Seal device for rotary machine, and rotary machine

Abstract

To provide a seal device for a rotary machine capable of realizing high shaft stability of a rotor while reducing a risk of contact between an outer peripheral surface of the rotor and a stationary wall surface.SOLUTION: A seal device for a rotary machine comprises an inner peripheral surface facing an outer peripheral surface of a rotor of a rotary machine, a seal body part including a plurality of holes formed on the inner peripheral surface, and a plurality of axial fin parts provided at intervals in a circumferential direction of the rotor on the inner peripheral surface of the seal body part, where each of the plurality of axial fin parts extends along an axial direction of the rotor, and protrudes from the inner peripheral surface toward the outer peripheral surface of the rotor.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a seal device for a rotary machine and a rotary machine. [Background technology]

[0002] For example, in rotating machines such as turbines, unstable vibrations such as low-frequency vibrations may occur. When the rotor of a rotating machine is displaced, a swirl (rotating flow) that flows through the gap (seal portion) between the outer circumferential surface of the rotor and the stationary wall surface generates an uneven pressure distribution in the gap, and a fluid force perpendicular to the direction of the rotor displacement acts on the rotor, which has the effect of promoting the whirling of the rotor. This fluid force is called the seal excitation force, and the generation of the seal excitation force reduces the axial stability of the rotor (stability of the shaft system). For this reason, from the viewpoint of the axial stability of the rotor, it is important to reduce the seal excitation force.

[0003] As seal structures that reduce this seal excitation force, there are damper seals such as pocket damper seals, hole pattern seals and honeycomb seals (see, for example, Patent Document 1). When a damper seal is provided, the seal excitation force can be reduced by the swirl reduction effect of introducing a fluid into holes (recesses) provided on the stationary wall surface, and the vibration damping effect (squeeze film effect) that occurs in the narrow part of the gap between the stationary wall surface and the rotor. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6233640 Summary of the Invention [Problem to be solved by the invention]

[0005] In the damper seal described in Patent Document 1, the contact area between the rotor and the stationary wall surface is likely to become large when the rotor is displaced, and there is a high risk of thermal bending of the rotor due to frictional heat between the rotor and the stationary wall surface (hereinafter, sometimes referred to as the "risk of contact between the rotor and the stationary wall surface"). On the other hand, if the gap between the outer circumferential surface of the rotor and the stationary wall surface is simply increased in order to reduce the risk of contact between the rotor and the stationary wall surface, the above-mentioned squeeze film effect is weakened, and the effect of reducing the seal excitation force is weakened. For this reason, there is a problem in that it is difficult to simultaneously reduce the risk of contact between the rotor and the stationary wall surface and achieve high axial stability of the rotor.

[0006] In view of the above circumstances, at least one embodiment of the present disclosure aims to provide a sealing device for a rotary machine that can achieve high axial stability of the rotor while reducing the risk of contact between the rotor and a stationary wall surface, and a rotary machine equipped with the same. [Means for solving the problem]

[0007] In order to achieve the above object, a seal device for a rotary machine according to at least one embodiment of the present disclosure includes: a seal body including an inner circumferential surface which is a stationary wall surface facing an outer circumferential surface of a rotor of a rotary machine, and a plurality of holes formed in the inner circumferential surface; a plurality of axial fin portions provided at intervals in the circumferential direction of the rotor on the inner circumferential surface of the seal body; Equipped with Each of the multiple axial fin portions extends along the axial direction of the rotor and protrudes from the inner circumferential surface toward the outer circumferential surface of the rotor.

[0008] In order to achieve the above object, a rotary machine according to at least one embodiment of the present disclosure includes: A rotor, The rotary machine seal device; Equipped with. Effect of the Invention

[0009] According to at least one embodiment of the present disclosure, a sealing device for a rotary machine and a rotary machine equipped with the same are provided, which are capable of achieving high axial stability of the rotor while reducing the risk of contact between the outer peripheral surface of the rotor and a stationary wall surface. [Brief description of the drawings]

[0010] [Figure 1] 1 is a schematic diagram illustrating an example of a cross section perpendicular to an axial direction of a rotating machine 2 according to an embodiment. [Diagram 2] 2 is a schematic diagram showing an example of a cross section along the axial direction of the rotary machine 2 shown in FIG. [Diagram 3] FIG. 3 is a schematic diagram showing an example of an arrangement of multiple axial fin portions 14 and multiple circumferential fin portions 18 when the inner surface 12a (stationary wall surface) of the seal main body 12 in the rotating machine 2 shown in FIGS. 1 and 2 is expanded in the circumferential direction. [Figure 4] 4 is a schematic diagram illustrating another example of a cross section perpendicular to the axial direction of the rotating machine 2 according to one embodiment. FIG. [Diagram 5] 4 is a schematic diagram illustrating another example of a cross section along the axial direction of the rotating machine 2 according to one embodiment. FIG. [Figure 6] FIG. 13 is a diagram showing a schematic diagram of another example of an arrangement of multiple axial fin portions 14 and multiple circumferential fin portions 18 when the inner surface 12a (stationary wall surface) of the seal main body 12 in the rotary machine 2 is expanded in the circumferential direction. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, some embodiments of the present disclosure will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of components described as the embodiments or shown in the drawings are merely illustrative examples and are not intended to limit the scope of the invention. For example, expressions expressing relative or absolute configuration, such as "in a certain direction," "along a certain direction," "parallel," "orthogonal," "center," "concentric," or "coaxial," not only strictly express such a configuration, but also express a state in which there is a relative displacement with a tolerance or an angle or distance to the extent that the same function is obtained. For example, expressions indicating that things are in an equal state, such as "identical," "equal," and "homogeneous," not only indicate a state of strict equality, but also indicate a state in which there is a tolerance or a difference to the extent that the same function is obtained. For example, expressions describing shapes such as a rectangular shape or a cylindrical shape do not only refer to rectangular shapes, cylindrical shapes, etc. in the strict geometric sense, but also refer to shapes that include uneven portions, chamfered portions, etc., to the extent that the same effect is obtained. On the other hand, the expressions "comprise," "include," "have," "includes," or "have" of one element are not exclusive expressions excluding the presence of other elements.

[0012] 1 is a schematic diagram illustrating an example of a cross section perpendicular to an axial direction of a rotary machine 2 according to an embodiment. The rotary machine 2 may be, for example, a turbine such as a steam turbine or a compressor. 1, the rotary machine 2 includes a rotor 4 and a casing 6 that houses the rotor 4. The casing 6 includes a casing body 8 that houses the rotor 4, and a seal device 10 (seal device for a rotary machine).

[0013] In this specification, unless otherwise specified, "axial direction" means the axial direction of the rotor 4, "circumferential direction" means the circumferential direction of the rotor 4, and "radial direction" means the radial direction of the rotor 4, unless otherwise specified. Additionally, the upstream side in the axial direction means the upstream side of the axial flow of the fluid in the gap g between the rotor 4 and the casing 6 (the gap between the rotor 4 and an inner circumferential surface 12a of the seal main body 12 described below), i.e., the high-pressure side in the axial direction in the gap g, and the downstream side in the axial direction means the downstream side of the axial flow of the fluid in the gap g, i.e., the low-pressure side in the axial direction in the gap g.

[0014] 1, the seal device 10 includes a seal body portion 12 and a plurality of axial fin portions 14. In the illustrated exemplary embodiment, the seal body portion 12 is formed in an annular (e.g., cylindrical) shape and is held on the inner surface 8a of the casing body 8. The seal body portion 12 includes an inner circumferential surface 12a which is a stationary wall surface facing the outer circumferential surface 4a of the rotor 4, and an outer circumferential surface 12b which is fixed to the inner surface 8a of the casing body 8.

[0015] A plurality of holes 16 (a plurality of recesses) are formed in the inner circumferential surface 12a of the seal body 12. In the cross section shown in Fig. 1, the plurality of holes 16 formed in the inner circumferential surface 12a of the seal body 12 includes a plurality of holes 16 arranged at intervals in the circumferential direction.

[0016] The axial fin portions 14 are provided at intervals in the circumferential direction on the inner peripheral surface 12a of the seal body 12. Each of the axial fin portions 14 extends along the axial direction and protrudes radially inward from the inner peripheral surface 12a of the seal body 12 toward the outer peripheral surface 4a of the rotor 4. In the illustrated exemplary embodiment, each of the axial fin portions 14 is provided at a position between two holes 16 adjacent in the circumferential direction on the inner peripheral surface 12a of the seal body 12. That is, in the cross section shown in FIG. 1, the holes 16 and the axial fin portions 14 are provided alternately in the circumferential direction, and the holes 16 and the axial fin portions 14 are provided in one-to-one correspondence. In the illustrated exemplary embodiment, each of the axial fin portions 14 is located at a downstream end 16a1 in the rotation direction r of the rotor 4 at the opening edge 16a of the corresponding hole 16 (the inner end of the hole 16 in the radial direction).

[0017] 1, the above-mentioned seal device 10 can reduce the swirl (leakage flow) flowing in the gap g between the outer peripheral surface 4a of the rotor 4 and the inner peripheral surface 12a (stationary wall surface) of the seal body 12 by guiding the swirl (leakage flow) to the holes 16 in the inner peripheral surface 12a of the seal body 12 by the multiple axial fin portions 14. This can reduce the above-mentioned seal exciting force and achieve high axial stability of the rotor 4.

[0018] In addition, by increasing the gap g between the outer peripheral surface 4a of the rotor 4 and the inner peripheral surface 12a of the seal body 12, the risk of contact between the outer peripheral surface 4a of the rotor 4 and the inner peripheral surface 12a of the seal body 12 due to displacement of the rotor 4 is reduced, while by reducing the gap between the multiple axial fin portions 14 and the outer peripheral surface 4a of the rotor 4, the seal excitation force can be reduced by the squeeze film effect. Even if the multiple axial fin portions 14 come into contact with the outer peripheral surface 4a of the rotor 4, the contact area can be made smaller than when the outer peripheral surface 4a of the rotor 4 comes into contact with the inner peripheral surface 12a of the seal body 12, so the risk of thermal bending of the rotor 4 due to heat generation can be reduced.

[0019] Furthermore, by providing each axial fin portion 14 at a position between two circumferentially adjacent holes 16 on the inner surface 12a of the seal main body portion 12, each axial fin portion 14 can be fixed more firmly to the seal main body portion 12 than if the axial fin portion 14 were provided so as to straddle the holes 16.

[0020] In addition, by providing each axial fin portion 14 at the downstream end 16a1 of the opening edge 16a of the hole 16 in the rotational direction r of the rotor 4, the swirls flowing in the gap g between the outer peripheral surface 4a of the rotor 4 and the inner peripheral surface 12a of the seal main body portion 12 can be effectively guided by the axial fin portions 14 to the hole 16 in the inner peripheral surface 12a of the seal main body portion 12, thereby enhancing the effect of reducing the above-mentioned swirl.

[0021] Fig. 2 is a schematic diagram showing an example of a cross section along the axial direction of the rotary machine 2 shown in Fig. 1. In the cross section shown in Fig. 2, the multiple holes 16 formed in the inner circumferential surface 12a of the seal main body 12 include multiple holes 16 arranged at intervals in the axial direction. In some embodiments, the seal device 10 may include a plurality of circumferential fins 18, as shown for example in FIG.

[0022] The multiple circumferential fin portions 18 are provided at intervals in the axial direction on the inner peripheral surface 12a of the seal body 12. Each of the multiple circumferential fin portions 18 extends along the circumferential direction and protrudes radially inward from the inner peripheral surface 12a of the seal body 12 toward the outer peripheral surface 4a of the rotor 4. Each of the multiple circumferential fin portions 18 may be formed in an annular shape centered on the rotational axis of the rotor 4.

[0023] As shown in Fig. 2, each of the multiple circumferential fin portions 18 may be provided at a position between two axially adjacent holes 16 on the inner peripheral surface 12a of the seal body portion 12. In the cross section shown in Fig. 2, the holes 16 and the circumferential fin portions 18 are alternately arranged in the axial direction, and the holes 16 and the circumferential fin portions 18 are provided in one-to-one correspondence. Each of the multiple circumferential fin portions 18 is located on the downstream side in the axial direction with respect to the corresponding hole 16. In the illustrated exemplary embodiment, each of the multiple circumferential fin portions 18 is located at the downstream end 16a2 in the axial direction at the opening edge 16a of the corresponding hole 16 (the inner end of the hole 16 in the radial direction).

[0024] 2, as indicated by the arrow F2, the swirl (leakage flow) flowing in the gap g between the outer peripheral surface 4a of the rotor 4 and the inner peripheral surface 12a (stationary wall surface) of the seal body 12 can be reduced by being guided to the multiple holes 16 in the inner peripheral surface 12a of the seal body 12 by the multiple circumferential fin portions 18. This reduces the seal excitation force and achieves high axial stability of the rotor 4.

[0025] In addition, by increasing the gap g between the outer peripheral surface 4a of the rotor 4 and the inner peripheral surface 12a of the seal body 12, the risk of contact between the outer peripheral surface 4a of the rotor 4 and the inner peripheral surface 12a of the seal body 12 due to displacement of the rotor 4 is reduced, while by reducing the gap between the multiple circumferential fin portions 18 and the outer peripheral surface 4a of the rotor 4, the seal excitation force can be reduced by the squeeze film effect. Even if the multiple circumferential fin portions 18 come into contact with the outer peripheral surface 4a of the rotor 4, the contact area can be made smaller than when the outer peripheral surface 4a of the rotor 4 comes into contact with the inner peripheral surface 12a of the seal body 12, so the risk of thermal bending of the rotor 4 due to heat generation can be reduced.

[0026] In addition, since the axial flow in the gap g between the outer peripheral surface 4a of the rotor 4 and the inner peripheral surface 12a of the seal main body portion 12 can be effectively impeded by the multiple circumferential fin portions 18, the flow rate of leakage flow in the gap g can be effectively reduced.

[0027] Furthermore, by providing each circumferential fin portion 18 at a position between two axially adjacent holes 16 on the inner surface 12a of the seal main body portion 12, each circumferential fin portion 18 can be fixed more firmly to the seal main body portion 12 than when each circumferential fin portion 18 is provided so as to straddle the holes 16 (see Figure 6).

[0028] In addition, by providing each circumferential fin portion 18 at the axial downstream end 16a2 of the opening edge 16a of the hole 16, the swirl flowing in the gap g between the outer peripheral surface 4a of the rotor 4 and the inner peripheral surface 12a of the seal main body portion 12 can be effectively guided by the circumferential fin portions 18 to the hole 16 in the inner peripheral surface 12a of the seal main body portion 12, thereby enhancing the effect of reducing swirl.

[0029] FIG. 3 is a diagram showing an example of the arrangement of a plurality of axial fin portions 14 and a plurality of circumferential fin portions 18 when the inner peripheral surface 12a (stationary wall surface) of the seal main body portion 12 in the rotary machine 2 is developed in the circumferential direction. In FIG. 3, the arrangement of each of the plurality of axial fin portions 14 is indicated by a broken line, and the arrangement of each of the plurality of circumferential fin portions 18 is indicated by a two-dot chain line.

[0030] In some embodiments, for example, as shown in FIG. 3, the plurality of axial fin portions 14 and the plurality of circumferential fin portions 18 may be arranged in a lattice pattern such that each of the plurality of axial fin portions 14 intersects with each of the plurality of circumferential fin portions 18.

[0031] In some embodiments, for example, in the rotary machine 2 described with reference to FIGS. 1 to 3, the radial height ha (see FIG. 1) of each axial fin portion 14 from the inner peripheral surface 12a of the seal main body portion 12 and the radial height hc (see FIG. 2) of each circumferential fin portion 18 from the inner peripheral surface 12a may be different. In this case, the radial height ha of each axial fin portion 14 from the inner peripheral surface 12a may be lower than the height hc of each circumferential fin portion 18 from the inner peripheral surface 12a.

[0032] According to such a configuration, when the rotor 4 is displaced in a direction orthogonal to the axial direction, the rotor 4 can be brought into contact with only one of the axial fin portion 14 and the circumferential fin portion 18 (the circumferential fin portion 18 when ha < hc). Therefore, compared with the case where the height ha of the axial fin portion 14 from the inner peripheral surface 12a and the height of the circumferential fin portion 18 from the inner peripheral surface 12a are made the same, the contact area of the rotor 4 can be reduced, and the risk of thermal bending of the rotor 4 due to heat generation can be reduced. Further, by setting ha < hc, it is possible to effectively reduce the flow rate of the axial leakage flow in the gap g between the outer peripheral surface 4a of the rotor 4 and the inner peripheral surface 12a of the seal main body portion 12, while reducing the risk of thermal bending of the rotor 4 due to heat generation.

[0033] 4, for example, each of the multiple axial fin portions 14 of the rotary machine 2 may be inclined toward the upstream side in the rotation direction r of the rotor 4 as it moves radially inward. With this configuration, as shown by arrow F3, the multiple axial fin portions 14 can effectively guide swirls flowing through the gap g between the outer circumferential surface 4a of the rotor 4 and the inner circumferential surface 12a of the seal main body 12 to the multiple holes 16 in the inner circumferential surface 12a of the seal main body 12, thereby enhancing the effect of reducing the swirl.

[0034] In some embodiments, as shown in Fig. 5, for example, each of the multiple circumferential fin portions 18 of the rotary machine 2 may be inclined toward the upstream side in the axial direction as it moves radially inward. With this configuration, as shown by arrow F4, the multiple circumferential fin portions 18 can effectively guide the swirl flowing through the gap g between the outer circumferential surface 4a of the rotor 4 and the inner circumferential surface 12a of the seal main body 12 to the multiple holes 16 in the inner circumferential surface 12a of the seal main body 12, thereby enhancing the effect of reducing the swirl.

[0035] The present disclosure is not limited to the above-described embodiments, and includes modifications to the above-described embodiments and appropriate combinations of these modifications.

[0036] For example, in some of the embodiments described above, the rotating machine 2 was provided with a plurality of axial fin portions 14 and a plurality of circumferential fin portions 18, but in other embodiments, the rotating machine 2 may be provided with only a plurality of axial fin portions 14 out of the plurality of axial fin portions 14 and the plurality of circumferential fin portions 18, and may not be provided with a circumferential fin portion 18.

[0037] Furthermore, the casing body 8, the seal body portion 12, the axial fin portion 14 and the circumferential fin portion 18 do not need to be configured as separate parts, and any combination of these may be integrally configured as a single part.

[0038] Also, for example, as shown in Fig. 6, each of the multiple axial fin portions 14 may be provided so as to straddle multiple holes 16. That is, when viewed in the radial direction, each of the multiple axial fin portions 14 may be provided so as to overlap at least a portion of the multiple holes 16. In Fig. 6, the arrangement of each of the multiple axial fin portions 14 is indicated by a dashed line, and the arrangement of each of the multiple circumferential fin portions 18 is indicated by a two-dot chain line.

[0039] 6, for example, each of the multiple circumferential fin portions 18 may be provided so as to straddle multiple holes 16. That is, each of the multiple circumferential fin portions 18 may be provided so as to overlap at least a portion of the multiple holes 16 when viewed in the radial direction.

[0040] In addition, for example, only one of all of the axial fin portions 14 of the seal device 10 may be provided at a position between two circumferentially adjacent holes 16 on the inner surface 12a of the seal main body portion 12, or any number of all of the axial fin portions 14 of the seal device 10 may be provided at a position between two circumferentially adjacent holes 16 on the inner surface 12a of the seal main body portion 12.

[0041] In addition, for example, only one of all the circumferential fin portions 18 of the seal device 10 may be provided at a position between two axially adjacent holes 16 on the inner surface 12a of the seal main body portion 12, or any number of all the circumferential fin portions 18 of the seal device 10 may be provided at a position between two axially adjacent holes 16 on the inner surface 12a of the seal main body portion 12.

[0042] In addition, only one of all the axial fin portions 14 of the sealing device 10 may be located at the downstream end 16a1 of the opening edge 16a of the hole 16 in the rotational direction r of the rotor 4, or any number of all the axial fin portions 14 of the sealing device 10 may be located at the downstream end 16a1 of the opening edge 16a of the hole 16 in the rotational direction r of the rotor 4.

[0043] In addition, only one of all the circumferential fin portions 18 of the sealing device 10 may be located at the axial downstream end 16a2 of the opening edge 16a of the hole 16, or any number of all the circumferential fin portions 18 of the sealing device 10 may be located at the axial downstream end 16a2 of the opening edge 16a of the hole 16.

[0044] In addition, only one of all the axial fin portions 14 of the sealing device 10 may be inclined toward the upstream side of the rotation direction r of the rotor 4 as it moves radially inward, or any number of all the axial fin portions 14 of the sealing device 10 may be inclined toward the upstream side of the rotation direction r of the rotor 4 as it moves radially inward.

[0045] In addition, only one of all the circumferential fin portions 18 of the sealing device 10 may be inclined toward the upstream axial direction as it moves radially inward, or any number of all the circumferential fin portions 18 of the sealing device 10 may be inclined toward the upstream axial direction as it moves radially inward.

[0046] In addition, in some embodiments shown in Figures 3 and 6, the height ha of each axial fin portion 14 from the inner surface 12a of the seal body portion 12 and the height hc of each circumferential fin portion 18 from the inner surface 12a of the seal body portion 12 may be the same.

[0047] The contents described in each of the above embodiments can be understood, for example, as follows.

[0048] (1) A seal device for a rotary machine according to at least one embodiment of the present disclosure (e.g., seal device 10) includes: an annular seal main body (e.g., the above-mentioned seal main body 12) including an inner circumferential surface (e.g., the above-mentioned inner circumferential surface 12a) which is a stationary wall surface facing an outer circumferential surface (e.g., the above-mentioned outer circumferential surface 4a) of a rotor (e.g., the above-mentioned rotor 4) of a rotary machine (e.g., the above-mentioned rotary machine 2) and a plurality of holes (e.g., the above-mentioned holes 16) formed on the inner circumferential surface; a plurality of axial fin portions (e.g., the above-mentioned plurality of axial fin portions 14) provided at intervals in the circumferential direction of the rotor on the inner peripheral surface of the seal body; Equipped with Each of the multiple axial fin portions extends along the axial direction of the rotor and protrudes from the inner circumferential surface toward the outer circumferential surface of the rotor.

[0049] According to the seal device for a rotary machine described in (1) above, the swirl (leakage flow) flowing in the gap between the outer peripheral surface of the rotor and the inner peripheral surface (stationary wall surface) of the seal body can be reduced by guiding the swirl (leakage flow) through the holes in the inner peripheral surface of the seal body by the multiple axial fins, thereby reducing the seal excitation force and achieving high axial stability of the rotor. In addition, by increasing the gap between the outer peripheral surface of the rotor and the inner peripheral surface of the seal body, the risk of contact between the outer peripheral surface of the rotor and the inner peripheral surface of the seal body due to rotor displacement is reduced, while by reducing the gap between the multiple axial fin portions and the outer peripheral surface of the rotor, the seal excitation force can be reduced by the squeeze film effect. Even if the multiple axial fin portions come into contact with the outer peripheral surface of the rotor, the contact area can be made smaller than when the outer peripheral surface of the rotor comes into contact with the inner peripheral surface of the seal body, thereby reducing the risk of thermal bending of the rotor due to frictional heat associated with the contact.

[0050] (2) In some embodiments, in the rotary machine seal device described in (1) above, At least one of the plurality of axial fin portions is provided at a position between two of the holes adjacent to each other in the circumferential direction on the inner circumferential surface of the seal body.

[0051] According to the sealing device for a rotary machine described in (2) above, by providing the axial fin portion at a position between two circumferentially adjacent holes on the inner surface of the seal main body, the axial fin portion can be fixed more firmly to the seal main body than in the case where the axial fin portion is provided so as to straddle the holes.

[0052] (3) In some embodiments, in the rotary machine seal device according to (1) or (2), At least one of the plurality of axial fin portions is located at a downstream end (eg, the aforementioned downstream end 16a1) in the rotation direction of the rotor at an opening edge (eg, the aforementioned opening edge 16a) of the hole.

[0053] According to the sealing device for a rotary machine described in (3) above, by providing an axial fin portion at the downstream end in the rotor rotation direction at the opening edge of the hole, the axial fin portion can effectively guide swirls flowing in the gap between the outer peripheral surface of the rotor and the inner peripheral surface of the seal body to the hole on the inner peripheral surface of the seal body, thereby enhancing the effect of reducing swirl.

[0054] (4) In some embodiments, in the rotary machine seal device according to any one of (1) to (3), At least one of the plurality of axial fin portions is inclined toward the upstream side in the rotation direction of the rotor as it moves toward the inside in the radial direction of the rotor.

[0055] According to the sealing device for a rotary machine described in (4) above, by providing an axial fin portion that is inclined so as to move toward the upstream side in the rotational direction of the rotor as it moves toward the radially inward side of the rotor, the swirls flowing in the gap between the outer peripheral surface of the rotor and the inner peripheral surface of the seal main body can be effectively guided by the axial fin portion to the holes in the inner peripheral surface of the seal main body, thereby enhancing the effect of reducing swirl.

[0056] (5) In some embodiments, in the rotary machine seal device according to any one of (1) to (4), The seal further includes a plurality of circumferential fin portions (e.g., the above-mentioned plurality of circumferential fin portions 18) provided at intervals in the axial direction on the inner peripheral surface of the seal body, Each of the multiple circumferential fin portions extends along the circumferential direction and protrudes from the inner circumferential surface toward the outer circumferential surface of the rotor.

[0057] According to the seal device for a rotary machine described in (5) above, the swirl (leakage flow) flowing in the gap between the outer peripheral surface of the rotor and the inner peripheral surface (stationary wall surface) of the seal body can be reduced by guiding the swirl (leakage flow) through the holes in the inner peripheral surface of the seal body by the multiple circumferential fins, thereby reducing the seal excitation force and achieving high axial stability of the rotor. In addition, by increasing the gap between the outer peripheral surface of the rotor and the inner peripheral surface of the seal body, the risk of contact between the outer peripheral surface of the rotor and the inner peripheral surface of the seal body due to rotor displacement is reduced, while by reducing the gap between the multiple circumferential fin portions and the outer peripheral surface of the rotor, the seal excitation force can be reduced by the squeeze film effect. Even if the multiple circumferential fin portions come into contact with the outer peripheral surface of the rotor, the contact area can be made smaller than when the outer peripheral surface of the rotor and the inner peripheral surface of the seal body come into contact, thereby reducing the risk of thermal bending of the rotor due to heat generation. In addition, since the axial flow in the gap between the outer peripheral surface of the rotor and the inner peripheral surface of the seal main body can be effectively impeded by the multiple circumferential fin portions, the flow rate of leakage flow in the gap can be effectively reduced.

[0058] (6) In some embodiments, in the rotary machine seal device described in (5) above, At least one of the plurality of circumferential fin portions is provided at a position between two of the holes adjacent to each other in the axial direction on the inner peripheral surface of the seal body.

[0059] According to the sealing device for a rotary machine described in (6) above, by providing the circumferential fin portion at a position between two axially adjacent holes on the inner surface of the seal main body, the circumferential fin portion can be fixed more firmly to the seal main body than in the case where the circumferential fin portion is provided so as to straddle the holes.

[0060] (7) In some embodiments, in the rotary machine seal device according to (5) or (6), At least one of the plurality of circumferential fin portions is located at a downstream end (eg, the aforementioned downstream end 16a2) in the axial direction of an opening edge (eg, the aforementioned opening edge 16a) of the hole.

[0061] According to the sealing device for a rotary machine described in (7) above, by providing a circumferential fin portion at the axial downstream end of the opening edge of the hole, the swirl flowing through the gap between the outer peripheral surface of the rotor and the inner peripheral surface of the seal body can be effectively guided by the circumferential fin portion to the hole on the inner peripheral surface of the seal body, thereby enhancing the effect of reducing swirl.

[0062] (8) In some embodiments, in the rotary machine seal device according to any one of (5) to (7), At least one of the plurality of circumferential fin portions is inclined toward the upstream side in the axial direction as it moves toward the inside in the radial direction of the rotor.

[0063] According to the sealing device for a rotary machine described in (8) above, by providing an axial fin portion that is inclined toward the axial upstream side as it moves radially inward of the rotor, the circumferential fin portion can effectively guide swirls flowing in the gap between the outer peripheral surface of the rotor and the inner peripheral surface of the seal main body to the holes in the inner peripheral surface of the seal main body, thereby enhancing the effect of reducing swirl.

[0064] (9) In some embodiments, in the seal device for a rotary machine according to any one of (5) to (8), The height of the axial fin portion from the inner peripheral surface (for example, the above-mentioned height ha) and the height of the circumferential fin portion from the inner peripheral surface (for example, the above-mentioned height hc) are different.

[0065] According to the sealing device for a rotary machine described in (9) above, when the rotor is displaced in a direction perpendicular to the axial direction, the rotor can be brought into contact with only one of the axial fin portion and the circumferential fin portion. Therefore, compared to a case in which the height of the axial fin portion from the inner circumferential surface and the height of the circumferential fin portion from the inner circumferential surface are made the same, the contact area of ​​the rotor can be reduced, thereby reducing the risk of thermal bending of the rotor due to heat generation.

[0066] (10) In some embodiments, in the seal device for a rotary machine according to any one of the above (9), The height of the axial fin portion from the inner circumferential surface (for example, the above-mentioned height ha) is less than the height of the circumferential fin portion from the inner circumferential surface (for example, the above-mentioned height hc).

[0067] According to the sealing device for a rotary machine described in (10) above, the flow rate of axial leakage flow in the gap between the outer peripheral surface of the rotor and the inner peripheral surface of the seal body can be effectively reduced, while the contact area of ​​the rotor can be reduced to reduce the risk of thermal bending of the rotor due to heat generation.

[0068] (11) A rotary machine according to at least one embodiment of the present disclosure (e.g., the rotary machine 2 described above) includes: A rotor (e.g., rotor 4 as described above), A rotary machine seal device according to any one of (1) to (10) above; Equipped with.

[0069] According to the rotary machine described in (11) above, since the rotary machine is equipped with the sealing device for a rotary machine described in any one of (1) to (10) above, it is possible to realize high axial stability of the rotor while reducing the risk of contact between the rotor and a stationary wall surface and the risk of thermal bending of the rotor due to heat generation accompanying such contact. [Explanation of symbols]

[0070] 2 Rotating Machinery 4 Rotors 4a Outer surface 6 Casing 8 Casing body 8a Inner surface 10 Sealing device 12 Seal body 12a Inner surface 12b Outer surface 14 Axial fin section 16 holes 16a1,16a2 downstream end 16a Opening edge 18 Circumferential fin section g Gap r Rotation direction

Claims

1. an annular seal body including an inner circumferential surface which is a stationary wall surface facing an outer circumferential surface of a rotor of a rotary machine and a plurality of holes formed in the inner circumferential surface; a plurality of axial fin portions provided at intervals in the circumferential direction of the rotor on the inner circumferential surface of the seal body; Equipped with A sealing device for a rotary machine, wherein each of the plurality of axial fin portions extends along the axial direction of the rotor and protrudes from the inner circumferential surface toward the outer circumferential surface of the rotor.

2. The seal device for a rotary machine according to claim 1 , wherein at least one of the plurality of axial fin portions is provided at a position between two of the holes adjacent to each other in the circumferential direction on the inner circumferential surface of the seal body.

3. The seal device for a rotary machine according to claim 1 , wherein at least one of the plurality of axial fin portions is located at a downstream end in a rotational direction of the rotor at an open end edge of the hole.

4. The seal device for a rotary machine according to claim 1 , wherein at least one of the plurality of axial fin portions is inclined toward an upstream side in a rotation direction of the rotor as it moves toward an inner side in a radial direction of the rotor.

5. The seal further includes a plurality of circumferential fin portions provided at intervals in the axial direction on the inner peripheral surface of the seal body, The sealing device for a rotary machine according to claim 1 , wherein each of the plurality of circumferential fin portions extends along the circumferential direction and protrudes from the inner circumferential surface toward the outer circumferential surface of the rotor.

6. The seal device for a rotary machine according to claim 5 , wherein at least one of the plurality of circumferential fin portions is provided at a position between two of the holes adjacent to each other in the axial direction on the inner peripheral surface of the seal body.

7. The seal device for a rotary machine according to claim 5 , wherein at least one of the plurality of circumferential fin portions is located at a downstream end in the axial direction at an open end edge of the hole.

8. The steam turbine according to claim 5 , wherein at least one of the plurality of circumferential fin portions is inclined toward an upstream side in the axial direction as it moves toward an inner side in the radial direction of the rotor.

9. The seal device for a rotary machine according to claim 5 , wherein a height of the axial fin portion from the inner circumferential surface and a height of the circumferential fin portion from the inner circumferential surface are different.

10. The sealing device for a rotary machine according to claim 9 , wherein a height of the axial fin portion from the inner circumferential surface is lower than a height of the circumferential fin portion from the inner circumferential surface.

11. A rotor, A seal device for a rotary machine according to any one of claims 1 to 10; A rotating machine comprising:

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