EP1577501B1 - High pressure turbine stator of a turbo-engine and his assembling process - Google Patents

Description

Background of the invention

The present invention relates to the general field of game control at the top of the blades of a turbomachine high-pressure turbine. It relates more particularly to a method of assembling the sectorized components constituting the stator of a high-pressure turbomachine turbine.

The stator of a turbomachine high-pressure turbine consists mainly of an annular casing arranged around a longitudinal axis of the turbine, a plurality of sectorized spacers mounted on the casing and a plurality of segments of ring fixed on the spacers and which form a circular surface surrounding the blades of a rotor of the turbine.

It is known that to increase the efficiency of such a turbine, it is necessary to reduce as much as possible the clearance between the top of the rotor blades of the rotor of the turbine and the parts of the stator that face them.

This reduction of the clearance at the top of the blades is achieved by varying the diameter of the casing of the turbine according to its operating regime. Generally, annular conduits of the stator of the turbine are arranged around the casing and are traversed by air taken from other parts of the turbomachine. The air is injected onto the housing and thus causes thermal expansion or contraction of the stator of the turbine, varying its diameter. The air circulation lines form a game steering box at the top of the blades.

Previously known blade tip control housings do not always make it possible to obtain a great uniformity of temperature over the entire circumference of the turbine casing, which causes crankcase distortions which are particularly detrimental to the efficiency and to the life of the high-pressure turbine.

EP 1258599, for example, describes a method of assembling a game control system in a turbomachine.

Object and summary of the invention

The present invention therefore aims to overcome such drawbacks by proposing a method of assembling the sectorized elements of an annular stator of a high-pressure turbine which makes it possible to obtain a game control at the top of the blades leading to distortions. as low as possible and in all repetitive cases.

For this purpose, the subject of the invention is a method for assembling segmented elements of an annular stator of a turbomachine high-pressure turbine around a longitudinal axis of said turbine, characterized in that it consists of defining an angular distribution pattern of the stator elements for a predetermined angular sector, the distribution pattern being defined so as to avoid radial alignment between inter-sector areas of the stator elements defined between two adjacent sectors of the same element of the stator, and to repeat the pattern of distribution over the entire circumference of the stator.

Preferably, the angular distribution pattern is repeated symmetrically in rotation with respect to the predetermined angular sector.

When the stator elements consist of an annular housing, a plurality of sectorized spacers on which are fixed a plurality of ring sectors forming a continuous circular surface surrounding the blades of a rotor of the turbine, and a plurality of angular sectors of air flow boxes for discharging air on the housing to allow control of the clearance at the top of the rotor blades of the high-pressure turbine, the angular distribution pattern stator elements are advantageously defined so as to avoid radial alignment between the inter-spacer zones defined between two adjacent spacers and the inter-sector housing areas defined between two adjacent housing sectors.

In this way, it is avoided to align radially areas of the housing on which air is not discharged by the sectors of air flow boxes with inter-spacing zones. On the predetermined angular sector, the crankcase temperature distribution and the thermal distortions that result are therefore uniformly.

In addition, when the angular distribution is repeated symmetrically, the crankcase temperature distribution is symmetrical over the entire circumference of the housing. As a result, the thermal distortions of the housing are substantially repetitive, which facilitates control.

When the stator elements are furthermore composed of a plurality of air supply mouths arranged through the housing and intended to supply air to a stage of a low-pressure distributor of the turbomachine disposed downstream of the upper turbine pressure, the method further comprises radially aligning each air supply mouth with an inter-sector box area.

Preferably, the predetermined angular sector corresponds to an angular sector of air circulation box. In addition, at each angular sector of the air circulation box is advantageously associated three spacers and an air supply mouth.

The invention also relates to a high-pressure turbine stator whose angular distribution sectored elements leads to low thermal distortions and repetitive.

The high-pressure turbine stator is characterized in that the stator elements are distributed angularly about the longitudinal axis of the high-pressure turbine so as to avoid radial alignment between the inter-spacing zones defined between two adjacent spacers and the inter-housing areas defined between two adjacent housing sectors.

Preferably, the stator elements are angularly distributed about the longitudinal axis of the high-pressure turbine further in order to radially align each air supply mouth with an inter-sector housing area.

Advantageously, the stator comprises N angular sectors of air flow boxes, 3N spacers, N air supply vents and 6N ring sectors.

Brief description of the drawings

• la figure 1 est une vue en perspective d'un stator de turbine haute-pression selon l'invention ;
• la figure 2 est une vue schématique en coupe transversale du stator de la figure 1 ; et
• les figures 3 et 4 sont des vues schématiques en coupe transversale de stators selon d'autres modes de réalisation de l'invention.

Other features and advantages of the present invention will become apparent from the description given below, with reference to the drawings annexed which illustrate an embodiment without any limiting character. In the figures:

• Figure 1 is a perspective view of a high-pressure turbine stator according to the invention;
• Figure 2 is a schematic cross-sectional view of the stator of Figure 1; and
• Figures 3 and 4 are schematic cross-sectional views of the stators according to other embodiments of the invention.

Detailed description of an embodiment

The stator 10 of a high-pressure turbine comprises an annular casing 12 disposed around a longitudinal axis X-X of the high-pressure turbine.

On the inner surface of the annular housing 12 are mounted a plurality of sectorized spacers 14 and circumferentially disposed about the longitudinal axis X-X of the turbine. By sectored elements is meant for the remainder of the description, that the designated elements are in the form of angular sectors which, when placed end to end, form an annular assembly.

Ring sectors 16 are fixed on the inner surface of the spacers 14. The ring sectors 16 are circumferentially disposed about the longitudinal axis XX of the turbine and form a continuous circular surface surrounding moving blades (not shown in the drawings). figures) of a rotor (not shown) of the high-pressure turbine.

The inner surface of the ring sectors 16 partially defines the flow path of the gases from the combustion chamber (not shown) of the turbomachine and passing through the high pressure turbine.

A game (not shown) is left between the inner surface of the ring sectors 16 and the top of the rotor blades of the turbine to allow rotation of the latter.

To increase the efficiency of the turbine, it is necessary to reduce as much as possible this game. For this purpose, there is provided a game control device 18. This device consists in particular of an air collection tube 20 disposed around the housing 12 and supplied with air by the least one supply line 22 (only one is shown in Figure 1).

The air collection tube 20 supplies air with a plurality of angular sectors of air circulation housings 24 which are circumferentially attached to the housing 12 by means of fastening rules 26. Feeding the circulation casing sectors 24 air is effected by means of sealed V-clamps 28 connected to the collector tube 20.

In Figure 1, each housing sector 24 consists of three air circulation ramps spaced axially and substantially parallel to each other. Each of these ramps is pierced with a plurality of holes (not shown) which discharge air on the housing 14 to change the temperature.

Furthermore, a plurality of air supply vents 30 are arranged through the casing 12. These vents 30 are intended to supply air to a stage of a low-pressure distributor (not shown in the figures) of the turbomachine arranged downstream of the high-pressure turbine.

The invention provides a method of assembling these different elements of the stator of the turbine about its longitudinal axis X-X.

According to the invention, this method consists in defining an angular distribution pattern of the stator elements 10 for a predetermined angular sector ψ , and in repeating the pattern over the entire circumference of the stator.

The pattern of distribution of the elements of the stator 10 over a predetermined angular sector ψ is defined so as to avoid radial alignment between inter-sector areas of stator elements. The inter-sector zones are defined as zones located between two adjacent sectors of the same element of the stator.

The predetermined angular sector ψ is advantageously chosen so as to correspond to an angular sector of housing 24.

FIG. 2 illustrates an example of application of the method according to the invention. In this figure, the predetermined angular sector ψa has a sector of 60 °.

On this angular sector ψa , the stator elements 10 are arranged so as to avoid radial alignment between inter-sector areas of stator elements. In particular, the distribution angular is chosen so as to avoid radial alignment between the inter-strut zones 14a defined between two adjacent struts 14 and the inter-sector areas 24a of housing defined between two adjacent housing sectors 24.

Such a distribution of the spacers 14 with respect to the housing sectors 24 makes it possible to avoid aligning radially between zones of the casing 12 on which air is not discharged by the game control device 18 (this is to say at the inter-sector areas 24a of housing) and inter-spacing zones 14a.

In this way, the temperature distribution of the housing 12 on the angular sector ψa , and therefore the resulting thermal distortions, are substantially uniform.

The distribution pattern thus defined on the angular sector ψa is then repeated over the entire circumference of the stator 10. In the example of Figure 1, the distribution pattern is repeated five times to cover the entire circumference of the stator.

According to an advantageous characteristic of the invention, the distribution pattern is repeated over the entire circumference of the stator symmetrically in rotation with respect to the predetermined angular sector ψa .

Thus, the temperature distribution of the housing 12 is symmetrical over the entire circumference of the housing. As a result, the thermal distortions of the housing 12 are substantially repetitive, which facilitates control.

According to another advantageous characteristic of the invention, the angular distribution pattern of the stator elements 10 for the predetermined angular sector is also defined so as to radially align each air supply opening 30 with an inter-sector area of housing 24a. . This particular arrangement of the air supply vents 30 also contributes to improving the temperature homogeneity of the housing 12.

In Figure 2, we note that the vents 30 for supplying air a stage of a low-pressure distributor are each disposed between two housing sectors 24 adjacent.

FIG. 3 illustrates another example of application of the method according to the invention. In this figure, we chose as angular sector predetermined ψb a sector of 90 °. This angular sector ψb corresponds to an angular sector of housing 24.

On this angular sector ψb , the elements of the stator 10 are arranged, on the one hand so as to avoid radial alignment between inter-sector areas of stator elements, and on the other hand so as to radially align each mouth of the stator. air supply 30 with an inter-sector area of housing 24a.

This angular disposition is also respected on the stator of FIG. 4 which illustrates another example of application of the method according to the invention. In this figure, a sector of 30 ° corresponding to an angular sector of housing 24 has been chosen as predetermined angular sector ψc .

According to yet another advantageous characteristic of the invention, it is provided that each angular sector of the air circulation box 24 is associated with three spacers 14 and an air supply mouth 30. Moreover, it is also advantageous to associate two ring sectors 16 to each spacer 14.

In other words, the high-pressure turbine stator 10 according to the invention comprises N angular sectors of air flow boxes 24, 3N spacers 14, N air supply vents 30, and 6N ring sectors 16.

Thus, the configurations A, B and C of the following table are obtained, which respectively correspond to the stator embodiment examples of FIGS. 2, 3 and 4. This table indicates the number of elements segmented according to the configuration A, B or C . housing areas 24 spacers 14 mouths 30 ring sectors 16 A with N = 6 6 18 6 36 B with N = 4 4 12 4 24 C with N = 12 12 36 12 72

Claims (10)

1. A method of assembling sectored elements (14, 24) of an annular stator (10) of a high-pressure turbine of a turbomachine about a longitudinal axis (X-X) of said turbine, the stator comprising:

   - an annular casing (12) disposed about the longitudinal axis (X-X) of the high-pressure turbine;

   - a plurality of spacers (14) that are sectored and mounted on the casing (12) and onto which a plurality of ring sectors (16) are secured, said ring sectors being disposed circumferentially about the longitudinal axis (X-X) of the turbine so as to form a continuous circular surface encompassing the rotor blades of a turbine rotor; and

   - a plurality of angular air flow duct sectors (24) disposed circumferentially around the casing (12), and designed to discharge air onto the casing in order to enable clearance at the tips of the turbine rotor blades to be tuned;

   said method being characterised in that it consists in:

   - defining an angular distribution pattern for distributing elements of the stator over a predetermined angular sector (Ψ), said pattern being defined so as to prevent the inter-spacer zones (14a) defined between two adjacent spacers (14) being in radial alignment with the duct inter-sector zones (24a) defined between two adjacent duct sectors (24); and in:

   - repeating said distribution pattern around the entire circumference of the stator.
2. A method according to claim 1, characterised in that the angular distribution pattern is repeated symmetrically in rotation relative to the predetermined angular sector (Ψ).
3. A method according to claim 1 or claim 2, in which the stator elements further consist of a plurality of air supply inlets (30) disposed through the casing (12) and designed to supply air to a stage of a low-pressure distributor of the turbomachine, said stage being disposed downstream from the high-pressure turbine, said method being
   characterised in that it further consists in aligning each air supply inlet (30) radially with a duct inter-sector zone (24a).
4. A method according to any one of claims 1 to 3, characterised in that an angular air flow duct sector (24) corresponds to the predetermined angular sector (Ψ).
5. A method according to any one of claims 1 to 4, characterised in that three spacers (14) and one air supply inlet (30) are associated with each angular air flow duct sector (24).
6. A method according to claim 5, characterised in that two ring sectors (16) are connected to each spacer (14).
7. A stator of a high-pressure turbine of a turbomachine comprising the following elements:

   - an annular casing (12) disposed about a longitudinal axis (X-X) of the high-pressure turbine;

   - a plurality of spacers (14) that are sectored and mounted on the casing (12) and onto which a plurality of ring sectors (16) are secured, said ring sectors being disposed circumferentially about the longitudinal axis (X-X) of the high-pressure turbine so as to form a continuous circular surface encompassing the rotor blades of a high-pressure turbine rotor;

   - a plurality of angular air flow duct sectors (24) disposed circumferentially around the casing (12) and designed to discharge air onto the casing in order to enable clearance at the tips of the high-pressure turbine rotor blades to be tuned; and

   - a plurality of air supply inlets (30) disposed through the casing (12) and designed to supply air to a low-pressure distributor stage of the turbomachine, said stage being disposed downstream from the high-pressure turbine;

   said stator being characterised in that the stator elements are distributed angularly about the longitudinal axis (X-X) of the high-pressure turbine so as to prevent the inter-spacer zones (14a) defined between two adjacent spacers (14) being in radial alignment with the duct inter-sector zones (24a) defined between two adjacent duct sectors (24).
8. A stator according to claim 7, characterised in that the stator elements are distributed angularly about the longitudinal axis (X-X) of the high-pressure turbine, so as also to cause each air supply inlet 30 to be in radial alignment with a duct inter-sector zone (24a).
9. A stator according to claim 7 or claim 8, characterised in that it has N angular air flow duct sectors (24), 3N spacers (14), and N air supply inlets (30).
10. A stator according to claim 9, characterised in that it has 6N ring sectors (16).

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