Rotor for a turbomachine, and turbomachine having such a rotor

Abstract

A rotor (10) for a turbomachine, in particular for an aircraft engine, having a rotor base body (12), on which at least one sealing fin (14), which is disposed on a base (16), is provided for cooperating with an associated sealing element (20) of the turbomachine; relative to an axial direction of the rotor (10), the base (16) having a base portion (16a) disposed upstream of the sealing fin (14) and a base portion (16b) disposed downstream thereof, for supporting masks during the coating of sealing fins; the upstream base portion (16a) and the downstream base portion (16b) having different radial distances (A1, A2) to a radially outer sealing tip (18) of the sealing fin (14). Also, a turbomachine having at least one such rotor (10).

Claims

1. A rotor for a turbomachine, the rotor comprising: a rotor base body having a sealing fin disposed on a base, the rotor base body having a radially inner surface and a radially outer surface, the sealing fin for cooperating with a seal of the turbomachine; and, relative to an axial direction of the rotor, the base protruding from the radially outer surface and having a base portion upstream of the sealing fin, and a base portion downstream of the sealing fin, the upstream and downstream base portions defining support surfaces extending parallel to the axial direction for supporting masks during coating of the sealing fin, wherein the sealing fin has the coating; wherein the upstream base portion and the downstream base portion have different radial distances to a radially outer sealing tip of the sealing fin and wherein the upstream base portion and the downstream base portion have different axial extents.

2. The rotor as recited in claim 1 wherein a ratio between the radial distance of the upstream base portion and the radial distance of the downstream base portion is between 0.25 and 4, the ratio not being 1.

3. The rotor as recited in claim 1 wherein the rotor is a compressor rotor, and the upstream base portion has a larger distance to the radially outer sealing tip of the sealing fin than the downstream base portion.

4. The rotor as recited in claim 1 wherein the rotor is a turbine rotor, and the upstream base portion has a smaller distance to the radially outer sealing tip of the sealing fin than the downstream base portion.

5. The rotor as recited in claim 1 wherein the rotor is a compressor rotor, and the upstream base portion has a smaller axial extent than the downstream base portion.

6. The rotor as recited in claim 1 wherein the rotor is a turbine rotor, and the upstream base portion has a larger axial extent than the downstream base portion.

7. The rotor as recited in claim 1 wherein the sealing fin has a sealing tip asymmetric in cross section.

8. The rotor as recited in claim 1 wherein, axially, the rotor base body has at least two sealing fins disposed one behind the other in a direction of flow.

9. The rotor as recited in claim 8 wherein the at least two sealing fins have different radial distances to an axial axis of rotation of the rotor.

10. A turbomachine comprising the rotor as recited in claim 1 and the seal, the sealing fin cooperating with the seal.

11. The turbomachine as recited in claim 10 wherein the seal is held by a seal carrier.

12. The turbomachine as recited in claim 11 wherein the seal includes an abradable seal.

13. The turbomachine as recited in claim 12 wherein the abradable seal is a honeycomb seal.

14. The turbomachine as recited in claim 10 further comprising a second sealing fin disposed on a second base for cooperating with a second seal and spaced axially from the sealing fin, the seal disposed relative to the second seal in a radially stepped configuration.

15. The turbomachine as recited in claim 10 wherein the seal is held on a casing of the turbomachine or on at least one guide vane.

16. The turbomachine as recited in claim 10 wherein the seal is held in a guide vane ring.

17. An aircraft engine comprising the turbomachine as recited in claim 10.

18. The rotor as recited in claim 1 wherein the radially outer surface has a constant radius section and a radially expanding section, the base being located on the radially expanding section.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Other features of the present invention will become apparent from the claims, the figures, and the detailed description. The features and feature combinations mentioned above in the description, as well as the features and feature combinations mentioned below in the detailed description and/or shown in isolation in the figures may each be used not only in the indicated combination, but also in other combinations, without departing from the scope of the present invention. Thus, embodiments of the present invention that are not explicitly shown and explained in the figures, but derive from and can be produced from the explained embodiments using separate feature combinations, are also considered to be included and disclosed herein. In addition, embodiments and combinations of features that, therefore, do not have all of the features of an originally formulated independent claim are also considered to be disclosed herein. Moreover, in particular by the above explanations, variants and feature combinations are also considered to have been disclosed herein that go beyond or deviate from the feature combinations described in the antecedent references to the claims. In the drawing,

(2) FIG. 1 is a schematic, axial sectional view of a rotor according to the present invention;

(3) FIG. 2 is a schematic, axial sectional view of the rotor in the area of a sealing fin that cooperates with a sealing element of a turbomachine;

(4) FIG. 3 is a schematic, axial sectional view of the rotor according to the present invention in the cold assembly condition; and

(5) FIG. 4 is a schematic, axial sectional view of the rotor according to the present invention in two possible operating conditions of the associated turbomachine.

DETAILED DESCRIPTION

(6) FIG. 1 shows a schematic, axial sectional view of an inventive rotor 10 of an aircraft engine. Rotor 10, which in the present case is in the form of a compressor rotor and, in the installed state, rotates about an axis of rotation D, includes a rotor base body 12, which bears three circumferentially extending sealing fins 14. Each sealing fin 14 is configured on a base 16. Base 16 may also be referred to as a platform. It is discernible that, relative to a direction of flow S of a working fluid of the associated flow direction, each base 16 has a base portion 16a disposed upstream of sealing fin 14 thereof and a base portion 16b disposed downstream of sealing fin 14 thereof. In the present exemplary embodiment, it is discernible that most downstream base 16 has an asymmetrical design, so that upstream base portion 16a thereof and downstream base portion 16b thereof have different radial distances to sealing tip 18 of respective sealing fin 14. However, an opposite design is also conceivable, for example, in the case of turbines. On the other hand, viewed in direction of flow S, first two bases 16 have a symmetrical design, so that upstream base portions 16a thereof and downstream base portions 16b thereof each have the same radial distance to respective sealing tip 18. In addition, base portions 16a, 16b of the two first bases 16 are also equally wide or, starting from sealing fin 14, have the same axial overhang. Alternatively, it may basically be provided, that, instead, one of the more upstream bases 16 has an asymmetric design with respect to the radial and possibly axial embodiment of base 16 thereof, or that a plurality of or all bases 16 have an asymmetric design with respect to the radial and possibly axial embodiment thereof. It is likewise generally possible for a greater or smaller number of bases 16 to be provided and a correspondingly greater or smaller number of sealing fins 14.

(7) FIG. 2 shows a schematic, axial sectional view of rotor 10 in the installed state, in the area of most downstream sealing fin 14, which cooperates with an associated sealing element 20 of the turbomachine. In the present case, sealing element 20 is in the form of a honeycomb seal and held by a seal carrier 22 on a guide vane (not shown) of a compressor stage of the turbomachine. It is discernible that seal carrier 22 is designed as a stepped labyrinth seal of an inner seal (inner air seal, IAS), so that upstream sealing element 20 has a smaller radial distance to axis of rotation D of the rotor than downstream sealing element 20. It is also discernible that sealing tips 18 of all sealing fins 14 are asymmetrically formed in cross section and are provided with a coating 24, which may also be referred to as tip hardfacing. The ratio of left radial height A1 of upstream base portion 16a to right radial height A2 of downstream base portion 16b is approximately A1:A2=1.5 in the illustrated example; deviating ratios also being possible, in principle. The overhangs or the axial widths of base portions 16a, 16b may generally be the same or different. Because of the desired axially short design of a compressor stage and the radially stepped labyrinth seal for enhanced leakage reduction, the axial sealing fin positions are defined on rotor base body 12, and the overhang of individual bases 16 is limited. The axial overhangs of bases 16 are necessary to permit sufficient masking during the process of coating sealing tips 18. A too short width of base portions 16a, 16b may result in the lifting off of sealing lips, which are used for masking in coating or spraying processes. The possible consequence of such a lifting off is spraying right through, thereby undesirably coating the base faces or rotor base body 12. This is unacceptable for structural/mechanical reasons.

(8) FIG. 3 shows a schematic, axial sectional view of rotor 10 according to the present invention in the cold assembly condition and is clarified in the following in conjunction with FIG. 4, which shows a schematic, axial sectional view of rotor 10 according to the present invention in two possible operating conditions of the associated turbomachine. The dotted-line position of sealing element 20 or of seal carrier 22 thereby corresponds to the cold assembly condition, while the solid-line position corresponds to the condition of what is generally referred to as compressor surge. The basic design of rotor 10 will become apparent from the preceding description. At certain operating points of the turbomachine, for example, in the presence of what is generally referred to as compressor surge, there is the risk of axial contact between the left or upstream base portion 16a of a base 16 and a sealing element 20 of inner-ring seal carrier 22. This contact is unacceptable, so the bases 16 must be designed to be correspondingly narrower. However, this, in turn, would reduce the supporting surface for a coating mask and entail the risk of unacceptable coatings. Generally, an alternative axial displacement of the sealing fin position is also not possible due to the stepping or the necessary axial overhangs of sealing elements 20. Both of these problems may be overcome with the aid of the inventive radial stepping of at least one base 16. As is especially discernible in region IV in FIG. 4, even a considerable relative displacement of sealing elements 20 relative to rotor 10 does not lead to a collision between sealing element 20 and the left or upstream base portion 16a of rear base 16. The design in accordance with the present invention of reducing the radial height of base 16 on one side makes it thereby nevertheless possible to maintain the necessary axial width of both base sides 16a, 16b, without any radial or axial contact occurring between base 16 and honeycomb 20. The individually requisite radial distance between sealing tip 18 and base portions 16a, 16b is implemented in a clearance-gap design for all operating points. It makes possible an enhanced producibility of sealing fin coating 24 along with a lower reworking rate, thereby leading to a reduction of the manufacturing costs. Radially stepping at least one base 16 facilitates or allows for the use of stepped sealing elements 20 in the case of small compressor dimensions, since a smaller axial design is possible. This leads to an improvement in the efficiency and surge line of the turbomachine that is equipped accordingly.

LIST OF REFERENCE NUMERALS

(9) 10 rotor 12 rotor base body 14 sealing fin 16 base 16a base portion 16b base portion 18 sealing tip 20 sealing element 22 seal carrier 24 coating D axis of rotation S flow direction A1 distance A2 distance