EP3521562A1 - Shroud segment to be mounted on a blade of a turbomachine and blade - Google Patents

Abstract

The present invention relates to a shroud segment (100) for mounting on a blade of a turbomachine, in particular a gas turbine, with a stiffening structure raised relative to a shroud segment surface (15), wherein the stiffening structure has at least three interconnected ribs (3, 5, 7), and a first end region of the ribs (3, 5, 7) with an upstream sealing tip (11) of the shroud segment (100) and a second end region of these ribs (3, 5, 7) with a sealing tip (13) of the shroud segment (100) arranged downstream ) are connected. The angles (W1, W2, W3) between the direction of the axis of rotation (a) of the blade and the longitudinal orientations (21, 23, 25) of the ribs (3, 5, 7), viewed in the flow direction (9) of the turbomachine, respectively, between zero degrees and eighty degrees. Furthermore, the present invention relates to a blade (200) of a turbomachine.

Description

The present invention relates to a shroud segment for arrangement on a blade of a turbomachine according to the preamble of claim 1 and a blade according to claim 13.

Rotors of compressor stages and / or turbine stages of turbomachines can be exposed to high forces, in particular centrifugal forces at high speeds. These centrifugal forces can lead to deformations or material damage to the rotors. To counteract such deformations and material damage, outer shrouds of high-speed turbine blades can be structurally reinforced. A possible reinforcement is an improved rigidity of the outer shroud by constructive measures.

An object of the present invention is to propose a shroud segment having a high rigidity. Another object of the present invention is to propose a blade with a shroud segment having high rigidity.

The object of the invention is achieved by a shroud segment with the features of claim 1. Furthermore, the object of the invention is achieved by a blade having the features of claim 13.

According to the invention, a shroud segment is claimed for arrangement on a blade of a turbomachine, in particular of a gas turbine, with a stiffening structure raised in relation to a shroud segment surface. The stiffening structure has at least three interconnected ribs. The ribs can be referred to as stiffening ribs or webs. A first end region of the respective at least three ribs is connected to an upstream sealing tip of the shroud segment, wherein the end region relates to the longitudinal orientation or main axis of the ribs. A second end region extending to the second, longitudinally opposite end of the Ribs is connected to a downstream sealing tip of the shroud segment. The angles between the direction of the axis of rotation of the blade and the longitudinal orientations of the ribs, each viewed in the flow direction of the turbomachine, are between zero degrees and eighty degrees.

The blade according to the invention comprises a shroud segment for arrangement on a blade of a turbomachine with a stiffening structure raised in relation to a shroud segment surface. The stiffening structure has at least three interconnected ribs. A first end region of the at least three ribs is connected to an upstream sealing tip of the shroud segment. A second end region, which refers to the second, opposite end of the ribs, is connected to a downstream sealing tip of the shroud segment. The angles between the direction of the axis of rotation of the blade and the longitudinal orientations of the ribs, each viewed in the flow direction of the turbomachine, are between zero degrees and eighty degrees. In some embodiments, the blade according to the invention is made in one piece, for example by means of a casting process or by means of a generative manufacturing process.

The blade according to the invention may be a compressor blade and / or turbine blade of a gas turbine.

Advantageous developments of the present invention are the subject of subclaims and embodiments.

Exemplary embodiments according to the invention may have one or more of the following features in any combination, provided that one or the concrete combination is not apparent to the person skilled in the art as obviously technically impossible. The subject matters of the dependent claims in each case according to the invention, exemplary embodiments.

In all of the statements made above and below, the use of the term "may be" or "may have" etc. is synonymous with "preferably" or "preferably", etc., and is intended to illustrate exemplary embodiments of the invention. Whenever alternatives are introduced herein with "and / or", those skilled in the art will understand the "or" contained therein as preferably "either or" and preferably not "and".

Embodiments referred to herein are to be understood as being purely exemplary embodiments of the present invention, which are not to be considered as limiting.

In particular, a raised stiffening structure is a structure of material accumulations, such as ribs, ridges or the like, extending radially outwardly from the shroud segment surface. The stiffening structure may be made of the same material or other material as the rest of the shroud, or parts of the remaining shroud.

In some embodiments, the three interconnected ribs of the shroud of the invention form a Z-shaped rib structure.

A sealing tip can be referred to as Dichtfin. A shroud or shroud segment may be disposed on a blade tip. One, two or more sealing tips on these shrouds or shroud segments may, in the event of a rotation of the shroud or shroud segment, rub against an abradable region of an inlet seal in a housing section of the turbomachine. As a result of this rubbing, a sealing gap can form between the shroud and the housing, which minimizes the flow losses due to a backflow or a leakage flow. In other words, the shroud segment can reduce the flow around the radially outer blade tip and thereby increase the efficiency of the turbomachine. The shroud segments of adjacent or adjacent blades of a rotor thereby form a continuous shroud.

The upstream sealing tip is referred to below as the front sealing tip and the downstream arranged sealing tip as a rear sealing tip.

In some embodiments, a first end portion of a first rib is connected to a first end portion of a second rib. The two interconnected end portions are arranged on the front sealing tip, in particular, they are materially connected to the sealing tip. A first end portion of a third rib is offset in the circumferential direction, wherein the staggered arrangement refers to the connected end portions of the first and second rib. This first end portion of the third rib is arranged at the front sealing tip, in particular materially connected to the sealing tip. The pitch of the staggered arrangement of the end portion of the third rib opposite to the connected end portions of the first and second ribs is more particularly at least the width (in the circumferential direction) of the front sealing tip arranged interconnected end portions of the first and second ribs.

In particular, the angle between the direction of the axis of rotation of the blade and the longitudinal orientation of the first rib may be between 0 ° and 45 °, the angle between the direction of the axis of rotation of the blade and the longitudinal orientation of the third rib between 0 ° and 45 ° and / / or the angle between the direction of the axis of rotation of the blade and the longitudinal orientation of the second rib between 30 ° and 80 °.

Preferably, the skeleton line of the blade profile intersects - in the radial direction of view - the second rib, preferably all three ribs, (each) at an angle between 30 ° and 90 °, preferably between 45 ° and 90 °. The skeleton line passes through the center of each circle, which is completely inscribed in the blade profile at a certain axial position as the maximum circle.

The respective arrangements of the end portions of the ribs at the sealing tips may be referred to as roots.

In some embodiments, a second end portion of the first rib is disposed on the rear sealing tip, in particular materially connected to the sealing tip. A second end portion of the second rib is connected to a second end portion of the third rib. These connected end portions are circumferentially offset from the second end portion of the first rib at the rear sealing tip.

By means of the described, arranged at the front and rear sealing tip end portions of the respective ribs advantageously the stiffness of the shroud segment can be increased.

In some embodiments, a first polygonal pocket is formed between the side surfaces of the first and second ribs, the rear sealing tip, and the shroud segment surface as the bottom surface. Furthermore, a second polygonal pocket is formed between the second and third ribs, the front sealing tip and the shroud segment surface. A bag can be referred to as a depression, tub, shell or the like. A polygonal bag is a bag with multiple sides. The pockets have more than three side surfaces. The side surfaces of the first polygonal bag are essentially formed by the first rib, the second rib and the rear sealing tip. The side surfaces of the second polygonal bag are essentially formed by the second rib, the third rib and the front sealing tip. Both pockets can each have multiple side surfaces. For example, further side surfaces may be formed at the respective roots and / or at the transition regions between the ribs and the shroud segment surface. By means of the polygonal pockets, in particular with more than three side surfaces per pocket, the rigidity of the shroud segment can advantageously be increased.

In some embodiments, the three ribs are substantially straight in their longitudinal and major axes, respectively. In other embodiments, some or all of the major axes are curved, such as single or multiple curved.

In some embodiments, the end region of the third rib located at the front sealing tip is arranged on the connecting surface of the shroud segment to the closest shroud segment. Several shroud segments can form a shroud.

In some embodiments, the end region of the first rib located at the rear sealing tip is located in the middle third, relative to the length of the shroud segment in the circumferential direction.

In some embodiments, the angle between the direction of the axis of rotation of the blade, that is, the axial direction a, and the longitudinal directions of the first and third rib, each viewed in the flow direction of the turbomachine, between twenty degrees and seventy degrees, in particular between thirty degrees and fifty degrees , further in particular about forty-five degrees. In other embodiments, the angle is between the directions the rotational axis of the blade and the longitudinal directions of the first and the third rib zero degrees or approximately zero degrees.

In some embodiments, the ribs have a substantially radially constant height above the circumference.

In some embodiments, the shroud segment is manufactured in one piece by means of a casting method, by means of a material-removing method, in particular by means of milling, or by means of a generative manufacturing method.

Some or all embodiments according to the invention may have one, several or all of the advantages mentioned above and / or below.

The shroud segment according to the invention advantageously allows a high rigidity of the shroud strip or of the outer strip, in particular in the case of high-speed turbine blades. A parameter in this context is the product AN ² , where A is the annular region formed by the blades, in particular turbine blades, and more particularly by the downstream stage. N corresponds to the speed of the blade in the application. Especially with low blade numbers or with very high AN ² , large shroud overhangs can occur. The surface taper can be very large in the radial direction from the inside out. So that these shroud overhangs do not bend too much due to possible high centrifugal forces, according to the invention ribs can be introduced into the shroud. Furthermore, it is also advantageous that the increase in mass should be minimized by the stiffening structures designed as ribs.

Fig. 1

zeigt ein erfindungsgemäßes Deckbandsegment mit einer Versteifungsstruktur und ein mit dem Deckbandsegment verbundenem Schaufelblatt in einer perspektivischen Ansicht; und

Fig. 2

zeigt das erfindungsgemäße Deckbandsegment aus Fig. 1 in einer Aufsicht von radial außen.

The present invention will be explained in the following with reference to the accompanying drawings, in which identical reference numerals designate identical or similar components, by way of example. In each case greatly simplified schematic figures:

Fig. 1

shows a shroud segment according to the invention with a stiffening structure and an airfoil connected to the shroud segment in a perspective view; and

Fig. 2

shows the shroud segment of the invention Fig. 1 in a plan view from radially outside.

Fig. 1 shows a shroud segment 100 according to the invention with a stiffening structure and connected to the shroud segment 100 airfoil 1 in a perspective view.

The stiffening structure has three interconnected ribs 3, 5, 7. The ribs 3, 5, 7 extend in their longitudinal direction or along their main axes in each case from one, viewed in relation to a main flow direction 9 of the turbomachine, upstream sealing tip 11 to a sealing tip 13 arranged downstream Seal tip 11 referred to as the front sealing tip 11 and the downstream arranged sealing tip 13 as a rear sealing tip 13. The front sealing tip 11 may further be referred to as a sealing tip leading edge and the rear sealing tip 13 as a sealing tip trailing edge. The sealing tips 11, 13 may be referred to as sealing fins. The ribs 3, 5, 7 are connected to a shroud segment surface 15.

In a purely exemplary application of the shroud segment 100 in a gas turbine, for example in an application in a compressor stage and / or in a turbine stage, the sealing tips 11, 13 upon rotation of the shroud segment 100 with the airfoil 1 or during rotation of an entire shroud with blades in a rubbing area of an inlet seal in a housing portion of the gas turbine. As a result of this rubbing, a sealing gap can form between the shroud and the housing, which minimizes the flow losses due to a backflow or a leakage flow. In other words, the shroud segment 100 can reduce the flow around the radially outer blade tip and thereby increase the efficiency of the turbomachine. The shroud segments 100 of adjacent or adjacent blades of a rotor thereby form a continuous shroud.

The shroud segment 100 arranged at the radial end region of the blade 1 can basically be used for damping blade vibrations, in particular in the case of gas turbine blades for turbine stages arranged at the rear, that is to say downstream. To improve or increase the rigidity, in particular of high-speed turbine blades, the shrouds may advantageously have the shroud segments 100 according to the invention. The raised stiffening structures of the shroud segments 100 of the invention may further contribute to the reduction of stress concentrations of the shroud.

The three interconnected ribs 3, 5, 7 are hereinafter referred to the simplified description as the first rib 3, as the second rib 5 and third rib 7. The angle between the direction of the axis of rotation of the blade, which is referred to as the axial direction a and the Hautdurchströmungsrichtung 9, and the longitudinal orientations of the three ribs 3, 5, 7, viewed in the axial direction a, is exemplary in this embodiment, approximately between thirty degrees and eighty degrees. This will be in Fig. 2 described in more detail.

Between the first rib 3, the second rib 5 and the rear sealing tip 13, a first polygonal-shaped pocket 17 is formed, which may be referred to as a trough-shaped depression. The first polygonal-shaped pocket 17 is disposed between the connecting portions of the first rib 3 and the second rib 5, the first rib 3 and the rear sealing tip 13 and between the second rib 5 and the rear sealing tip 13. Analogously, a second polygonal pocket 19 is formed between the second rib 5, the third rib 7 and the front sealing tip 11. The second polygonal-shaped pocket 19 is disposed between the connecting portions of the second rib 5 and the third rib 7, the second rib 5 and the front sealing tip 11 and between the third rib 7 and the front sealing tip 11.

The sealing tips 11, 13 extend in their entire extent from below the shroud segment surface 15, ie in the region of the radially outer blade edge of the blade 1, to above the shroud segment surface 15. In the radially outer region of the sealing tips 11, 13, the engagement region is an optional Inlet seal arranged in the housing region of the turbomachine.

The blade according to the invention comprises at least one shroud segment 100 according to the invention, an airfoil 1 and a blade root (in FIG Fig. 1 not shown). The blade can be produced as a one-piece cast component, by means of a material-removing method, in particular by means of milling, or by means of a generative production method.

Fig. 2 shows the shroud segment 100 according to the invention Fig. 1 in a plan view from radially outside. The first rib 3, the second rib 5 and the third rib 7 extend in their Longitudinal orientations, ie in the first main axis 17 of the first rib 3, in the second major axis 19 of the second rib 5 and in the third major axis 21 of the third rib 7, from the front sealing tip 11 to the rear sealing tip 13. The three ribs 3, 5 7 are aligned substantially straight along their major axes 21, 23, 25.

The ribs 3, 5, 7 are connected to the sealing tips 11, 13 and, in this exemplary embodiment, to the shroud segment surface 15. In particular, the raised stiffening structure designed as ribs 3, 5, 7 is produced integrally with the shroud segment surface 15 and the sealing tips 11, 13, for example by means of a casting process or by means of a generative production process. The in Fig. 2 shown distance between on the one hand the upstream end portions of the first rib 3, the second rib 5 (which is connected to the first rib 3 in this end region) and the third rib 9 and on the other hand, the front sealing tip 11, a compound of the ribs 3, 5, Indicate 7 in the area of the shroud segment surface 15. In contrast, the downstream end portions of the ribs 3, 5, 7 are connected in this view directly to the rear sealing tip 11, which indicates a connection in the radially outer region of the sealing tip 13. This is also directly in Fig. 1 recognizable.

Further, in this exemplary embodiment, the end portion of the downstream joint of the second rib 5 with the third rib 7 is directly adjacent to the connecting surface 27 of the shroud segment 100 to the shroud segment (see FIG Fig. 2 not shown). The connection surface 27 may be referred to as a contact surface.

The bonding surface 27 in this exemplary embodiment is a substantially Z-shaped joint surface 27. A shroud having such Z-shaped bonding surfaces 27 may be referred to as a so-called Z-Shroud.

The already to Fig. 1 described polygonal-shaped pockets 17, 19 have a plurality of adjacent surfaces. The surfaces are in particular side surfaces. Depending on the configuration, the pockets 17, 19 may have four, five, six or more side surfaces. The side surfaces may be arranged, for example, at the junction of the first rib 3 and the second rib 5, at the juncture of the second rib 5 and the third rib 7 and at the junctures of the ribs 3, 5, 7 with the sealing tips 11, 13. More As three side surfaces, the rigidity of the shroud segment 100 according to the invention can advantageously increase.

The three angles W1, W2, W3 between the direction of the axis of rotation of the blade, that is the axial direction a, and the longitudinal orientations or main axes 21, 23, 25 of the ribs 3, 5, 7 are, in each case viewed in the flow direction 9, between zero and eighty degrees. In this exemplary embodiment, the angle W1 between the axial direction a and the major axis 21 is approximately thirty degrees (30 °), the angle W2 between the axial direction a and the major axis 23 is approximately sixty degrees (60 °), and the angle W3 between Axial direction a and the major axis 25 about thirty degrees (30 °).

The end region of the first rib 3 located at the rear sealing tip 13 is arranged in the middle third L1 relative to the length L of the shroud segment 100 in the circumferential direction u.

LIST OF REFERENCE NUMBERS

100

Shroud segment

W1, W2, W3

Angle between axial axis a and main axes of the ribs

L

Length of the shroud segment in the circumferential direction

1

airfoil

a

axis direction; Rotary axis of the blade

u

circumferentially

r

radial direction

3

first rib

5

second rib

7

third rib

9

Main flow direction of the turbomachine

11

front sealing tip; upstream sealing tip

13

rear sealing tip; downstream sealing peak

15

Shroud segment surface

17

first polygonal bag

19

second polygonal bag

21

first main axis

23

second major axis

25

third main axis

27

Connecting surface; contact area

Claims (15)

A shroud segment (100) for mounting on a blade of a turbomachine, in particular a gas turbine, with a stiffening structure raised relative to a shroud segment surface (15), wherein the stiffening structure has at least three interconnected ribs (3, 5, 7) and a first end region of the ribs (3, 5, 7) having an upstream sealing tip (11) of the shroud segment (100) and a second end portion of these ribs (3, 5, 7) are connected to a downstream sealing tip (13) of the shroud segment (100), characterized in that the angles (W1, W2, W3) between the direction of the rotational axis (a) of the blade and the longitudinal orientations (21, 23, 25) of the ribs (3, 5, 7), in each case in the flow direction (9) of the turbomachine considered to be between zero degrees and eighty degrees. A shroud segment (100) according to claim 1, wherein the three interconnected ribs (3, 5, 7) form a Z-shaped rib structure. A shroud segment (100) according to claim 1 or 2, wherein a first end portion of a first rib (3) is connected to a first end portion of a second rib (5) and these two interconnected end portions are disposed on the upstream sealing tip (11) a first end portion of a third rib (7) offset in the circumferential direction (u), opposite to the connected end portions of the first rib (3) and the second rib (5) is arranged on the upstream sealing tip (11). A shroud segment (100) according to any one of the preceding claims, wherein the angle between the direction of the axis of rotation of the blade and the longitudinal orientation of the first rib (3) is between 0 ° and 45 °, the angle between the direction of the axis of rotation of the blade and the longitudinal orientation the third rib (7) is between 0 ° and 45 ° and / or the angle between the direction of the axis of rotation of the blade and the longitudinal orientation of the second rib (5) is between 30 ° and 80 °. Shroud segment (100) according to one of the preceding claims, wherein the skeleton line of the blade profile - in the radial direction - the second rib (5), preferably all three ribs (3, 5, 7), at an angle or in angles between 30 ° and 90 °, preferably between 45 ° and 90 °. A shroud segment (100) according to any one of the preceding claims, wherein a second end portion of the first rib (3) is disposed on the downstream sealing tip (13) and a second end portion of the second rib (5) is arranged with a second end portion of the third rib (7). is connected, and the connected end portions of the second rib (5) and the third rib (7) in the circumferential direction (u) offset, relative to the second end portion of the first rib (3), are arranged on the downstream sealing tip (13). A shroud segment (100) according to any one of the preceding claims, wherein between the first rib (3), the second rib (5) and the downstream sealing tip (13) a first polygonal shaped pocket (17) is formed, and between the second rib (Fig. 5), the third rib (7) and the upstream sealing tip (11), a second polygonal-shaped pocket (19) is formed. A shroud segment (100) according to any one of the preceding claims, wherein the three ribs (3, 5, 7) are substantially straight in their longitudinal orientation (21, 23, 25). Shroud segment (100) according to one of the preceding claims, wherein the end region of the third rib (7) located at the downstream sealing tip (13) is arranged on the connecting surface (29) of the shroud segment (100) to the closest shroud segment. Shroud segment (100) according to one of the preceding claims, wherein the end region of the first rib (3) located at the downstream sealing tip (13) is arranged in the central third L1, relative to the length L of the shroud segment (100) in the circumferential direction (u) is. Shroud segment (100) according to one of the preceding claims, wherein the angles W1, W3 between the direction of the axis of rotation (a) of the blade and the Longitudinal alignments (21, 25) of the first rib (3) and the third rib (5), each viewed in the flow direction (9) of the turbomachine, zero degrees or between twenty degrees and seventy degrees, in particular between thirty degrees and fifty degrees, more particularly is about forty-five degrees. The shroud segment (100) according to any one of the preceding claims, wherein the ribs (3, 5, 7) have a height substantially constant in the radial direction (r) about the circumference (u). Shroud segment (100) according to one of the preceding claims, wherein the shroud segment (100) is produced in one piece by means of a casting method, by means of a material-removing method, in particular by means of milling, or by means of a generative manufacturing method. A bucket (200) of a turbomachine comprising a shroud segment (100) according to any one of claims 1 to 13. A blade (200) according to the preceding claim, wherein the blade (200) is a turbine blade of a gas turbine.

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