Sealing fin having an axially asymmetric tip portion

Abstract

A rotor member is described for a gas turbine that is adapted for rotating about a central axis, the rotor member being a blisk having a rotor blade row that extends around the central axis or a rotor disk having a mounting portion for installing rotor blades of a rotor blade row that extends around the central axis, and being axially offset from the rotor blade row and/or the mounting portion and, extending coaxially, having at least one annular and axially asymmetrical sealing fin that has a radially outer tip portion having a front flank facing the rotor blade row and/or the mounting portion, and an opposite flank facing away from the rotor blade row and/or the mounting portion; the front flank being less steep than the opposite flank; a turbine and a compressor having such a rotor member, and a method for manufacturing such a rotor member having at least one sealing fin coating.

Claims

1. A rotor member for a gas turbine adapted for rotating about a central axis, the rotor member comprising: a blisk having a blisk rotor blade row extending around the central axis or a rotor disk having a mounting portion for installing rotor blades of a rotor blade row extending around the central axis; and at least one annular sealing fin axially offset from the blisk rotor blade row or the rotor blade row or the mounting portion and extending coaxially therewith, and having a radially outer tip portion having a front flank facing the blisk rotor blade row or the rotor blade row or the mounting portion, and an opposite flank facing away from the front flank, the front flank being less steep than the opposite flank.

2. The rotor member as recited in claim 1 wherein the front flank and the opposite flank at the tip side merge over an annular surface.

3. The rotor member as recited in claim 2 wherein the annular surface has at least one plane surface.

4. The rotor member as recited in claim 2 wherein the annular surface has at least one arched surface.

5. The rotor member as recited in claim 1 wherein the tip portion extends radially outwardly from a neck portion, the neck portion tapering radially outwardly.

6. The rotor member as recited in claim 5 wherein the neck portion has a neck front flank steeper than the front flank.

7. The rotor member as recited in claim 5 wherein the neck portion has a neck opposite flank having a same steepness as the opposite flank.

8. The rotor member as recited in claim 5 wherein the neck portion extends radially outwardly from a base portion having a greater axial thickness than the neck portion.

9. The rotor member as recited in claim 5 wherein the tip portion has a height greater than a height of the neck portion.

10. The rotor member as recited in claim 1 wherein at least the tip portion is covered with a coating.

11. A compressor for a gas turbine comprising: a rotor; and a stator including a guide vane row having radially inwardly extending guide vanes with guide vane tips, an abradable coating being provided on the guide vane tips; the rotor having at least one rotor member as recited in claim 1, the annular sealing fin engaging at least partly into the abradable coating.

12. A turbine for a gas turbine, comprising: a rotor; and a stator including a guide vane row having radially inwardly extending guide vanes with guide vane tips, an abradable coating being provided on the guide vane tips; the rotor having at least one rotor member as recited in claim 1, the annular sealing fin engaging at least partly into the abradable coating.

13. A method for manufacturing a rotor member for a gas turbine, the method comprising: manufacturing a blisk having a blisk rotor blade row extending around a blisk central axis, or manufacturing a rotor disk having a mounting portion for installing rotor blades of a rotor blade row extends around a central axis, the rotor member having at least one annular sealing fin axially offset from the blisk rotor blade row or the rotor blade row or the mounting portion and being configured to extend coaxially therewith, the rotor member having a radially outer tip portion having a front flank facing the blisk rotor blade row or the rotor blade row or the mounting portion, and an opposite flank facing away from the front flank; the front flank being less steep than the opposite flank, and applying a coating to the tip portion.

14. The rotor member as recited in claim 1 wherein the radially outer tip portion is asymmetrical.

15. The rotor member as recited in claim 1 wherein the front flank has an angle of 25 to 45 degrees with respect to a radial plane.

16. The rotor member as recited in claim 15 wherein the opposite flank has an angle of 1 to 10 degrees with respect the radial plane.

17. The rotor member as recited in claim 15 wherein the front flank has an angle of 30 degrees with respect to a radial plane.

18. The rotor member as recited in claim 17 wherein the opposite flank has an angle of 5 degrees with respect the radial plane.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Schematically, in the drawings,

(2) FIG. 1: shows a design of an exemplary rotor member according to the present invention in a perspective view;

(3) FIG. 2: shows a portion of a meridional section through an exemplary compressor according to the present invention; and

(4) FIG. 3: shows a meridional, cross-sectional, detail view of a sealing fin according to the present invention.

DETAILED DESCRIPTION

(5) FIG. 1 shows a rotor member 1 according to the present invention, exemplarily as a blisk 1 having a drum portion 2, a rotor blade row 4 having rotor blades 6, and a plurality of annular sealing fins 8. Rotor blade row 4 and sealing fins 8 extend coaxially, thus about a common central axis X that represents the axis of rotation during use of blisk 1. Sealing fins 8 are axially spaced apart (thus offset) from rotor blade row 4. Sealing fins 8 are mutually spaced apart axially and configured here exemplarily on one side of rotor blade row 4. In accordance with the representation in FIG. 1, sealing fins 8 are configured to the left or upstream of rotor blade row 4. It is self-evident that sealing fins 8 may also be configured on both sides or basically also only to the right or downstream of a rotor blade row 4. In the exemplary embodiment shown here, three sealing fins 8 are provided on each side of rotor blade row 4. For the sake of clarity, merely one sealing fin 9 of these is numbered in each case.

(6) FIG. 1 through 3 actually refer to a blisk as rotor member 1; however, rotor member 1 may also be a rotor disk having a mounting portion that, for example, has a plurality of receiving grooves for installing rotor blades 6 to form a rotor blade row 4.

(7) FIG. 2 schematically shows a detail view of a meridional section of a compressor 10 according to the present invention. For the sake of clarity, not all of the recurring elements are provided with a reference numeral in FIG. 2. The detail view shows a portion of a blisk 1 along central axis X, as well as a portion of a stator 11 of compressor 10. Stator 11 features a casing 12 and, secured to casing 12, guide vane rows having guide vanes 13. Formed between a drum portion 2 of blisk 1, which, together with other components, forms a rotor, and casing 12 is an annular flow channel 14 through which a primary flow streams during normal operational use in the direction indicated by arrow 16.

(8) Guide vanes 13 are accommodated radially outwardly in casing 12. Provided at the radially inner tips thereof are abradable coatings 18 into which sealing fins 8 engage, thereby minimizing or eliminating any leakage between abradable coatings 18 and sealing fins 8.

(9) FIG. 3 provides a detail view of a sealing fin 8 according to a specific embodiment of the present invention, where the at least one sealing fin 8 is positioned downstream of a rotor blade row. This figure, too, shows a detail view of a meridional section along central axis X.

(10) Illustrated sealing fin 8 has a radially inner base portion 20, a radially outer tip portion 24, and a neck portion 22 that extends therebetween.

(11) Base portion 20 forms the radially inner annular portion of sealing fins 8. It extends radially outwardly from drum portion 2 via unnumbered fillets and has a front flank 20a facing a rotor blade row and an opposite flank 20b facing away therefrom. Front flank 20a and opposite flank 20b extend orthogonally to central axis X and thus along a radial plane E. Radial plane E is a plane that is pierced by central axis X. Sealing fin 8 is configured asymmetrically to radial plane E, in particular due to a difference in the steepness in tip portion 24 (to be described in greater detail below). Thus, there is no radial plane of symmetry through sealing fin 8. However, sealing fin 8 is axially symmetric to central axis X. Due to the orthogonal configuration of flanks 20a, 20b relative to central axis X, they extend mutually parallel in the radial direction. Base portion 20 hereby has a constant thickness d.sub.1 over the radial extent or radial height h.sub.1 thereof. Thickness refers herein to the maximum extent or extension thereof in the axial direction. It is self-evident that the thickness of base portion 20 may also vary; for example, it may have a trapezoidal cross section, whose thickness is greater radially inwardly than radially outwardly.

(12) Neck portion 22 forms the radially middle annular portion of sealing fin 8. It extends approximately axially centrally from base portion 20, radially outwardly. It has a thickness d.sub.2 that is smaller than thickness d.sub.1 of base portion 20. Viewed in the primary flow direction, this forms a front base surface 20c and a rear base surface 20d, which preferably have the same axial extent. Base surfaces 20c, 20d extend here axially. However, they may also extend at a radially outward angle toward neck portion 22 and thus be formed as inclined surfaces. Load introduction from neck portion 22 into base portion 20 may be influenced by the angled orientation of base surfaces 20c, 20d. Neck portion 22 preferably has a radial height h.sub.2 that is smaller than radial height h.sub.1 of base portion 20.

(13) Neck portion 22 has a front flank 22a facing the rotor blade row and an opposite flank 22b facing away therefrom. Neck portion 22 tapers radially outwardly. The tapering is achieved in that either front flank 22a, opposite flank 22b or both front flank 22a and opposite flank 22b is/are oriented at an angle relative to radial plane E. In the exemplary embodiment shown here, front flank 22a has a flank angle of .sub.2=0 to radial plane E. Opposite flank 22b has a flank angle .sub.2=5 to radial plane E. In this exemplary embodiment, front flank 22a essentially extends along radial plane E. Alternatively, however, it may also be oriented at a flank angle of preferably 0.sub.215.

(14) Tip portion 24 forms the radially outer annular portion of sealing fin 8. It extends radially outwardly from neck portion 22. It has a front flank 24a facing the rotor blade row, an opposite flank 24b facing away from the rotor blade row, and an axial annular surface 24c that extends radially outwardly.

(15) Tip portion 24 tapers radially outwardly. In the transition region from neck portion 22 to tip portion 24, both portions 22, 24 have the same thickness d.sub.3, so that no neck portion surfaces are created that are comparable to base surfaces 20c, 20d. Measured from neck portion 22 to annular surface 24c, tip portion 24 has a radial height h.sub.3 that is greater than radial height h.sub.2 of neck portion 22 and smaller than height h.sub.1 of base portion 20. When tip portion 24 is provided with a coating 26 (still to be explained in the following), height h.sub.3 thereof is approximately 1.50 mm to 1.82 mm; preferably h.sub.3=1.66 mm. The aforementioned absolute values are only indicated exemplarily. It is important that height h.sub.3 be greater than height h.sub.z (h.sub.3>h.sub.z). Height h.sub.3 may likewise be greater than height h.sub.1 (h.sub.3>h.sub.1).

(16) Front flank 24a and opposite flank 24b of tip portion 24 are oriented at an angle relative to radial plane E; relative to radial plane E, front flank 24a has a larger flank angle .sub.3 and thus is less steep than opposite flank 24b. Flank angle .sub.3 of front flank 24a is within an angular range of approximately 25 and 45; preferably, flank angle .sub.3=30. In other words, front flank 24a of tip portion 22a essentially extends along a lateral surface of an abstract, thus imaginary, preferably straight circular cone about central axis X. The corresponding cone has an opening angle within the range from approximately 90 to 130; opening angle is preferably =120.

(17) In this exemplary embodiment, opposite flank 24b has a flank angle .sub.3 within an angular range of 1 to 10 to radial plane E; preferably, flank angle .sub.3=5. Flank angle .sub.3 of opposite flank 24b of tip portion 24 and flank angle .sub.2 of opposite flank 22b of neck portion 22 are preferably selected to be the same, so that the two opposite flanks 24a, 24b merge into one another kink-free.

(18) Annular surface 24c extends axially between front flank 24a and opposite flank 24b. It joins front flank 24a and opposite flank 24b radially outwardly. Edges 24d, 24e between front flank 24a and annular surface 24c, as well as between opposite flank 24b and annular surface 24c are rounded.

(19) To protect tip portion 24 from damage, it is completely provided with aforementioned coating 26, as indicated by the dotted line. Thus, front flank 24a, opposite flank 24b and annular surface 24c thereof are configured underneath coating 26 and, via the same, come into frictional contact with abradable coating 18. Coating 26 follows the particular shape of front flank 24a, opposite flank 24b and annular surface 24c. It is a chromium carbide coating and/or an MCrAlY coating, for example. It may have been or be applied by thermal spraying and/or plasma spraying. For instance, in the area of annular surface 24c, it has a preferred thickness of 0.30 mm. Coating 26 may be less thick in the area of front flank 24a and opposite flank 24b. As indicated by broken line 28, coating 26 may also extend to neck portion 22, base portion 20, and to a portion of drum portion 2 between adjacent sealing fins 8, so that sealing fin 8 is completely coated over total height H thereof, and drum portions 2 are also completely coated radially outwardly between sealing fins 8.

(20) An inventive blisk 1 for a gas turbine includes a rotor blade row 4 extending around a central axis X and, axially spaced therefrom and extending coaxially therewith, at least one annular sealing fin 8. Sealing fin 8 has a radially outer tip portion 24a having a front flank 24a facing rotor blade row 4 and an opposite flank 24b facing away therefrom, front flank 24a being less steep than opposite flank 24b. However, this is not absolutely necessary.

(21) A turbine according to the present invention includes a rotor and a stator 11. Stator 11 includes at least one guide vane row 13 having at least one abradable coating 18. The rotor includes at least one blisk 1 according to an embodiment of the invention described herein, whose at least one sealing fin 8 at least partly engages in abradable coating 18.

(22) Analogously, a compressor 1 according to the present invention includes a rotor and a stator 11. This includes at least one guide vane row 13 having at least one abradable coating 18. The rotor includes at least one blisk 1 according to an embodiment of the invention described herein, whose at least one sealing fin 8 at least partly engages in abradable coating 18.

(23) A method according to the present invention for manufacturing a blisk 1 for a gas turbine includes manufacturing a blisk 1 having at least one annular sealing fin 8, as well as applying a coating 26 to at least a tip portion 24 of sealing fin 8 that has a front flank 24a facing a rotor blade row 4 and an opposite flank 24b facing away therefrom; front flank 24a being less steep than opposite flank 24b.

(24) A rotor member is described for a gas turbine that is adapted for rotating about a central axis, the rotor member being a blisk having a rotor blade row that extends around the central axis or a rotor disk having a mounting portion for installing rotor blades of a rotor blade row that extends around the central axis, and being axially offset from the rotor blade row and/or the mounting portion and, extending coaxially, having at least one annular and axially asymmetrical sealing fin that features a radially outer tip portion having a front flank facing the rotor blade row and/or the mounting portion, and an opposite flank facing away therefrom; the front flank being less steep than the opposite flank, a turbine and a compressor having such a rotor member, and a method for manufacturing such a rotor member having at least one sealing fin coating.

LIST OF REFERENCE NUMERALS

(25) 1 rotor member 2 drum portion 4 rotor blade row 6 rotor blade 8 sealing fin 10 compressor 11 stator 12 casing 13 guide vane 14 flow channel 16 direction of a primary flow 18 abradable coating 20 base portion 20a front flank 20b opposite flank 20c front base surface 20d rear base surface 22 neck portion 22a front flank 22b opposite flank 24 tip portion 24a front flank 24b opposite flank 24c annular surface 24d edge 24e edge 26 coating 28 additional extent of the coating d.sub.1 thickness of the base portion d.sub.2 thickness of the neck portion d.sub.3 thickness of the tip portion h.sub.1 height of the base portion h.sub.2 height of the neck portion h.sub.3 height of the tip portion .sub.2 flank angle of the front flank of the neck portion .sub.3 flank angle of the front flank of the tip portion .sub.2 flank angle of the opposite flank of the neck portion .sub.3 flank angle of the opposite flank of the tip portion E radial plane H total height of a sealing fin without coating X central axis opening angle