Classifications

• • 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
  • 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
  • F01D11/08—Preventing or minimising internal leakage of working-fluid, e.g. between stages for sealing space between rotor blade tips and stator
• • 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
  • F01D11/08—Preventing or minimising internal leakage of working-fluid, e.g. between stages for sealing space between rotor blade tips and stator
  • F01D11/12—Preventing or minimising internal leakage of working-fluid, e.g. between stages for sealing space between rotor blade tips and stator using a rubstrip, e.g. erodible. deformable or resiliently-biased part
  • F01D11/127—Preventing or minimising internal leakage of working-fluid, e.g. between stages for sealing space between rotor blade tips and stator using a rubstrip, e.g. erodible. deformable or resiliently-biased part with a deformable or crushable structure, e.g. honeycomb
• • 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
  • F01D5/00—Blades; Blade-carrying members; Heating, heat-insulating, cooling or antivibration means on the blades or the members
  • F01D5/12—Blades
  • F01D5/22—Blade-to-blade connections, e.g. for damping vibrations
  • F01D5/225—Blade-to-blade connections, e.g. for damping vibrations by shrouding
• • 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
  • F05D2240/00—Components
  • F05D2240/55—Seals

Definitions

• the subject of the present invention is a labyrinth seal comprising a wiper with a deflector.
• the labyrinth seals are well known and of a very common use in aeronautics for example. They tolerate a small leakage flow through them. They are normally used to separate chambers containing gases at different pressures, succeeding one another along a rotor and a stator facing the rotor, or more generally two structures in relative rotation.
• the labyrinth seals referred to herein comprise a base attached to one of the structures and carrying at least one wiper, ie a circular ridge rising from the base and of which the top is directed towards the other structures, which can carry a seal such as a honeycomb, very close to the top of the wiper, or another so-called abradable material that the wiper can easily erode when the clearance disappears, in the case of differential thermal expansions, for example between the rotor and the stator, or during sudden accelerations generating large centrifugal displacements.
• the leakage rate is reduced by the narrowness of the clearance between the top of the wiper and the lining of the opposite seal, as well as by the sudden variation of section offered to the leakage flow, that produces the wiper. This sudden variation effect is reinforced in the usual case where several wipers succeed one another along the direction of flow.
• Document FR 2 825 411 A1 describes a wiper composed of segments whose height (in the radial direction) is variable; EP 2 116 692 A2, wipers which can be composed of curved segments in the axial direction of the rotor; US 6,478,304 B1, a wiper provided with cutting elements projecting from the side faces and the top face of the wiper; and FR 2 963 403 A1, wipers provided with side deflectors, but on a stator.
• the fundamental object of the present invention is to further reduce the leakage rates through the labyrinth seals, by means of an innovation in the design of the wipers.
• a general aspect of the invention is a labyrinth seal of a turbomachine, the seal comprising at least one wiper standing on a base of a rotor of the turbomachine, the wiper being circular while extending along a said tangential direction, comprising two lateral faces each connected to the base and, at an end opposite the base, to a top face of the wiper, wherein at least one of the side faces carries at least one baffle comprising a secant deflecting face at said lateral face and having an inclination with respect to the tangential direction. And the inclination of the deflecting face with respect to the tangential direction is increasing when approaching the crown face, the deflecting face thus being concave.
• the deflector is a projecting structure on a lateral side of the wiper and having a so-called deflecting face directed in the tangential direction of the rotor so as to intercept a portion of the flow having locally a direction with a preponderant radial component since it flows along this lateral side of the wiper, to deflect it by increasing its tangential component, so as to disturb the leakage flow in the direction mainly axial and perpendicular, and thus reduce its flow.
• the concavity of the deflecting face increases the particularly beneficial tangential component.
• the deflector is repeated on the wiper with regular angular steps in the tangential direction; the wiper is movable in the tangential direction and the deflecting face is directed in a direction of movement of the wiper;
• the deflecting face being from the base to the summit face
• the lateral face carrying the deflector is directed upstream of a flow passing through the labyrinth seal in an axial direction perpendicular to the tangential direction;
• the wiper is inclined from the base, upstream of a flow through the labyrinth seal in an axial direction perpendicular to the tangential direction.
• FIG. 5 illustrates the flow prevailing in the joint.
• Figures 1 and 2 show a conventional labyrinth seal, in axial section and in cross section.
• a rotor shaft 1 extending in an axial direction X of a turbomachine is surrounded by a stator 2.
• the labyrinth seal 3 comprises a seal 4, which can assume the appearance of a honeycomb, fixed to the stator 2, and wipers 5 standing on a base 6 fixed to the rotor 1.
• the wipers 5 stand in a radial direction R of the machine and extend in a tangential direction T, these three directions being perpendicular to each other .
• the stator 2 and the seal 4 are annular, the wipers 5 are circular around the central axis of the machine.
• the wipers 5 are each delimited by two lateral faces 7 and 8 connected to the base 6, and by a crown face 9, which may be a simple edge, connecting to the opposite ends of the lateral faces 7 and 8.
• the seal labyrinth 3 separates two gas chambers 10 and 11 succeeding one another along the rotor 1 and defined by it and by the stator 2. If one of the enclosures 10 is at a higher pressure than the other, a leakage flow 12 is established at through the labyrinth seal S, through the clearances between the top faces 9 of the wipers 5 and the seal 4.
• the side face 7 is directed upstream of the leakage flow 12, and the face lateral 8 downstream for each of the wipers 5.
• the wipers 5 are provided at least at one of their lateral faces, in particular at the lateral face 7 directed upstream of the leakage flow 12, deflectors 13 may consist of platelets and anyway including a secant deflector face 14 to the side face 7 on which the deflectors are installed, and directed in the direction of movement T + of the rotor 1 in the tangential direction T.
• the deflectors 13 may be installed at regular angular steps by the tangential direction T along the wiper 5.
• the deflector faces 14 are inclined relative to the tangential direction T, that is to say they extend over at least a portion of the height of the wiper 5 between the base 6 and the crown face 9 in the radial direction R, and advantageously over this entire height.
• This inclination is variable, lower near the base 6 (that is to say that the deflecting face 13 is almost horizontal on the tangential direction T) and then increasing constantly, approaching the vertex face 9 (that is, the angle with the radial direction R decreases continuously): the deflector face 14 is concave.
• the effect of the deflector 13 can be explained as follows.
• the leakage flow 12 takes a vortex shape 15 in front of the wiper 5, especially if the wiper 5 is preceded by another of the same nature, delimiting a cavity 16 for forming the vortex 15.
• the vortex regions 15 which are close the wiper 5 receive from it a significant tangential component of speed imposed by the movement of the rotor 1.
• the fraction of the leakage flow 12 candidate to cross the wiper 5 thus undergoes a collision with this gas deflected by the deflectors 13, and which therefore has a component radial and a significant tangential component.
• the flow fraction is then disturbed, which reduces the leakage rate through the wiper 5.
• the tangential component, favored by the change of inclination of the deflector 13, is considered more useful for producing this effect.
• the radial component imposed on the gas intercepted by the deflectors 13 is here centrifugal, the rotor 1 being central and surrounded by the stator 2 (or more generally by the carrier body of the seal 4).
• An inverse arrangement would be possible, the wiper-bearing rotor surrounding the stator, and the deflectors would then carry wipers placed to impose a centripetal radial component to the gas.
• Deflectors 13 ' (FIG. 3) could still be placed on the lateral face 8 of the wipers directed downstream of the leakage flow 12, in addition to or instead of the deflectors 13 described here; their shape could be identical.
• the wipers 5 could be inclined axially without change for the invention, as shown in Figure 5 (where they are inclined upstream of the leakage flow 12 from the base 6) , or straight lines (standing in a purely radial direction), as shown in Figure 3; the inclination of the lateral faces 7 and 8 in the axial direction is also not a critical parameter.
• the number of deflectors 13 in the angular direction may be a few tens, or greater than a hundred for example, with an angular pitch ranging from 2 ° to 10 °.
• the angular pitch of the deflectors 13 may be identical to that of the blades .

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Sealing Using Fluids, Sealing Without Contact, And Removal Of Oil (AREA)
• Turbine Rotor Nozzle Sealing (AREA)
• Joints Allowing Movement (AREA)

Priority Applications (1)

Applications Claiming Priority (2)

Publications (2)

Family

ID=61003196

Family Applications (1)

Country Status (6)

Family Cites Families (9)

• 2017
  • 2017-11-15 FR FR1760758A patent/FR3073595B1/fr active Active
• 2018
  • 2018-11-16 US US16/763,390 patent/US11143049B2/en active Active
  • 2018-11-16 CN CN201880073495.7A patent/CN111356821B/zh active Active
  • 2018-11-16 PL PL18821725T patent/PL3695102T3/pl unknown
  • 2018-11-16 EP EP18821725.1A patent/EP3695102B1/de active Active
  • 2018-11-16 WO PCT/IB2018/001314 patent/WO2019097286A1/fr unknown

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