Gas turbine

Abstract

The aircraft-engine gas turbine includes an outer sealing ring for sealing an array of rotor blades that can be attached to a housing by a clamping mechanism (80) in a friction fit, and a plurality of ring segments (20.sub.i, 20.sub.i+1), wherein a free axial path length (a.sub.f) of a sealing ring segment counter to the direction of through-flow is at least as large as an axial engagement (a.sub.1) of a rotation locking member (10) of the outer sealing ring (a.sub.f≧a.sub.1), which is free of form fit counter to the direction of through-flow, and/or an axial overhang (a.sub.2) of a radial mounting rail (23) of the outer sealing ring (a.sub.f≧a.sub.2), and/or an axial offset (a.sub.3, a.sub.4) of a sealing fin (31, 41); and/or a quotient of a specific clearance sum of the outer sealing ring attached to the housing in a friction fit.

Claims

1. An aircraft-engine gas turbine, having a housing that has a flow channel inlet, a first array of rotor blades in a direction of through-flow arranged in the housing, an outer sealing ring for sealing the first array of rotor blades attached to the housing by a clamp in a friction fit, and a plurality of ring segments; wherein a free axial path length of each of the plurality of ring segments counter to the direction of through-flow is at least as large as a quotient of a clearance sum $\left(\underset{i=1}{\overset{n}{.Math.}}{u}_i\right)$ of the outer sealing ring attached to the housing in a friction fit and pi (π) is at least as large as a difference between a maximum outer diameter of the outer sealing ring, attached to the housing in a friction fit, and a minimum inner diameter of the flow channel inlet of the housing $\left(\underset{i=1}{\overset{n}{.Math.}}{u}_i\ge \left(D_{20}-d_{16}\right).Math.\pi \right).$

2. The aircraft-engine gas turbine according to claim 1, wherein a rotation locking member has a groove arrangement with at least one axial groove in the housing that is open counter to the direction of through-flow, in which a radial flange of the outer sealing ring attached to the housing in a friction fit engages in the peripheral direction in a form-fitting manner, and wherein the free axial path length of each of the plurality of ring segments counter to the direction of through-flow is at least as large as a maximum groove length of the groove arrangement.

3. The aircraft-engine gas turbine according to claim 1, wherein the array of rotor blades has a first and a second sealing fin, the second sealing fin is spaced apart axially from the first sealing fin, and the outer sealing ring has a first sealing face for sealing the first sealing fin and a second sealing face for sealing the second sealing fin, the second sealing face is spaced apart axially and radially from the first sealing face, and the free axial path length of each of the plurality of ring segments counter to the direction of through-flow is at least as large as an axial offset of the first sealing fin with respect to a downstream edge of the first sealing face and at least as large as an axial offset of the second sealing fin with respect to a downstream edge of the second sealing face.

4. The aircraft-engine gas turbine according to claim 1, wherein the maximum outer diameter of the outer sealing ring attached to the housing in a friction fit is larger than the minimum inner diameter of the flow channel inlet.

5. The aircraft-engine gas turbine according to claim 1, wherein the array of rotor blades is configured and arranged to convert flow energy into mechanical work and/or a flow channel outlet of the housing has a larger inner diameter than the flow channel inlet of the housing.

6. A method for dismounting an array of rotor blades of a gas turbine, comprising the steps of: providing a housing that has a flow channel inlet, a first array of rotor blades in a direction of through-flow arranged in the housing, an outer sealing ring for sealing the first array of rotor blades attached to the housing by a clamp in a friction fit, and a plurality of ring segments; wherein a free axial path length of each of the plurality of ring segments counter to the direction of through-flow is at least as large as a quotient of a clearance sum $\left(\underset{i=1}{\overset{n}{.Math.}}{u}_i\right)$ of the outer sealing ring attached to the housing in a friction fit and pi (π) is at least as large as a difference between a maximum outer diameter of the outer sealing ring, attached to the housing in a friction fit, and a minimum inner diameter of the flow channel inlet of the housing $\left(\underset{i=1}{\overset{n}{.Math.}}{u}_i\ge \left(D_{20}-d_{16}\right).Math.\pi \right);$ releasing the clamp; withdrawing the plurality of ring segments of the outer sealing ring, as a whole set, from the housing counter to the direction of through-flow through the flow channel inlet; and withdrawing the first array of rotor blades from the housing counter to the direction of through-flow through the flow channel inlet.

7. The method according to claim 6, further comprising the steps of: displacing the plurality of ring segments after release of the clamp, without any tilt and/or all together, axially counter to the direction of through-flow until a rotation locking member and/or a radial mounting rail is disengaged and/or a sealing fin is arranged downstream of a downstream edge; and/or displacing the plurality of ring segments radially inward until the maximum outer diameter is at most as large as the minimum inner diameter of the flow channel inlet.

8. The method according to claim 6, further comprising the steps of: inserting the first array of rotor blades into the housing in the direction of through-flow through the flow channel inlet; inserting the plurality of ring segments of the outer sealing ring into the housing in the direction of through-flow through the flow channel inlet; and attaching the clamp to the outer sealing ring.

9. The method according to claim 8, wherein the plurality of ring segments are displaced, prior to the attachment of the clamp, without any tilt and/or all together, axially in the direction of through-flow until a rotation locking member and/or a radial mounting rail is engaged and/or a sealing fin is displaced with respect to an edge counter to the direction of through-flow; and/or are displaced radially outward until the maximum outer diameter is larger than the minimum inner diameter of the flow channel inlet.

10. The aircraft-engine gas turbine according to claim 1, wherein the free axial path length of each of the plurality of ring segments counter to the direction of through-flow is at least as large as an axial engagement of a rotation locking member of the outer sealing ring, fit counter to the direction of through-flow.

11. The aircraft-engine gas turbine according to claim 1, wherein the free axial path length of each of the plurality of ring segments counter to the direction of through-flow is at least as large as an axial overhang of a radial mounting rail of the outer sealing ring.

12. The aircraft-engine gas turbine according to claim 1, wherein the free axial path length of each of the plurality of ring segments counter to the direction of through-flow is at least as large as an axial offset of a sealing fin of the outer sealing ring counter to the direction of through-flow with respect to a downstream edge of a sealing face of each of the plurality of ring segments for sealing of the sealing fin.

13. The method according to claim 6, wherein the free axial path length of each of the plurality of ring segments counter to the direction of through-flow is at least as large as an axial engagement of a rotation locking member of the outer sealing ring, fit counter to the direction of through-flow.

14. The method according to claim 6, wherein the free axial path length of each of the plurality of ring segments counter to the direction of through-flow is at least as large as an axial overhang of a radial mounting rail of the outer sealing ring.

15. The method according to claim 6, wherein the free axial path length of each of the plurality of ring segments counter to the direction of through-flow is at least as large as an axial offset of a sealing fin of the outer sealing ring counter to the direction of through-flow with respect to a downstream edge of a sealing face of each of the plurality of ring segments for sealing of the sealing fin.

Description

BRIEF DESCRIPTION OF THE DRAWING FIGURES

(1) Additional advantageous enhancements of the present invention ensue from the dependent claims and the following description of preferred embodiments. Shown, in part schematically, for this purpose are:

(2) FIG. 1 a part of a gas turbine according to an embodiment of the present invention in an axial section along an axis of rotation; and

(3) FIG. 2 a part of the gas turbine according to FIG. 1 in a plan view indicated by II.

DESCRIPTION OF THE INVENTION

(4) FIG. 1 shows, in a manner similar to FIG. 2 of US 2007/0231132 A1, mentioned in the beginning, a part of a gas turbine according to an embodiment of the present invention in an axial section along a horizontal axis of rotation. Additional reference to US 2007/0231132 A1 is made; in particular, elements corresponding to each other are identified by identical reference numbers, so that, in the following, differences will be particularly addressed.

(5) The gas turbine has a housing 16 with a circular flow channel inlet, the minimum inner diameter of which is indicated by d.sub.16.

(6) In an operating position illustrated in FIGS. 1, 2, a first array of rotor blades 18 is arranged in the direction of through-flow (from left to right in FIG. 1) in the flow channel. Interposed radially between the housing and the array of rotor blades is an outer sealing ring for sealing of this array of rotor blades, said outer sealing ring being attached to the housing through a clamping mechanism 80 in the form of a plurality of C-clips in a friction fit, and having a plurality of ring segments 20.sub.i, 20.sub.i+1, . . . , which are spaced apart from each other by the clearance u.sub.i in the peripheral direction (see FIG. 2).

(7) The sealing ring segments have a free axial path length a.sub.f, which is indicated by an arrow in FIG. 1, counter to the direction of through-flow. After the C-clips have been released, the sealing ring segments can be displaced purely axially by at counter to the direction of through-flow until the housing limits any further, purely axial displacement counter to the direction of through-flow.

(8) The free axial path length a.sub.f is larger than an axial engagement a.sub.1 of a rotation locking member 10 of the outer sealing ring counter to the direction of through-flow in a manner free of form fit. The rotation locking member has a groove arrangement with a plurality of open axial grooves 12 in the housing counter to the direction of through-flow (toward the left in FIG. 1), in which a radial flange 11 of the outer sealing ring, attached to the housing in a friction fit, engages in the peripheral direction in a form-fitting manner. The maximum groove length a.sub.1 of the groove arrangement can correspond, at least substantially, to the axial engagement of the rotation locking member.

(9) The free axial path length a.sub.f is, at the same time, greater than an axial overhang a.sub.2 of a radial mounting rail 23 of the outer sealing ring. The axial overhang a.sub.2 is defined by the axial length a.sub.2 on which an axial flange 22 of the outer sealing ring engages over a radial groove 21 of the housing in the axial direction (horizontal in FIG. 1) or engages behind it in the radial direction (vertical in FIG. 1). The radial groove of the housing is indicated by an array of rotor blades, which is shown rudimentally in FIG. 1.

(10) The array of rotor blades has a first sealing fin 31 and a second sealing fin 41, which is spaced apart axially from the first sealing fin. The outer sealing ring, which is insofar stepped, has a first, bent sealing face for sealing the first sealing fin and a second, straight sealing face for sealing the second sealing fin, which is spaced apart axially and radially from the first sealing face.

(11) The free axial path length a.sub.f is also larger than an axial offset a.sub.3 of the first sealing fin with respect to a downstream edge 32 of the first sealing face and larger than an axial offset a.sub.4 of the second sealing fin with respect to a downstream edge 42 of the second sealing face.

(12) A quotient of a clearance sum of the outer sealing ring attached to the housing in a friction fit in the operating position and pi (π) is greater than or equal to the difference between the maximum outer diameter D.sub.20 of the outer sealing ring, attached to the housing in a friction fit in the operating position, and the minimum inner diameter d.sub.16 of the flow channel inlet:

(13) $\frac{\underset{i=1}{\overset{n}{.Math.}}{u}_i}{\pi }\ge \left(D_{20}-d_{16}\right)$
where, in the operating position, the maximum outer diameter of the outer sealing ring is larger than the minimum inner diameter of the flow channel inlet.

(14) For dismounting the array of rotor blades, initially one or more and preferably all C-clips of the clamping mechanism 80 are released.

(15) Afterwards, the sealing ring segments 20.sub.i, 20.sub.i+1, . . . of the outer sealing ring are withdrawn from the housing 16 one by one, in groups, or all together through the flow channel inlet counter to the direction of through-flow.

(16) For this purpose, the sealing ring segments are displaced, after release of the clamping mechanism 80, axially, without any tilt, counter to the direction of through-flow until the rotation locking member 10 and the radial mounting rail 23 are disengaged and the sealing fins 31, 41 are arranged downstream after the edges 32 and 42, respectively, of the respective sealing faces (at the right in FIG. 1).

(17) Afterwards, the sealing ring segments 20.sub.i, 20.sub.i+1, . . . of the outer sealing ring are displaced one by one, in groups, or all together radially inward until their maximum outer diameter is as large as or smaller than the minimum inner diameter d.sub.16 of the flow channel inlet. This is possible owing to the clearance sum. If D′.sub.20 indicates the maximum outer diameter of the radially compressed outer sealing ring with radially inward displaced sealing ring segments, so that the latter abut one another in the peripheral direction or their clearance sum is equal to zero, then the following holds:

(18) $\left(D_{20}-D_{20}^{\prime }\right).Math.\pi =\underset{i=1}{\overset{n}{.Math.}}{u}_i\ge \left(D_{20}-d_{16}\right).Math.\pi .Math.D_{20}^{\prime }\le d_{16}$
that is, the compressed outer diameter D′.sub.20 is smaller than the inner diameter d.sub.16 of the flow channel inlet. Accordingly, the sealing ring segments 20.sub.i, 20.sub.i+1, . . . of the outer sealing ring can be displaced one by one, in groups, or all together further axially counter to the direction of through-flow and thus withdrawn from the housing 16 through the flow channel inlet.

(19) Afterwards, the array of rotor blades 18 is withdrawn from the housing through the flow channel inlet counter to the direction of through-flow.

(20) The mounting is performed analogously in the reverse sequence: initially, the array of rotor blades is inserted into the housing in the direction of through-flow through the flow channel inlet and secured axially in the operating position. The sealing ring segments of the outer sealing ring can be then inserted into the housing in the direction of through-flow through the flow channel inlet.

(21) For this purpose, the sealing ring segments of the radially compressed outer sealing ring are displaced or inserted one by one, in groups, or all together axially into the housing 16 in the direction of through-flow through the flow channel inlet. Afterwards, the sealing ring segments 20.sub.i, 20.sub.i+1, . . . of the outer sealing ring are displaced one by one, in groups, or all together radially outward until they rest radially against the housing. They are then displaced further in the direction of through-flow into the operating position, in which the rotation locking member 10 and the radial mounting rail 23 are engaged and the sealing fins 31, 41 are arranged upstream in front of the edges 32 and 42 of the associated sealing faces. Finally, the clamping mechanism 80 and, therewith, the outer sealing ring are attached to the housing in a friction fit.

(22) Even though, in the above description, exemplary embodiments have been described, it is noted that a large number of modifications are possible. In addition, it is noted that the exemplary embodiments merely involve examples that are in no way intended to limit the protective scope, the applications, and the construction. Instead, the person skilled in the art will be afforded a guideline for implementation of at least one of the exemplary embodiments by the above description, with it being possible to make diverse changes, in particular in regard to the function and arrangement of the components described, without departing from the protective scope, as ensues from the claims and combinations of features equivalent thereto.