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
  • F01D25/24—Casings; Casing parts, e.g. diaphragms, casing fastenings
• • 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
  • F01D11/122—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 erodable or abradable material
• • 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
  • F01D21/00—Shutting-down of machines or engines, e.g. in emergency; Regulating, controlling, or safety means not otherwise provided for
  • F01D21/003—Arrangements for testing or measuring
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
  • F04D27/00—Control, e.g. regulation, of pumps, pumping installations or pumping systems specially adapted for elastic fluids
  • F04D27/001—Testing thereof; Determination or simulation of flow characteristics; Stall or surge detection, e.g. condition monitoring
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
  • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
  • F04D29/00—Details, component parts, or accessories
  • F04D29/08—Sealings
  • F04D29/16—Sealings between pressure and suction sides
  • F04D29/161—Sealings between pressure and suction sides especially adapted for elastic fluid pumps
  • F04D29/164—Sealings between pressure and suction sides especially adapted for elastic fluid pumps of an axial flow wheel
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
  • G01B1/00—Measuring instruments characterised by the selection of material therefor
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
  • G01B7/00—Measuring arrangements characterised by the use of electric or magnetic techniques
  • G01B7/14—Measuring arrangements characterised by the use of electric or magnetic techniques for measuring distance or clearance between spaced objects or spaced apertures
• • 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 a stage of a turbomachine comprising a mobile wheel and game control means at the top of the blade.
• a turbomachine with a double flow comprises, from upstream to downstream, a fan at the outlet of which the flow of air is divided into a flow of primary air circulating inside a turbojet engine in a compressor, a combustion chamber and a turbine and a secondary air flow circulating around the turbojet engine.
• the blower is formed of a mobile wheel having a disk bearing on its outer periphery a plurality of blades evenly distributed around the axis of the disk.
• a housing surrounds the vanes externally.
• a coating of abradable material is carried by the inner surface of the fan casing and disposed at the blades of the fan.
• each boss comprising an orifice opening into and out of the housing for the insertion of a cylindrical capacitive type sensor engaged so that its inner face substantially flush with the inner surface of the housing.
• the inner surface of the casing facing the radially outer ends of the vanes is covered with abradable material with the exception of the zones bearing the sensors.
• a cavity is thus formed between the active face of each sensor and the radially outer ends of the blades. These cavities are necessary to avoid any contact between the radially outer ends of the blades and the sensors.
• the invention aims in particular to provide a simple, economical and effective solution to these various problems.
• a turbomachine stage comprising a movable wheel comprising a plurality of vanes surrounded externally by a housing bearing on its inner surface a layer of abradable material facing the free ends of the blades, characterized in that at least one planar blade clearance measurement sensor is carried by the internal surface of the housing and covered by the layer of abradable material.
• planar sensors do not require the production of bosses or holes in the housing, which makes it possible to improve the mechanical strength of the housing and to reduce the noise nuisance since the cavities facing the radially outer ends of the vanes are removed.
• the fouling of the sensors is also avoided since they are protected by the abradable material.
• the covering of the sensors by the layer of abradable material makes it possible to protect them against humidity.
• the planar sensor is a capacitive type sensor. It has a circular shape with a diameter of about 30 millimeters and a thickness of less than 1 millimeter.
• the senor is covered by a layer of about 5 to 7 millimeters of abradable.
• three aforementioned flat sensors are carried by the housing.
• a sensor is placed in a lateral position, the two other sensors being positioned symmetrically on the casing on either side of the first sensor
• These other two sensors can be placed in upper and lower position on the housing.
• the housing comprises at least one orifice for the passage of a connection cable to the sensor, this orifice being positioned axially outside the blade rotation zone, so as to avoid the addition of noise nuisance by the formation of air cavities in the axial zone of passage of the radially outer ends of the blades.
• the aforementioned orifice is formed upstream of the leading edge of the blades.
• the invention also relates to a blower or a compressor comprising at least one stage as described above.
• the invention also relates to a turbomachine, such as an aircraft turbojet, comprising at least one stage, a blower or a compressor equipped with blade tip clearance measuring sensors of the type described above.
• FIG. 1 is a schematic half-view in axial section of a fan of a turbojet engine
• FIG. 2 is a schematic axial sectional view of a sensor carried by the fan casing of Figure 1, in the prior art;
• FIG. 3 is a schematic representation of an exemplary embodiment of the invention.
• FIG. 4 is a front view of a planar sensor used in the example of FIG. 3.
• FIG. 1 shows a fan 10 of a shaft turbomachine 12, comprising a wheel formed of a disc 14 carrying at its periphery a plurality of blades 16 whose feet are engaged in grooves of the disc 14 and whose blades 18 extend radially outwards in the direction of a fan casing 20 carrying a nacelle 22 externally surrounding the vanes 16.
• the blower wheel is rotated about the axis 12 the turbomachine by a shaft 24 fixed by bolts 26 to a frustoconical wall 28 integral with the fan wheel.
• the shaft 24 is supported and guided by a bearing 30 which is carried by the upstream end of an annular support 32 attached downstream to an intermediate casing (not shown) disposed downstream of a low-pressure compressor 34 whose rotor 36 is secured to the blower wheel via a connecting wall 38.
• the fan casing 20 comprises on an inner face a coating of abradable material 40 disposed at the right of the fan blades 16 and intended to wear during contact with the radially outer ends of the blades 1 6. This layer of abradable material 40 reduces the clearances between the tops of the blades 16 and the fan casing 20 and thus optimize the performance of the turbomachine.
• the low-pressure compressor 34 comprises an alternation of stationary vanes 42 carried by an outer casing 44 and movable wheels 46 carried by the rotor 36. Each movable wheel 46 comprises a plurality of blades regularly distributed around the axis 12 of the turbomachine and surrounded externally by a layer 48 of abradable material carried by the inner surface of the housing 44 of the low pressure compressor.
• This casing 20 comprises bosses 50 formed on its outer surface and spaced circumferentially from each other.
• Each boss 50 comprises an orifice 52 opening inside the housing 20 in the flow passage of the air flow and contains a sensor 54 of substantially cylindrical shape, connected by a cable to the processing means 56.
• Each sensor 54 comprises an annular base 57 at its radially outer end.
• An annular wedge 58 is interposed between the base 57 and the outer surface of the boss 50. This wedge 58 provides adjustment of the insertion level of the sensor inside the orifice.
• Each sensor 54 is inserted from outside the housing into an orifice 52 and the thickness of the shim 58 is such that the active face of the sensor is recessed within the orifice 52 relative to at the outlet of the orifice in the air flow vein.
• the layer of abradable material 40 covers the internal surface of the casing with the exception of the outlets of the orifices 52.
• a cavity 60 is thus formed between the radially outer ends of the vanes 18 and the active face 62 of each sensor 54.
• this type of mounting with cylindrical sensors 54 generates high noise levels because of the high speed passage of the blades in front of the cavities 60.
• the invention proposes to avoid this drawback as well as those mentioned above by replacing the cylindrical sensors by planar sensors 64 and covering them with a layer of abradable material 70 (FIG. 3).
• Each sensor 64 is mounted on the inner surface of the casing 66 to the right of the radially outer ends of the blades 18 and is connected by a flat cable 68 to processing means 56 arranged outside the housing 66.
• the cable 68 travels on the internal surface of the casing 66 between the abradable layer 70 and the housing 66 and then passes through the housing through an orifice 72 formed upstream of the leading edge of the blades 18.
• the orifices 72 for passage of the cables 68 of the sensors 64 are offset upstream of the blade rotation zone 18, which prevents the formation of noise because of the high speed of the blades.
• a thin layer of abradable material is interposed between the sensor 64 and the inner surface of the casing 66 so as to carry out the initial bonding of the sensor 64 to the casing 66 before the abradable layer 70 is put in place.
• the sensors 64 have a circular shape and the abradable layer 70 covering the sensors has a thickness of between 5 and 7 millimeters.
• the diameter of the sensor 64 is of the order of 30 millimeters and its thickness is less than 1 millimeter and for example between 0.4 and 0.7 millimeter.
• the diameter of the active portion 74 of the sensor is of the order of 8 to 9 millimeters.
• the blower comprises three sensors, a first being arranged in the upper position on the housing, that is to say at noon relative to the dial of a watch, another being arranged in the lower position, that is to say that is arranged diametrically opposite the first sensor, the third being arranged between the two other sensors at 90 ° of each of them.
• the sensors 64 for measuring the sets of blade tips are for example of the capacitive type.
• the fact of covering the capacitive sensor with abradable material makes it possible to improve the measurement of the set of blade tips compared to the prior art because the permittivity of the abradable material is approximately twice as great as that of the air .
• the abradable material may be for example a resin obtained by room temperature vulcanization (RTV) or Minnesota Ec 3524 ® .
• turbomachine fan 10 also applies to any other part of a turbomachine allowing the installation of sensors 64 for measuring the sets of vanes in an abradable layer as described above.
• the invention is applicable to the low-pressure compressor 34 of FIG. 1 and which comprises layers of abradable material 48 facing the radially outer ends of the blades.
• the orifices 72 for the passage of the cables 68 of the sensors 64 have a diameter of the order of 3 millimeters, which is very much smaller than the diameter of the mounting orifices 52 for mounting sensors of the prior art which is of the order of 30 millimeters .
• the orifices 72 therefore have a sufficiently small section to have no impact on the mechanical strength of the casing 66 in operation.

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

Applications Claiming Priority (2)

Publications (1)

Family

ID=44318136

Family Applications (1)

Country Status (8)

Cited By (1)

Families Citing this family (3)

Citations (2)

Family Cites Families (13)

• 2011
  • 2011-01-28 FR FR1150680A patent/FR2971020B1/fr active Active
• 2012
  • 2012-01-25 BR BR112013018594A patent/BR112013018594A2/pt not_active IP Right Cessation
  • 2012-01-25 CA CA2825260A patent/CA2825260A1/fr not_active Abandoned
  • 2012-01-25 WO PCT/FR2012/050159 patent/WO2012101380A1/fr active Application Filing
  • 2012-01-25 RU RU2013139738/06A patent/RU2585154C2/ru not_active IP Right Cessation
  • 2012-01-25 US US13/981,797 patent/US20130309063A1/en not_active Abandoned
  • 2012-01-25 CN CN201280006284.4A patent/CN103429850B/zh not_active Expired - Fee Related
  • 2012-01-25 EP EP12705373.4A patent/EP2668372A1/fr not_active Withdrawn

Patent Citations (2)

Non-Patent Citations (1)

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