EP3287604B1 - Positioning element with recesses for a guide vane assembly - Google Patents

Description

The present invention relates to a positioning element for a guide vane arrangement of a guide vane stage of a gas turbine, with at least one base section curved in the circumferential direction; a plurality of receiving openings arranged adjacent to one another in the circumferential direction on the base section, the opening axis of which extends essentially in the radial direction and which are set up to receive a respective radially inner guide vane section; a coupling section provided on the base section, which can be coupled or coupled to a seal carrier of a sealing arrangement. An example of a positioning element for a guide vane arrangement of a guide vane stage of a gas turbine is in the document US 2007/0128020 given.

Directional information such as "axial" or "axial", "radial" or "radial" and "circumferential" are basically to be understood in relation to the machine axis of the gas turbine, unless something else explicitly or implicitly results from the context. An addressed vane stage can be arranged in the area of a compressor or in the area of the turbine. The feature coupling section is to be understood broadly and includes, for example, a section that enables a positive connection with a counterpart of a seal carrier. However, the coupling section can also simply be an area or a surface of the base section to which a sealing element can be attached directly.

Such a positioning element can also be referred to as a position ring or position half ring. As a rule, the circular arrangement in a gas turbine is achieved by two semicircular position half-rings which abut one another in a common parting plane. It has been shown that, due to the thermal conditions, a radial temperature gradient forms in the position half rings, the position half rings radially on the outside being subject to greater expansion in the circumferential direction than radially on the inside. This greater radially outer circumferential expansion leads in particular in the region of the parting plane to severe deformations of the positioning element and the seal carrier coupled to it. These deformations can also be described as constrictions and are known under the term cording effect. The result of this is that, in particular, the seal carrier or its sealing elements come into contact with sealing fins rotating relative to these, so that the sealing elements are subject to severe wear. The cording effect leads in particular to a narrowing or localization in the area of the parting plane Reduction in diameter when the gas turbine is accelerated and widening or local increase in diameter when the gas turbine is slowed down.

The object of the invention is to provide a positioning element in which the cording effect is reduced.

For this purpose, it is proposed that at least one recess is provided in the base section, which is arranged between two adjacent receiving openings and extends at least in the radial direction from the inside outwards. The provision of such recesses enables the positioning element in the region of the recess to have a smaller effective radial height, to which the temperature gradient acts and which has an influence on the expansion of the positioning element. If such cutouts are provided along the circumference at a plurality of locations between the respective receiving openings, the cording effect can be influenced, since the deformations that occur are less than in the case of a continuous positioning element without cutouts. The recesses in the positioning element also lead to a reduced bending stiffness of the positioning element. In addition to the thermal effects, the cording effect is also influenced by the ratio of the bending stiffness of the positioning element and seal carrier. It is advantageous if the positioning element is "softer" or less stiff, because this reduces the cording effect. Furthermore, with a less rigid positioning element, a stiffer seal carrier can counteract the constriction of the positioning element.

The positioning element can have an annular design and two semicircular base sections.

A reduction in the cording effect and thus in constrictions on the positioning element also leads to a reduction in local inlets at a division level from the semicircular base sections. By reducing constrictions, the formation of gaps and leaks can be avoided, which has a positive influence on the efficiency and the surge limit, in particular because leaks on the sealing elements can be reduced.

Furthermore, due to the small inlets, a lower load on the sealing elements, in particular also on rotor sealing fins and their coating, can be achieved. this leads to to an improved or extended shelf life, so that the repair and maintenance effort can be reduced.

The coupling portion may include at least one axially front groove and one axially rear groove that run along the circumferential direction at the base portion. These two circumferential grooves are used in particular to couple a seal carrier to the positioning element.

According to a first embodiment, the axially front groove and the axially rear groove can have essentially the same distance in the radial direction from a radial inside of the base section. In other words, the two grooves are at approximately the same level or are at substantially the same distance (radius) from a machine axis.

In the first embodiment, the recess can also extend in the axial direction between two receiving openings and extend from an axially front surface of the base section to an axially rear surface of the base section. The recess can be designed as a slot in the base section.

Furthermore, in the first embodiment, the recess can have a changing radial height along the axial direction or have a constant height. Furthermore, the recess along the axial direction can have a changing width in the circumferential direction or have a constant width. The cording effect can be influenced in a targeted manner by an appropriate design or dimensioning of the cutouts or of the slot, in particular also taking into account that the radial temperature gradient also changes over the axial length.

According to a second embodiment, the cutout can run in the circumferential direction in an axially rear region of the base section, such that outer walls of the receiving openings which are essentially cylindrical are visible from the axially rear. The recess can be limited in the axial direction by an axially front wall section. The result is a continuous recess in an axially rear region, which extends forward in the axial direction between the receiving openings and ends at the axially front wall section.

In the second embodiment, the axially front groove and the axially rear groove can have a different distance from a radial inside of the base section.

The positioning element of the second embodiment can be produced by means of an additive manufacturing method, in particular by means of selective laser melting.

The invention also relates to a seal carrier for a seal arrangement with a base section which is curved in the circumferential direction and on which a sealing element is provided radially on the inside; a counter-coupling section which can be coupled or coupled to a coupling section of a positioning element, the counter-coupling section having an axially front spring section and an axially rear spring section which can be inserted or introduced with corresponding grooves in the coupling section of the positioning element. It is proposed that the axially front spring section and the axially rear spring section have a different distance from a radial inside of the base section. Such a seal carrier is particularly suitable for coupling to a positioning element of the second embodiment.

The spring sections can be attached to an axially front support wall and to an axially rear support wall, such that the two spring sections face each other in the axial direction.

The base section can have a cover section which is inclined radially on the outside in relation to the axial direction and the radial direction. Such an inclined cover section serves in particular in a coupled state to cover the recess on the positioning element.

In the base section, in particular in its cover section, a plurality of openings can be provided next to one another in the circumferential direction.

Finally, the invention also relates to a guide vane carrier arrangement for a gas turbine, in particular an aircraft gas turbine, with at least one positioning element according to the first embodiment and at least one associated seal carrier or with at least one positioning element according to the second embodiment and at least one seal carrier described above.

• Fig. 1 zeigt in einer schematischen Darstellung eine Draufsicht auf eine axiale Vorderseite eines Positionierungselements gemäß einer ersten Ausführungsform.
• Fig. 2 zeigt in einer schematischen Perspektivansicht von axial vorne einen Teil des Positionierungselements gemäß der ersten Ausführungsform.
• Fig. 3 zeigt in einer schematischen Perspektivdarstellung von radial innen etwa das halbe das Positionierungselement der Fig. 1
• Fig. 4 zeigt in einer schematischen Perspektivansicht von radial innen einen vergrößerten Teil des Positionierungselements der Fig. 3.
• Fig. 5 zeigt eine vergrößerte Perspektivdarstellung des Positionierungselements von axial hinten.
• Fig. 6 zeigt in den Teilfiguren A) und B) jeweilige Schnittdarstellungen des Positionierungselement, die in etwa der Schnittlinie VI-VI der Fig. 3 entsprechen, wobei die Fig. 6A) eine Variante darstellt mit variabler radialer Höhe der Aussparung, und Fig. 6B) eine Variante darstellt mit gleichbleibender radialer Höhe der Aussparung, was dem Beispiel der Fig. 1-4 entspricht.
• Fig. 7 zeigt in den Teilfiguren A) und B) Varianten des Positionierungselements der ersten Ausführungsform in einer zur Fig. 1 ähnlichen Darstellung.
• Fig. 8 zeigt in einer schematischen Perspektivansicht von axial schräg hinten einen Teil eines Positionierungselements einer zweiten Ausführungsform.
• Fig. 9 zeigt in einer schematischen Perspektivansicht von axial schräg vorne einen Teil eines Dichtungsträgers, der mit dem Positionierungselement der Fig. 8 koppelbar ist.

The invention is described below by way of example and not by way of limitation with reference to the attached figures.

• Fig. 1 shows a schematic representation of a top view of an axial front of a positioning element according to a first embodiment.
• Fig. 2 shows in a schematic perspective view from the front axially a part of the positioning element according to the first embodiment.
• Fig. 3 shows in a schematic perspective view from the radial inside about half of the positioning element of FIG Fig. 1
• Fig. 4 shows a schematic perspective view from the radially inside of an enlarged part of the positioning element of FIG Fig. 3 .
• Fig. 5 shows an enlarged perspective view of the positioning element from the axially rear.
• Fig. 6 shows in the partial figures A) and B) respective sectional views of the positioning element, which is approximately the section line VI-VI of Fig. 3 correspond, the Figure 6A ) represents a variant with variable radial height of the recess, and Figure 6B ) represents a variant with constant radial height of the recess, which is the example of the Fig. 1-4 corresponds.
• Fig. 7 shows in the partial figures A) and B) variants of the positioning element of the first embodiment in one Fig. 1 similar representation.
• Fig. 8 shows in a schematic perspective view from the rear axially obliquely part of a positioning element of a second embodiment.
• Fig. 9 shows in a schematic perspective view from the front axially obliquely a part of a seal carrier which with the positioning element of Fig. 8 can be coupled.

Fig. 1 shows a simplified schematic plan view in the axial direction of a first embodiment of a positioning element 10 and Fig. 2 shows an enlarged section of the positioning element 10. As can be seen from these figures, the positioning element 10 has a base section 12 which is curved in a semicircle. A plurality of receiving openings 14 arranged next to one another in the circumferential direction UR are provided in the base section 12. The receiving openings 14 are used in particular for receiving guide vanes, not shown here. Recesses 16 can be seen in the circumferential direction UR between two adjacent receiving openings 14. These recesses 16 extend in the radial direction RR from the inside to the outside. In the area of the dashed line TE ( Fig. 1 ) the so-called parting plane is indicated. In the area of this parting plane, two semicircular base sections 12 abut one another, so that a complete circular positioning element 10 can be formed. The base section 12 further comprises a coupling section 18 located radially on the inside. A sealing carrier (not shown here) can be attached to this coupling section 18. In this first embodiment, the cutouts 16 extend in particular through the coupling section 18. As already mentioned in the introduction, the feature coupling section can be understood broadly and comprises, for example, a section which enables a form-fitting connection to a counterpart of a seal carrier. However, the coupling section can also simply be an area or a surface of the base section to which a sealing element can be attached directly.

3 and 4 show the positioning element 10, which is also referred to in technical jargon as a locating ring or positioning ring, in a perspective view from the radial inside. In the Fig. 3 In particular, an abutting surface 20 of the base section 12 can be seen. With this abutting surface 20, the base section 12 lies in the area of the parting plane TE ( Fig. 1 ) on the other semicircular base section. It can also be seen from this illustration that the coupling section 18 has a type of inverted T-profile. As a result, an axially front groove 22 and an axially rear groove 24 are formed. Corresponding counterparts or spring-like counter-coupling sections of a seal carrier are to be connected with these two grooves 22, 24. The recesses 16 in particular also extend through the grooves 22, 24.

While in the 1 to 4 A recess 18 is arranged between each two adjacent receiving openings 14 Fig. 5 schematically and simplified a variant in which a recess 16 is provided only every two receiving openings 14. Fig. 5 is a view from the axially rear of the base section 12. From this illustration and also from the previous illustrations it can be seen that the cutouts 16 of FIG extend radially inward to radially outward. However, the cutouts 16 do not cut through the base section 12. Rather, the recesses 16 are slit-like. The width in the circumferential direction of such a recess 16 along the axial direction and / or along the radial direction can be constant or variable.

The 6A) and 6B ) are sectional views in the area of a recess 16 or slot, as shown by the section line VI-VI of Fig. 3 is indicated. A radial height RH of the recesses 16 can, as can be seen from the sectional views in FIG 6A) and 6B ) can be seen, also be constant or changeable. In the 6 A) a variable height RH of the recess 16 or the slot is shown. In Figure 6B ) a constant height RH is shown over the axial extent.

From the variants of 6A) and 6B ) and the above description regarding the possible adaptation of the width of the recesses, it is clear that the recesses can be adapted to respective properties, in particular the radial temperature gradients, by changing their dimensions in height and width. Such temperature gradients also depend in particular on further structural boundary conditions of an inner ring and guide vane arrangement of a gas turbine.

In Fig. 7 two variants of a base section 12 are shown in sub-figures A) and B). The base section 12 in Figure 7A ) has a few, here in each case five recesses 16, starting from the division level TE. The recesses are therefore not distributed along the circumference of the entire base section 12, but rather only near the parting plane TE.

At the base section 12 of the Figure 7B ) cutouts 16 are provided along the entire circumference, but a cutout 16 is only provided every two receiving openings 14. The Figure 7B ) corresponds to the Fig. 5 .

From the Fig. 7 it can be seen that the cutouts 16 can be provided at different distances from one another and in part or in total along the circumference of the base section 12. This also shows that the number and arrangement of the cutouts 16 can be selected in accordance with the framework conditions, such as radial temperature gradient and / or rigidity of the positioning element or seal carrier, so that the cording effect can be kept as low as possible depending on the construction of the gas turbine . Fig. 8 shows a second embodiment of a positioning element 110 with a base section 112 in a perspective view obliquely from behind (axial direction). Recesses 116 are provided between receiving openings 114 and extend at least in the radial direction RR. In contrast to the cutouts 16 of the first embodiment ( Fig. 1-7 ), the recesses 116 are not designed as slots, but are designed such that the outer peripheral walls 115 of the receiving openings 114 are visible.

The base section also has a coupling section 118, which has an axially front groove 122 and an axially rear groove 124. In contrast to the first embodiment, the axially rear groove 124 is arranged radially on the outside of the base section 112. This changed arrangement of the axially rear groove 124 is due to the larger recesses 116 and material missing radially on the inside, on which an axially rear groove could be formed as in the first embodiment. The axially rear groove 124 is located radially further outward than the axially front groove 122 with respect to a machine axis of the gas turbine. The recesses 116 are delimited axially at the front by an axially front wall section 117. The axially front wall section 117 also forms the back or opposite side of a groove base of the axially front groove 122.

The shape of the base section 112 with the recesses 116 and the coupling section 118 with the two grooves 122, 124 presented here is optimized in such a way that the base section 112 can be produced by means of an additive manufacturing method, in particular by means of selective laser melting. The semicircular base section 112 can be built up in layers, for example, from axially front to axially rear.

Due to the changed construction of the base section 112, in Fig. 9 part of a seal carrier 130 adapted to this construction is presented. The seal carrier 130 comprises counter-coupling sections 132, 134. The counter-coupling sections 132, 134 project in the axial direction, such that spring-like projections are formed. Accordingly, the counter coupling section 132 can engage in the axially front groove 122 of the base section, and the counter coupling section 134 can engage in the axially rear groove 124 of the base section 112. A sealing element, not shown here, would have to be provided on the radial inside 136 of the seal carrier 130. The negative feedback sections 132, 134 are designed as axially front spring section 132 and as axially rear spring section 134. In particular, they are at a different distance from a radial inside of a base section 138.

The seal carrier 130 has the base section 138 which is arranged opposite (radially inside) the receptacle openings 114 in the assembled state. This base section merges into or comprises an inclined covering section 140. The covering section 140 is used in particular to enable producibility by means of selective laser melting. A plurality of openings 142 are provided in the inclined cover section 140. These openings 142 also serve to produce them by means of selective laser melting. The shape of the seal carrier 130 is thus designed such that it can be manufactured by means of an additive manufacturing method, in particular by means of selective laser melting.

Both embodiments have in common that recesses 16, 116 are provided in the base section 12, 112, which serve to reduce the cording effect on the positioning element 10, 110. The cutouts act in particular to provide interruptions so that a radial temperature gradient cannot develop its full effect along the entire circumference of the positioning element 10, 110. The cutouts also serve to reduce the bending stiffness of the positioning element, which likewise reduces the cording effect.

Reference list

10, 110

Positioning element

12, 112

Base section

14, 114

Receiving opening

115

outer peripheral wall

16, 116

Recess

117

axially front wall section

18, 118

Coupling section

20

Bump

22, 122

axially front groove

24, 124

axially rear groove

130

Seal carrier

132

Negative feedback section

134

Negative feedback section

136

radial inside

138

Basic section

140

Cover section

142

openings

Claims (15)

1. Positioning element (10) for a guide vane arrangement of a guide vane stage of a gas turbine, comprising

   at least one base portion (12; 112)which is curved in the circumferential direction (UR);

   a plurality of receiving openings (14; 114) arranged on the base portion (12; 112) so as to be adjacent to one another in the circumferential direction (UR), the opening axis of which openings extends substantially in the radial direction and which openings are designed to receive a radially innerguide vane portion in each case;

   a coupling portion (18; 118) provided on the base portion (12; 112), which coupling portion can be or is coupled to a seal carrier (130) of a seal arrangement;

   characterized in that at least one recess (16; 116) is provided in the base portion (12; 112), which recess is arranged between two adjacent receiving openings (14; 114) and extends from the inside to the outside at least in the radial direction (RR).
2. Positioning element according to claim 1, characterized in that it is annular and comprises two semicircular base portions (12; 112).
3. Positioning element according to either claim 1 or claim 2, characterized in that the coupling portion (18; 118) comprises at least one axially front groove (22; 122) and one axially rear groove (24; 124), which grooves extend along the circumferential direction (UR) on the base portion (12; 112).
4. Positioning element according to claim 3, characterized in that the axially front groove (22) and the axially rear groove (24) are at substantially the same distance from a radial inner side of the base portion (12) in the radial direction (RR).
5. Positioning element according to any of claims 1 to 4, characterized in that the recess (16) extends in the axial direction (AR) between two receiving openings (14) and runs from an axially front surface of the base portion (12) to an axially rear surface of the base portion (12).
6. Positioning element according to claim 5, characterized in that the recess (16) is designed as a slit in the base portion (14).
7. Positioning element according to claim 6, characterized in that, along the axial direction (AR), the recess (16) has a changing radial height(RH) or has a constant height (RH).
8. Positioning element according to either claim 6 or claim 7, characterized in that, along the axial direction (AR), the recess (16) has a changing width in the circumferential direction (UR) or has a constant width.
9. Positioning element according to any of claims 1 to 3, characterized in that the recess (116) extends in the circumferential direction (UR) in an axially rear region of the base portion (112) such that substantially cylindrical outerwalls (115) of the receiving openings (114) are visible axially from the rear.
10. Positioning element according to any of claims 1 to 3 or according to claim 9, characterized in that the recess (116) is delimited by an axially front wall portion (117) in the axial direction (AR).
11. Positioning element according to either claim 9 or claim 10 or according to any of claims 1 to 3, characterized in that the axially front groove (122) and the axially rear groove (124) are at a different distance from a radial inner side of the base portion (112).
12. Positioning element according to any of claims 9 to 11, characterized in that it is produced by means of an additive manufacturing process, in particular by means of selective laser melting.
13. Guide vane carrier arrangement for a gas turbine, in particular an aircraft gas turbine, comprising at least one positioning element (10) according to any of claims 1 to 3 and at least one associated seal carrier.
14. Guide vane carrier arrangement for a gas turbine, in particular an aircraft gas turbine, comprising
    at least one positioning element (110) according to any of claims 9 to 12 and at least one seal carrier (130), wherein the seal carriercomprises:

    a main portion (138) which is curved in the circumferential direction (UR), on which portion a sealing element is provided radially on the inside;

    a counter coupling portion (132,134) which can be or is coupled to the coupling portion (122, 124) of the positioning element (110), wherein the countercoupling portion comprises an axially front spring portion (132) and an axially rear spring portion (134) which can be or are inserted into corresponding grooves (122, 124) of the coupling portion of the positioning element (110),

    and wherein the axially front spring portion (132) and the axially rear spring portion (134) are at a different distance from a radial inner face of the main portion (130).
15. Guide vane arrangement according to claim 14, characterized in that the spring portions (132, 134) are attached to an axially front support wall and to an axially rear support wall such that the two spring portions (132, 132) face one other in the axial direction (AR), the main portion (138) preferably having, radially on the outside, a cover portion (140) which is inclined with respect to the axial direction (AR) and the radial direction (RR), a plurality of openings (142) being provided side by side in the circumferential direction (UR) preferably in the main portion (138), in particular in the cover portion (140) thereof.

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