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
  • F01D25/00—Component parts, details, or accessories, not provided for in, or of interest apart from, other groups
  • F01D25/04—Antivibration arrangements
• • 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
  • F05D2220/00—Application
  • F05D2220/30—Application in turbines
• • 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
  • F05D2220/00—Application
  • F05D2220/30—Application in turbines
  • F05D2220/36—Application in turbines specially adapted for the fan of turbofan engines
• • 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
  • F05D2230/00—Manufacture
  • F05D2230/60—Assembly methods
• • 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
  • F05D2260/00—Function
  • F05D2260/96—Preventing, counteracting or reducing vibration or noise

Definitions

• the invention relates to an assembly comprising a turbomachine rotor module.
• the invention more specifically relates to a turbomachine assembly comprising two rotor modules and a damping device.
• a turbomachine rotor module generally comprises one or more stages, each stage comprising a disc centered on a longitudinal axis of a turbomachine, corresponding to the axis of rotation of the rotor module.
• the rotation of the disc is generally provided by a rotary shaft to which it is integrally connected, for example by means of a rotor module journal, the rotary shaft extending along the longitudinal axis of the turbomachine.
• Blades are mounted at the outer periphery of the disc and distributed circumferentially evenly about the longitudinal axis.
• Each blade extends from the disc, and further includes a blade, a platform, a stilt and a foot. The foot is embedded in a housing of the disk configured for this purpose, the blade is scanned by a flow through the turbomachine, and the platform forms a portion of the inner surface of the flow stream.
• the operating range of a rotor module is limited, in particular because of aeroelastic phenomena.
• the modern turbine engine rotor modules which have a high aerodynamic load, and a small number of blades, are more sensitive to this type of phenomena. In particular, they have reduced margins between the zones of operation without instability and the unstable zones. It is nevertheless imperative to guarantee a sufficient margin between the stability domain and that of the instability, or to demonstrate that the rotor module can operate in the instability zone without exceeding its endurance limit. This ensures a safe operation throughout the life and the entire operating range of the turbomachine.
• Operation in the instability zone is characterized by coupling between the fluid and the structure, the fluid supplying energy to the structure, and the structure responding on its own modes to levels that can exceed the endurance limit of the material constituting the blade. This generates vibratory instabilities that accelerate the wear of the rotor module, and reduce its life.
• An object of the invention is to dampen the zero-phase vibration modes for all types of turbomachine rotor modules. Another object of the invention is to influence the damping of non-zero phase-shift vibration modes, for all types of turbomachine rotor modules.
• Another object of the invention is to provide a damping solution that is simple and easy to implement.
• the invention proposes in particular an assembly for a turbomachine comprising:
• a first rotor module comprising a first blade
• a second rotor module connected to the first rotor module, and comprising a second blade of shorter length than the first blade
• a damping device extending along at least one component along a longitudinal axis of a turbomachine, characterized in that the damping device is annular extending circumferentially around the longitudinal axis of the turbomachine, and in that the damping device comprises a first outer radial surface bearing frictionally against the first module and a second outer radial surface bearing frictionally against the second module, so as to couple the modules to dampen their respective vibratory movements in operation.
• the mechanical coupling between the first and second rotor modules makes it possible to increase the tangential stiffness of the connection between these two rotors, while allowing a certain axial and radial flexibility of the damping device in order to maximize the contact between the various elements of the rotor. together. This makes it possible to limit the instabilities related to the zero phase phase vibration mode, but also to participate in the damping of non-zero phase shift vibration modes.
• such an assembly has the advantage of easy integration within existing turbomachines, whether during manufacture or during maintenance. Indeed, the annular nature of the damping device reduces its bulk between the two motor modules.
• the damping device is an annular tongue, the section of which is V-shaped, an outer surface of a first branch of the V forming the first outer radial surface bearing frictionally against the first rotor module, an outer surface of a second branch of the V forming the second outer radial surface abutting against the second rotor module,
• the first rotor module comprises a disk centered on the longitudinal axis of a turbomachine, the first blade being mounted on the outer periphery of the disk from which it extends, and further comprising a blade, a platform, a stilt and an embedded foot; in a disk slot, and
• the second module comprises a ferrule comprising a circumferential extension extending towards the platform of the first blade
• the first radial outer surface of the damping device being in abutment with friction on a radially inner surface of the platform of the first blade, the second radial outer surface of the damping device being in abutment with friction on the ferrule,
• a fixing ferrule is shrunk on the circumferential extension, the second outer radial surface of the damping device being in abutment with friction on the fixing ferrule,
• the extension carries radial sealing lip, the second radial outer surface of the damping device being in frictional abutment on the sealing lips,
• the bearing surfaces of the damping device and the surfaces of the platform and the radial sealing lips are treated, for example by a carbon-carbon deposit, so as to guarantee their respective supports,
• the damping device comprises a dissipative-type coating, defining the bearing surfaces,
• the damping device comprises a viscoelastic type coating
• the damping device comprises bores intended to lighten the damping device
• the damping device comprises inserts, for example of the type metal, intended to weigh down the damping device,
• the first module is a blower
• the second module is a compressor, for example a low-pressure compressor
• the damping device is slotted so as to define two ends facing one another.
• the invention also relates to a turbomachine comprising an assembly as previously described.
• the invention furthermore relates to an annular damping device extending circumferentially around a longitudinal axis of a turbomachine, and comprising a first external radial surface configured to bear frictionally against a first rotor module and a second radial surface. external configuration configured to bear against a second rotor module of an assembly as described above, so as to couple the modules in order to damp their respective vibratory movements during operation.
• the invention finally relates to a method of mounting an assembly as previously described, comprising the steps of:
• FIG. 1 is a diagrammatic sectional view of an exemplary embodiment of the assembly according to the invention
• FIG. 2 is a front view of a rotor module subjected to tangential vibrations whose bending mode is out of phase
• FIG. 3a schematically illustrates tangential displacements of turbomachine rotor modules, as a function of the position of said modules along a turbomachine axis;
• FIG. 3b is a diagrammatic perspective enlargement of the interface between two turbomachine rotor modules illustrating its relative tangential displacements of said rotor modules
• FIG. 4 schematically illustrates a first exemplary embodiment of a damping device according to the invention
• FIG. 5 schematically illustrates an enlargement of a second exemplary embodiment of a damping device according to the invention
• FIG. 6 schematically illustrates a portion of another embodiment of an assembly according to the invention.
• FIG. 7 is a flowchart detailing an embodiment of a mounting method according to the invention.
• the upstream and downstream are defined with respect to the direction of normal flow of air through the turbomachine.
• a longitudinal axis XX of a turbomachine is defined.
• the axial direction corresponds to the direction of the longitudinal axis XX of a turbomachine
• a radial direction is a direction which is perpendicular to this longitudinal axis XX of the turbomachine and which passes through said longitudinal axis XX of a turbomachine
• a direction circumferential corresponds to the direction of a flat and closed curved line, all points of which are equidistant from the longitudinal axis XX of a turbomachine.
• inner (or inner) and outer (or outer) are used with reference to a radial direction so that the inner portion or face (ie radially inner) an element is closer to the longitudinal axis XX of the turbomachine than the part or the outer face (ie radially outer) of the same element.
• such an assembly 1 comprises:
• a first rotor module 2 comprising a first blade 20
• a second rotor module 3 connected to the first rotor module 2, and comprising a second blade 30 of shorter length than the first blade 20, and
• a damping device 4 which extends along at least one component which is along a longitudinal axis X-X turbomachine.
• the damping device 4 is annular extending circumferentially about a longitudinal axis XX of a turbomachine, and comprises a first radial outer surface 40 bearing frictionally against the first module 2 and a second radial outer surface 42 in frictional abutment against the second module 3, so as to couple the modules 2, 3 to dampen their respective vibratory movements in operation.
• the first rotor module is a fan 2
• the second rotor module is a low-pressure compressor 3 located immediately downstream of the fan 2.
• the blower 2 and the low-pressure compressor 3 comprise a disk 21, 31 centered on a longitudinal axis XX of a turbomachine, the first 20 and the second blade 30 being respectively mounted at the outer periphery of the disk 21, 31, and further comprising a blade 23, 33, a platform 25, a stag 27, 37 and a foot 29, 39 recessed in a housing 210, 310 of the disc 21, 31.
• the distance separating the foot 29, 39 from the end of the blade 23, 33 constitute the respective lengths of the first 20 and the second blade 30.
• the length of the first blade 20 and second blade 30 is here considered substantially radially. relative to the longitudinal axis XX of rotation of the rotor modules 2, 3.
• blower 2 and low-pressure compressor 3 comprise a plurality of blades 20, 30 distributed circumferentially about the longitudinal axis XX.
• the low pressure compressor 3 further comprises an annular ferrule 32 also centered on the longitudinal axis XX.
• the ferrule 32 comprises a circumferential extension 34, also annular, extending towards the platform 25 of the first blade 20. This annular extension 34 carries radial sealing strips 36 configured to prevent losses of air flow from the stream vein 5.
• ferrule 32 is fixed to the fan disc 21 by means of fasteners 22 distributed circumferentially around the longitudinal axis XX.
• fasteners 22 may for example be bolted connections 22.
• fasteners 22 may be made by hooping which is associated with an anti-rotation device and / or an axial locking system.
• the assembly formed of the fan 2 and the compressor 3 is rotated by a rotary shaft 6, called a low-pressure shaft, to which the fan 2 and the low-pressure compressor 3 are integrally connected, by means of a rotor journal 60, the low-pressure shaft 6 being also connected to a low-pressure turbine 7, downstream of the turbomachine, and extending along the longitudinal axis XX of a turbomachine.
• the fan 2 draws air, all or part of which is compressed by the low-pressure compressor 3.
• the compressed air then circulates in a high-pressure compressor (not shown) before being mixed with fuel and then ignited within the combustion chamber (not shown), to finally be successively expanded in the upper turbine (not shown) and the low pressure turbine 7.
• the opposing compression forces upstream, and relaxation downstream give rise to aeroelastic floating phenomena, which couple the aerodynamic forces on the blades 20, 30, and the vibration movements in flexion and torsion in the blades 20, 30. As illustrated in FIG. 2, this floating causes in particular intense torsional torsional forces of the tree low pressure 6 which are reflected in the blower 2 and the low-pressure compressor 3.
• the blades 20, 30 are then subjected to tangential beats, in particular in a zero-phase vibration mode. It is indeed a bending mode with an inter-blade phase shift 20, zero zero, involving a non-zero moment on the low pressure shaft 6, whose natural frequency is about one and a half times greater than that of first harmonic vibration, and whose deformation has a nodal line at mid-height of the blade 20, 30.
• Such vibrations limit the mechanical strength of the fan 2 and the low-pressure compressor 30, accelerate the wear of the turbomachine , and decreases its life.
• the tangential floating displacement of the fan blade 2 is different from that of the low-pressure compressor shell 3.
• the length of the fan blades 2 being greater than that of the 3, the tangential bending moment driven by the blower vane beats 2 is much greater than that caused by the vane beats 30 of the low pressure compressor 3.
• the stiffness of assembly within the blower 2 is different from that of mounting within the compressor 3. With reference to FIG. 3b, this difference in tangential beats is notably visible at the interface between the platform 25 of a fan blade 20, and sealing lugs 36 of ferrule 32.
• the damping device 4 is housed under the platform 25 of a fan blade 20, between the stilt 27 and the shell 32 of the low-pressure compressor 3.
• the low-pressure compressor 3 comprises an annular fixing ferrule 38, shrunk onto the circumferential extension 34 of ferrule 32 of low-pressure compressor 3.
• the fixing ferrule 38 can be assembled to the circumferential extension 34 of ferrule 32 by via fasteners such as those provided by radial fingers (not shown) belonging to said fixing ferrule 38 and screwed to said extension 34.
• the wipers 36 comprise, in the traditional manner, substantially radial free ends for sealing against a stator.
• the wipers 36 comprise an annular root which connects these ends to the circumferential extension 34 of ferrule 32.
• the first outer radial surface 40 is supported with friction against the blower 2 at the inner surface 250 of the platform 25 of the fan blade 20 2, and the second radial outer surface 42 is frictionally supported on the fixing ferrule 38.
• This ensures a tangential coupling of significant stiffness between blower 2 and low pressure compressor 3, so as to reduce the tangential vibrations described above.
• Coupling is also important as the area within which the damping device 4 is disposed has the highest relative tangential displacements for zero phase shift mode considered, as shown in Figures 3a and 3b. Typically, these relative displacements are of the order of a few millimeters.
• the damping device 4 also advantageously retains an efficiency on the vibratory modes of the fan blades 2 with non-zero phase shift.
• the damping device 4 is an annular tongue, whose section is V-shaped.
• the radially outer surface 40 of the first leg 41 of the V forming the first surface 40 in support with friction against the blower 2, the outer surface 42 of the second leg 43 of the V forming the second outer radial surface 42 bears against the low-pressure compressor 3.
• the tongue structure advantageously makes it possible to reduce the space requirement of the damping device 4, within the set 1.
• the V-shaped structure makes it possible to increase the contact area between the blower 2 and the damping device 4 on the one hand, and between the damping device 4 and the low-pressure compressor 3 on the other hand. This configuration thus favors the coupling between these two rotors elements, in order to dampen their vibratory movements.
• the annular tongue 4 does not constitute a ring in one piece, but is slotted so as to define two ends 44, 46 facing one another.
• the mechanical stresses in operation are such that slight tangential, axial and radial movements of the damping device 4 are to be expected. These movements are due in particular to the tangential beats to be damped, but also to the centrifugal loading of the assembly 1. It is necessary that these movements do not wear the blades 20 or the shell 32, whose coatings are relatively fragile.
• the bearing surfaces 40, 42 of the damping device can be treated by dry lubrication, in order to perpetuate the value of the coefficient of friction between damping device 4 and low-pressure compressor 3 and / or blade platform 20. This lubrication is for example of MoS2 type.
• the damping device 4 comprises, in a second embodiment, an additional coating 48, 49, as can be seen in FIG. 5, defining the bearing surfaces 40, 42.
• a coating 48, 49 is configured to reduce the friction and / or the wear of the engine parts between the damping device 4 and the rotor modules 2, 3.
• This coating 48, 49 is for example dissipative type 48 and / or viscoelastic and / or damping.
• the dissipative coating 48 then comprises a material chosen from those having mechanical properties similar to those of vespel, teflon or any other material with lubricating properties. More generally, the material has a coefficient of friction of between 0.3 and 0.07.
• the friction coating 48 is an effective alternative to the dry lubrication treatment, which requires to be implemented regularly.
• this coating 48, 49 is of the viscoelastic type 49.
• a coating 49 then advantageously comprises a material having properties similar to those of a material such as those of the range having the trade name "SMACTANE®", for example a material of the type "SMACTANE® 70".
• Another way of increasing the tangential stiffness of the assembly 1 is to sufficiently preload the viscoelastic coating 44, for example during assembly of the assembly 1, so that the relative tangential displacement between blade 20 and ferrule 32 is transformed into shear. viscoelastic coating 44 alone.
• the damping by tangential coupling can be adjusted by controlling the mass of the damping device 4, which influences the shear inertia.
• This control passes through modifications of the mass of the damping device 4.
• This mass can be modified in all or part of the damping device 4, typically by practicing bores 45 for lightening, and / or adding one or more inserts 47, for example metal, to weigh down.
• the control of the mass of the damping device 4 allows to adjust its efficiency through the centrifugal forces it undergoes in operation.
• This detail of embodiment with bores and / or insert may correspond to a third embodiment.
• the combination of the second and the third embodiment makes it possible to adjust the contact forces between the damping device 4 and the fan 2 as well as the low-pressure compressor 3. In fact, too high contact forces between the dawn 20 of blower 2 and the damping device 4 limit the dissipation of vibrations in operation.
• the damping device 4 is an annular cylinder, whose section is diamond-shaped.
• the diamond-shaped section is indeed denser than the V-shaped section, which makes it possible to increase the mechanical coupling between the fan 2 and the low-pressure compressor 3, by promoting the tangential stiffness of the together 1.
• the first outer radial surface 40 bears against the blower 2 at the internal surface 250 of the platform 25 of the fan blade 20, and the second external radial surface 42 is also supported with friction on the radial sealing wipers 36.
• the bearing surfaces 40, 42 of the damping device 4, and the surfaces 250, 360 of the platform 25 and radial sealing wipers 36 are treated so as to guarantee their respective supports.
• the treatment consists of a carbon-carbon deposit which ensures a high coefficient of friction, while limiting the wear of the surfaces 250, 360 of the platform 25 and radial sealing lips 36. This support with friction is on the root of the wipers 36, that is to say at a distance from their free sealing ends.
• the cylinder 4 does not constitute a ring in one piece, but is slotted so as to define two ends facing one another.
• the damping device 4 comprises a dense material, preferably steel or a nickel-based alloy, so as to maximize the tangential stiffness of the coupling between the fan 2 and the low-pressure compressor 3.
• first rotor module 2 is a fan
• second rotor module 3 is a low pressure compressor
• first rotor module 2 can also be a first compressor stage, high or low pressure, and the second rotor module 3 a second stage of the compressor, successive to the first compressor stage, upstream or downstream from it.
• first rotor module 2 is a first turbine stage, high or low pressure, and the second rotor module 3 a second stage of said turbine, successive to the first turbine stage, upstream or downstream thereof.
• a first step E1 the damping device 4 is disposed between the first rotor module 2 and the second rotor module 3 so that a first radial outer surface 40 of the damping device 4 bears against the first module 2, and a second external radial surface 42 of the damping device 4 bears against the second module 3 with friction.
• the damping device 4 is prestressed against the first 2 and the second rotor module 3 so as to couple them in order to damp their respective vibratory movements in operation.
• Such a mounting method E is advantageously favored by the simple character resulting from the annular shape of the damping device 4.
• the damping device 4 is simply arranged within an assembly 1 already mounted, without requiring the adding links, for example bolted, which would increase both the mass of the assembly 1, and its assembly time and / or maintenance.

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

Applications Claiming Priority (3)

Publications (2)

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ID=65023923

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• 2018
  • 2018-12-18 CN CN201880087214.3A patent/CN111615584B/zh active Active
  • 2018-12-18 EP EP18833974.1A patent/EP3728794B1/de active Active
  • 2018-12-18 WO PCT/FR2018/053375 patent/WO2019122691A1/fr not_active Ceased
  • 2018-12-18 US US16/955,518 patent/US11536157B2/en active Active

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