THICKENED RADIALLY OUTER ANNULAR PORTION OF A SEALING FIN

Abstract

A blisk 10 for a gas turbine includes a rotor blade row 12 extending around a central axis X and, axially spaced therefrom and extending coaxially therewith, at least one annular sealing fin 11. The sealing fin has a radially outer annular portion 111 that is thickened as compared to a radially more inward annular portion 113. A compressor 1 includes a rotor and a casing 30. The casing includes at least one stator vane row having at least one abradable liner. The rotor includes at least one blisk 10, whose at least one sealing fin 11 at least partly engages in the abradable liner. A turbine is constructed analogously. A method for manufacturing a blisk 10 for a gas turbine includes producing a blisk 10 having least one annular sealing fin 11, as well as applying a coating 116 to a radially outer surface 115 of a thickened annular portion 111 of sealing fin 11.

Claims

1. A blisk for a gas turbine, the blisk comprising: a rotor blade row extending around a central axis; and at least one annular sealing fin axially spaced from the rotor blade row and extending coaxially with the rotor blade row, the annular sealing fin having a radially outer annular portion thickened as compared to a radially more inward annular portion of the sealing fin.

2. The blisk as recited in claim 1 wherein the thickened annular portion is provided with a coating on a radially outer surface.

3. The blisk as recited in claim 1 wherein the thickened annular portion includes a radially outermost section, the thickened annular portion tapering radially outwardly in the radially outermost section.

4. The blisk as recited in claim 1 wherein the radially more inward annular portion thickens radially inwardly.

5. The blisk as recited in claim 1 wherein an extent (a.sub.2) of the radially more inward annular portion in the radial direction is at least twice an extent (a.sub.1) of the thickened annular portion in the radial direction.

6. The blisk as recited in claim 1 wherein the radially more inward annular portion or the thickened annular portion is configured symmetrically to a plane extending perpendicular to the central axis.

7. The blisk as recited claim 1 wherein the radially more inward annular portion and the thickened annular portion are sections of a rub-in portion of the sealing fin, the rub-in portion being disposed on a sealing fin base, the sealing fin base having an axial thickness greater than an axial thickness of the thickened annular portion.

8. A compressor for a gas turbine, the compressor comprising: a rotor; and a casing, the casing including at least one stator vane row having radially inwardly extending stator vanes with stator vane tips provided with an abradable liner, the rotor includes at least one blisk as recited in claim 1, the annular sealing fin at least partly engaging in the abradable liner.

9. A turbine for a gas turbine, the turbine comprising: a rotor; and a casing, the casing including at least one stator vane row having stator vanes with stator vane tips each provided with an abradable liner, the rotor including at least one blisk as recited in claim 1, the annular sealing fin at least partly engaging in the abradable liner.

10. A method for manufacturing a blisk for a gas turbine, the method comprising: producing a blisk having a rotor blade row extending around a central axis and at least one annular sealing fin axially spaced from the rotor blade row and extending coaxially with the rotor blade row, the annular sealing fin having a radially outer annular portion thickened as compared to a radially more inward annular portion; and applying a coating to a radially outer surface of the thickened annular portion.

11. The method as recited in claim 10 wherein the surface provided with the coating includes a surface of a radially outermost section where the thickened annular portion tapers radially outwardly from a maximum thickness.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Preferred exemplary embodiments of the present invention will be described in greater detail below with reference to the drawings. It is understood that individual elements and components may be combined in other ways than those described. Corresponding elements are identified by the same reference characters throughout the figures and may not be described again for each figure.

[0036] In the schematic drawings,

[0037] FIG. 1 shows a perspective view of the configuration of an exemplary blisk according to the present invention;

[0038] FIG. 2 shows part of a meridional section through an exemplary compressor according to the present invention; and

[0039] FIG. 3 shows a meridional cross-sectional detail view of a sealing fin according to the present invention.

DETAILED DESCRIPTION

[0040] FIG. 1 shows an exemplary blisk 10 having a ring section 13, a rotor blade row 12 (having rotor blades 12a), and a plurality of annular sealing fins 11 which, although not discernible in this figure, preferably have a radially outer annular portion and a radially more inward annular portion, as described herein. Rotor blade row 12 and sealing fins 11 extend coaxially about a common central axis X which forms the axis of rotation during use of the blisk. Sealing fins 11 are spaced apart (i.e., offset) from rotor blade row 12 in the axial direction.

[0041] FIG. 2 shows part of a schematic meridional section through a compressor 1 according to the present invention. This partial view shows a portion of a blisk 10 with a central axis X, as well as a casing 30 of the compressor, to which are attached stator vane rows having stator vanes 20a. A flow duct 40 is formed between casing 30 and a ring section 13 of the blisk which, together with other components, forms a rotor shaft. During normal operational use, air is passed through flow duct 40 in the direction indicated by the arrow.

[0042] The radially inner tips of stator vanes 20a are provided with abradable liners 21 which engage sealing fins 11, thereby minimizing the passage of air between abradable liners 21 and sealing fins 11.

[0043] FIG. 3 presents a detail view of a sealing fin according to an embodiment of the present invention. This figure, too, shows part of a schematic meridional section taken along central axis X.

[0044] Sealing fin 11 (in particular its thickened annular portion 111 and its radially more inward annular portion 113) is configured symmetrically to a plane E which is perpendicular to the plane of the drawing of FIG. 3 and pierced orthogonally by central axis X. Sealing fin 11 includes a radially outer annular portion 111 and a radially more inward annular portion 113. Radially outer annular portion 111 is thickened as compared to radially more inward annular portion 113, because its axial thickness d.sub.1 is greater than the axial thickness d.sub.2 of radially more inward annular portion 113. The axial thicknesses of the annular portions are their respective greatest extent in the axial direction. In the meridional cross-sectional view shown in the figure, such a maximum thickness is thus a maximum width of the representation of the respective annular portion (parallel to the central axis).

[0045] In the example shown, radially outer annular portion 111 and radially more inward annular portion 113 adjoin each other and form part of a rub-in portion 117 of the sealing fin which may engage in an abradable liner 21 (such as is shown in FIG. 2) during normal operational use. Radially more inward annular portion 113 thickens toward central axis X, which improves the stability thereof.

[0046] In radial direction R, radially more inward annular portion 113 has an extent a.sub.2 which, in the example shown, is more than twice the radial extent a.sub.1 of radially outer annular portion 111 in the radial direction. Thus, detrimental lateral contact of the sealing fin with an abradable liner may occur only in a relatively small section of rub-in portion 117, and this small section is protected by the coating.

[0047] Rub-in portion 117 of the illustrated sealing fin 11 is disposed on a sealing fin base 118, which is intended to remain spaced from abradable liner 21, in particular not to engage therein.

[0048] Sealing fin base 118 has a greater axial thickness than rub-in portion 117 of the sealing fin, in particular than the thickened radially outer annular portion 111 thereof, which serves to advantageously stabilize the sealing fin.

[0049] In the example shown, thickened radially outer annular portion 111 has a surface 119 on both sides (i.e., on the side facing the rotor blade row not shown in FIG. 3 and on the side facing away therefrom), which surface 119 faces the central axis and radially inwardly bounds an overhang of thickened annular portion 111 over radially more inward annular portion 113.

[0050] Thickened radially outer annular portion 111 is provided with a coating 116 on a radially outer surface 115. The coating spans thickened radially outer annular portion 111 over the entire thickness thereof and thus acts as a protective layer also for the thinner, radially more inward annular portion during axial movement of the sealing fin (and, respectively, of the blisk of which it forms part) relative to an abradable liner.

[0051] Thickened radially outer annular portion 111 assumes its maximum axial thickness d.sub.1 along edges 114a, 114b. The applied coating 116 extends slightly beyond the edges in the axial direction (due to the viscosity of coating material and/or a minimal inclination of a coating direction), thereby forming a possible contact surface at which sealing fin 11 may contact an abradable liner, and thus protecting the sealing fin laterally.

[0052] A radially outermost section 112 of thickened annular portion 111 tapers strictly monotonically radially outwardly. In the example shown, the base of radially outermost section 112 lies in an imaginary plane connecting the edges 114a, 114b, so that the full axial thickness of the thickened annular portion, which is from where the radially outermost section tapers strictly monotonically radially outwardly, is reached in this section 112.

[0053] In particular, thickened annular portion 111 is chamfered on both of its sides (which each may face or face away from a rotor blade row not shown). Hence, radially outer surface 115 of the thickened annular portion spans the thickened annular portion partially also laterally and faces away from the central axis at these sides as well. This made it possible to reach also the sloped lateral surfaces during the application of the coating radially from the outside.

[0054] The sloped sides of the thickened annular portion each extend substantially along the lateral surface of an (abstract; i.e., imaginary, and preferably straight) circular cone about central axis X. In the figure, for the sake of clarity, this is only shown for one of the sloped sides. The associated cone has a cone angle α of preferably no more than 120°, more preferably no more than 100° and/or at least 60°, more preferably at least 80°.

[0055] An inventive blisk 10 for a gas turbine includes a rotor blade row 12 extending around a central axis X and, axially spaced therefrom and extending coaxially therewith, at least one annular sealing fin 11. The sealing fin has a radially outer annular portion 111 that is thickened as compared to a radially more inward annular portion 113.

[0056] A turbine according to the present invention includes a rotor and a casing. The casing includes at least one stator vane row having at least one abradable liner 21. The rotor includes at least one blisk according to an embodiment of the invention disclosed herein, whose at least one sealing fin 11 at least partly engages in the abradable liner.

[0057] Analogously, a compressor 1 according to the present invention includes a rotor and a casing 30. The casing includes at least one stator vane row having at least one abradable liner. The rotor includes at least one blisk 10 according to an embodiment of the invention disclosed herein, whose at least one sealing fin 11 at least partly engages in the abradable liner.

[0058] A method according to the present invention for manufacturing a blisk 10 for a gas turbine includes producing a blisk 10 having least one annular sealing fin 11, as well as applying a coating 116 to a radially outer surface 115 of a thickened annular portion 111 of sealing fin 11.

LIST OF REFERENCE NUMERALS

[0059] 1 compressor [0060] 10 blisk [0061] 11 sealing fin [0062] 12 rotor blade row [0063] 12a rotor blade [0064] 13 ring [0065] 20a stator vane [0066] 21 abradable liner [0067] 30 casing [0068] 40 flow duct [0069] 111 thickened annular portion [0070] 112 radially outermost section of the thickened annular portion [0071] 113 radially more inward annular portion [0072] 111a, 114b edge along which thickened annular portion 111 has its greatest axial thickness [0073] 115 radially outer surface [0074] 116 coating [0075] 117 rub-in portion [0076] 118 sealing fin base [0077] 119 surface facing the central axis [0078] a.sub.1 extent of the thickened annular portion in the radial direction [0079] a.sub.2 extent of the radially more inward annular portion in the radial direction [0080] d.sub.1 thickness of the thickened annular portion [0081] d.sub.2 thickness of the radially more inward annular portion [0082] E plane [0083] R radial direction [0084] X central axis [0085] α cone angle