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
  • F01D5/00—Blades; Blade-carrying members; Heating, heat-insulating, cooling or antivibration means on the blades or the members
  • F01D5/30—Fixing blades to rotors; Blade roots ; Blade spacers
  • F01D5/3007—Fixing blades to rotors; Blade roots ; Blade spacers of axial insertion type
  • F01D5/3015—Fixing blades to rotors; Blade roots ; Blade spacers of axial insertion type with side plates
• • 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
  • F01D11/005—Sealing means between non relatively rotating elements
  • F01D11/006—Sealing the gap between rotor blades or blades and rotor
• • 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
  • F01D11/005—Sealing means between non relatively rotating elements
  • F01D11/006—Sealing the gap between rotor blades or blades and rotor
  • F01D11/008—Sealing the gap between rotor blades or blades and rotor by spacer elements between the blades, e.g. independent interblade platforms
• • 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
• • 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 invention relates to the control of leakage zones under the platforms of the blades of a bladed wheel in a turbomachine. More precisely, it relates to a bladed wheel of a turbomachine comprising a disc having at its periphery a plurality of substantially axial cells, a plurality of blades whose feet are retained in said cells and which have platforms intended to delimit, on the side radially inside, the gas flow stream and upstream and downstream radial walls which extend from said platforms towards the periphery of said disc, inter-blade cavities delimited by said platforms and the periphery of said disc, and sealing devices for the inter-blade spaces produced in the form of liners having flared edges radially inwards and arranged in said cavities against the walls of the platforms of two neighboring blades.
• Figure 1 shows in perspective a sealing jacket 1 according to the state of the art which has an upstream edge 2 and a downstream edge 3 flared radially inwardly, as well as two curved longitudinal flared edges which follow the flanks of the blades under the platforms.
• the upstream 2 and downstream 3 edges are intended to come in the immediate vicinity of the adjacent radial walls upstream and downstream of the two adjacent blades, in order to limit the leaks through the space separating the adjacent side walls.
• the upper wall 6 of each liner bears against the lower faces of two neighboring platforms under the action of centrifugal forces when the wheel is in rotation and seals the gap separating the neighboring platforms.
• the flared edges are practically non-deformable under the action of centrifugal forces, and it cannot be guaranteed that the flared edges upstream 2 and downstream 3 are effectively applied against the radial walls upstream and downstream of the blades. As shown in Figure 2, these edges may be spaced from the adjacent radial walls, which causes air leakage f between the cavity under the platform and the gas flow stream in these areas, which is detrimental to the performance of the wheel.
• the object of the invention is to better control the leakage area under a blade platform, in particular at the interstices between the radial walls under platforms.
• each liner has on one of its flared edges, upstream or downstream, an elastic zone and the radial walls adjacent to these edges are connected to the platforms by internal surfaces inclined relative to to a radial plane, and against which said elastic zone is in abutment, so that said elastic zone can slide radially inwards in the event of the rotation of said wheel, and radially outwards under the action of centrifugal forces in order to urge said jacket to move axially towards the radial walls distant from said elastic zone in order to improve the seal in this zone. If the bladed wheel stops, the elastic zone slides radially inwards and the jacket is put out of stress and moves away from the lower walls of the two platforms at least in the regions close to the elastic zone.
• the centrifugal forces will apply the jacket against the lower walls of the platforms, and the elastic forces will push the opposite flared edge towards the opposite side walls of the elastic edge, in order to improve the tightness in this place.
• the elastic zones are always supported on the adjacent side walls, sealing is guaranteed in this zone.
• the radial walls remote from the elastic zones include stops to limit the axial displacement of the liners under the action of centrifugal forces.
• the side walls adjacent to the elastic zones also include stops to limit the sliding inward of said elastic zones.
• the elastic zones are delimited circumferentially by two notches formed in the corresponding flared edge of the shirts. This arrangement makes it easy to implement the invention without additional cost.
• the invention applies in particular to padded turbine wheels.
• the elastic zone is provided on the upstream edge, and the angle of the inclined surface relative to the radial plane is greater than the slope of the platform relative to the axis of rotation of the turbomachine.
• FIG. 1 is a view from below and in perspective of a shirt of 'sealing according to the prior art
• Figure 2 is a side sectional view of a liner edge and a radial blade wall according to the prior art
• Figure 3 is a top view in perspective of a sealing jacket according to the invention
• Figure 4 is a bottom view in perspective of the sealing jacket of Figure 3
• Figure 5 is a section along a plane containing the axis of the bladed wheel, which shows the arrangement of the sealing jacket according to the invention in the cavity under platforms, after assembly and in the absence of centrifugal forces
• FIG. 6 is similar to FIG. 5 and shows the position of the sealing jacket, when it is subjected to centrifugal forces as a result of the rotation of the bladed wheel.
• Figures 1 and 2 show the state of the art which has been discussed above in this memo.
• Figures 3 and 4 show a sealing jacket 10 according to the invention which has edges flared radially inward, namely an upstream edge 12, a downstream edge 13, and between the upstream edge 12 and the downstream edge 13 two longitudinal curved flared edges which follow the shape of the sides of the two adjacent blades.
• the upstream edge 12 has two notches 16 and 17 which delimit between them an elastic zone 18 which, at rest, emerges on the front relative to the upstream edge 2 of the jacket 1 according to the state of the art shown in Figure 1
• the elastic zone 18 is outside the imaginary surface which would connect the ends 12a and 12b of the upstream edge 12 continuously and smoothly, located beyond the notches 16 and 17, and connected respectively to the longitudinal edges 14 and 15 by convex surfaces.
• Figures 5 and 6 show a bladed wheel 30 which has a disc 31 which has at its periphery a plurality of substantially axial cells 32 in each of which houses the foot of a blade 33.
• Each blade 33 has above its foot a platform
• each blade 33 has a portion of platform on the right and a portion of platform on the left. The same is true of the radial walls
• Each cavity under platforms 37 is thus delimited by right and left platform portions of two adjacent blades, and by their portions of upstream and downstream side walls, right and left.
• a clearance or gap separates the right and left portions which must be sealed with a sealing jacket.
• connection 38 between the upstream radial wall 35 and the platform 34 has, on the side of the cavity 37, a surface 39 which forms an angle oc with the radial plane perpendicular to the axis of rotation of the bladed wheel 30.
• the downstream radial wall 36 is connected to the platform 34 by a zone 40 which has, on the side of the cavity 37, a curved surface 41 complementary to the flaring of the upstream edge 13 of the jacket 10.
• the downstream radial wall 36 also has a protuberance 42 on its internal face which serves as a stop for the downstream edge of the jacket 10.
• the upstream radial wall 35 also has a protrusion 43 on its face located on the side of the cavity 37 .
• the jacket 10 is mounted in the cavity 37 in such a way that the downstream edge 13 is positioned above the projection 42 and that the elastic zone 18 is positioned above the projection 43. In this position, the elastic zone 18 of the jacket 10 bears on the inclined surface 39.
• the angle of the inclined surface 39 is calculated as a function of the slope of the platform 34 relative to the axis of rotation of the wheel and as a function of the friction angle ⁇ of the liner 10 against the internal surface of the platform 34, so that, in the absence of centrifugal force, that is to say when the bladed wheel 30 is stopped, the elastic zone 18 slides radially inwards on the inclined surface 39.
• the upper wall 19 of the jacket is spread over its greatest extent from the underside of the platform 34, as can be seen in FIG. 5, the jacket 10 tilting around an axis cutting the plane of FIG. 5 at the point referenced 44 and located in the vicinity of the downstream flared edge 13.
• the protuberance 43 of the upstream radial wall 35 makes it possible to limit the sliding of the elastic zone 18, and to retain the jacket 10 in the upper zone of cavity 37.
• FIG. 6 shows the position of the jacket 10 during the rotation of the bladed wheel 30.
• the jacket 10 is subjected to centrifugal forces which tend to press it against the internal face of the platform 34.
• the elastic zone 18 is biased radially outwards and it slides against the inclined wall 39.
• the angle ⁇ is advantageously greater than the slope of the platform 34.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Turbine Rotor Nozzle Sealing (AREA)
• Structures Of Non-Positive Displacement Pumps (AREA)

Applications Claiming Priority (3)

Publications (2)

Family

ID=29558830

Family Applications (1)

Country Status (9)

Cited By (1)

Families Citing this family (28)

Family Cites Families (11)

• 2002
  • 2002-05-30 FR FR0206599A patent/FR2840352B1/fr not_active Expired - Lifetime
• 2003
  • 2003-05-28 CA CA2487471A patent/CA2487471C/fr not_active Expired - Fee Related
  • 2003-05-28 UA UA20041109828A patent/UA81764C2/uk unknown
  • 2003-05-28 RU RU2004138597/06A patent/RU2313671C2/ru not_active IP Right Cessation
  • 2003-05-28 AU AU2003249424A patent/AU2003249424A1/en not_active Abandoned
  • 2003-05-28 EP EP03756014.1A patent/EP1507960B1/de not_active Expired - Lifetime
  • 2003-05-28 WO PCT/FR2003/001611 patent/WO2003102380A1/fr not_active Ceased
  • 2003-05-28 JP JP2004509241A patent/JP2005528550A/ja active Pending
  • 2003-05-28 US US10/514,559 patent/US7214034B2/en not_active Expired - Lifetime

Non-Patent Citations (1)

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