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
  • F01D5/12—Blades
  • F01D5/14—Form or construction
• • 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
  • F01D5/14—Form or construction
  • F01D5/141—Shape, i.e. outer, aerodynamic form
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22C—FOUNDRY MOULDING
  • B22C7/00—Patterns; Manufacture thereof so far as not provided for in other classes
  • B22C7/02—Lost patterns
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22C—FOUNDRY MOULDING
  • B22C9/00—Moulds or cores; Moulding processes
  • B22C9/10—Cores; Manufacture or installation of cores
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
  • B22D25/00—Special casting characterised by the nature of the product
  • B22D25/02—Special casting characterised by the nature of the product by its peculiarity of shape; of works of art
• • 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
  • F05D2220/32—Application in turbines in gas 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
  • F05D2230/00—Manufacture
  • F05D2230/20—Manufacture essentially without removing material
  • F05D2230/21—Manufacture essentially without removing material by casting
• • 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
  • F05D2240/20—Rotors
  • F05D2240/30—Characteristics of rotor blades, i.e. of any element transforming dynamic fluid energy to or from rotational energy and being attached to a rotor

Definitions

• the present invention relates to the general field of turbomachine turbine blades, and more particularly to the raw blades of turbine blade foundry produced by the lost wax foundry technique.
• a turbomachine comprises a combustion chamber in which air and fuel are mixed before being burned. The gases from this combustion flow downstream of the combustion chamber and then feed a high pressure turbine and a low pressure turbine.
• Each turbine has one or more rows of stationary blades (called distributors) alternating with one or more rows of moving blades (called moving wheels), circumferentially spaced around the rotor of the turbine.
• Figure 4A illustrates in part a conventional structure of distributors currently equipping many aircraft engines and having a plurality of blades.
• Each of these vanes 10 comprises an aerodynamic profile or blade inserted between an outer platform 14 joining the blade heads and an inner platform 16 joining the blade roots.
• Each blade has a leading edge 18 and a trailing edge 20 opposite to each other and intrados 22 and extrados 24 extending radially between a blade root and a blade head in one direction XX 'elongation of the blade, which direction of elongation is perpendicular to the longitudinal central axis (not shown) of the turbomachine.
• FIG. 4B illustrates a conventional hollow gas turbine blade 30 having an aerodynamic profile or blade having a leading edge 32 and a trailing edge 34 opposite to each other and connected by an intrados wall 36 and a extrados wall 38 extending radially between a blade root 40 and a blade head 42 in the direction XX 'of elongation of the blade.
• the turbine blades are essentially made using a lost wax casting technique.
• this one foundry technique does not allow to obtain fins on the trailing edge end and it is therefore necessary to use an additional subsequent polishing step to mechanically retouch the trailing edge and so be able to thin it.
• an additional step of material removal at the raw die of the foundry did not allow to respect the final shape of the aerodynamic profile and its dimensional tolerances.
• the polishing of a fine surface generates warming then a local deformation of the aerodynamic profile whose shape is no longer respected, whether it is the tangency or the radius of the trailing edge, which will then result in a deterioration of turbine performance, which is the opposite of what is desired.
• the present invention therefore aims to overcome the drawbacks associated with the deformation of the trailing edge during the polishing of the trailing edge by proposing a modification of the dawn processing process by lost-wax foundry which does not generate no dimensional conformities and allows to respect the desired shape for the aerodynamic profile.
• a gross casting of a turbine engine blade made using the lost wax technique the blade having a blade having a leading edge and a trailing edge opposite one of the and other connected by a lower wall and an extrados wall extending between a blade root and a blade head, characterized in that, to achieve on said blade a thin trailing edge which is not deformed by a subsequent material removal operation, said rough casting of said blade comprises on an extrados wall and / or an intrados wall of said blade intended to form respectively said extrados wall and / or said intrados wall of the blade, an excess thickness of foundry extending from a trailing edge of said blade intended to form said trailing edge of the blade over a determined width in the direction of a leading edge of said blade intended to form said leading edge of the blade, with the exception of a reserved area adjacent to said trailing edge of the blade and at least one radius of said trailing edge of the blade, on at least a portion of the height of the blade.
• the foundry process is more robust at the trailing edge and can therefore withstand subsequent material removal such as polishing without risk of deformation of the dawn .
• said foundry allowance is made over the entire height of the vane.
• said foundry thickness has a variable thickness that varies in a decreasing manner on said determined width between a first value equal to zero and a second value of between half a time and once a desired thickness e for the blade and determined to a predetermined distance d from said trailing edge of the blade.
• said first value is determined at a first junction line, parallel to said trailing edge of the blade and constituting a line of tangency between said foundry allowance and said extrados wall of the blade
• said second value is determined at a second junction line also parallel to the trailing edge of the vane and delimiting said reserved area.
• said foundry excess thickness joins said upper surface of the blading at a first edge along said line of tangency and at second, third and fourth edges by sloping connections.
• said sloped connections each comprise a slope of between 20 ° and 50 °.
• said line of tangency is parallel to said trailing edge and located at a distance from said trailing edge of the blade equal to 40 to 60% of a length L of rope of the blade.
• the invention also relates to a method for manufacturing a turbomachine blade made by the lost-wax casting technique, the blade comprising a hollow blade having a leading edge and a blade. trailing edge opposite each other and connected by a lower surface wall and an extrados wall extending between a blade root and a blade head, the method being characterized in that, for casting by a blade dawn thin end, it comprises on the one hand a step comprising the realization of a rough casting of the foundry with a thickening of variable thickness foundry at the level of an extrados wall and / or a wall intrados said blade intended respectively forming said extrados wall and / or said intrados wall of the blade and extending from a trailing edge of said blade intended to form said trailing edge of the blade and towards a leading edge of the blade; vane for forming said leading edge of the vane, except for a reserved area adjacent to said trailing edge of the vane and at least one radius wide of said vanishing edge of the vane, and secondly
• said casting allowance is made over all or part of the height of the blading.
• said material removal operation is polishing.
• the invention also relates to a turbomachine comprising a blade manufactured according to the aforementioned manufacturing method.
• FIG. 1 illustrates the aerodynamic profile of a turbine blade according to the invention
• FIG. 2 is a partial sectional view of the blade of FIG. 1 at the trailing edge
• FIG. 3 is a partial view in elevation of the blade of FIG. 1 at the level of the extrados wall
• FIGS. 4A and 4B are perspective views of a prior art dispenser portion showing a plurality of blades and a prior art turbine blade, respectively. Detailed description of embodiments
• FIGS. 1 and 2 show an aerodynamic profile or blade of a rough cast blade intended to form a turbine blade having a leading edge 18 and a trailing edge 20 opposite to each other and connected by a intrados wall 22 and an extrados wall 24 extending between a blade root and a blade head.
• the elements of raw castings are the same numbers as those of the finished blade to a factor of 10.
• leading edge of the finished blade 18 corresponds to a leading edge of the raw blade 180, to the trailing edge of the finished blade 20, a trailing edge of the raw blade 200, to the wall intrados of the finished vane 22 a wall intrados of the rough vane 220 and the extrados wall of the finished vane 24 an extrados wall of the raw vane 240.
• the foundry allowance is, however, advantageously arranged on the upper surface of the raw blade 240.
• the value of 1mm of the end of the trailing edge is a determined threshold for measuring and retouching the thickness of trailing edge while maintaining a safety margin with respect to this end. Indeed, a machining of the trailing edge insufficiently Controlled would risk machining the end of the trailing edge and thus shorten the rope length L of the blade, which would have a significant impact on the aerodynamic performance.
• a sloping link 210a ideally between 20 ° and 50 ° so as to be large enough to increase the trailing edge without impairing the wax injection and the flowability
• the desired thickness e of the blade is defined at a predetermined distance d from the trailing edge 20 of this blade.
• the first junction line 260 is preferably located at a distance from the trailing edge 200 equal to 40 to 60% of this length L.
• the man the trade will choose for example a distance of 10 mm to 15 mm for a length of rope of 25 mm.
• this first junction line must form a line of tangency between the two tangent surfaces that form the outer face of the foundry allowance and the outer face of the extrados wall.
• the second junction line 280 defining the end of the reserved zone 250 must be far enough away from the trailing edge to avoid the deformation of this trailing edge but also relatively close to not penalize the smelter casting operation. Indeed, if this second junction line 280 is too close to the trailing edge 200 then the aerodynamic profile will be deformed during the material removal operation because the machined strip will be too close to the desired end trailing edge. And to position the second junction line too far from the trailing edge would be to achieve this end trailing edge directly foundry with the disadvantages mentioned above.
• a distance between the trailing edge 200 and this second junction line 280 to preferably be between 0.5 mm and 1 mm, that is to say of the order of 2 at 4 times the radius of the trailing edge can be estimated at 0.25 mm for a thickness of 0.5 mm.
• Figure 3 illustrates more precisely the foundry thickness 210 which extends on the extrados wall 240 of the raw blade, parallel to the trailing edge 200, between the first 260 and second 280 lines of junction.
• this extra thickness of the foundry also has junctions with the extrados wall 240 forming third and fourth edges opposite one another and defining towards the head of the blade a sloping link 210b and towards the blade root a sloping link 210c.
• the method for manufacturing a turbine blade according to the invention produced by the lost-wax casting technique does not differ from the conventional method in that it requires the production of a wax model and a ceramic mold, the casting of the metal constituting the blade to replace the wax previously introduced into the mold is then liquefied by heating before demolding the blade.
• the only difference lies in the manufacture of the wax model, which therefore includes a thickness of the foundry variable thickness at the upper surface of the blade to facilitate the foundry of a thin trailing edge (whose radius remains so foundry) and to be removed by subsequent material removal operation such as polishing.

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

Applications Claiming Priority (2)

Publications (2)

Family

ID=62874994

Family Applications (1)

Country Status (5)

Family Cites Families (15)

• 2018
  • 2018-05-23 FR FR1854282A patent/FR3081497B1/fr active Active
• 2019
  • 2019-05-23 CN CN201980031951.6A patent/CN112118923B/zh active Active
  • 2019-05-23 US US17/055,364 patent/US11396813B2/en active Active
  • 2019-05-23 EP EP19737169.3A patent/EP3797009B1/de active Active
  • 2019-05-23 WO PCT/FR2019/051180 patent/WO2019224486A1/fr not_active Ceased

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