US20170241427A1 - Seal mechanism and rotating machine - Google Patents

Seal mechanism and rotating machine Download PDF

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Publication number
US20170241427A1
US20170241427A1 US15/503,536 US201415503536A US2017241427A1 US 20170241427 A1 US20170241427 A1 US 20170241427A1 US 201415503536 A US201415503536 A US 201415503536A US 2017241427 A1 US2017241427 A1 US 2017241427A1
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US
United States
Prior art keywords
hole
rotor
seal
seal mechanism
circumferential surface
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Abandoned
Application number
US15/503,536
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English (en)
Inventor
Akihiro Nakaniwa
Shinichiro Tokuyama
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Mitsubishi Heavy Industries Compressor Corp
Original Assignee
Mitsubishi Heavy Industries Ltd
Mitsubishi Heavy Industries Compressor Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Mitsubishi Heavy Industries Ltd, Mitsubishi Heavy Industries Compressor Corp filed Critical Mitsubishi Heavy Industries Ltd
Assigned to MITSUBISHI HEAVY INDUSTRIES, LTD., MITSUBISHI HEAVY INDUSTRIES COMPRESSOR CORPORATION reassignment MITSUBISHI HEAVY INDUSTRIES, LTD. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: NAKANIWA, AKIHIRO, TOKUYAMA, SHINICHIRO
Publication of US20170241427A1 publication Critical patent/US20170241427A1/en
Assigned to MITSUBISHI HEAVY INDUSTRIES COMPRESSOR CORPORATION reassignment MITSUBISHI HEAVY INDUSTRIES COMPRESSOR CORPORATION ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: MITSUBISHI HEAVY INDUSTRIES, LTD.
Abandoned legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D29/00—Details, component parts, or accessories
    • F04D29/08—Sealings
    • F04D29/083—Sealings especially adapted for elastic fluid pumps
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
    • F01D11/00—Preventing or minimising internal leakage of working-fluid, e.g. between stages
    • F01D11/02—Preventing or minimising internal leakage of working-fluid, e.g. between stages by non-contact sealings, e.g. of labyrinth type
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D17/00—Radial-flow pumps, e.g. centrifugal pumps; Helico-centrifugal pumps
    • F04D17/08—Centrifugal pumps
    • F04D17/10—Centrifugal pumps for compressing or evacuating
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D29/00—Details, component parts, or accessories
    • F04D29/08—Sealings
    • F04D29/10—Shaft sealings
    • F04D29/102—Shaft sealings especially adapted for elastic fluid pumps
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D29/00—Details, component parts, or accessories
    • F04D29/26—Rotors specially for elastic fluids
    • F04D29/28—Rotors specially for elastic fluids for centrifugal or helico-centrifugal pumps for radial-flow or helico-centrifugal pumps
    • F04D29/284—Rotors specially for elastic fluids for centrifugal or helico-centrifugal pumps for radial-flow or helico-centrifugal pumps for compressors
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D29/00—Details, component parts, or accessories
    • F04D29/40—Casings; Connections of working fluid
    • F04D29/42—Casings; Connections of working fluid for radial or helico-centrifugal pumps
    • F04D29/44—Fluid-guiding means, e.g. diffusers
    • F04D29/441—Fluid-guiding means, e.g. diffusers especially adapted for elastic fluid pumps
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16J—PISTONS; CYLINDERS; SEALINGS
    • F16J15/00—Sealings
    • F16J15/44—Free-space packings
    • F16J15/444—Free-space packings with facing materials having honeycomb-like structure
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16J—PISTONS; CYLINDERS; SEALINGS
    • F16J15/00—Sealings
    • F16J15/44—Free-space packings
    • F16J15/447—Labyrinth packings
    • F16J15/4472—Labyrinth packings with axial path
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
    • F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
    • F05D2250/00—Geometry
    • F05D2250/10—Two-dimensional
    • F05D2250/19—Two-dimensional machined; miscellaneous
    • F05D2250/191—Two-dimensional machined; miscellaneous perforated
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
    • F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
    • F05D2250/00—Geometry
    • F05D2250/20—Three-dimensional
    • F05D2250/28—Three-dimensional patterned
    • F05D2250/283—Three-dimensional patterned honeycomb

Definitions

  • the present invention relates to a seal mechanism provided in a rotating machine such as a turbine, and a rotating machine.
  • a centrifugal compressor which compresses gas is widely known as one of rotating machines.
  • an impeller is provided inside the casing, and gas suctioned from a suction port is compressed by the rotation of the impeller and is discharged from a discharge port.
  • a mouthpiece seal is provided in an impeller mouthpiece portion, an intermediate stage seal is provided between the impeller stages, and a balance piston portion seal is provided in a final stage, thereby reducing the amount of leakage of the gas compressed by the impeller.
  • a damper seal, a labyrinth seal or the like may be used for such various kinds of seal.
  • the labyrinth seal is configured by alternately providing annular protrusions provided on a rotating rotary shaft, and protrusions protruding annularly toward the rotary shaft from a stationary side member facing the rotary shaft at an interval therebetween, along the rotary shaft.
  • this labyrinth seal it is possible to reduce leakage of fluid by causing a pressure loss in the fluid flowing in the vicinity of the tip of the protrusions.
  • a honeycomb seal, a hole pattern seal and the like are known as a damper seal.
  • a hole pattern seal in an annular stationary side member disposed at an interval from a rotary shaft, a plurality of hole portions are formed in a facing surface facing the rotary shaft, and the leakage of fluid can be reduced by a pressure loss occurring in the hole portions (see, for example, Patent Document 1).
  • the hole pattern seal has an attenuation effect greater than that of the labyrinth seal, and is advantageous in terms of stabilization of oscillation of the rotary shaft.
  • the labyrinth seal can reduce the amount of leakage of fluid as compared to the damper seal.
  • the seal structure may be subjected to self-excited vibration by a swirl flow (hereinafter, simply referred to as swirling) of inflowing fluid.
  • swirling a swirl flow
  • An object of the present invention is to provide a seal mechanism and a rotating machine capable of further reducing the swirling generated between the rotary side and the stationary side and limiting the self-excited vibration due to the swirling, while reducing the amount of leakage of the process gas G from the high-pressure side to the low-pressure side.
  • a seal mechanism which is disposed on an outer circumferential side of a rotor extending along an axis to perform sealing between the seal mechanism and the outer circumferential surface of the rotor.
  • the seal mechanism includes a cylindrical main body portion into which the rotor is inserted; and a plurality of hole portions formed on an inner circumferential surface of the main body portion to face an outer circumferential surface of the rotor.
  • the hole portions have a hole depth h within a range equal to or smaller than a hole diameter d.
  • the hole portions may be formed such that a relationship between the hole depth h and the hole diameter d is 0.5d ⁇ h ⁇ d.
  • the hole portions may have a circular cross-section or a hexagonal cross-section.
  • the hole diameters d and the hole depths h of the plurality of hole portions may be of a uniform size,.
  • bottom surfaces of the hole portions may have a conical shape or a flat bottom shape.
  • a fin portion protruding toward the rotor side and extending in a circumferential direction may be provided on an inner circumferential surface of the main body portion.
  • a rotating machine includes a rotor extending along an axis; and a stator which is disposed on an outer circumferential side of the rotor and relatively rotates about the axis with respect to the rotor.
  • the rotating machine further includes a hole pattern seal which is fixed to the stator to partition a space between the rotor and the stator into a high-pressure side and a low-pressure side, and has hole rows in which a plurality of hole portions facing the outer circumferential surface of the rotor are formed at an interval therebetween in a circumferential direction.
  • the hole portions of the rotating machine are within a range in which a hole depth is equal to or smaller than a hole diameter.
  • the rotating machine according to the seventh aspect may include a fin portion which is formed on the inner circumferential surface of the hole pattern seal, protrudes toward the rotor side and extends in the circumferential direction.
  • the rotating machine may further include a protruding portion which protrudes from the outer circumferential surface of the rotor toward the hole portion, extends in the circumferential direction and faces the hole portion on the low-pressure side of the fin portion.
  • FIG. 1 is a cross-sectional view showing a schematic configuration of a centrifugal compressor according to first and second embodiments of the present invention.
  • FIG. 2 is a perspective view showing a hole pattern seal of the seal mechanism of the centrifugal compressor according to the first embodiment of the present invention.
  • FIG. 3 is a partial cross-sectional view of the seal mechanism of the centrifugal compressor according to the first embodiment of the present invention.
  • FIG. 4 is an expanded view of an inner circumferential surface of the hole pattern seal according to the first embodiment of the present invention.
  • FIG. 5 is a diagram showing a result of analysis of a relationship between the hole depth and equivalent attenuation in the example of the first embodiment of the present invention.
  • FIG. 6 is a perspective view showing a hole pattern seal in a seal mechanism of a centrifugal compressor according to a second embodiment of the present invention.
  • FIG. 7 is an expanded view of the inner circumferential surface of the hole pattern seal according to the second embodiment of the present invention.
  • FIG. 8 is a partial cross-sectional view of the seal mechanism in the centrifugal compressor according to the second embodiment of the present invention.
  • FIG. 9 is an explanatory view of the operation of the seal mechanism in the second embodiment of the present invention.
  • FIG. 1 is a cross-sectional view showing a schematic configuration of a centrifugal compressor 1 according to a first embodiment of the present invention.
  • the centrifugal compressor 1 in this embodiment is a multistage centrifugal compressor.
  • the centrifugal compressor 1 includes, for example, two sets of three-stage impeller groups.
  • the centrifugal compressor 1 includes a rotary shaft (rotor) 2 , an impeller 3 , a casing (stator) 5 and a seal mechanism 20 A.
  • the rotary shaft 2 rotates around the axis O.
  • the impeller 3 is mounted on the rotary shaft 2 and compresses the process gas (fluid) G using a centrifugal force.
  • the casing 5 rotatably supports the rotary shaft 2 .
  • the casing 5 has a return flow passage 4 formed therein through which the process gas G flows from the high-pressure side to the low-pressure side.
  • the seal mechanism 20 A is provided along the outer circumferential surface of the rotary shaft 2 .
  • the casing 5 is formed in a columnar shape having a circular cross-sectional profile.
  • the rotary shaft 2 is disposed to penetrate the center of the casing 5 .
  • a journal bearing 5 a and a thrust bearing 5 b are provided at opposing end portions of the casing 5 .
  • the opposing end portions of the rotary shaft 2 are rotatably supported by the journal bearings 5 a and the thrust bearings 5 b .
  • the rotary shaft 2 is supported by the casing 5 via the journal bearings 5 a and the thrust bearings 5 b.
  • Suction ports 5 c and 5 e for suctioning the process gas G from the outside in the radial direction are provided on the side surfaces near the opposing end portions of the casing 5 .
  • Discharge ports 5 d and 5 f are provided at the central portion of the casing 5 in the direction of the axis O to discharge the process gas G outward in the radial direction.
  • the casing 5 is provided with an internal space 6 a ( 6 ) for communicating the suction port 5 c and the discharge port 5 d each other, and an internal space 6 b for communicating the suction port 5 e and discharge port 5 f each other.
  • a plurality of impellers 3 housed in the casing 5 constitute two sets of a three-stage impeller group 3 A and a three-stage impeller group 3 B in which the directions of the blades 3 b in the direction of the axis O of the rotary shaft 2 face sides opposite to each other.
  • the three-stage impeller group 3 A and the three-stage impeller group 3 B are mounted on the rotary shaft 2 in a state in which their back surfaces face the center in the direction of the axis O.
  • the impeller 3 includes a disk 3 a , a blade 3 b , and a cover portion 3 c.
  • the disk 3 a is formed in a substantially disc shape which gradually enlarges in diameter toward the discharge ports 5 d and 5 f in the direction of the axis O.
  • the blade 3 b is formed radially on the disk 3 a . That is, a plurality of the blades 3 b are arranged in the circumferential direction.
  • the cover portion 3 c is formed in a disc shape to cover the tip sides of the plurality of blades 3 b.
  • the impellers 3 constituting the three-stage impeller group 3 A and the impellers 3 constituting the three-stage impeller group 3 B are directed in directions opposite to each other in the direction of the axis O.
  • the three-stage impeller group 3 A flows and compresses the process gas G from the suction port 5 c toward the discharge port 5 d .
  • the three-stage impeller group 3 B flows and compresses the process gas G from the suction port 5 e toward the discharge port 5 f.
  • the internal space 6 is provided with a return flow passage 4 .
  • the return flow passage 4 flows the process gas G from the flow passage outlet of the impeller 3 toward the flow passage inlet.
  • the return flow passage 4 has a diffuser portion 12 , a bend portion 13 , and a return portion 14 .
  • the diffuser portion 12 guides the process gas G, which has been compressed by the impeller 3 and discharged outward in the radial direction from the flow passage outlet of the impeller 3 , to the outside in the radial direction.
  • the radially outer portion of the diffuser portion 12 communicates with the return portion 14 via a bend portion 13 .
  • discharge ports 5 d and 5 f are formed in the radially outer portion of the diffuser portion 12 connected to the third stage impellers 3 of each of the three-stage impeller group 3 A and the three-stage impeller group 3 B.
  • the bend portion 13 forms a curved flow passage.
  • the first end on the upstream side of the bend portion 13 is connected to the diffuser portion 12 .
  • the second end on the downstream side of the bend portion 13 is connected to the return portion 14 .
  • the bend portion 13 reverses the direction of the process gas G flowing outward in the radial direction through the diffuser portion 12 so as to be directed inward in the radial direction and sends the process gas G to the return portion 14 .
  • the return portion 14 is connected to the second end of the bend portion 13 on the radially outer side.
  • the return portion 14 is connected to the flow passage inlet of the impeller 3 on the radially inner side.
  • the centrifugal compressor 1 of this embodiment includes the aforementioned configuration. Next, the operation of the centrifugal compressor 1 will be described.
  • the process gas G suctioned from the suction port 5 c is caused to flow into the return flow passage 4 , and is compressed, while flowing from the first stage to the third stage in the order of the impeller 3 , the diffuser portion 12 , the bend portion 13 and the return portion 14 . Thereafter, the compressed process gas G flowing to the third stage diffuser portion 12 is discharged from the discharge port 5 d .
  • the process gas G discharged from the discharge port 5 d is sent to the suction port 5 e through a pipe line (not shown) leading from the discharge port 5 d to the suction port 5 e.
  • the process gas G suctioned from the suction port 5 e is caused to flow into the return flow passage 4 , and is further compressed, while flowing from the first stage to the third stage in the order of the impeller 3 , the diffuser portion 12 , the bend portion 13 and the return portion 14 . Thereafter, the compressed process gas G that has reached the third stage diffuser portion 12 is discharged from the discharge port 5 f.
  • the process gas G near the discharge port 5 f of the three-stage impeller group 3 B reaches a high pressure only by being compressed by the three-stage impeller group 3 B. That is, a pressure difference is generated between the process gas G around the rotary shaft 2 near the discharge port 5 d in the direction of the axis O and the process gas G around the rotary shaft 2 near the discharge port 5 f in the direction of the axis O.
  • a seal mechanism 20 A which partitions the high-pressure side and the low-pressure side of the rotary shaft 2 in the direction of the axis O to prevent leakage of the process gas G; while allowing rotation of the rotary shaft 2 .
  • the seal mechanism 20 A is disposed on the outer circumferential side of the rotary shaft 2 and is rotatable around the axis O with respect to the rotary shaft 2 .
  • a hole pattern seal (main body) 21 A constituting the seal mechanism 20 A is disposed on the inner circumference of an annular casing 5 disposed at an interval from the rotary shaft 2 .
  • the hole pattern seal 21 A has a cylindrical shape, and the rotary shaft 2 is inserted into the hole pattern seal 21 A.
  • FIG. 2 is a perspective view showing the hole pattern seal of the seal mechanism of the centrifugal compressor.
  • FIG. 3 is a partial cross-sectional view of the seal mechanism of the centrifugal compressor.
  • FIG. 4 is an expanded view of the inner circumferential surface of the hole pattern seal.
  • a plurality of hole portions 22 opened toward the inner circumferential side are formed on an inner circumferential surface 21 a of the hole pattern seal 21 A.
  • the plurality of hole portions 22 are formed in a circular cross-section having the same hole diameter.
  • the hole portions 22 are disposed such that all the their axes (not shown) extend in the radial direction of the rotary shaft 2 .
  • the bottom surfaces 22 a of each hole portion 22 are conical (see FIG. 3 ). In other words, the bottom surfaces 22 a are formed to reduce in diameter toward the outside in the radial direction.
  • Opening portions 22 b of the hole portions 22 are disposed on the inner circumferential surface 21 a of the hole pattern seal 21 A in a zigzag shape.
  • a first row L 1 in which the opening portions 22 b of the plurality of hole portions 22 are arranged at equal intervals in the circumferential direction (up-down direction of sheet of FIG. 4 ), is formed on a first side (a left side of sheet of FIG. 4 ) serving as the high-pressure side in the direction of the axis O.
  • a third row L 3 is formed on a second side (a right side of sheet of FIG. 4 ) serving as the low-pressure side in the direction of the axis O of the first row L 1 .
  • the opening portions 22 b of the plurality of hole portions 22 are arranged at equal intervals in the circumferential direction, like the first row L 1 .
  • a second row L 2 in which the opening portions 22 b of the plurality of hole portions 22 are arranged at equal intervals in the circumferential direction is formed.
  • the opening portions 22 b constituting the second row L 2 are disposed at the center between the adjacent opening portions 22 b of the first row L 1 (and the third row L 3 ) in the circumferential direction and at positions of the center between the adjacent opening portions 22 b in the direction of the axis O of the first row L 1 and the third row L 3 in the direction of the axis O.
  • the reference numerals of the first row L 1 to the third row L 3 are drawn from a straight line (one-dot chain line in FIG. 4 ) passing through the center of each opening portion 22 b.
  • the first row L 1 and second row L 2 are formed as a set of row groups R, and plurality of sets of row groups R are formed side by side in the direction of the axis O.
  • a shearing force acts on the process gas G around the rotary shaft 2 in a rotational tangential direction from the rotating body including the impeller 3 .
  • a swirling having a velocity component in the circumferential direction is generated by the action of the shearing force.
  • the process gas G including the swirling tries to flow from the high-pressure side to the low-pressure side due to the pressure difference between both sides in the direction of the axis O.
  • the process gas G including the swirling is contracted by a gap g between the end portion on the highest pressure side of the hole pattern seal 21 A and the outer circumferential surface 2 a of the rotary shaft 2 .
  • the process gas G entering the gap g advances toward the low-pressure side in the direction of the axis O.
  • a part of the process gas G is directed toward the hole portion 22 side of the first row L 1 of the hole pattern seal 21 A.
  • a part of the process gas G directed toward the hole portion 22 side of the first row L 1 enters the interior of the hole portion 22 and turns back toward the opening portion 22 b from the bottom surface 22 a to become a swirl flow F 1 .
  • a partition wall K 2 also exists in the hole portion 22 in the circumferential direction, the swirling of the process gas G entering the hole portion 22 collides with the partition wall K 2 and is canceled out.
  • a part of the process gas G leaving the hole portion 22 interferes with the main flow F 0 of the process gas G flowing toward the low-pressure side in the direction of the axis O.
  • the directions of the flow are different between the swirl flow F 1 generated by the part of the process gas G generated in the hole portion 22 and the main flow F 0 of the process gas G flowing toward the low-pressure side along the direction of the axis O.
  • the energy of the main flow F 0 of the process gas G flowing to the low-pressure side in the direction of the axis O is attenuated.
  • the process gas G flows toward the low-pressure side in the direction of the axis O, and a part thereof flows into the hole portions 22 after the third row L 3 .
  • the process gas G meanders in the radial direction, while advancing in the direction of the axis O of the rotary shaft 2 . Thereafter, the aforementioned actions are repeated according to the number of row groups R of the hole pattern seal 21 A.
  • the hole depth h of each hole portion 22 in each row is set to be equal to or smaller than the hole diameter d (h ⁇ d).
  • the hole depth h of the hole portion 22 increases with respect to the hole diameter d, the flow velocity of the process gas G entering the hole portion 22 becomes slower, and the energy attenuation effect on the main flow F 0 of the process gas G decreases. Also, when the hole depth h of the hole portion 22 increases, the machining cost increases.
  • the hole portion 22 becomes shallow. Accordingly, it is hard for the process gas G to enter the hole portion 22 , and it is difficult to obtain the energy attenuation effect. Further, since scale accumulates in the hole portion 22 and the hole portion 22 easily becomes shallow, the energy attenuation effect also decreases in this respect.
  • the relationship of the hole depth h of the hole portion 22 to the hole diameter d is preferably h ⁇ d. More preferably, the relation is d/2 ⁇ h ⁇ d.
  • the hole diameters d and the hole depths h of all the hole portions 22 constituting the hole pattern seal 21 A are preferably of a uniform size.
  • the swirl flow F 1 formed at the hole portion 22 by a part of the process gas G entering the hole portion 22 of the hole pattern seal 21 A can be made to interfere with the main flow F 0 flowing toward the low-pressure side in the direction of the axis O without entering the hole portion 22 . Therefore, it is possible to attenuate the energy of the main flow F 0 of the process gas G and to remove the swirling contained in the process gas G.
  • the swirl flow F 1 is easily generated, and it is possible to effectively exhibit the swirling reduction effect and the energy attenuation effect.
  • the bottom surface 22 a of the hole portion 22 has a conical shape. As a result, a part of the process gas G entering the hole portion 22 hits against the bottom surface 22 a , the direction of flow easily changes, and the swirl flow F 1 easily occurs in the hole portion 22 .
  • FIG. 5 is a diagram showing a result of analysis of the relationship between the hole depth h and the equivalent attenuation.
  • centrifugal compressor shown in the second embodiment is different from the centrifugal compressor according to the first embodiment only in that a fin portion is provided in a hole pattern seal. Therefore, in the description of the second embodiment, the same parts as those in the first embodiment are denoted by the same reference numerals, and repeated description will not be provided. That is, a description of the overall configuration of the centrifugal compressor shared by the configuration described in the first embodiment will not be provided.
  • FIG. 6 is a perspective view showing a hole pattern seal in the seal mechanism of the centrifugal compressor according to the second embodiment of the present invention.
  • FIG. 7 is a developed view of the inner circumferential surface of the hole pattern seal.
  • FIG. 8 is a partial cross-sectional view of the seal mechanism in the centrifugal compressor.
  • the hole pattern seal (main body) 21 B of the seal mechanism 20 B of the centrifugal compressor 1 in this embodiment has hole portions 22 and fin portions 24 on its inner circumferential surface 21 a.
  • a first row L 1 in which the opening portions 22 b of a plurality of first hole portions 22 A are arranged with the same spacing S 1 in the circumferential direction (up-down direction of sheet of FIG. 7 ) is formed.
  • a second side (the right side of sheet of FIG. 7 ) serving as the low-pressure side in the direction of the axis O of the first row L 1 a third row L 3 is formed at an interval S 2 sufficiently smaller than the spacing S 1 .
  • the opening portions 22 b of the plurality of third hole portions 22 C are arranged at an interval S 1 in the circumferential direction like the first row L 1 .
  • a second row L 2 is formed in which the opening portions 22 b of the plurality of second hole portions 22 B are arranged at the space S 1 in the circumferential direction.
  • the opening portions 22 b constituting the second row L 2 are arranged at the center of the space S 1 between the adjacent opening portions 22 b in the first row L 1 (and the third row L 3 ) in the circumferential direction, and at the positions of the center of the space S 2 between the adjacent opening portions 22 b in the direction of the axis O of the first row L 1 and the third row L 3 in the direction of the axis O, respectively.
  • the reference numerals of the first row L 1 to the third row L 3 are drawn from a straight line (one-dot chain line in FIG. 7 ) passing through the center of each opening portion 22 b.
  • the above-described first row L 1 to third row L 3 are defined as a set of row groups R, and a plurality of sets of row groups R are formed side by side in the direction of the axis O.
  • the opening portions 22 b of the first row L 1 and the opening portions 22 b of the third row L 3 of each row group R adjacent to each other are disposed at a space S 2 therebetween.
  • fin portions 24 protruding toward the inner circumference side, that is, toward the rotary shaft 2 side, in the radial direction are formed on the first side serving as the high-pressure side of each row group R.
  • the fin portions 24 are continuously formed on the entire circumference of the hole pattern seal 21 B in the circumferential direction.
  • the fin portions 24 are formed in an annular plate shape having a uniform thickness. In other words, the fin portions 24 extend from the high-pressure side partition wall K 1 (see FIG. 8 ) surrounding the first hole portions 22 A of the first row L 1 toward the rotary shaft 2 side.
  • the fin portion 24 is provided on the high-pressure side of each first row L 1 .
  • a second row L 2 and a third row L 3 are disposed on the low-pressure side of the first row L 1 .
  • the tip portions 24 a of the fin portions 24 are disposed at a predetermined clearance C from the outer circumferential surface 2 a of the rotary shaft 2 .
  • the rotary shaft 2 has a protruding portion 25 on the outer circumferential surface 2 a facing the aforementioned hole pattern seal 21 B.
  • the protruding portion 25 protrudes toward the hole pattern seal 21 B and is continuously formed around the entire circumference in the circumferential direction.
  • the protruding portion 25 faces the opening portions 22 b of the first hole portion 22 A of the first row L 1 on the lower pressure side of each fin portion 24 .
  • the vertical wall 25 b on the high-pressure side of the protruding portion 25 is disposed on the higher pressure side of the surface on the high-pressure side of the partition wall K 3 in the direction of the axis O.
  • the outer circumferential surface 25 a of the protruding portion 25 is disposed between fin portions 24 adjacent to each other.
  • the outer circumferential surface 25 a is disposed at a predetermined clearance with respect to the partition wall K 3 between the first hole portion 22 of the first row L 1 and the third hole portion 22 C of the third row L 3 to overlap the fin portion 24 as seen from the direction of the axis O.
  • the fin portion 24 is disposed at the center between adjacent protruding portions 25 and 25 in the direction of the axis O. That is, the protruding portion 25 has a symmetrical shape about the central portion between adjacent partition walls K 3 in the direction of the axis O.
  • the hole portions 22 of each row constituting the hole pattern seal 21 B preferably have a hole depth h with respect to the hole diameter d of h ⁇ d. More preferably, there is a relationship of d/2 ⁇ h ⁇ d.
  • FIG. 9 is an explanatory view of the operation of the seal mechanism.
  • the process gas G containing the swirling is contracted by the gap g 1 between the tip portion 24 a of the fin portion 24 on the highest pressure side of the hole pattern seal 21 B and the outer circumferential surface 2 a of the rotary shaft 2 .
  • the process gas G entering the gap g 1 moves toward the low-pressure side in the direction of the axis O.
  • the process gas G collides with the vertical wall 25 b of the high-pressure side of the protruding portion 25 and flows toward the outer side in the radial direction of the protruding portion 25 , that is, toward the first hole portion 22 A side of the first row L 1 of the hole pattern seal 21 B.
  • the process gas G advances toward the gap g 3 disposed on the lower pressure side of the outer circumferential surface 25 a of the protruding portion 25 and on the inner side in the radial direction, and the process gas meanders in the radial direction at that time.
  • This meandering disturbs the flow so that the same sealing effect as in a general labyrinth seal can be obtained.
  • the aforementioned operations are repeated according to the number of row groups R of the hole pattern seal 21 B.
  • a swirl flow F 1 of the same degree as with the general hole pattern seal 21 B is also generated in the interior of the third hole portion 22 C of the third row L 3 , and the swirl flow contributes to the reduction of the swirling.
  • the process gas G entering from the gap g 1 between the fin portion 24 of the hole pattern seal 21 B and the rotary shaft 2 can be brought into contact with the vertical wall 25 b of the protruding portion 25 of the rotary shaft 2 to flow toward the hole portion 22 side of the hole pattern seal 21 B.
  • the partition wall K 2 disposed on the partition wall of the hole portion 22 in the circumferential direction of the rotary shaft 2 can hinder the flow of the process gas G in the turning direction, thereby reducing the swirling.
  • the process gas G meanders in the radial direction. Therefore, it is possible to reduce the amount of leakage of the process gas G by the so-called sealing effect provided by the labyrinth structure. As a result, it is possible to limit self-excited vibration caused by the swirling, while reducing the amount of leakage of the process gas G from the high-pressure side to the low-pressure side.
  • the hole depth h of the hole portion 22 is set to be equal to or smaller than the hole diameter d, it is possible to exhibit the above-described swirling reduction effect and energy attenuation effect.
  • the present invention is not limited to each of the aforementioned embodiments, and the design can be changed within a range that does not depart from the gist of the present invention.
  • the interval at which the fin portions 24 are provided that is, the number of rows of the hole portions 22 constituting each row group R can be suitably changed.
  • the hole portions 22 are disposed in a zigzag shape in the hole pattern seals 21 A and 21 B, it is possible to suitably set the space in the circumferential direction and in the axial direction.
  • the hole portions 22 constituting the hole pattern seals 21 A and 21 B are not limited to a zigzag shape in which the rows of hole portions 22 adjacent to each other in the axial direction are phased in the circumferential direction, and the spaces and phases of the hole portions 22 adjacent to each other may be disposed as a uniform square array.
  • the tip portion 24 a of the fin portion 24 extends in the radial direction, but the fin portion 24 may be formed in an inclined state such that the tip portion 24 a is disposed on the higher pressure side of the base portion 24 b.
  • the fin portion 24 is formed to have a constant thickness, but the fin portion 24 may be formed in a tapered shape in which the width size is formed to become thinner toward the tip portion 24 a.
  • the hole portions 22 constituting the hole pattern seals 21 A and 21 B of the seal mechanisms 20 A and 20 B are formed to have a circular cross-section having a substantially equal hole diameter d, but the present invention is not limited thereto.
  • the hole diameter d may be varied, depending on the axial position, the circumferential position or the like of the hole portions 22 .
  • hole portion 22 is not limited to a circular cross-section, and may constitute a so-called honeycomb seal having a hexagonal cross-section.
  • the bottom surface 22 a of the hole portion 22 is not limited to a conical shape, and may be a flat bottom.
  • the hole depth of the hole portion constituting the seal mechanism By setting the hole depth of the hole portion constituting the seal mechanism to be equal to or less than the hole diameter, it is possible to limit self-excited vibration due to the swirling, while reducing the amount of leakage of the process gas G from the high-pressure side to the low-pressure side.

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Structures Of Non-Positive Displacement Pumps (AREA)
  • Sealing Using Fluids, Sealing Without Contact, And Removal Of Oil (AREA)
US15/503,536 2014-08-25 2014-08-25 Seal mechanism and rotating machine Abandoned US20170241427A1 (en)

Applications Claiming Priority (1)

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PCT/JP2014/072203 WO2016030952A1 (ja) 2014-08-25 2014-08-25 シール機構、回転機械

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US20170241427A1 true US20170241427A1 (en) 2017-08-24

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US (1) US20170241427A1 (ja)
EP (1) EP3168510A4 (ja)
JP (1) JPWO2016030952A1 (ja)
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WO (1) WO2016030952A1 (ja)

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US20180073638A1 (en) * 2015-03-24 2018-03-15 Mitsubishi Heavy Industries, Ltd. Rotary machine
CN112855286A (zh) * 2019-11-27 2021-05-28 通用电气公司 用于涡轮机中旋转鼓的阻尼器密封件
US20230175411A1 (en) * 2021-12-07 2023-06-08 Mitsubishi Heavy Industries, Ltd. Rotary machine
US20230279865A1 (en) * 2021-01-04 2023-09-07 Danfoss A/S Step seal for refrigerant compressors
US11927195B2 (en) * 2022-03-14 2024-03-12 Mitsubishi Heavy Industries, Ltd. Sealing device, rotary machine, and design method for sealing device preliminary class

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CN108397416B (zh) * 2018-02-24 2020-04-28 西安交通大学 一种非均匀可控腔旋转密封结构
CN110332016B (zh) * 2019-06-24 2021-05-28 西安交通大学 一种能够增强密封性能的孔型密封结构
CN114033753A (zh) * 2021-11-11 2022-02-11 顺达空调设备集团有限公司 一种便于拆装固定的地铁风机安装结构

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CN112855286A (zh) * 2019-11-27 2021-05-28 通用电气公司 用于涡轮机中旋转鼓的阻尼器密封件
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US11927195B2 (en) * 2022-03-14 2024-03-12 Mitsubishi Heavy Industries, Ltd. Sealing device, rotary machine, and design method for sealing device preliminary class

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JPWO2016030952A1 (ja) 2017-04-27
CN106537007A (zh) 2017-03-22
EP3168510A4 (en) 2017-08-09
WO2016030952A1 (ja) 2016-03-03
EP3168510A1 (en) 2017-05-17

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