EP1445421B1 - Apparatus for the ventilation of a high pressure turbine rotor - Google Patents

Description

TECHNICAL AREA

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 ventilation device of a high pressure turbine rotor, comprising an upstream turbine disk and a downstream turbine disk.

STATE OF THE PRIOR ART

FIG. 1 represents a conventional high-pressure turbine rotor 1 of the prior art, disposed downstream of a combustion chamber 2, and comprising an upstream turbine disk 3 equipped with vanes 4, as well as a disk downstream turbine 5 equipped with vanes 6.

The upstream disk 3 is provided on the one hand with an upstream flange 8 ensuring its fixing on a spacer 9 disposed around a rotor shaft 11 of a low-pressure turbine, and on the other hand with a downstream flange 10 fixedly assembled to an upstream flange 12 of the downstream disc 5. It is specified that an inter-disc seal 14, carried by a hollow structure 16 integral with a stationary distributor stage 18 or stator, is situated at the level of the assembly between the two flanges 10 and 12. The inter-disc seal 14, of the labyrinth seal type, thus makes it possible to create a separation between the two rotor stages 20 and 22, arranged on either side of the stage distributor 18.

Furthermore, the downstream disk 5 comprises a downstream flange 13, also assembled on the spacer 9 surrounding the shaft 11 of the low pressure turbine.

In this type of conventional turbine 1 of the prior art, a first cooling air flow D1 taken from the bottom of the combustion chamber 2 is delivered into a cavity 26 delimited on the one hand by means of a downstream face. an upstream labyrinth 24 disposed near the upstream disk 3, and secondly with the aid of an upstream face of the same upstream disk 3. This air flow D1 is actually taken from the bottom of the chamber combustion 2, then conveyed in a cavity 30 in particular delimited by an upstream labyrinth seal 32 and a downstream labyrinth seal 34, via a conduit 28 disposed in an enclosure 29 separating the upstream labyrinth 24 from the bottom of the combustion chamber 2, and using injectors 36 arranged in the extension of the conduit 28 and opening into the cavity 30. Note that the seals 32 and 34 are arranged to be in contact with the upstream labyrinth 24 .

In addition, the cooling air situated in the cavity 30 is able to penetrate into the cavity 26 by passing orifices 38 provided in an upstream part of the upstream labyrinth 24, these orifices 38 being axes substantially perpendicular to the longitudinal axis 40 of the turbine.

In this way, the cooling air flow D1 flows in the cavity 26 first longitudinally and then radially outwards along the upstream face of the upstream labyrinth 24 in order to cool it, then enters the cells 4a containing the feet of the blades 4 to cool them too.

In addition, a second cooling air flow D2, also taken from the bottom of the combustion chamber 2, enters the chamber 29 and flows through orifices 44 and 42 respectively provided in the upstream portion of the upstream labyrinth 24, and in the upstream flange 8 of the upstream disk 3. Once the orifices 44 and 42 crossed, the second cooling air flow D2 borrows an annular chamber 46 internally defined by the spacer 9, and externally delimited successively, from upstream to downstream, the flange 8, an inner bore 48 of the upstream disk 3, the flanges 10 and 12, an inner bore 50 of the downstream disk 5, and the flange 13.

From the annular chamber 46, a first portion D2a of the second cooling air flow D2 flows through orifices 52 formed in the downstream flange 10 of the upstream disk 3, in order to join the gap 19 located between the fixed distributor stage 18 and the rotor stage 20, as schematically represents the arrow referenced D2a. As an indication, it is noted that the air flow of Diagrammatically shown in Figure 1 corresponds to an air leak at the cells 4a.

In addition, a second portion D2b of the second cooling air flow D2 flows through orifices 54 formed in the downstream flange 13 of the downstream disk 5, to penetrate inside a cavity 56 delimited by a part using an upstream face of a downstream labyrinth 58 disposed near the downstream disk 5, and secondly with the aid of a downstream face of the same downstream disk 5.

Thus, the second cooling air flow D2b circulates substantially radially in the cavity 56 outwards along the downstream face of the downstream labyrinth 58 in order to cool it, then enters cells 6a containing the roots of the vanes 6 so as to to cool them as well.

In this type of conventional turbine of the prior art, the rotor ventilation device thus has two separate cooling circuits, each associated with one of the two turbine disks, and respectively powered by the first and second air flow rates. D1 and D2 cooling.

Nevertheless, this conventional solution of the prior art proves to be restrictive in that the upstream labyrinth is a piece of extremely complex design, of large mass, and whose production cost is very high, in particular because of the need to use special materials that can withstand high thermal loads.

In addition, it is specified that even when the materials used are of good quality, the lifespan of the labyrinth upstream remains relatively limited.

In addition, it is known from the prior art DE 19854907 A1 which discloses all the features of the preamble of claim 1, with a single labyrinth positioned near a downstream face of the downstream turbine disk. However, the upstream turbine disk is still cooled on its upstream face by means of additional means of the radial turbine type which are added to the single labyrinth, which makes the cooling device heavy and bulky.

STATEMENT OF THE INVENTION

The purpose of the invention is therefore to propose a device for ventilating a high-pressure turbine rotor of a turbomachine, the turbine being disposed downstream of a combustion chamber and comprising upstream and downstream turbine disks equipped with vane, the device comprising a cooling circuit provided with injectors arranged upstream of the upstream disk and being fed by a cooling air flow D taken from the bottom of the combustion chamber, the device at least partially overcoming the disadvantages mentioned herein above relative to the achievements of the prior art.

For this purpose, the subject of the invention is a device for ventilating a high-pressure turbine rotor of a turbomachine, the turbine being disposed downstream of a combustion chamber and comprising an upstream turbine disk equipped with blades and a downstream turbine disk also equipped with blades, the device comprising a cooling circuit provided with injectors arranged upstream of the upstream disk, the circuit being fed by a cooling air flow D taken from the bottom combustion chamber. According to the invention, the cooling circuit is arranged in such a way that the flow of cooling air D coming from the injectors passes through orifices formed in an upstream flange of the an upstream disk allowing its attachment to an upstream flange of the downstream disk, so that this cooling air flow D flows axially downstream between an internal bore of the upstream disk and an upstream flange of the downstream disk allowing its attachment to a downstream flange a high-pressure compressor and the centering of the upstream disk, the ventilation device further comprising a single labyrinth integral with one of the two turbine disks and being interposed between these two disks, so that the air flow rate cooling circuit D separates into a first flow F1 flowing between a downstream face of the upstream disk and an upstream face of the single labyrinth in the direction of the blades of the upstream disk, and a second flow F2 flowing between an upstream face of the downstream disk and a face downstream of the single labyrinth towards the blades of the downstream disk.

Advantageously and unlike the embodiments of the prior art, the ventilation device no longer has two labyrinths respectively associated with upstream and downstream turbine disks, but has a single inter-disk labyrinth, each of the upstream and downstream faces is intended for guide a flow of cooling air towards the blades. The reduction in the number of parts used consequently makes it possible to considerably reduce the mass, the bulk and the production cost of the rotor. In addition, the specific positioning of the single labyrinth leads the latter to be less thermally stressed than a labyrinth arranged upstream of the upstream disk, mainly because of its location relative to the combustion chamber, and to the extent that the temperature of the cooling air flow D drops substantially as it passes through the inner bore of the upstream disk. This characteristic thus gives rise to an increase in the lifetime of this labyrinth, compared to the lifetime that an upstream labyrinth of the prior art could present.

Furthermore, it is indicated that the injection of the cooling air upstream of the upstream disk, the bypass of this upstream disk by the inner bore and the possibility of producing constituent elements of the rotor of small dimensions, allows, by a single cavity defined jointly by a downstream face of the upstream disk and by an upstream face of the single labyrinth, to obtain sufficient pressure at the blades of the upstream disk.

In this respect, 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 reduce the supply pressure of the vanes of the downstream disk. The low pressure inside this adjacent cavity effectively avoids having to provide feed holes of the blades of too small dimensions, which are difficult to achieve.

Advantageously, the rotor made more compact by reducing the number of constituent elements of the rotor makes it possible to bring the under-chamber bearing of the upstream and downstream disks closer together, so that that it is then possible to obtain a better control of the games at the top of the blades, and therefore a better efficiency of the high pressure turbine.

On the other hand, it is noted that the flow of cooling air D passing through the internal bore of the upstream turbine disk is large enough to allow it to have a relatively short response time, and therefore to provide a game at low peaks of blades.

Finally, such an arrangement according to the invention allows fast and easy disassembly of the stator, insofar as this task requires only removal of the vanes of the downstream turbine disk without having to separate the two rotor disks, the latter operation having yet always been mandatory with the achievements of the prior art.

Other advantages and features of the invention will become apparent in the detailed non-limiting description below.

BRIEF DESCRIPTION OF THE DRAWINGS

• la figure 1, déjà décrite, représente en demi-coupe une turbine à haute pression d'un turboréacteur selon l'art antérieur, et
• la figure 2 représente en demi-coupe une turbine à haute pression d'un turboréacteur, comportant un dispositif de ventilation selon un mode de réalisation préféré de la présente invention.

This description will be made with reference to the appended drawings among which;

• FIG. 1, already described, represents in half-section a high-pressure turbine of a turbojet according to the prior art, and
• FIG. 2 shows in half section a high-pressure turbine of a turbojet, comprising a ventilation device according to a preferred embodiment of the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

With reference to FIG. 2, there is shown a turbine 100 at high pressure of a turbojet engine, comprising a device for ventilating the rotor of the turbine according to a preferred embodiment of the present invention. Note that in Figure 2, the elements bearing the same reference numerals as those attached to the elements shown in Figure 1 correspond to the same or similar elements.

Thus, FIG. 2 shows a turbine 100 which differs first of all from the turbine 1 of the prior art in that a cooling air flow D, taken from the bottom of the combustion chamber 2 and adapted to passing through the injectors 36, is intended simultaneously to feed the vanes 4 and 6 of the upstream 3 and downstream 5 disks.

Indeed, the cooling air from the combustion chamber 2 passes through the conduit 28 to join the injectors 36, this assembly consisting of the conduit 28 and the injectors 36 being located in a chamber 62 separating the upstream disk 3 bottom of the combustion chamber 2.

The cooling air flow D from the injectors 36 then enters a cavity 64 partially delimited by an upstream flange 66 of the upstream turbine disk 3, this upstream flange 66 whose main function is to ensure the attachment of this upstream disk 3 on an upstream flange 78 of the downstream disk 5. On the other hand, this cavity 64 is also delimited jointly by the upstream seal 32 and the downstream seal 34, preferably of the labyrinth seal type, arranged near the injectors 36 respectively upstream and downstream of the latter. As such, it is specified that the upstream gasket 32 cooperates with a downstream flange 70 of the high pressure turbine, this downstream flange 70 being arranged to be located radially outwardly relative to the upstream flange 66. , the upstream seal 32 closes the cavity 64 by marrying the upstream end of the upstream flange 66. In addition, the downstream seal 34 cooperates with a secondary upstream flange 72 of the upstream turbine disk 3, arranged so as to be located radially towards the outside with respect to the upstream flange 66. Thus, the cooling air escaping from the cavity 64 through the downstream gasket 34 can circulate radially outwards, along the upstream face of the upstream disk 3, by direction of blades 4.

Orifices 74 are provided in the upstream flange 66 of the upstream turbine disk 3 so that the flow of cooling air D can be conveyed towards the two turbine disks 3 and 5. The orifices 74 are preferably arranged to be located radially next to the injectors 36.

Once the orifices 74 are crossed, the cooling air flow D enters an annular chamber 76 of axis 40, delimited externally via the upstream flange 66 of the upstream disk 3, and with the aid of the inner bore 48 of this same disc. In addition, the annular chamber 76 is delimited internally by the upstream flange 78 of the downstream disc 5, this upstream flange 78 whose main function is to ensure the attachment of this downstream disk 5 to the upstream flange 66 of the upstream disk 3, and to center the assembly of the high-pressure turbine 100 on a downstream flange 79 d 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 suitably cooled by contacting the cooling air with its internal bore 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 inter-disk labyrinth, is attached to a secondary upstream flange 82 of the downstream turbine disk 5, the latter being arranged to be located radially outwardly. relative to the upstream flange 78. In addition, the labyrinth 80 extends radially to match the fixed distributor stage 18 or stator provided between the two rotor stages 20 and 22, and has an inner bore 83 surrounding the upstream flange 78 of the disk 5, this bore 83 preferably having a diameter substantially identical to the diameter of the inner bore 48 of the disk 3.

Therefore, the flow of cooling air D passing through the annular chamber 76 and arriving at the downstream face of the disk upstream 3, separates into two flows F1 and F2, respectively intended to feed the blades 4 and the blades 6 of the discs 3 and 5.

The first stream F1 therefore flows in 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, then enters cells 4a containing the feet of the blades 4. to cool them too.

In the same way, the second flow F2 flows in a cavity 69 located between the upstream face of the downstream turbine disk 5 and the downstream face of the same labyrinth 80 to cool the upstream face of the disk 5, then enters the cells 6a containing the feet of the blades 6 to also cool them. Note that for the second flow F2 reaches the vanes 6 of the downstream turbine disk 5, a plurality of orifices 84 is formed in the secondary upstream flange 82 of the downstream disk 5.

Therefore, the ventilation device according to the invention is such that the flow of cooling air D taken from the bottom of the combustion chamber 2 and intended to simultaneously feed the blades 4 and 6, borrows a single cooling circuit to the outlet 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 greatly simplifies the design of the turbine 100 with respect to that of the turbine 1 of the prior art, in which two cooling air flows were taken at the bottom of the chamber of combustion 2, in order to borrow two totally separate cooling circuits.

On the other hand, the upstream flange 78 of the downstream turbine disk 5 comprises a plurality of orifices 86 able to be traversed by a third flow F3 of the cooling air flow D. This third flow F3 is thus conveyed from the chamber annular 76 to an annular space 88 of 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 the same downstream disk 5, and on the other hand the spacer 9 disposed around the rotor shaft 11 of the low pressure turbine. Thus, the cooling air flow F3 can flow axially downstream in the annular space 88, in order to cool the downstream disc 5 by contacting the air with its internal bore 50. The third flow F3 is then evacuated downstream of the turbine 100 through the orifices 54 formed on the downstream flange 13 of the downstream turbine disk 5, this downstream flange 13 also participating in the outer delimitation of the annular space 88 and being assembled on the axis spacer 9 40.

Of course, various modifications may be made by those skilled in the art to the turbine 100 and its ventilation device which have just been described, solely by way of non-limiting examples.

Claims (4)

1. Ventilation device for a high pressure turbine rotor (100) of a turbomachine, the turbine (100) being arranged on the downstream part of a combustion chamber (2) and comprising an upstream turbine disk (3) fitted with blades (4) and a downstream turbine disk (5) fitted with blades (6), said device comprising a cooling circuit fitted with injectors (36) on the upstream side of the upstream disk (3) and supplied with a cooling airflow (D) taken from the back of the combustion chamber (2), said cooling circuit being arranged such that the cooling airflow (D) originating from the injectors (36) passes through orifices (74) formed in an upstream flange (66) of the upstream disk (3) so that it can be fixed on an upstream flange (78) of the downstream disk (5), so that this cooling airflow (D) circulates in the axial downstream direction between an inner reaming (48) in the upstream disk (3) and the upstream flange (78) of the downstream disk (5) so that it can be fixed on a downstream flange (79) of a high pressure compressor and so that the upstream disk (3) can be centred, said ventilation device also comprising a single labyrinth (80) fixed to one of the two turbine disks (3, 5), characterized in that the single labyrinth (80) is inserted between the two disks, such that the cooling airflow (D) is divided into a first flow (F1) circulating between a downstream face of the upstream disk (3) and an upstream face of the single labyrinth (80) towards the blades (4), and into a second flow (F2) circulating between an upstream face of the downstream disk (5) and a downstream face of the single labyrinth (80) towards the blades (6).
2. Device according to claim 1, characterized in that the injectors (36) penetrate into a cavity (64) partially delimited by the upstream flange (66) of the upstream turbine disk (3), and by an upstream seal (32) and a downstream seal (34), this downstream seal cooperating with a secondary upstream flange (72) of the upstream turbine disk (3).
3. Device according to claim 1, characterized in that several orifices (86) are formed in the upstream flange (78) of the downstream turbine disk (5), so that a third flow (F3) of the cooling airflow (D) can pass through them, said third flow (F3) circulating in the downstream axial direction within an annular space (88) formed between firstly the upstream flange (78) of the downstream disk (5) and an inner reaming (50) of this downstream disk (5), and secondly a spacer (9) located around a rotor shaft (11) of a low pressure turbine.
4. Device according to any one of the preceding claims, characterized in that the single labyrinth (80) is fixed to a secondary upstream flange (82) of the downstream turbine disk (5), in which several orifices (84) are formed through which the second flow (F2) of the cooling airflow (D) can circulate towards the blades (6).

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