Apparatus for the ventilation of a high pressure turbine rotor

255 697 T3

DESCRIPTION

Ventilation device of a high pressure turbine rotor of a turbomachine.

Technical field

The present invention relates generally to the field of ventilation of a high pressure turbine rotor of a turbomachine.

More specifically, the invention relates to a high pressure turbine rotor ventilation device comprising an upstream turbine disk and a downstream turbine disk.

Prior state of the art

Figure 1 represents a conventional high pressure turbine rotor 1 of the prior art, arranged downstream of a combustion chamber 2, and comprising an upstream turbine disc 3, provided with blades 4, and a disc 5 of downstream turbine, fitted with 6 blades.

The upstream disk 3 is provided, on the one hand, with an upstream flange 8, which ensures its fixation in a spacer 9 arranged around a rotor shaft 11 of a low-pressure turbine, and, on the other hand , of a downstream flange 10, fixedly mounted on an upstream flange 12 of the downstream disc 5. It is specified that there is a joint 14 between discs, mounted in a hollow structure 16 integral with a stage 18 of fixed distributor or stator, located at the level of the set of the two flanges 10 and 12. In this way, the joint 14 between discs, of the labyrinth seal type, it makes it possible to form a gap between the two rotor stages 20 and 22, arranged on either side of the distributor stage 18.

On the other hand, the downstream disk 5 comprises a downstream flange 13, also mounted on the spacer 9 that surrounds the shaft 11 of the low pressure turbine.

In this type of classical turbine 1 of the prior art, a first flow D1 of cooling air, obtained at the bottom of the combustion chamber 2, is fed to a cavity 26 delimited, on the one hand, by a downstream face of an upstream labyrinth 24 arranged next to the upstream disk 3, and, on the other hand, on an upstream face of this same upstream disk 3. This air flow D1 is effectively obtained at the bottom of the combustion chamber 2, and is then directed to a cavity 30 delimited, in particular, by an upstream labyrinth joint 32 and a labyrinth joint 34 downstream, by means of a conduit 28, arranged in an enclosure 29 that separates the upstream labyrinth 24 from the bottom of the combustion chamber 2, and by means of injectors 36, provided in the extension of conduit 28 and leading in cavity 30. It is noted that the seals 32 and 34 are provided to be in contact with the upstream labyrinth 24.

Furthermore, the cooling air found in the cavity 30 can enter the cavity 26 through holes 38 provided in an upstream part of the upstream labyrinth 24, these holes 38 having axes substantially perpendicular to the longitudinal axis 40 of the turbine.

In this way, the cooling air flow D1 circulates through the cavity 26 first longitudinally and then radially outward along the upstream face of the upstream labyrinth 24, in order to cool it, and then , penetrates the alveoli 4a containing the feet of the blades 4 in order to also cool said feet.

Furthermore, a second flow D2 of cooling air, also obtained at the bottom of the combustion chamber 2, enters the chamber 29 and flows through the orifices 44 and 42, provided, respectively, in the water part. above the upstream labyrinth 24, and on the upstream flange 8 of the upstream disc 3. After having passed through the orifices 44 and 42, the second flow D2 of cooling air is directed to an annular chamber 46 delimited internally by the separator 9, and externally, successively, from upstream to downstream, the flange 8, an inner bore 48 of the upstream disc 3, the flanges 10 and 12, an inner bore 50 of the downstream disc 5 and the flange 13.

From the annular chamber 46, a first part D2a of the second flow D2 of cooling air flows through the holes 52 made in the downstream flange 10 of the upstream disk 3, in order to access the gap 19 located between stage 18 of the fixed distributor and stage 20 of the rotor, as represented schematically by the arrow with reference D2a. By way of indication, it should be noted that the air flow rate d schematically represented in FIG. 1 corresponds to an air leak at the alveoli 4a.

Furthermore, a second part D2b of the second flow D2 of cooling air flows through the holes 54 made in the downstream flange 13 of the downstream disk 5, in order to penetrate a delimited cavity 56, on the one hand , on an upstream face of a downstream labyrinth 58 arranged next to the downstream disk 5, and, on the other, on a downstream face of this same downstream disk 5.

Thus, the second flow D2b of cooling air circulates in a substantially radial direction in the cavity 56 towards the outside, along the upstream face of the downstream labyrinth 58, in order to cool it, and then penetrates in the cells 6a that contain the feet of the blades 6, in order to also cool said feet.

Therefore, in this type of classical turbine of the prior art, the rotor ventilation device has two different cooling circuits, each associated with one of the two turbine discs, and fed, respectively, by the first and second flow rates. D1 and D2 cooling air.

But this classical solution of the prior art has restrictions, in the sense that the upstream labyrinth is an extremely complex design part, of considerable mass, and therefore the production cost increases a lot, in particular, due to the need to use special materials capable of withstanding high intensity thermal stresses.

Furthermore, it is specified that even when the materials used are of good quality, the useful life of the upstream labyrinth is relatively limited.

On the other hand, document DE 19854907 A1 of the prior art is known which discloses all the characteristics of the preamble of claim 1, with a single labyrinth positioned next to a downstream face of the downstream turbine disk. But the upstream turbine disk is cooled on its upstream face, always, thanks to additional means of the ra2 turbine type

ES 2 255 697 T3 dial that are added to the unique labyrinth, which makes the cooling device heavy and bulky. Compendium of the invention

The object of the invention is to propose a ventilation device for a high pressure turbine rotor of a turbomachine, the downstream turbine being provided with a combustion chamber and comprising upstream and downstream turbine discs fitted with blades, the device comprising a cooling circuit provided with injectors arranged upstream of the upstream disk and being fed by a flow D of cooling air obtained at the bottom of the combustion chamber, the device remedying, at least partially, the aforementioned drawbacks above relating to prior art embodiments.

To this end, the invention has as its object a ventilation device for a high-pressure turbine rotor of a turbomachine, the turbine being arranged downstream of a combustion chamber and comprising an upstream turbine disk provided with blades as well as a downstream turbine disk also provided with blades, the device comprising a cooling circuit provided with injectors arranged upstream of the upstream disk, the circuit being fed by a flow D of cooling air obtained at the bottom of the combustion chamber. According to the invention, the cooling circuit is designed so that the flow D of cooling air coming from the injectors passes through holes made in an upstream flange of the upstream disk, which allows it to be fixed on a flange of upstream of the downstream disk, in order for this flow D of cooling air to circulate axially downstream between an inner bore of the upstream disk and an upstream flange of the downstream disk, which allows it to be attached to a downstream flange of a high pressure compressor as well as the centering of the upstream disc, the ventilation device also comprising a single labyrinth integral with one of the two turbine discs and which is interposed between these two discs so that the cooling air flow D is divided into a first flow F1, which circulates between a downstream face of the water disc upstream and an upstream face of the single labyrinth, in the direction of the vanes of the upstream disk, and a second flow F2, which circulates between an upstream face of the downstream disk and a downstream face of the single labyrinth , in the direction of the downstream disc blades.

Advantageously, and contrary to prior art embodiments, the ventilation device no longer comprises two labyrinths associated, respectively, with the upstream and downstream turbine discs, but instead has a single labyrinth between discs, each of the faces, upstream and downstream, being intended to guide a flow of cooling air in the direction of the blades. Consequently, reducing the number of parts used allows the mass, volume and manufacturing cost of the rotor to be considerably reduced. Furthermore, the specific positioning of the single labyrinth results in it being less thermally stressed than a labyrinth provided upstream of the upstream disk, mainly because of its location in relation to the combustion chamber, and to the extent that the The temperature of the cooling air flow D decreases significantly during its passage through the inner bore of the upstream disk. In this way, this characteristic generates an increase in the useful life of this labyrinth in relation to the useful life that an upstream labyrinth of the prior art could have.

On the other hand, it is indicated that the injection of the cooling air upstream of the upstream disk, the contouring of this upstream disk by the inner bore, as well as the possibility of manufacturing elements that make up the rotor of small dimensions, allows obtain, thanks to a simple cavity delimited, jointly, by a downstream face of the upstream disk and by an upstream face of the single labyrinth, sufficient pressure at the level of the blades of this upstream disk.

In this regard, the adjacent cavity delimited jointly by an upstream face of the downstream disk and by a downstream face of the single labyrinth is advantageously used to lower the supply pressure of the blades of the downstream disk. The small pressure inside this adjacent cavity makes it possible, in effect, not to have to provide holes for feeding the blades with dimensions that are too small, which are difficult to make.

Advantageously, the rotor, made more compact thanks to the reduction in the number of its constituent elements, allows an approach of the support element under the chamber to the upstream and downstream discs, so that, then, it is possible to obtain a better control of the clearances at the end of the blades, and therefore a better performance of the high pressure turbine.

On the other hand, it should be noted that the flow D of cooling air circulating at the level of the inner bore of the upstream turbine disk is large enough to allow it to have a relatively short response time and, therefore, to provide a small clearance at the end of the blades.

Finally, an arrangement of this type according to the invention allows a quick and easy disassembly of the stator, since this task only requires the removal of the blades from the downstream turbine disk without having to separate the two rotor disks, this operation having always been necessary, however, with the prior art embodiments.

Other advantages and characteristics of the invention will become apparent from the detailed, non-limiting description that follows.

Brief description of the drawings

This description will be made in relation to the attached drawings in which:

Figure 1, already described, represents, in semi-section, a high pressure turbine of a turbojet according to the prior art, and

FIG. 2 represents, in semi-section, a high pressure turbine of a turbojet that includes a ventilation device according to a preferred embodiment of the present invention. Detailed description of preferred embodiments

With reference to Figure 2, it represents a high-pressure turbine 100 of a turbojet, which comprises a ventilation device for the rotor of the turbine according to an embodiment

ES 2 255 697 T3 preferred of the present invention. It is pointed out that, in figure 2, the elements bearing the same numerical references as those assigned to the elements represented in figure 1 correspond to identical or similar elements.

Thus, Figure 2 shows a turbine 100 that differs from the turbine 1 of the prior art, essentially, because a flow D of cooling air, obtained at the bottom of the combustion chamber 2 and capable of passing through the injectors 36, it is intended to simultaneously feed the blades and 6 of the upstream 3 and downstream 5 discs.

Indeed, the cooling air that comes from the combustion chamber 2 circulates through the conduit 28 in order to reach the injectors 36, this set, consisting of the conduit 28 and the injectors 36, being located in an enclosure 62 separating the upstream disc 3 from the bottom of the combustion chamber 2.

Next, the flow D of cooling air coming from the injectors 36 enters a cavity 64 partially delimited by a flange 66 upstream of the turbine disk 3 upstream, this flange 66 having as its main function upstream ensure the fixing of this upstream disk 3 in an upstream flange 78 of the downstream disk. On the other hand, this cavity 64 is also delimited jointly by the upstream joint 32 and the downstream joint 34, preferably of the labyrinth type, provided next to the injectors 36, respectively, upstream and downstream. downstream of them. In this regard, it is specified that the upstream gasket 32 ​​cooperates with a downstream flange 70 of the high-pressure turbine, this downstream flange 70 being provided so that it is located radially outward relative to the flange. 66 upstream. In addition, the upstream gasket 32 ​​closes the cavity 64 by mating with the upstream end of the upstream flange 66. On the other hand, the downstream gasket 34 cooperates with an upstream secondary flange 72 of the upstream turbine disk 3, provided so that it is located radially outward in relation to the upstream flange 66. In this way, the cooling air that escapes from the cavity 64 through the downstream seal 34 can circulate radially outward along the upstream face of the upstream disk 3, in the direction of the blades. Four.

There are holes 74 made in the upstream flange 66 of the upstream turbine disc 3, so that the flow D of cooling air can be conducted in the direction of the two turbine discs 3 and 5. Preferably, the ports 74 are arranged so that they face radially the injectors 36.

Once the holes 74 have passed through, the flow D of cooling air enters an annular chamber 76 with axis 40, externally delimited by the upstream flange 66 of the upstream disk 3 and the inner bore 48 of this same disk. Furthermore, the annular chamber 76 is internally delimited by the upstream flange 78 of the downstream disc 5, this upstream flange 78 having as its main function to ensure the fixation of this downstream disc 5 on the upstream flange 66 upstream disc 3, and center the turbine assembly

100 pressure in a downstream flange 79 of a high pressure compressor.

The cooling air flow D can then flow axially downstream between the inner bore 48 and the upstream flange 78, so that the upstream turbine disk 3 can be conveniently cooled by the contact of the cooling air. with its internal soul 48.

As can be seen in figure 2, the ventilation device according to the invention comprises a single labyrinth 80 interposed between the turbine discs 3 and 5, and is integral with one of these two discs. By way of non-limiting example, the single labyrinth 80, also called the labyrinth between discs, is fixed to a secondary flange 82 upstream of the downstream turbine disc 5, this flange being provided so that it is located radially towards the exterior relative to the upstream flange 78. In addition, the labyrinth 80 extends radially until it marries the stage 18 of the fixed distributor or stator provided between the two stages 20 and 22 of the rotor, and has an internal bore 83 that surrounds the flange 78 upstream of the disk 5, presenting this bore 83, preferably, a diameter substantially identical to the diameter of the inner bore 48 of the disc 3.

Consequently, the flow D of cooling air circulating in the annular chamber 76 and reaching the level of the downstream face of the upstream disk 3, is divided into two flows F1 and F2, destined, respectively, to supply blades 4 and blades 6 of discs 3 and 5.

Therefore, the first flow F1 circulates through a cavity 68 located between the downstream face of the upstream turbine disk 3 and the upstream face of the labyrinth 80, in order to cool the downstream face of the disk 3 , and then penetrates the cells 4a containing the feet of the blades 4, in order to cool said feet as well.

In the same way, the second flow F2 circulates through a cavity 69 located between the upstream face of the downstream turbine disk 5 and the downstream face of the same labyrinth 80, in order to cool the upstream face of the disc 5, and then penetrates the cells 6a containing the feet of the blades 6 in order to cool said feet as well. It is noted that for the second flow F2 to reach the blades 6 of the downstream turbine disk 5, a plurality of holes 84 are made in the secondary flange 82 upstream of the downstream disk 5.

Consequently, the ventilation device according to the invention is such that the flow D of cooling air obtained at the bottom of the combustion chamber 2 and intended to simultaneously feed the blades 4 and 6, passes through a single cooling circuit up to the exit of the passage between the bore 48 of the upstream disk 3 and the upstream flange 78 of the downstream turbine disk 5. This specific characteristic considerably simplifies the design of the turbine 100 in relation to that of the turbine 1 of the prior art, in which two cooling air flows were obtained at the bottom of the combustion chamber 2, in order to use two totally separate refrigeration circuits.

On the other hand, the upstream flange 78 of the downstream turbine disk 5 comprises a plurality

ES 2 255 697 T3 of orifices 86 intended to be traversed by a third flow F3 of the flow D of cooling air. This third flow F3 is conducted from the annular chamber 76 towards an annular space 88 with the same axis, the space 88 being located between, on the one hand, the upstream flange 78 of the downstream disk 5 and the inner bore 50 of this same downstream disk 5, and, on the other hand, the separator 9 arranged around the shaft 11 of the rotor of the low pressure turbine. Thus, the flow F3 of cooling air can circulate axially downstream in the annular space 88, in order to cool the downstream disk 5 thanks to the contact of the air with its inner bore 50. Next, the third flow F3 is evacuated downstream of the turbine 100 through the holes 54 made in the downstream flange 13 of the downstream turbine disk 5, this downstream flange 13 also participating in the outer delimitation of annular space 88 and being mounted on spacer 9 of shaft 40.

It is evident that experts will be able to make various modifications to the turbine 100 and its ventilation device, which have been described only by way of non-limiting examples.