction of lubricating gas flow, the anti-spindle-shaped dynamic pressure groove 3 has an anti-spindle-shaped structure that first gradually converges and then gradually expands;

[0029] Example 2

[0030] Numerical simulation experiments were conducted to compare the reverse spindle-shaped dynamic pressure groove dry gas sealing ring of this embodiment with a straight groove dry gas sealing ring with the same groove area.

[0031] As attached Figure 3 As shown, the structural parameters of the reverse spindle type dynamic pressure groove dry gas sealing ring in this embodiment are: outer diameter 77.78 mm, inner diameter 58.42 mm, number of grooves 20, and the rest are the same as in embodiment 1; operating parameters: inlet pressure 4.5852 MPa, working temperature 30℃;

[0032] Except for the dynamic pressure groove being of the reverse spindle type, the parameters of the dry gas sealing ring in this embodiment are the same as those of the straight groove dry gas sealing ring; the results are compared in the table below.

[0033] Table 1 Comparison Results

[0034]

[0035] The comparison results show that, compared with the straight groove dry gas sealing ring with the same groove area, the reverse spindle type dynamic pressure groove dry gas sealing ring of the present invention has a higher opening force.

[0036] Example 3

[0037] The dry gas sealing structure of the reverse spindle-shaped dynamic pressure groove in this embodiment is the same as that in Embodiment 1, except that there is a sealing weir 4 between two adjacent reverse spindle-shaped dynamic pressure grooves in the circumferential direction and a sealing dam 5 on the side of the reverse spindle-shaped dynamic pressure groove facing the inner diameter of the moving ring.

[0038] Example 4

[0039] As attached Figure 4 As shown, the dry gas sealing structure of the reverse spindle-shaped dynamic pressure groove in this embodiment is the same as that in Embodiment 1, except that the bottom center of the reverse spindle-shaped dynamic pressure groove 3 is convex to form a reverse spindle-shaped arc surface, the groove depth is 0.1-20μm, the groove depth on the outer diameter side of the moving ring is 5-20μm, and the groove depth on the inner diameter side of the moving ring is 0.1-5μm; it can realize the conversion of the kinetic energy of the gas flow in the groove area adjacent to the inner diameter side of the moving ring into pressure potential energy, which is highly efficient and achieves a better flow obstruction effect.

[0040] Example 5

[0041] As attached Figure 5As shown, the dry gas sealing structure of the reverse spindle-shaped dynamic pressure groove in this embodiment is the same as that in Embodiment 1, except that the ratio of the arc length of the inlet 301 to that of the outlet 303 is 1.85:1, the ratio of the circumferential length W of the inlet 301 to the radial slot width L1 of the reverse spindle-shaped dynamic pressure groove 3 is 0.93:1, the groove depth of the reverse spindle-shaped dynamic pressure groove 3 is 3μm, and the reverse spindle-shaped dynamic pressure groove 3 has a gradually converging reverse spindle-shaped structure along the flow direction of lubricating gas.

[0042] Example 6

[0043] As attached Figure 6 As shown, the dry gas sealing structure of the reverse spindle-shaped dynamic pressure groove in this embodiment has 12 reverse spindle-shaped dynamic pressure grooves 3, the ratio of the arc length of the inlet 301 to that of the outlet 303 is 1.2:1, the ratio of the circumferential length W of the inlet 301 to the radial slot width L1 of the reverse spindle-shaped dynamic pressure groove 3 is 2.1:1, the groove depth of the reverse spindle-shaped dynamic pressure groove 3 is 4μm, and the radial slot width L1 (r) of the reverse spindle-shaped dynamic pressure groove 3 is... o -r g ) and the sealing end face width L2 (r) of the rotating ring 1 o -r i The ratio of 0.51:1 is the same as in Example 1.

[0044] Example 7

[0045] In this embodiment, the dry gas sealing structure of the reverse spindle-shaped dynamic pressure groove has four reverse spindle-shaped dynamic pressure grooves 3. The ratio of the arc length of the inlet 301 to that of the outlet 303 is 0.8:1, the ratio of the circumferential length W of the inlet 301 to the radial slot width L1 of the reverse spindle-shaped dynamic pressure groove 3 is 0.5:1, the groove depth of the reverse spindle-shaped dynamic pressure groove 3 is 0.1μm, and the radial slot width L1 (r) of the reverse spindle-shaped dynamic pressure groove 3 is... o -r g ) and the sealing end face width L2 (r) of the rotating ring 1 o -r i The ratio of 0.45:1 is the same as in Example 1.

[0046] Example 8

[0047] In this embodiment, the dry gas sealing structure of the reverse spindle-shaped dynamic pressure groove has the following characteristics: The number of reverse spindle-shaped dynamic pressure grooves 3 is 30; the ratio of the arc length of the inlet 301 to that of the outlet 303 is 3:1; the ratio of the circumferential length W of the inlet 301 to the radial slot width L1 of the reverse spindle-shaped dynamic pressure groove 3 is 3:1; the groove depth of the reverse spindle-shaped dynamic pressure groove 3 is 20 μm; and the radial slot width L1 (r) of the reverse spindle-shaped dynamic pressure groove 3 is... o -r g ) and the sealing end face width L2 (r) of the rotating ring 1 o -r i The ratio of 0.75:1 is the same as in Example 1.

[0048] Example 9

[0049] In this embodiment, the dry gas sealing structure of the reverse spindle-shaped dynamic pressure groove has 17 reverse spindle-shaped dynamic pressure grooves 3. The ratio of the arc length of the inlet 301 to that of the outlet 303 is 1.9:1. The ratio of the circumferential length W of the inlet 301 to the radial slot width L1 of the reverse spindle-shaped dynamic pressure groove 3 is 1.75:1. The groove depth of the reverse spindle-shaped dynamic pressure groove 3 is 10μm. The radial slot width L1 (r) of the reverse spindle-shaped dynamic pressure groove 3 is... o -r g ) and the sealing end face width L2 (r) of the rotating ring 1 o -r i The ratio of 0.6:1 is the same as in Example 1.

[0050] The working principle and process of this invention: Lubricating gas enters the inverted spindle-shaped dynamic pressure groove 3 through inlet 301; the inverted spindle-shaped dynamic pressure groove 3 has an inverted spindle structure that first gradually converges and then gradually expands. After the gas enters from the upstream of the groove area, it is promoted to compress the gas and increase the pressure under the action of the converging channel of the groove area. Then, it gradually expands into a funnel shape at the downstream of the groove area, so that the compressed high-pressure gas will generate pressure drop due to the increase of the three-dimensional flow channel and the gas flow velocity will increase. The downstream of the groove area is connected to the sealing dam. Under the obstruction of the sealing dam, the kinetic energy of the gas flow is converted into pressure potential energy, which increases the end face sealing opening capacity.

[0051] For the anti-spindle type dynamic pressure groove with a gradually converging anti-spindle structure, the drag reduction advantage of the anti-spindle shape of the dynamic pressure groove sidewall can be fully utilized to improve the pumping capacity of lubricating gas, thereby enhancing the gas film stability of the dry gas seal.

Claims

1. A dry gas seal structure of an anti-spindle type dynamic pressure groove, comprising a dynamic ring (1) and a static ring (2) corresponding to the dynamic ring (1), characterized in that A plurality of anti-harp dynamic pressure grooves (3) are evenly distributed on the sealing end face of the dynamic ring (1) in the circumferential direction, and the symmetry axis of the anti-harp dynamic pressure groove (3) passes through the center of the end face of the dynamic ring (1); the left groove wall (302) and the right groove wall (304) of the anti-harp dynamic pressure groove (3) are respectively formed into symmetrical arc-shaped groove walls by being inwardly convex in opposite directions, the curve at the inlet (301) of the anti-harp dynamic pressure groove (3) coincides with the outer edge of the dynamic ring (1), and the outlet (303) is located in the middle of the end face of the dynamic ring (1); the ratio of the arc length of the inlet (301) to the outlet (303) is 0.8-3:1; the middle of the groove bottom of the anti-harp dynamic pressure groove (3) is convex, forming an anti-harp arc surface; in the direction of lubricating gas flow, the anti-harp dynamic pressure groove (3) has an anti-harp structure that gradually converges and then gradually expands, or the anti-harp dynamic pressure groove (3) has an anti-harp structure that gradually converges.

2. The dry gas seal structure of the anti-swirl dynamic pressure groove according to claim 1, wherein The inner wall of the outlet (303) is an inwardly convex arc surface.

3. The dry gas seal structure of claim 1, wherein The number of the anti-harp dynamic pressure grooves (3) is 4-30.

4. The dry gas seal structure of claim 1 wherein The ratio of the circumferential length W of the inlet (301) to the radial slot width L1 of the anti-harp dynamic pressure groove (3) is 0.5-3:

1.

5. The dry gas seal structure of claim 1 wherein The groove depth of the anti-harp dynamic pressure groove (3) is 0.1-20μm.

6. The dry gas seal structure for a reverse spindle type dynamic pressure groove as set forth in claim 1, wherein The ratio of the radial slot width L1 of the anti-harp dynamic pressure groove (3) to the width L2 of the sealing end face of the dynamic ring (1) is 0.45-0.75:1.

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