Guide vane segment for a turbomachine

Description

[0001] The invention relates to a guide vane element for a turbomachine, in particular for an aircraft engine. Further aspects of the invention relate to a guide vane segment comprising such a guide vane element, a guide vane ring comprising at least one guide vane segment, and a turbomachine.

[0002] In the manufacture of turbomachines, it is known to assemble guide vane rings from a plurality of guide vane segments. Such guide vane rings serve to align a medium flowing through them (the working medium) during operation of turbomachines. By means of the guide vane rings, at least a portion of the kinetic energy of the flowing medium can be converted into swirl energy during alignment. This swirl energy can be used to move (drive) an impeller connected to the guide vane ring and thereby set a drive shaft of the turbomachine connected to the impeller in rotational motion. In order to operate turbomachines with the greatest possible efficiency, it is advisable to keep any gaps – for example, between the guide vane ring and a shaft housing part adjacent to it in a radial direction of extension – as small as possible.This can at least largely prevent unwanted fluid leakage of the medium.

[0003] EP 2 696 039 A1 discloses a gas turbine stage having a sealing ring element mounted on a guide vane root by a spoke centering mechanism. This spoke centering mechanism has an inner wall and a circumferential groove receiving the spoke centering mechanism. The inner wall has an end face facing the inner surface of the circumferential groove and an adjacent flank angled relative to the groove. A rounded portion is formed as a radius between the end face and the flank. If, during proper use of the gas turbine stage, the front end face in the flow direction comes into contact with the inner surface of the groove, this radius reduces the stress load and wear.

[0004] EP 2 722 486 A1 discloses a fish-mouth seal carrier for a guide vane assembly of a gas turbine. The fish-mouth seal carrier comprises a box profile with two axial legs and two radial legs, as well as a sealing element arranged on one of the axial legs. An integrally formed axial flange is provided on the box profile to form a fish-mouth seal.

[0005] EP 2 551 454 A2 discloses a low-pressure turbine comprising a plurality of stator stages. Honeycomb structures are arranged at the respective radial ends of the stator stages to form a sealing point with low fluid leakage on a shaft housing with labyrinth seals radially opposite them.

[0006] Furthermore, US 4,194,869 shows a guide vane cluster with fastening means for securing the position of the guide vane cluster in a gas turbine. This position securing can reduce any flow around the guide vane cluster at undesired locations. EP 2 559 849 A2 discloses a guide vane segment for a turbomachine. The guide vane segment has at least one guide vane element with a flange and a positioning means protruding therefrom. A partial surface of the positioning means is beveled relative to a support surface of the flange. A radially outer region of the positioning means rests against a seal carrier of the guide vane segment.

[0007] The object of the present invention is to improve a guide vane element, a guide vane segment, a guide vane ring, and a turbomachine of the type mentioned above, so that these components have a high degree of tightness against fluid leakage even under heavy loads.

[0008] This object is achieved by a guide vane element having the features of patent claim 1, by a guide vane segment having the features of patent claim 2, by a guide vane ring according to patent claim 4, and by a turbomachine according to patent claim 5. Advantageous embodiments with expedient further developments of the invention are specified in the respective subclaims.

[0009] The present invention comprises a guide vane element according to claim 1 for a guide vane segment as well as a guide vane segment with the guide vane element according to the invention and with a seal carrier according to claim 2.

[0010] According to the invention, in a transition from the flange to the positioning means, a partial surface of the positioning means borders the flange, and respective surface normals of the support surface and the partial surface enclose an angle with each other that is different from a zero angle, wherein the partial surface is designed such that it does not come into contact with the seal carrier. This has the advantage that the seal tightness between the seal carrier and the flange is improved, since the surface (support surface) on which the seal carrier is supported is smaller compared to systems known from the prior art, thus resulting in higher surface pressure between the seal carrier and the sealing surface. Furthermore, relative tilting of the seal carrier on the positioning means and the associated lifting of the seal carrier from the support surface can be prevented, even under high loads.The seal carrier can, for example, be designed as a one-piece, annular seal carrier.

[0011] The transition from the flange to the positioning means can be designed, for example, as a straight line or as a curved line, at which the flange and the partial surface can adjoin one another. The transition can also be designed as an edge, for example with a rounded edge, at which the flange and the partial surface adjoin one another. The inclusion of an angle other than a zero angle by the respective surface normals of the support surface and the partial surface means that the partial surface is offset relative to the support surface, at least in some regions. Accordingly, when the guide vane segment is used as intended as a component of a turbomachine, the partial surface is set back and / or beveled relative to the support surface in a main flow direction of a working medium flowing through the turbomachine during operation.The partial surface and the support surface can also form at least part of a shoulder on the flange. As a result, the support surface can be designed as a sealing surface running radially around the flange, relative to which the partial surface is set back and / or beveled. This is advantageous because the seal carrier, which can also be referred to as a SIAS (Static Inner Air Seal), only rests on the support surface and not - as is known from the prior art - also on the positioning means, thereby achieving a better sealing effect between the support surface and the seal carrier. If the seal carrier is subjected to load as a result of the operation of the turbomachine, this can effectively prevent the seal carrier from tilting about a contact point on the positioning means and thus lifting off the support surface, which could lead to fluid leakage.The partial surface of the positioning device, which is beveled and / or recessed relative to the support surface, ensures that even in the event of a load-induced relative movement between the SIAS and the guide vane element, the SIAS does not lift off the support surface, especially since the SIAS cannot be disadvantageously supported by the positioning device. Thus, in contrast to prior art solutions, tilting of the SIAS around the positioning device is prevented and, in contrast to prior art solutions, a high degree of tightness against fluid leakage is achieved even under heavy loads.

[0012] The guide vane segment, which comprises a guide vane element according to the invention and a seal carrier, can correspond to a part of a guide vane ring and can be designed, for example, as a guide vane ring segment. Accordingly, the guide vane segment can be designed, for example, as a third and thus as a 120° segment of such a guide vane ring. In addition to the flange and the positioning means, the guide vane segment can comprise, for example, a radially inner shroud segment, a guide vane blade or several guide vane blades, as well as a radially outer shroud segment. The seal carrier can have a sealing element, for example in the form of a brush seal or a honeycomb seal, at one radial end.Such a sealing element can at least reduce undesirable fluid leakage between the sealing element and, for example, a housing area of ​​a drive shaft of the turbomachine when the guide vane segment is used as intended in the turbomachine. The support surface can be designed as a sealing surface to reduce fluid leakage between the flange and the seal carrier. When the seal carrier is arranged on the flange, the positioning means engages in the circumferential radial groove of the seal carrier. This is advantageous because the groove enables at least partial engagement of the flange and the positioning means when the seal carrier is arranged. This easily restricts any degrees of freedom of movement between the seal carrier and the guide vane element.The seal carrier can further be fixed to the flange and thus to the guide vane element by means of a fixing element, which can be designed as a bolt, for example.

[0013] The support surface is designed as an annular surface segment. The support surface can be defined by a circular arc or, in some areas, by a straight line instead of a circular arc. This allows for a particularly uniform surface pressure between the seal carrier and the support surface. This has the advantage that a uniform sealing effect can be achieved at the support surface even under dynamic loads on the seal carrier.

[0014] In a further advantageous embodiment of the invention, the positioning means is connected to the flange as a single piece. This reduces the number of individual parts required to construct the guide vane element. This is advantageous because the guide vane segment can be manufactured with particularly minimal assembly effort.

[0015] The forked arrangement of the positioning pins can also be referred to as spoke centering. The forked design prevents any rotation of the seal carrier around the two positioning pins. This allows a simple way to restrict a further degree of freedom of movement of the seal carrier.

[0016] A guide vane element according to the invention achieves a particularly high sealing effect between the support surface and a seal carrier supported on it.

[0017] The present invention further encompasses a guide vane ring comprising at least one guide vane segment according to the invention. The guide vane ring can, for example, be composed of three 120° guide vane segments. Such a guide vane ring contributes in an improved manner to reducing fluid leakage.

[0018] Finally, the present invention also encompasses a turbomachine, in particular an aircraft engine, with at least one guide vane segment according to the invention and additionally or alternatively with at least one guide vane element according to the invention and additionally or alternatively with at least one guide vane ring. Such a turbomachine can be operated with reduced fluid leakage and thus with a particularly high level of efficiency.

[0019] In an advantageous embodiment of the invention, the turbomachine is a turbine, and the support surface of the flange faces a main flow direction of a working medium flowing through the turbomachine during operation. This is advantageous because, in the event of any loads on the seal carrier arranged on the flange as a result of an inflow of the working medium, any lifting of the seal carrier from the support surface can be at least largely prevented. The seal carrier thus rests flatly on the support surface even when subjected to load, which can reduce or even prevent fluid leakage between the seal carrier and the support surface.

[0020] In a further advantageous embodiment of the invention, the turbomachine is a compressor, and the support surface of the flange faces away from the main flow direction of a working medium flowing through the turbomachine during operation. This at least largely prevents any possible lifting of the seal carrier from the support surface, even in a compressor.

[0021] Further features of the invention emerge from the claims, the exemplary embodiments, and the drawings. The features and combinations of features mentioned above in the description, as well as the features and combinations of features mentioned below in the exemplary embodiments, can be used not only in the respective specified combinations, but also in other combinations without departing from the scope of the invention. The drawings show: Fig. 1 is a perspective view of a guide vane segment known from the prior art; Fig. 2a is a perspective view of a partially illustrated embodiment of a guide vane element which is exemplary for the invention; Fig. 2b is a side view of a partial area of ​​the Fig. 2a shown guide vane element, onto which a seal carrier is pushed; Fig. 3 is a side view of a partial area of ​​a further embodiment of the guide vane element, in which a partial surface of a positioning means of the guide vane element has a curvature and directly adjoins the support surface of the flange; Fig. 4a is a side view of a partial area of ​​a further embodiment of the guide vane element, in which the flange and the positioning means form a shoulder; and Fig. 4b is a detailed view of a Fig. 4a dashed area.

[0022] Fig. 1 shows a guide vane segment 50 for a turbomachine, known from the prior art. The guide vane segment 50 has a flat sealing surface 54 at a sealing area 52, against which a radial seal (not shown here) can be brought into contact. Furthermore, the guide vane segment 50 has a serrated centering 56 for the radial seal. The sealing surface 54 extends in this case over a particularly large, Fig. 1 hatched area, which also includes a partial surface area of ​​individual centering elements of the serrated centering 56. The sealing surface 54 extends up to a linear contact 57 of the centering 56. The contact 57 extends over two centering struts 58 of the centering 56, which are arranged in a fork-like manner. The contact 57 can also be referred to as a support point on an edge area of ​​the sealing surface 54. Due to the extension of the sealing surface 54 to the centering struts 58 and thus to areas of the centering 56, increased fluid leakage can occur between the sealing surface 54 and the radial seal if the sealing surface 54 and the radial seal are at an unfavorable angle to one another due to operational loads. This is because the radial seal tilts around the contact 57 on the centering as a result of operational deformations.One consequence of this is a lifting of the radial seal from the sealing surface 54 and a fluid leakage, particularly in a recess area 59 between the centering struts 58, especially since the sealing surface 54 extends partially around this recess area 59.

[0023] In Fig. 2a a guide vane element 12 is shown, which in Fig. 2b in a side view according to a Fig. 2a shown in the direction of view A indicated by an arrow together with a seal carrier 30.

[0024] The guide vane element 12 and the seal carrier 30 belong to a Fig. 2b A partially illustrated guide vane segment 10 for a turbomachine (not shown in detail here), which may be configured, for example, as an aircraft engine. The guide vane segment 10 thus comprises the guide vane element 12 and the seal carrier 30. A guide vane ring (not shown in detail here) can be assembled from several such guide vane segments 10 and used in the turbomachine.

[0025] The guide vane element 12 comprises in the present case at least one blade 36, a radially inner shroud segment 34, and a radially outer shroud segment not shown here.

[0026] The two shroud segments adjoin the at least one blade 36 on opposite sides thereof. Furthermore, the guide vane element 12 comprises a flange 14 formed in a radial direction of extension R of the guide vane element 12 and at least one positioning means 18 protruding from the flange 14 in the radial direction of extension R. In the present case, the positioning means 18 is integrally connected to the flange 14.

[0027] The guide vane segment is Fig. 2b pushed along an assembly direction M onto the presently annular seal carrier 30, so that the seal carrier 30 and the flange 14 abut one another. By means of the positioning means 18, the seal carrier 30 and the guide vane element 12 are aligned relative to one another. The flange 14 has a support surface 16, on which the seal carrier 30 is supported in its contact with the flange 14. The support surface 16 of the flange 14 faces a main flow direction H of a working medium flowing through the turbomachine during operation, provided the turbomachine is designed as a turbine. In the case of a turbomachine designed as a compressor, however, the support surface 16 of the flange 14 would face away from the main flow direction H.

[0028] The support surface 16 serves as a sealing surface with which the seal carrier 30 forms a sealing seat when arranged and supported on the flange 14. The support surface 16 is designed here as an annular surface segment. The support surface can be defined by a circular arc or, in some regions, by a straight line instead of a circular arc. This particularly includes the fact that the support surface 16 can also be defined in the radial direction R by a transition 19, designed, for example, as a straight line, and accordingly has no circumferential radial rounding at such a boundary point and deviates slightly from a ring segment shape.

[0029] In the transition 19 from the flange 14 to the positioning means 18, a partial surface 20 of the positioning means 18 borders the flange 14, with respective surface normals 17, 21 of the support surface 16 and the partial surface 20 enclosing an angle α different from a zero angle. The first surface normal 17 is assigned to the support surface 16, whereas the second surface normal 21 is assigned to the partial surface 20.

[0030] In this case, the seal carrier 30 has a circumferential radial groove 32, with which the positioning means 18 engages when the seal carrier 30 is arranged on the flange 14. A sealing element 31, designed, for example, as a brush seal or honeycomb seal, is arranged at one end of the seal carrier 30.

[0031] By means of a Fig. 2b The seal carrier 30 can be secured to the flange 14 by means of the fixing element shown, which in this case is designed as a bolt 28, as soon as the seal carrier 30 is brought into contact with the support surface 16. The positioning means 18 in this case has two positioning pins 22, 24 arranged in a fork-like manner relative to one another, which engage in the circumferential radial groove 32 when the seal carrier 30 is arranged on the flange 14. To secure the seal carrier 30, the bolt 28 can be passed through a recess 26 partially delimited by the two positioning pins 22, 24. The positioning pins 22, 24 can each also be referred to as a "tang."

[0032] In the Fig. 2b, Fig. 3 und Fig. 4a Different embodiments of the guide vane element 12 are shown in each case. In these figures, only the first positioning pin 22 is shown as a representative of both positioning pins 22, 24, which in these figures obscures the second positioning pin 24.

[0033] The partial surface 20 of the positioning mandrel 22 and thus of the positioning means 18 directly borders the transition 19. As already mentioned, the surface normals 17, 21 enclose the angle α, which can also be referred to as the so-called "tang angle."

[0034] While the partial area in Fig. 2b shown embodiment is designed as a straight surface which is bevelled relative to the support surface 16, the embodiment according to Fig. 3 a curved course of the partial surface 20 and thus a curvature of the partial surface 20. Just as in the Fig. 2b und Fig. 3 explained embodiments, is also the case in Fig. 4a The illustrated embodiment ensures that the seal carrier 30 can rest flat on the support surface 16 without coming into contact with the partial surface 20 and thus the positioning means 18. This ensures that the seal carrier 30 is arranged on the support surface 16 under a high surface pressure and thus with a particularly good sealing effect. Fig. 4a It is shown that the guide vane element 12 may have a shoulder which is in Fig. 4b is shown enlarged according to a detailed view B. The shoulder extends over a flange surface 15 of the flange 14 adjacent to the support surface 16.

[0035] In summary, the support surface 16 creates an uninterrupted contact surface segment that runs along the guide vane element 12 in some areas and on which a sealing seat can be formed with the seal carrier 30 (SIAS).

[0036] A radial position of a vertex of the angle α can be - as in Fig. 2b shown - lie on the transition 19, with the partial surface 20 adjoining it at a slant relative to the support surface 16. However, the angle α can also be, as in Fig. 3 shown, change over the course of the partial surface 20. Because the surface normals 17, 21 of the support surface 16 or the partial surface 20 enclose the angle α which is different from the zero angle, an offset results between the support surface 16 and the partial surface 20 in the main flow direction H. This offset makes it possible to allow operational deformations of the SIAS (seal carrier 30) without these deformations causing the seal carrier 30 to lift off the support surface 16.

[0037] Additional local projections, which may be adjacent to the support surface 16 surrounding the guide vane element 12, can also be provided with the angle α, so that the SIAS has space for operational deformations and the local projections are not touched by the SIAS during deformation. The term "projections" includes elements that protrude radially inward (in the radial direction of extension R) with respect to the support surface 16 (sealing surface on the flange 14). The term "projections" includes, for example, anti-rotation devices or sprues.

[0038] Even if strong deformations occur between the SIAS and the guide vane segment 10 or the guide vane ring, the present invention can prevent the SIAS from being deformed in the main flow direction H around a linear system 57 known from the prior art (on the Fig. 1shown centering 56) tilts, thereby forming a flat, conical gap between the SIAS and the support surface 16. When this gap occurs, increased fluid leakage can occur in systems known from the prior art. List of reference symbols:

[0039] 10 Guide vane segment 12 Guide vane element 14 Flange 15 Flange surface 16 Support surface 17 First surface normal 18 Positioning means 19 Transition 20 Partial surface 21 Second surface normal 22 Positioning pin 24 Positioning pin 26 Recess 28 Bolt 30 Seal carrier 31 Sealing element 32 Groove 34 Radial inner shroud segment 36 Guide vane blade 50 Guide vane part 52 Sealing area 54 Sealing surface 56 Centering 57 Attachment 58 Centering strut 59 Recess area α Angle H Main flow direction M Assembly direction R Radial extension direction

Claims

1. Guide vane element (12) for a guide vane segment (10) having the guide vane element (12) and a seal carrier (30), the guide vane element (12) comprising a flange (14) formed in a radial extension direction (R) of the guide vane element (12), which flange has a support surface (16) for the arrangement and support of a seal carrier (30), and comprising at least one positioning means (18) protruding from the flange (14) in the radial extension direction (R) for aligning the seal carrier (30) relative to the guide vane element (12), the positioning means (18) having at least two positioning mandrels (22, 24) arranged in a fork-like manner relative to one another, which are designed to engage in a circumferential radial groove (32) of the seal carrier (30) in the arrangement of the seal carrier (30) on the flange (14), and a partial surface (20) of the positioning means (18) adjoining the flange (14) in a transition from the flange (14) to the positioning means (18), and respective surface normals (17, 21) of the support surface (16) and the partial surface (20) enclosing an angle (α) different from a zero angle, the partial surface (20) being offset and / or beveled relative to the support surface and not coming into contact with the seal carrier (30) in the guide vane segment (10), characterized in that the support surface (16) is designed as an annular surface segment.

2. Guide vane segment (10) for a turbomachine, in particular for an aircraft engine, comprising: - at least one guide vane element (12) according to claim 1, - at least one seal carrier (30), which is arranged on the flange (14) and is aligned relative to the guide vane element (12) by means of the positioning means (18), wherein the flange (14) has a support surface (16) on which the seal carrier (30) is supported, wherein the at least two positioning mandrels (22, 24) arranged in a fork-like manner relative to one another engage in a circumferential radial groove (32) of the seal carrier (30) in the arrangement of the seal carrier (30) on the flange (14), and wherein the partial surface (20) does not come into contact with the seal carrier (30).

3. Guide vane segment (10) according to claim 2, characterized in that the positioning means (18) is integrally connected to the flange (14).

4. Guide vane ring comprising at least one guide vane segment (10) according to either of claims 2 to 3.

5. Turbomachine, in particular aircraft engine, having at least one guide vane segment (10) according to claim 2 or 3 and / or having at least one guide vane element (12) according to claim 1 and / or having at least one guide vane ring according to claim 4.

6. Turbomachine according to claim 5, characterized in that the turbomachine is a turbine and the support surface (16) of the flange (14) faces a main flow direction (H) of a working medium flowing through the turbomachine during operation thereof.

7. Turbomachine according to claim 5, characterized in that the turbomachine is a compressor, and the support surface (16) of the flange (14) faces away from a main flow direction (H) of a working medium flowing through the turbomachine during operation thereof.