US20120063904A1 - Lever-arm vibration damper for a rotor of a gas turbine engine - Google Patents
Lever-arm vibration damper for a rotor of a gas turbine engine Download PDFInfo
- Publication number
- US20120063904A1 US20120063904A1 US13/179,860 US201113179860A US2012063904A1 US 20120063904 A1 US20120063904 A1 US 20120063904A1 US 201113179860 A US201113179860 A US 201113179860A US 2012063904 A1 US2012063904 A1 US 2012063904A1
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- Prior art keywords
- plate
- rotor
- blade
- bearing surface
- blades
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Classifications
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- 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
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- 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
- F01D25/00—Component parts, details, or accessories, not provided for in, or of interest apart from, other groups
- F01D25/04—Antivibration arrangements
- F01D25/06—Antivibration arrangements for preventing blade vibration
-
- 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
- F01D5/26—Antivibration means not restricted to blade form or construction or to blade-to-blade connections or to the use of particular materials
-
- 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
- F01D5/28—Selecting particular materials; Particular measures relating thereto; Measures against erosion or corrosion
- F01D5/282—Selecting composite materials, e.g. blades with reinforcing filaments
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- 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
- F01D5/28—Selecting particular materials; Particular measures relating thereto; Measures against erosion or corrosion
- F01D5/284—Selection of ceramic materials
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- 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
- F05D2300/00—Materials; Properties thereof
- F05D2300/60—Properties or characteristics given to material by treatment or manufacturing
- F05D2300/603—Composites; e.g. fibre-reinforced
- F05D2300/6033—Ceramic matrix composites [CMC]
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T50/00—Aeronautics or air transport
- Y02T50/60—Efficient propulsion technologies, e.g. for aircraft
Definitions
- the present invention relates to the general field of damping the vibration that appears in operation between the outer platforms of two adjacent rotor blades in a gas turbine engine.
- a rotor of a gas turbine engine such as a rotary wheel of a low pressure turbine stage in a turbojet, for example, comprises a disk having a plurality of blades mounted thereon. At its free radial end, each blade presents a transverse element referred to as an “outer platform” that serves in particular to define the outside of the flow passage for the gas stream passing through the turbine.
- the outer platform of such a blade has an upstream edge and a downstream edge, which edges extend perpendicularly to the flow direction of the gas stream. These edges are connected together via two lateral edges whereby the outer platform of a blade comes into contact with the outer platforms of two blades of the rotor wheel that are directly adjacent thereto.
- vibration damping is not applicable to rotors having blades that are made of composite material.
- CMC ceramic matrix composite
- twisting the blades generates stresses that are too high compared with the strength of the composite material.
- using blades made of composite material also has the drawback of giving rise to large steps or large amounts of clearance between the outer platforms of adjacent blades in the event of the blades tilting relative to one another.
- a main object of the present invention is thus to mitigate such drawbacks by proposing effective damping of the vibration between the outer platforms of adjacent blades made of composite material and without generating excessive stress in the blades.
- a vibration damper for a rotor blade of a gas turbine engine comprising a plate for placing between an inner bearing surface and an outer bearing surface of the rotor, the bearing surfaces extending in directions that are substantially axial and being radially spaced apart from each other, the plate being folded so as to form two plate portions that are inclined relative to each other, the mass of the plate being distributed in such a manner that its center of gravity is situated on the side of one of these plate portions, the free end of the other plate portion being designed to bear radially against the inner bearing surface, and the junction zone between the two plate portions being designed to bear radially against the outer bearing surface under the effect of centrifugal force when the rotor is rotating, thereby providing axial sealing against gas.
- the damper further includes means for holding the plate between the two bearing surfaces of the rotor when the rotor is stopped.
- the plate may include at least one holder tab that extends in a direction that is substantially inclined relative to the radial direction and that is designed to pass through the outer bearing surface.
- the invention also provides a rotor element of a gas turbine engine, the element comprising first and second mutually adjacent blades, the first blade having, at a radially free end, a portion constituting a spoiler outer platform without a portion constituting a wiper outer platform, and the second blade having, at a radially free end, a portion constituting a wiper outer platform without a portion constituting a spoiler outer platform, and a vibration damper as defined above, with the plate thereof being arranged between the spoiler outer platform of the first blade forming an inner bearing surface and the wiper outer platform of the second blade forming an outer bearing surface.
- the invention also provides a rotor element of a gas turbine engine, the element comprising a pair of mutually adjacent blades, each comprising an airfoil presenting two faces, each connecting a leading edge to a trailing edge of the blade, each blade having a single portion extending from each of the faces of its airfoil, one of these portions forming a spoiler outer platform and the other portion forming a wiper outer platform, and a vibration damper as defined above, with the plate thereof being arranged between the spoiler outer platform of one of the blades forming an inner bearing surface and the wiper outer platform of the other blade forming an outer bearing surface.
- the damper plate may be positioned between the bearing surfaces in such a manner that the portion having its free end bearing radially against the inner bearing surface is located on the upstream side.
- the plate, and more particularly its portion provided with the free end bearing against the inner bearing surface serves to provide sealing against the gas passing through the gas turbine.
- the invention also provides a rotor element of a gas turbine engine, the element comprising a blade having an airfoil, a root for mounting in a disk of the rotor, and an inner platform situated between the root and the airfoil, and a vibration damper as defined above, with the plate thereof designed to be arranged between an outside surface of the disk forming an inner bearing surface and an inside surface of the platform of the blade forming an outer bearing surface.
- FIGS. 1 and 2 are diagrams showing how a vibration damper of the invention is mounted between the outer platforms of two composite material blades having shapes that are complementary, of the “even-odd” type;
- FIGS. 3 and 4 are views of the outer platforms of the two blades of FIG. 2 , respectively from upstream and from above;
- FIGS. 5A to 5C show how the damper moves in the event of radial clearance between the outer platforms of the blades
- FIGS. 6 to 8 are diagrams showing how a vibration damper of the invention is implanted between the outer platforms of two composite material blades having complementary shapes of the “asymmetrical” type.
- FIGS. 9 and 10 are diagrams showing how a vibration damper is implanted in another embodiment of the invention between the inner platforms of two adjacent blades.
- the invention is applicable to various types of gas turbine engine blade, in particular to compressor blades and to turbine blades of various gas turbine spools, for example to rotor blades of a low pressure turbine stage in an aviation turbomachine, such as those shown in FIGS. 1 to 4 .
- the rotor 10 of a low pressure turbine stage of a turbomachine comprises a disk 12 (shown in part) having an axis of rotation X-X and with a plurality of blades mounted thereon. For reasons of simplification, only two blades are shown in FIGS. 1 and 2 .
- the blades may be made of metal or they may be made of composite material, and in particular of ceramic matrix composite (CMC) material.
- CMC ceramic matrix composite
- the invention applies more particularly (but not exclusively) to composite material blades of the kind said to be of complementary shapes, of the “even-odd” blade type or of the “asymmetrical” blade type.
- the blades 100 and 200 are of the “even-odd” type.
- French patent application FR 10/55160 filed in the joint names of Snecma Propulsion Solide and Snecma describes the shape of such even-odd blades and the method of making them.
- the first blade 100 comprises an airfoil 102 , a root 104 , e.g. having a section in the shape of a bulb extended by a tang 106 , an inner platform 108 situated between the tang and the airfoil, and a spoiler outer platform 110 situated in the vicinity of the free end of the airfoil.
- the airfoil 102 extends longitudinally between the inner platform 108 and the outer platform 110 and presents a curved profile in cross-section between its leading edge 102 a and its trailing edge 102 b.
- the first blade 100 is mounted on the rotor disk 12 by engaging its root 104 in a housing 14 of complementary shape formed in the periphery of the disk.
- the airfoil 102 is connected to the outer platform 110 which defines the outside of the flow passage for the gas stream passing through the turbine.
- the outer platform 110 terminates with overlap spoilers 112 .
- the first blade does not have wipers on its outer platform at its radially outer end.
- the second blade 200 is designed to co-operate with the above-described first blade 100 so as to form an even-odd type pair of blades.
- the second blade 200 comprises an airfoil 202 , a root 204 extended by a tang 206 , an inner platform 208 situated between the tang and the airfoil, and an outer platform 210 having wipers situated in the vicinity of the free end of the airfoil.
- the airfoil 202 extends longitudinally between the inner platform 208 and the outer platform 210 with wipers and presents in cross-section a curved profile between its leading edge 202 a and its trailing edge 202 b.
- the second blade 200 is mounted on the rotor disk 12 by engaging its root 204 in a housing 14 of complementary shape formed in the periphery of the disk. Furthermore, it should be observed that this second blade does not have an outer platform with spoilers at its radially outer end.
- the inside surface 210 a of this portion of the wiper outer platform faces the outside surface 110 a of said portion of the spoiler outer platform. It should be observed that this inside surface 210 a and outside surface 110 a extend in directions that are substantially axial and that are radially spaced apart from each other by a gap e .
- the blades 100 , 200 of the rotor are subjected to vibration that needs to be damped.
- the vibration damper 300 of the invention comprises a plate, e.g. made of metal and of substantially rectangular general shape, which plate is positioned between the outside surface 110 a of the spoiler outer platform 110 of the first blade (forming the inner bearing surface of the rotor in the meaning of the invention) and the inside surface 210 a of the wiper outer platform 210 of the second blade (forming the outer bearing surface of the rotor in the meaning of the invention).
- This plate is folded so as to form two plate portions that are inclined relative to each other, namely a first portion 304 a and a second portion 304 b. More precisely, the first portion 304 a of the plate is arranged on the upstream side (upstream relative to the flow direction of the gas stream) and the second portion 304 b is positioned on the downstream side.
- junction zone between the two plate portions 304 a and 304 b may be constituted by a fold line 302 , as shown in FIGS. 1 , 5 A to 5 C, and 6 . Nevertheless, this junction zone could alternatively be constituted by one or more points.
- the free end 306 of the first portion 304 a of the plate comes to bear radially against the outside surface 110 a of the spoiler outer platform 110 of the first blade.
- Another feature of the vibration damper of the invention is that the mass of the plate is distributed in such a manner that its center of gravity (represented by point G in FIG. 5A ) is situated on the side of the second portion 304 b of the plate.
- Such permanent contact of the plate against the inner and outer bearing surfaces serves firstly to dissipate by friction the vibratory energy associated with the disk rotating, and secondly to provide sealing relative to the gas flowing through the turbine (by preventing the gas from penetrating from upstream between the outer platforms of the blades).
- the particular shape of the vibration damper of the invention adapts well to radial clearances appearing between the outer platforms of adjacent blades (as can happen as a result of the blades tilting relative to one another).
- the respective outer platforms 110 , 210 of the two blades are shown spaced apart from each other by gaps e 1 and e 2 that are greater than the gap e of FIG. 5A , the gap e 2 being the greatest that the damper can accommodate.
- the free end 306 of the first portion 304 a of the plate and the fold line 302 of the plate always remain in contact with their respective bearing surfaces.
- the damper functions of dissipating vibratory energy and of providing sealing continue to be performed even in the event of a large amount of radial clearance between the outer platforms.
- the vibration damper possesses mass that lies in the range 1% to 10%—and preferably in the range 4% to 6%—of the mass of the blades 100 and 200 between which it is mounted. Such a mass enables the plate to perform its vibration damper function well.
- the vibration damper of FIGS. 1 to 4 also has means for holding the plate 300 between the wiper outer platform 210 of the second blade and the spoiler outer platform 110 of the first blade.
- the plate 300 has at least one—and preferably two—holder tabs 308 that extend in a direction that is substantially inclined relative to the radial direction and that serve to pass through orifices 212 pierced through the wiper outer platform 210 of the second blade. More precisely, these holder tabs 308 are secured to the second portion 304 b of the plate. As a result, when the rotor disk stops, these holder tabs serve to prevent the vibration damper escaping from its position between the outer platforms of the blades.
- FIGS. 6 to 8 are diagrams showing how an above-described vibration damper 300 is installed relative to blades presenting complementary shapes of the “asymmetrical” blade type.
- Patent application FR 10/55161 filed jointly in the names of Snecma Propulsion Solide and Snecma describes the shape of such assymmetrical blades and the method of making them.
- the blades 400 of the low pressure turbine stage are all substantially identical to one another.
- Each blade has an airfoil 402 , a root (not shown) extended by a tang (not shown), an inner platform (not shown) situated between the tang and the airfoil, a portion forming a spoiler outer platform 414 , and a portion forming a wiper outer platform 416 .
- the airfoil 402 extends longitudinally between its root and its tip and in cross-section it presents a curved profile of varying thickness that defines two faces 418 and 420 , corresponding respectively to the suction side face and to the pressure side face of the airfoil, each connecting the leading edge 402 a to the trailing edge 402 b of the airfoil.
- the blade 400 is mounted on a turbine rotor (not shown) by engaging its root in a housing of complementary shape formed at the periphery of the rotor.
- the blade 402 is also connected at its radially outer end and via its suction side face 418 to the portion forming the spoiler outer platform 414 that defines the outside of the flow passage for the gas stream passing through the turbine. On this suction face 418 , the airfoil does not have a wiper outer platform portion. Similarly, on its pressure side face 420 , the airfoil 402 is connected at its radially outer end to the portion forming the wiper outer platform 416 and it does not have a portion forming a spoiler outer platform. In other words, each blade has a single portion extending from each of the faces 418 and 420 of its airfoil 402 .
- the blades 400 co-operate with one another in such a manner that the portion forming a wiper outer platform 416 takes up a position “above” the portion forming the spoiler outer platform 414 of the adjacent blade, defining a radial gap between these portions.
- a vibration damper 300 of the invention may be housed in this gap (the damper being strictly identical to that described with reference to FIGS. 1 to 4 , and 5 A to 5 C).
- each vibration damper is arranged more precisely between the outside surface 414 a of the portion forming the spoiler outer platform 414 of one blade (constituting an inner bearing surface of the rotor in the meaning of the invention) and the inside surface 416 a of the portion forming the wiper outer platform 416 of the adjacent blade (constituting an outer bearing surface of the rotor in the meaning of the invention).
- the free end 306 of the first plate portion comes to bear radially against the outside surface 414 a of the portion forming the spoiler outer platform 414 of one blade and under the effect of centrifugal force when the rotor is rotating, the fold line 302 of the plate comes to bear radially against the inside surface 416 a of the portion forming the wiper outer platform 416 of the adjacent blade.
- This vibration damper dissipates vibratory energy and provides sealing in the same manner as that described for the above embodiment, and that is not described again.
- the vibration damper 300 has two holder tabs 308 that pass through orifices 418 pierced in the wiper portion of the outer platform 416 of the corresponding blade in order to hold the plate between the two bearing surfaces when the rotor disk is stopped.
- a vibration damper 300 ′ in another embodiment of the invention that is designed to be received at the level of the inner platforms of the rotor blades, these blades possibly being blades of complementary shapes (of the even-odd or asymmetrical type) as described above or blades of the kind commonly used in the field of gas turbine engines.
- FIGS. 9 and 10 show part of a rotor disk 12 and two blades 500 mounted adjacent to each other on the disk by having their roots 504 engaged in housings 14 of complementary shape arranged in the periphery of the disk.
- Each blade 500 includes in particular an airfoil 502 , a root 504 extended by a tang 506 , and an inner platform 508 situated between the tang and the airfoil.
- the vibration damper 300 ′ comprises a plate, e.g. made of metal and of substantially rectangular general shape, which plate is disposed between the outside surface 12 a of the rotor disk 12 (forming an inner bearing surface of the rotor in the meaning of the invention) and the inside surface 508 a of the inner platforms 508 of the two blades (forming an outer bearing surface of the rotor in the meaning of the invention). Circumferentially, the damper plates extends between the two blade platforms 508 .
- the plate is folded in a junction zone formed by a fold line 302 ′ so as to form two plate portions that are inclined relative to each other, namely a first portion 304 ′ a and a second portion 304 ′ b .
- the free end 306 ′ of the first portion 304 ′ a of the plate comes to bear radially against the outside surface 12 a of the rotor disk 12 .
- the mass of the plate is distributed in such a manner that its center of gravity (represented by the point G in FIG. 9 ) is situated on the side of the second portion 304 ′ b of the plate.
- Such permanent contact of the plate against the inner and outer bearing surfaces serves firstly to ensure that the vibratory energy associated with the rotation of the disk is dissipated by friction, and secondly provides sealing relative to the gas flowing through the turbine (preventing the gas from penetrating from the flow passage between the platforms of the blades).
- the vibration damper 300 ′ does not have any holder tabs.
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- Turbine Rotor Nozzle Sealing (AREA)
Abstract
Description
- The present invention relates to the general field of damping the vibration that appears in operation between the outer platforms of two adjacent rotor blades in a gas turbine engine.
- A rotor of a gas turbine engine, such as a rotary wheel of a low pressure turbine stage in a turbojet, for example, comprises a disk having a plurality of blades mounted thereon. At its free radial end, each blade presents a transverse element referred to as an “outer platform” that serves in particular to define the outside of the flow passage for the gas stream passing through the turbine.
- The outer platform of such a blade has an upstream edge and a downstream edge, which edges extend perpendicularly to the flow direction of the gas stream. These edges are connected together via two lateral edges whereby the outer platform of a blade comes into contact with the outer platforms of two blades of the rotor wheel that are directly adjacent thereto.
- Generally, with metal blades, these lateral edges, present a so-called “Z” profile, i.e. each of them has two axial portions that are connected together by a substantially transverse portion. In order to damp the vibration to which the blades are subjected while the turbine is in operation, it is known to mount the blades on the disk with pre-stress in twisting about their respective main axes. At the outer platform of any particular blade, this twist gives rise to the transverse portions of the outer platform of the blade being pressed against the transverse portions of the outer platforms of the adjacent blades. The contact and friction forces that are generated in this way between the outer platforms of the blades serve to dissipate the vibratory energy that results from operation of the turbine.
- Nevertheless, such vibration damping is not applicable to rotors having blades that are made of composite material. Specifically, when using ceramic matrix composite (CMC) material blades, twisting the blades generates stresses that are too high compared with the strength of the composite material. Furthermore, using blades made of composite material also has the drawback of giving rise to large steps or large amounts of clearance between the outer platforms of adjacent blades in the event of the blades tilting relative to one another.
- A main object of the present invention is thus to mitigate such drawbacks by proposing effective damping of the vibration between the outer platforms of adjacent blades made of composite material and without generating excessive stress in the blades.
- This object is achieved by a vibration damper for a rotor blade of a gas turbine engine, the damper comprising a plate for placing between an inner bearing surface and an outer bearing surface of the rotor, the bearing surfaces extending in directions that are substantially axial and being radially spaced apart from each other, the plate being folded so as to form two plate portions that are inclined relative to each other, the mass of the plate being distributed in such a manner that its center of gravity is situated on the side of one of these plate portions, the free end of the other plate portion being designed to bear radially against the inner bearing surface, and the junction zone between the two plate portions being designed to bear radially against the outer bearing surface under the effect of centrifugal force when the rotor is rotating, thereby providing axial sealing against gas.
- In operation, under the effect of centrifugal force when the rotor is rotating, the junction zone between the two portions of the damper plate comes to bear against the under side of the outer bearing surface of the rotor. Given the particular distribution of mass in the plate, this centrifugal force then creates a lever arm between the center of gravity of the plate and its free end that is bearing radially against the inner bearing surface. In operation, this lever arm thus ensures permanent contact of the plate against both the inner and the outer bearing surfaces, in particular in the event of large steps or large amounts of clearance between the outer platforms of the blades, thereby providing axial sealing against gas. Furthermore, in operation, the junction zone between the two plate portions rubs against the outer bearing surface of the rotor. This friction serves to dissipate the vibratory energy associated with rotation of the rotor. No stress is applied to the blades in order to obtain such energy dissipation. This serves to increase the lifetime of the blades.
- Advantageously, the damper further includes means for holding the plate between the two bearing surfaces of the rotor when the rotor is stopped. For this purpose, the plate may include at least one holder tab that extends in a direction that is substantially inclined relative to the radial direction and that is designed to pass through the outer bearing surface.
- The invention also provides a rotor element of a gas turbine engine, the element comprising first and second mutually adjacent blades, the first blade having, at a radially free end, a portion constituting a spoiler outer platform without a portion constituting a wiper outer platform, and the second blade having, at a radially free end, a portion constituting a wiper outer platform without a portion constituting a spoiler outer platform, and a vibration damper as defined above, with the plate thereof being arranged between the spoiler outer platform of the first blade forming an inner bearing surface and the wiper outer platform of the second blade forming an outer bearing surface.
- The invention also provides a rotor element of a gas turbine engine, the element comprising a pair of mutually adjacent blades, each comprising an airfoil presenting two faces, each connecting a leading edge to a trailing edge of the blade, each blade having a single portion extending from each of the faces of its airfoil, one of these portions forming a spoiler outer platform and the other portion forming a wiper outer platform, and a vibration damper as defined above, with the plate thereof being arranged between the spoiler outer platform of one of the blades forming an inner bearing surface and the wiper outer platform of the other blade forming an outer bearing surface.
- The mass of the damper plate may lie in the range 1% to 10%—and preferably lies in the range 4% to 6%—of the mass of a blade.
- The damper plate may be positioned between the bearing surfaces in such a manner that the portion having its free end bearing radially against the inner bearing surface is located on the upstream side. As a result, the plate, and more particularly its portion provided with the free end bearing against the inner bearing surface, serves to provide sealing against the gas passing through the gas turbine.
- The invention also provides a rotor element of a gas turbine engine, the element comprising a blade having an airfoil, a root for mounting in a disk of the rotor, and an inner platform situated between the root and the airfoil, and a vibration damper as defined above, with the plate thereof designed to be arranged between an outside surface of the disk forming an inner bearing surface and an inside surface of the platform of the blade forming an outer bearing surface.
- The invention also provides a gas turbine engine rotor having a plurality of rotor elements as defined above. Finally, the invention also provides a gas turbine engine including at least one such rotor.
- Other characteristics and advantages of the present invention appear from the following description made with reference to the accompanying drawings that show embodiments having no limiting character. In the figures:
-
FIGS. 1 and 2 are diagrams showing how a vibration damper of the invention is mounted between the outer platforms of two composite material blades having shapes that are complementary, of the “even-odd” type; -
FIGS. 3 and 4 are views of the outer platforms of the two blades ofFIG. 2 , respectively from upstream and from above; -
FIGS. 5A to 5C show how the damper moves in the event of radial clearance between the outer platforms of the blades; -
FIGS. 6 to 8 are diagrams showing how a vibration damper of the invention is implanted between the outer platforms of two composite material blades having complementary shapes of the “asymmetrical” type; and -
FIGS. 9 and 10 are diagrams showing how a vibration damper is implanted in another embodiment of the invention between the inner platforms of two adjacent blades. - The invention is applicable to various types of gas turbine engine blade, in particular to compressor blades and to turbine blades of various gas turbine spools, for example to rotor blades of a low pressure turbine stage in an aviation turbomachine, such as those shown in
FIGS. 1 to 4 . - In well-known manner, the
rotor 10 of a low pressure turbine stage of a turbomachine comprises a disk 12 (shown in part) having an axis of rotation X-X and with a plurality of blades mounted thereon. For reasons of simplification, only two blades are shown inFIGS. 1 and 2 . - The blades may be made of metal or they may be made of composite material, and in particular of ceramic matrix composite (CMC) material. The invention applies more particularly (but not exclusively) to composite material blades of the kind said to be of complementary shapes, of the “even-odd” blade type or of the “asymmetrical” blade type.
- In the embodiment of
FIGS. 1 and 2 , theblades patent application FR 10/55160 filed in the joint names of Snecma Propulsion Solide and Snecma describes the shape of such even-odd blades and the method of making them. - The
first blade 100 comprises anairfoil 102, aroot 104, e.g. having a section in the shape of a bulb extended by atang 106, aninner platform 108 situated between the tang and the airfoil, and a spoilerouter platform 110 situated in the vicinity of the free end of the airfoil. - The
airfoil 102 extends longitudinally between theinner platform 108 and theouter platform 110 and presents a curved profile in cross-section between its leadingedge 102 a and itstrailing edge 102 b. Thefirst blade 100 is mounted on therotor disk 12 by engaging itsroot 104 in ahousing 14 of complementary shape formed in the periphery of the disk. - At its radially outer end, the
airfoil 102 is connected to theouter platform 110 which defines the outside of the flow passage for the gas stream passing through the turbine. In its upstream and downstream end portions (upstream and downstream relative to the flow direction of the gas stream), theouter platform 110 terminates withoverlap spoilers 112. Furthermore, it should be observed that the first blade does not have wipers on its outer platform at its radially outer end. - The
second blade 200 is designed to co-operate with the above-describedfirst blade 100 so as to form an even-odd type pair of blades. - The
second blade 200 comprises anairfoil 202, aroot 204 extended by atang 206, aninner platform 208 situated between the tang and the airfoil, and anouter platform 210 having wipers situated in the vicinity of the free end of the airfoil. Theairfoil 202 extends longitudinally between theinner platform 208 and theouter platform 210 with wipers and presents in cross-section a curved profile between its leadingedge 202 a and itstrailing edge 202 b. Thesecond blade 200 is mounted on therotor disk 12 by engaging itsroot 204 in ahousing 14 of complementary shape formed in the periphery of the disk. Furthermore, it should be observed that this second blade does not have an outer platform with spoilers at its radially outer end. - As shown in
FIG. 2 , when the first andsecond blades rotor disk 12, a portion of the wiperouter platform 210 of thesecond blade 200 takes up a position “above” a portion of the spoiler outer platform withspoilers 110 of thefirst blade 100. - Furthermore, as shown in
FIG. 5A , theinside surface 210 a of this portion of the wiper outer platform faces theoutside surface 110 a of said portion of the spoiler outer platform. It should be observed that this insidesurface 210 a andoutside surface 110 a extend in directions that are substantially axial and that are radially spaced apart from each other by a gap e. - In operation, the
blades vibration dampers 300 between the outer platforms of a pair ofblades FIGS. 3 and 4 ). - The
vibration damper 300 of the invention comprises a plate, e.g. made of metal and of substantially rectangular general shape, which plate is positioned between theoutside surface 110 a of the spoilerouter platform 110 of the first blade (forming the inner bearing surface of the rotor in the meaning of the invention) and theinside surface 210 a of the wiperouter platform 210 of the second blade (forming the outer bearing surface of the rotor in the meaning of the invention). - This plate is folded so as to form two plate portions that are inclined relative to each other, namely a
first portion 304 a and asecond portion 304 b. More precisely, thefirst portion 304 a of the plate is arranged on the upstream side (upstream relative to the flow direction of the gas stream) and thesecond portion 304 b is positioned on the downstream side. - The junction zone between the two
plate portions fold line 302, as shown inFIGS. 1 , 5A to 5C, and 6. Nevertheless, this junction zone could alternatively be constituted by one or more points. - Furthermore, as shown in
FIG. 5A , thefree end 306 of thefirst portion 304 a of the plate comes to bear radially against theoutside surface 110 a of the spoilerouter platform 110 of the first blade. - Another feature of the vibration damper of the invention is that the mass of the plate is distributed in such a manner that its center of gravity (represented by point G in
FIG. 5A ) is situated on the side of thesecond portion 304 b of the plate. - As a result, under the effect of centrifugal force when the disk is rotating, the
fold line 302 of the plate comes to press under theinside surface 210 a of the wiperouter platform 210 of the second blade. Given the particular distribution of the mass of the plate, this centrifugal force creates a lever arm between the center of gravity G of the plate and thefree end 306 of thefirst portion 304 a of the plate, which is bearing radially against theoutside surface 110 a of the spoiler outer platform of the first blade. In operation, this lever arm thus ensures permanent contact of the plate against the inner and outer bearing surfaces. - Such permanent contact of the plate against the inner and outer bearing surfaces serves firstly to dissipate by friction the vibratory energy associated with the disk rotating, and secondly to provide sealing relative to the gas flowing through the turbine (by preventing the gas from penetrating from upstream between the outer platforms of the blades).
- Furthermore, as shown in
FIGS. 5B and 5C , the particular shape of the vibration damper of the invention adapts well to radial clearances appearing between the outer platforms of adjacent blades (as can happen as a result of the blades tilting relative to one another). - In these figures, the respective
outer platforms FIG. 5A , the gap e2 being the greatest that the damper can accommodate. In these figures, it can be seen that regardless of the gap between theouter platforms free end 306 of thefirst portion 304 a of the plate and thefold line 302 of the plate always remain in contact with their respective bearing surfaces. As a result, the damper functions of dissipating vibratory energy and of providing sealing continue to be performed even in the event of a large amount of radial clearance between the outer platforms. - The vibration damper possesses mass that lies in the range 1% to 10%—and preferably in the range 4% to 6%—of the mass of the
blades - The vibration damper of
FIGS. 1 to 4 also has means for holding theplate 300 between the wiperouter platform 210 of the second blade and the spoilerouter platform 110 of the first blade. - To this end, the
plate 300 has at least one—and preferably two—holder tabs 308 that extend in a direction that is substantially inclined relative to the radial direction and that serve to pass throughorifices 212 pierced through the wiperouter platform 210 of the second blade. More precisely, theseholder tabs 308 are secured to thesecond portion 304 b of the plate. As a result, when the rotor disk stops, these holder tabs serve to prevent the vibration damper escaping from its position between the outer platforms of the blades. -
FIGS. 6 to 8 are diagrams showing how an above-describedvibration damper 300 is installed relative to blades presenting complementary shapes of the “asymmetrical” blade type. -
Patent application FR 10/55161 filed jointly in the names of Snecma Propulsion Solide and Snecma describes the shape of such assymmetrical blades and the method of making them. - The
blades 400 of the low pressure turbine stage are all substantially identical to one another. Each blade has anairfoil 402, a root (not shown) extended by a tang (not shown), an inner platform (not shown) situated between the tang and the airfoil, a portion forming a spoilerouter platform 414, and a portion forming a wiperouter platform 416. - The
airfoil 402 extends longitudinally between its root and its tip and in cross-section it presents a curved profile of varying thickness that defines twofaces leading edge 402 a to the trailingedge 402 b of the airfoil. Theblade 400 is mounted on a turbine rotor (not shown) by engaging its root in a housing of complementary shape formed at the periphery of the rotor. - The
blade 402 is also connected at its radially outer end and via itssuction side face 418 to the portion forming the spoilerouter platform 414 that defines the outside of the flow passage for the gas stream passing through the turbine. On thissuction face 418, the airfoil does not have a wiper outer platform portion. Similarly, on itspressure side face 420, theairfoil 402 is connected at its radially outer end to the portion forming the wiperouter platform 416 and it does not have a portion forming a spoiler outer platform. In other words, each blade has a single portion extending from each of thefaces airfoil 402. - As shown in
FIGS. 7 and 8 , when they are mounted side by side on a rotor disk, theblades 400 co-operate with one another in such a manner that the portion forming a wiperouter platform 416 takes up a position “above” the portion forming the spoilerouter platform 414 of the adjacent blade, defining a radial gap between these portions. - A
vibration damper 300 of the invention may be housed in this gap (the damper being strictly identical to that described with reference toFIGS. 1 to 4 , and 5A to 5C). - The plate of each vibration damper is arranged more precisely between the
outside surface 414 a of the portion forming the spoilerouter platform 414 of one blade (constituting an inner bearing surface of the rotor in the meaning of the invention) and theinside surface 416 a of the portion forming the wiperouter platform 416 of the adjacent blade (constituting an outer bearing surface of the rotor in the meaning of the invention). - In this position, the
free end 306 of the first plate portion comes to bear radially against theoutside surface 414 a of the portion forming the spoilerouter platform 414 of one blade and under the effect of centrifugal force when the rotor is rotating, thefold line 302 of the plate comes to bear radially against theinside surface 416 a of the portion forming the wiperouter platform 416 of the adjacent blade. - This vibration damper dissipates vibratory energy and provides sealing in the same manner as that described for the above embodiment, and that is not described again.
- It should be observed that the
vibration damper 300 has twoholder tabs 308 that pass throughorifices 418 pierced in the wiper portion of theouter platform 416 of the corresponding blade in order to hold the plate between the two bearing surfaces when the rotor disk is stopped. - With reference to
FIGS. 9 and 10 , there follows a description of avibration damper 300′ in another embodiment of the invention that is designed to be received at the level of the inner platforms of the rotor blades, these blades possibly being blades of complementary shapes (of the even-odd or asymmetrical type) as described above or blades of the kind commonly used in the field of gas turbine engines. -
FIGS. 9 and 10 show part of arotor disk 12 and twoblades 500 mounted adjacent to each other on the disk by having theirroots 504 engaged inhousings 14 of complementary shape arranged in the periphery of the disk. Eachblade 500 includes in particular anairfoil 502, aroot 504 extended by atang 506, and aninner platform 508 situated between the tang and the airfoil. - The
vibration damper 300′ comprises a plate, e.g. made of metal and of substantially rectangular general shape, which plate is disposed between theoutside surface 12 a of the rotor disk 12 (forming an inner bearing surface of the rotor in the meaning of the invention) and theinside surface 508 a of theinner platforms 508 of the two blades (forming an outer bearing surface of the rotor in the meaning of the invention). Circumferentially, the damper plates extends between the twoblade platforms 508. - As in the preceding embodiment, the plate is folded in a junction zone formed by a
fold line 302′ so as to form two plate portions that are inclined relative to each other, namely a first portion 304′a and a second portion 304′b. Thefree end 306′ of the first portion 304′a of the plate (arranged on the upstream side) comes to bear radially against theoutside surface 12 a of therotor disk 12. Furthermore, the mass of the plate is distributed in such a manner that its center of gravity (represented by the point G inFIG. 9 ) is situated on the side of the second portion 304′b of the plate. - As a result, under the effect of centrifugal force when the disk is rotating, the
fold line 302′ of the plate comes to bear against theinside surface 508 a of theinner platforms 508 of the two blades. Given the particular distribution of mass in the plate, this centrifugal force creates a lever arm between the center of gravity G of the plate and thefree end 306′ of the first portion 304′a of the plate that is bearing radially, thereby ensuring permanent contact in operation of the plate against the inner and outer bearing surfaces. - Such permanent contact of the plate against the inner and outer bearing surfaces serves firstly to ensure that the vibratory energy associated with the rotation of the disk is dissipated by friction, and secondly provides sealing relative to the gas flowing through the turbine (preventing the gas from penetrating from the flow passage between the platforms of the blades).
- Compared with the other embodiments described with reference to
FIGS. 1 to 4 , thevibration damper 300′ does not have any holder tabs.
Claims (12)
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
FR1055673A FR2962481B1 (en) | 2010-07-12 | 2010-07-12 | VIBRATION DAMPER WITH LEVER ARM FOR A ROTOR OF A GAS TURBINE ENGINE |
FR1055673 | 2010-07-12 |
Publications (1)
Publication Number | Publication Date |
---|---|
US20120063904A1 true US20120063904A1 (en) | 2012-03-15 |
Family
ID=43768723
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US13/179,860 Abandoned US20120063904A1 (en) | 2010-07-12 | 2011-07-11 | Lever-arm vibration damper for a rotor of a gas turbine engine |
Country Status (2)
Country | Link |
---|---|
US (1) | US20120063904A1 (en) |
FR (1) | FR2962481B1 (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20150369075A1 (en) * | 2012-12-13 | 2015-12-24 | Mitsubishi Hitachi Power Systems, Ltd. | Rotating fluid machine |
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US2310412A (en) * | 1941-03-08 | 1943-02-09 | Westinghouse Electric & Mfg Co | Vibration dampener |
US2315611A (en) * | 1942-02-14 | 1943-04-06 | Westinghouse Electric & Mfg Co | Turbine blade shroud fastening |
US4177013A (en) * | 1977-01-11 | 1979-12-04 | Rolls-Royce Limited | Compressor rotor stage |
US4494909A (en) * | 1981-12-03 | 1985-01-22 | S.N.E.C.M.A. | Damping device for turbojet engine fan blades |
US5156528A (en) * | 1991-04-19 | 1992-10-20 | General Electric Company | Vibration damping of gas turbine engine buckets |
US5746578A (en) * | 1996-10-11 | 1998-05-05 | General Electric Company | Retention system for bar-type damper of rotor |
US6371727B1 (en) * | 2000-06-05 | 2002-04-16 | The Boeing Company | Turbine blade tip shroud enclosed friction damper |
US6450769B2 (en) * | 2000-03-22 | 2002-09-17 | Alstom (Switzerland) Ltd | Blade assembly with damping elements |
US6821087B2 (en) * | 2002-01-21 | 2004-11-23 | Honda Giken Kogyo Kabushiki Kaisha | Flow-rectifying member and its unit and method for producing flow-rectifying member |
US7291946B2 (en) * | 2003-01-27 | 2007-11-06 | United Technologies Corporation | Damper for stator assembly |
US20100028135A1 (en) * | 2008-08-01 | 2010-02-04 | Rolls-Royce Plc | Vibration damper |
Family Cites Families (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5281097A (en) * | 1992-11-20 | 1994-01-25 | General Electric Company | Thermal control damper for turbine rotors |
US5522705A (en) * | 1994-05-13 | 1996-06-04 | United Technologies Corporation | Friction damper for gas turbine engine blades |
FR2915510B1 (en) * | 2007-04-27 | 2009-11-06 | Snecma Sa | SHOCK ABSORBER FOR TURBOMACHINE BLADES |
-
2010
- 2010-07-12 FR FR1055673A patent/FR2962481B1/en active Active
-
2011
- 2011-07-11 US US13/179,860 patent/US20120063904A1/en not_active Abandoned
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Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2310412A (en) * | 1941-03-08 | 1943-02-09 | Westinghouse Electric & Mfg Co | Vibration dampener |
US2315611A (en) * | 1942-02-14 | 1943-04-06 | Westinghouse Electric & Mfg Co | Turbine blade shroud fastening |
US4177013A (en) * | 1977-01-11 | 1979-12-04 | Rolls-Royce Limited | Compressor rotor stage |
US4494909A (en) * | 1981-12-03 | 1985-01-22 | S.N.E.C.M.A. | Damping device for turbojet engine fan blades |
US5156528A (en) * | 1991-04-19 | 1992-10-20 | General Electric Company | Vibration damping of gas turbine engine buckets |
US5746578A (en) * | 1996-10-11 | 1998-05-05 | General Electric Company | Retention system for bar-type damper of rotor |
US6450769B2 (en) * | 2000-03-22 | 2002-09-17 | Alstom (Switzerland) Ltd | Blade assembly with damping elements |
US6371727B1 (en) * | 2000-06-05 | 2002-04-16 | The Boeing Company | Turbine blade tip shroud enclosed friction damper |
US6821087B2 (en) * | 2002-01-21 | 2004-11-23 | Honda Giken Kogyo Kabushiki Kaisha | Flow-rectifying member and its unit and method for producing flow-rectifying member |
US7291946B2 (en) * | 2003-01-27 | 2007-11-06 | United Technologies Corporation | Damper for stator assembly |
US20100028135A1 (en) * | 2008-08-01 | 2010-02-04 | Rolls-Royce Plc | Vibration damper |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20150369075A1 (en) * | 2012-12-13 | 2015-12-24 | Mitsubishi Hitachi Power Systems, Ltd. | Rotating fluid machine |
US9995164B2 (en) * | 2012-12-13 | 2018-06-12 | Mitsubishi Hitachi Power Systems, Ltd. | Rotating fluid machine |
Also Published As
Publication number | Publication date |
---|---|
FR2962481B1 (en) | 2012-08-31 |
FR2962481A1 (en) | 2012-01-13 |
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