FR2667353A1 - Rotor vane for turbomachine - Google Patents

Abstract

The invention relates to a faired rotor blade. The fairing (16) is provided with at least one primary plenum chamber (19) arranged to receive in operation at least part of the cooling fluid and to direct this cooling fluid to the outside of the fairing (16) by means of cooling channels (20) extending through at least a portion of the interior of the shroud (16) and connecting the primary plenum chamber (19) and areas of the shroud (16) arranged to come into contact with the corresponding areas of the fairings of adjacent similar rotor blades.

Description

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  The present invention relates to a turbo rotor blade

  machine and a method of manufacturing this dawn.

  The turbomachines are frequently provided with rotor blades which are cooled to allow their operation at high temperature, which improves the efficiency of the engine. These are in fact the turbine blades of such engines which are cooled although in some cases it is desirable to

  cool the blades of compressions.

  The rotor blades are often cooled by means of internal cooling passages in which a cooling fluid, generally compressed air, flows. Although such passages are effective for refiidir the portion of the aerodynamic profile rotor blades. Difficulties arise when the vanes comprise fairings A fairing is a small segment attached to the end of a rotor blade, and when a row of carved rotor vanes is mounted on a common rotor dique, the fairings can touch each other to form a peripheral ring around the ends of the blades,

  which reduces gas leakage at these ends.

  the efficiency of the engine, it is necessary for fairings to be able to operate at high temperatures, they must also be equipped, to a certain extent, with an internal cooling Unfortunately, this often results in voluminous and heavy fairings which therefore impose charges

  unwanted centrifuges on their respective blades.

  According to one aspect of the present invention, a rotor blade for a turbomachine has at its base means for attaching it to a rotor disk with a plurality of other similar rotor blades, and a fairing at its end, said blade being arranged to be cooled by the passage of a cooling fluid therethrough, said fairing being provided with at least one primary plenum arranged to receive in operation at least a portion of said cooling fluid and to direct the cooling fluid to outside the fairing, via cooling channels extending through at least a portion of the interior of said fairing and connecting said primary plenum to areas of said fairing arranged to operate against the corresponding areas fairings of the rotor blades

  likewise mounted on said rotor disk.

  Preferably, the fairing of said rotor blade is arranged so that in operation it corresponds with the fairing

  adjacent adjacent rotor blades, to form two secondary chambers, one on each side of said fairing, each chamber being arranged to receive the cooling fluid;

  said cooling channels of said fairing and for ejecting said fluid from said fairing.

  Each of said secondary tranqaillisation rooms 1 o may be provided with openings arranged to eject the cooling fluid on at least a portion of the outer surface of said fairing. Alternatively, said secondary plenums may be arranged to eject the coolant

  downstream in the gas stream which, in operation, passes over the aerodynamic profile of said rotor blade.

  Said cooling channels preferably extend transversely with respect to the fairing.

  According to another aspect of the present invention, a method of manufacturing a streamlined rotor blade for turbomilling comprises the steps of: forming a rotor blade having at least one internal cooling passage, means at its base for fixing it to a rotor disk-with a plurality of other similar blades and a platform at its end, forming a cap arranged to fit on said platform so as to define with it a fairing, forming at least one primary plenum in said platform or in said cap or both, forming a plurality of open channels in said platform or in said cap, or both, inserting a leachable and heat-resistant material into said open channels, placing said cap on said platform so that at least one cooling passage is arranged to feed said primary plenum and that the said open channels connect said primary plenum chamber and the areas of said platform arranged in operation to contact the corresponding areas of the adjacent adjacent rotor blade shrouds mounted on said disk,

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  brazing said cap on said platform to form a fairing

and leaching said material.

  At least one secondary plenum may be formed in said hat or platform, or both. Preferably, said primary and secondary plenums and open channels are formed in said cap. Said primary plenum and said open channels are preferably formed in said cap by

electrochemical machining.

  Said material is preferably in the form

of quartz tubes.

  Said quartz tubes may be leached using a

soda solution.

  The invention will now be described by way of example with reference to the accompanying drawings, in which FIG. 1 is a partial sectional side view of a turbomachine fitted with vaned turbine rotor blades according to FIG.

present invention.

  Figure 2 is a side view of a rotor blade of

  turbine, according to the present invention.

  Figure 3 is an enlarged view of the dawn fairing of -

  turbine rotor shown in Figure 2.

  Figure 4 is a section along the line A-A of Figure 3.

  Figure 5 is a section along the line B-B of Figure 3, and

  Figure 6 is a view along arrow C of Figure 3.

  As shown in FIG. 1, a turbomachine 10 comprises a compression part 11, a combustion equipment 12 and a turbine part 13. In operation, the air is compressed by the compressor 11 before entering the combustion equipment. 12 o it is mixed with the fuel and burned The resulting hot gases relax and drive the turbine 13 before being ejected into the atmosphere 1 ere The turbine 13 and the compressor 11 are connected, so that the turbine 13 may cause the compressor 11 Part of the casing of the turbine 13 is torn off to show the first stage of rotor blades of

turbines 14.

  One of the turbine rotor blades 14 is shown more

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  details in Figure 2 The rotor blade 14 comprises an aerodynamic profile 15 having a fairing 16 at its end and a fir-shaped heel 17 at its base The fir-shaped heel 17 is arranged to place

  the rotor blade 14 on a rotor disk (not shown)

  to allow the rotor blade 14 to withstand the high temperatures of the hot gases from the combustion equipment 12, it is provided with an internal cooling air Compressed air from the compressor It is brought to the disc of rotor on which rotor blades 14 are mounted and from there; by passages, in the fir heel 17, in a plurality of cooling passages 18 in the blade 14, one of which can be seen at

Figure 4

  The cooling passages 18 bring the compressed air into a primary plenum 19 located in the shroud 16. The air is then directed by a plurality of cooling channels 20 extending across the shroud 16 to escape along the side edges 21 and 22 of the fairing The cooling passages 20, which terminate along the lateral edge 21 of the fairing, open into a slot 23 prevail in this side edge 21 This slot is placed so that, when the dawn of Turbine rotor 14 is mounted with other similar rotor blades on a rotor disk, the side edge 22 of the rotor blade shroud adjacent on one side to the rotor blade 14 comes into contact and matches with the slot 23 to form a secondary plenum 24 into which the cooling air from both the rotor blade and the adjacent similar rotor blade flows. A series of orifices inc Linen 25, provided on the radially outer surface of the fairing 16 (Figure 6), then direct the cooling air of the secondary plenum 24 to the radially outer surface of the fairing 16, to provide cooling by air film. The side edge 22 of the fairing 16 does not have a slot to form a similar secondary plenum with the slot provided in the rotor blade shroud which, in use, is located against the other side of the rotor blade 14 Thus, in an annular row of turbine rotor blades 14 mounted on a rotor disk, a plurality of secondary plenums 24 are formed by the side edges.

  4 in contact 21 and 22 of their fairing 16.

  In order to reduce any tendency of the cooling channels to be blocked by dust etc. which can be carried by the cooling air, the primary plenum

  has three inclined dust vents 26.

  In a variant of the arrangement comprising cooling orifices 25 on the radially outer surface of the fairing 16, the secondary cooling chambers can

  have openings arranged to eject the cooling air

  downstream of the hot gas stream which, in operation, passes over the aerodynamic profile 15 of the rotor blade 14. If such an arrangement is used, the radially outer surface of the shroud 16 may have more blades. as is possible in the previously described embodiment in which only two sealing wings 27 and 28 are possible. It is not possible to provide more than two sealing wings 27 and 28 on the fairing 16 thereof. embodiment because of their interference with the effect of

  film cooling produced by the cooling air ejection

  by the inclined orifices 25.

  The fairing 16 is made in two parts 29 and -30 The part 29 is formed in one piece as a platform with the aerodynamic profile 15, the part 30 is formed as

  a hat arranged to fit on the platform 29.

  The cooling channels 20, the room of tranquility

  19 and the chambers 23 are formed in the cap by electrochemical machining. It will be understood that the cooling channels 20 have a U-section given the limitations of the electrochemical machining. Quartz tubes having a diameter approximately equal to the width. channels 20 in U, are then placed in the channels 20 before the cap 30 is brazed on the platform 29 All the intervals between the quartz tubes, the channels 20 in U and the platform 29,

  fill with molten solder, due to the capillary action.

  After cooling, the fairing 16 oltenu is immersed in a solution of soda to dissolve the quartz tubes, leaving

  thus cooling channels with circular section (Figure 3).

  The method for forming a cooled fairing as described above can be used to transform a cooled rotor blade having an uncooled fairing into a blade having a cooled shroud. Thus the uncooled fairing of such a blade

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  can be ground until its radially outer surface

  either flat or frustoconical A suitable cap machined electro-

  chemically as described above can then be brazed on the

fairing rectifies.

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Claims (11)

  1. A rotor blade for a turbomachine, having at its base means for attaching it to a rotor disc with a plurality 6 of other similar rotor blades, and at its end 6 a fairing, said blade being arranged to be cooled by the passage of a cooling fluid, characterized in that said fairing (16) is provided with at least one primary plenum (19) arranged to receive in operation at least a portion   coolant and to direct this coolant   outwardly from the fairing (16) by cooling channels (20) extending through at least a portion of the interior of the shroud (16) and connecting the primary plenum   (19) and the areas of the fairing (16) arranged to come into operation.   in contact with the corresponding areas of the fairings of the   adjacent similar rotor blades mounted on the rotor disc.   2. Rotor blade according to claim 1, characterized in that   the fairing (16) of said rotor blade (14) is arranged such that in operation it corresponds with the shrouds of said adjacent adjacent rotor blades to form two secondary plenums (24), one on each side of said fairing (16), each chamber (24) being arranged to be supplied with cooling air by said cooling channels (20) of said fairing (16), and to eject this fluid of said fairing (16).   Rotor blade according to Claim 2, characterized in that each of said secondary plenums (24) is provided with orifices (25) arranged to eject the cooling fluid on at least a part of the outer surface. said fairing (16).   4 rotor blade according to claim 2, characterized in that said secondary plenums (24) are arranged to eject the rerslaval cooling fluid and into the gas stream which, in operation, passes on the profile   aerodynamic (15) of said rotor blade (14).   Rotor blade according to any one of the claims   i to 4, characterized in that said cooling channels (20)   extend transversely with respect to said fairings 16.   A method of manufacturing a ducted rotor blade for a turbomachine, comprising the steps of: forming a rotor blade having at least one internal cooling passage, means at its base for attachment to a rotor disk with a plurality of other similar blades and a platform at its end, characterized by forming a cap (30) arranged to fit on each platform (29) so as to define with this platform a fairing (16). at least one primary plenum (19) is formed in said platform (29), said cap (30) or both, a plurality of open channels (20) are formed in the platform (29) or in said cap (29). (30) or both, inserting a leachable and heat-resistant material into said open channels), placing said cap (30) on said platform (29) such that at least one passage of cooling (18) is arranged p to feed-said primary plenum (19) and that   said open channels (20) connect said room of tranquility   primary (19) and the areas of said platform (29) arranged to operate in contact with the corresponding areas of adjacent adjacent rotor blade cowlings mounted on said rotor rotor disk;   said platform (29) for forming a fairing (16).   7. A method of manufacturing a streamlined rotor blade according to claim 6, characterized in that at least one secondary plenum (24) is formed in this hat   (30) or in said platform (29) or both.   8 Proc 6 of manufacturing a faired rotor blade according to   Claim 7, characterized in that said open channels -   (20) are formed in said cap (30).   9. A process for manufacturing a careened rotor blade according to Claim 8, characterized in that said open channels (20)   are formed in said cap (30) by electrochemical machining.   10. Procedure 6 for manufacturing a keeled rotor blade   according to any one of Claims 6 to 9, characterized in that   that said material is in the form of quartz tubes.   11. A method of manufacturing a careened rotor blade, according to claim 10, characterized in that said tubes of   quartz are leached with a solution of soda.