SEALING ARRANGEMENT ON COMBUSTOR TO TURBINE INTERFACE IN A GAS TURBINE

Abstract

A gas turbine unit having a combustor having a liner, a turbine, arranged downstream of the liner along a main flow gas direction and including a plurality of first stage vanes, a rotor cover support located inwardly of the vanes, and a sealing arrangement at a combustor to turbine interface, wherein the sealing arrangement includes a first dogbone seal extending between the rotor cover support and an inner downstream end of the liner or between the rotor cover support and a bulkhead located at the inner downstream end of the liner.

Claims

1. A gas turbine unit comprising: a combustor having a liner; a turbine, arranged downstream of the liner along a main flow gas direction (M) and including a plurality of first stage vanes; a rotor cover support located inwardly of the vanes; a sealing arrangement at a combustor to turbine interface, the sealing arrangement having a first dogbone seal extending between the rotor cover support and an inner downstream end of the liner, or between the rotor cover support and a bulkhead located at an inner downstream end of the liner.

2. Gas turbine unit as claimed in claim 1, wherein the first dogbone seal comprises: a central laminar portion; and a first and a second bulged edge, the edges being straight.

3. Gas turbine unit as claimed in claim 2, wherein a first end of the flat dogbone seal is housed in a groove of the rotor cover support.

4. Gas turbine unit as claimed in claim 3, wherein a portion of the rotor cover support provided with the groove is configured as an additional part.

5. Gas turbine unit as claimed in claim 1, wherein the sealing arrangement comprises: a second dogbone seal extending between the rotor cover support and a vane inner platform.

6. Gas turbine unit as claimed in claim 5, wherein the second dogbone seal comprises: a central laminar portion and a first and a second bulged edge, at least the second edge being curved.

7. Gas turbine unit as claimed in claim 1, comprising: a honeycomb seal arranged on a bulkhead portion facing an inner platform vane tooth at an inner diameter of a combustor to turbine interface of the gas turbine.

8. Gas turbine unit as claimed in claim 7, wherein the honeycomb seal is a brazed and inclined seal.

9. Gas turbine unit as claimed in claim 1, wherein the bulkhead and the combustor sequential liner end are configured to define a near wall cooling passage.

10. Gas turbine unit as claimed in claim 1, wherein the dogbone seals are disposed along 360 about a turbine axis in a segmented manner.

11. Gas turbine unit as claimed in claim 10, wherein a seal arrangement comprises: side seals laterally connected to the dogbone seals.

12. Gas turbine unit as claimed in claim 10 comprising: a fixing plate mounted on the rotor cover support to retain a position of a first end of the dogbone seal which is curved.

13. Gas turbine as claimed in claim 1, wherein the rotor cover support comprises: a hole located inwardly to the flat dogbone seal.

14. Method of assembly a gas turbine, the method comprising: a) providing on the rotor cover support a groove for receiving a first edge of the flat dogbone; b) arranging in position a curved dogbone between the rotor cover support and the inner platform vane by a fixing plate mounted on rotor cover support; c) arranging a second edge of the flat dogbone in a bulkhead groove; d) entering the first edge of the flat dogbone in the rotor cover support groove; e) moving a liner end towards the vane for causing a rotation of the flat dogbone towards a vertical position.

15. Method as claimed in claim 14, wherein the step a) of providing the rotor cover support with a groove comprises: providing an additional part with the groove to be fixed to the rotor cover support.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0039] Further benefits and advantages of the present invention will become apparent after a careful reading of the detailed description with appropriate reference to the accompanying drawings.

[0040] The invention itself, however, may be best understood by reference to the following detailed description of the invention, which describes some exemplary embodiments of the invention, taken in conjunction with the accompanying drawings, in which:

[0041] FIG. 1 is a schematic view of a combustor to turbine interface of a gas turbine according the prior art;

[0042] FIG. 2 is a schematic sectional view of a sealing arrangement of the combustor to turbine interface according to an embodiment of the invention;

[0043] FIG. 3 is a schematic sectional view of a sealing arrangement of the combustor to turbine interface according to another embodiment of the invention;

[0044] FIG. 4 is a partial perspective schematic view of the sealing arrangement of FIG. 3;

[0045] FIG. 5 is a perspective schematic view of some elements of the sealing arrangement according the invention;

[0046] FIG. 6A is a partial perspective schematic view of some elements suitable for installing the sealing arrangement according to the invention in an existing turbine;

[0047] FIGS. 6B and 6C are respectively a front schematic view and a perspective schematic view of an element of the sealing arrangement of FIG. 6A suitable for installing the sealing arrangement in a current turbine;

[0048] FIG. 7 and FIG. 8 are sectional schematic views of two embodiments of a element of the sealing arrangement according to the invention;

[0049] FIG. 9A to FIG. 9F are sectional schematic views of six different design variants of the embodiment of sealing arrangement of FIG. 3;

[0050] FIG. 10A to FIG. 10D are sectional schematic views of the method steps for installing the sealing arrangement according to the invention;

[0051] FIG. 11 is a schematic prospective view of a sealing arrangement according to another embodiment of the invention;

[0052] FIG. 12 is a schematic prospective view of an element of the sealing arrangement of FIG. 11.

DETAILED DESCRIPTION OF THE INVENTION

[0053] In cooperation with the attached drawings, the technical contents and detailed description of the present invention are described thereinafter according to preferable embodiments, being not used to limit its executing scope. Any equivalent variation and modification made according to appended claims is all covered by the claims claimed by the present invention.

[0054] Reference will now be made to the drawings to describe the present invention in detail.

[0055] Reference is made to FIG. 1 which is a schematic view of a combustor to turbine interface of a gas turbine unit according the prior art.

[0056] The gas turbine unit comprises at least a combustor and at least a turbine along a main flow gas direction A. In particular, a combustor to turbine interface is defined by: [0057] a combustor sequential liner B, [0058] a vane C with a vane tooth D facing the combustor sequential liner B, [0059] a rotor cover support E located between the rotor (not shown) and the vane C, and [0060] a sealing arrangement F;
According to this prior art embodiment, the sealing arrangement F is located at the inner diameter I of the combustor to turbine interface consists in an honeycomb seal F.

[0061] Reference is now made to FIG. 2 that is a schematic sectional view of portion of a gas turbine unit. The gas turbine unit comprises a combustor, that may be a can combustor, a turbine and a sealing arrangement 1 according to a first embodiment of the invention at an interface between the combustor and the turbine (combustor to turbine interface 1). In particular, FIG. 2 shows an inner portion of a downstream end of a combustor liner 4 and a vane inner platform 2 of a stator vane 28 of a first turbine stage.

[0062] The vane inner platform may be a single ring along 360 about the turbine axis common to all vanes or each vane may be provided with relevant platform segment.

[0063] The main flow M defines the hot gas flow that flows from the combustor toward the first vane 28.

[0064] The expression inner or inwardly refer to elements or portions near to the gas turbine axis.

[0065] Facing the inner end of the sequential liner 4, the gas turbine is provided with the first turbine vane that in FIG. 2 is shown as only the inner portion 2.

[0066] Between the rotor and the vane inner platform 2, the gas turbine unit comprises a rotor cover support 6 configured to realize a plenum 10 between the vane 2 and the rotor cover support 6.

[0067] In particular, the plenum 10 is closed outwardly by the vane inner platform 2, inwardly and downstream by the rotor cover support 6 and upstream by a flat dogbone seal 3 extending from the front portion of the rotor cover support 6 to a bulkhead 5 arranged inwardly the sequential liner end 4.

[0068] The expressions downstream and upstream refer to the main flow M direction.

[0069] The flat dogbone seal 3 comprises a middle laminar thin portion 29 (which in the embodiment of FIG. 2 is perpendicular to rotor axis with a vertical development) and two opposite bulged edges 18 20 wherein the first inner edge 18 is coupled to the rotor support 6 and the second outer edge 20 is coupled to the bulkhead 5.

[0070] In particular, the first dogbone seal 3 is defined as a flat dogbone seal 3 because the edges 18 20 are straight.

[0071] The inner edge 18 of the flat dogbone seal 3, is arranged in a groove 11 in the rotor cover support 6 whereas the outer end 20 of the flat dogbone seal 3 is arranged in a groove 21 of the bulkhead 5.

[0072] In one embodiment, the gas turbine unit may not have the bulkhead 5 and the flat dogbone outer edge 20 may be sealable coupled directly to the sequential liner 4.

[0073] Reference is made to FIGS. 3 and 4 that are respectively a schematic sectional view and a partial perspective schematic view of a sealing arrangement according to a second embodiment of the invention.

[0074] The vane platform 2 comprises a vane tooth 13 facing a portion of the bulkhead 5 provided with a diagonal honeycomb seal 12. Between the vane tooth 13 and the diagonal honeycomb seal 12 a gap is present.

[0075] A wall cooling passage 14 is defined between the bulkhead 5 and the sequential liner end 4.

[0076] According to this second embodiment of the invention, the gas turbine interface 1 also comprises a second dogbone seal 7 extending between the rotor cover support 6 and the inner portion of the vane inner platform 2, in addition to the flat dogbone seal 3.

[0077] This second dogbone seal 7 comprises a middle thin laminar portion (which in the embodiment of FIG. 3 is perpendicular to rotor axis with a vertical development) and two opposite bulged edges 19 22. The first inner edge 19 is coupled to the rotor support 6 and the second outer edge 22 is coupled to the vane inner platform 2.

[0078] In particular, the second dogbone seal 7 is shape curved because at least the outer edge 22 is curved shaped about the turbine axis. This outer edge 22 is arranged in a groove 23 of the vane inner platform 2 facing the plenum 10.

[0079] A curved dogbone inner edge 19 is arranged at a step portion 24 of rotor cover support 6. This step portion 24 is closed upstream by a fixing plate 9.

[0080] The rotor cover support 6 comprises a hole 15 for fluidly connecting the plenum 10 with the volume upstream the seal arrangement inwardly the liner 4. In particular, the hole 15 is a horizontal hole arranged inwardly the flat dogbone seal 3 and passing the groove 11 where the inner edge 18 of the flat dogbone seal 3 is located.

[0081] The flat, or straight, and curved dogbones 3, 7 are segmented along the 360 around the gas turbine axis and FIG. 4 discloses side seals 17 laterally arranged to two adjacent sectors.

[0082] Reference is made to FIG. 5 that is a perspective schematic view of some elements of the sealing arrangement according the invention.

[0083] In particular, FIG. 5 discloses the bulkhead 5, the relevant honeycomb seal 12, the flat dogbone seal 3, and a radial seal 8 connecting two adjacent flat dogbone seals 3.

[0084] Reference is made to FIGS. 6A, 6B and 6C that are respectively a partial perspective schematic view, a front schematic view a perspective rear schematic view of an additional element suitable for installing the sealing arrangement according to the invention in an existing turbine.

[0085] As previously described, the inner edge 18 of the flat dogbone seal 3 is arranged in a groove 11 of the rotor cover support 6 and the inner edge 19 of the curved dogbone 7 is arranged on a step 24 of the rotor cover support 6.

[0086] Since the existing rotor cover support may not be originally provided with such above groove 11 and step 24, in one embodiment of the invention these portion can be provided in an additional part 16 which is fixed to the rotor cover support 6 during rework operations.

[0087] FIG. 6B discloses an upstream view of the additional part 16 provided with the curved dogbone 7 arranged in position by the fixing plate 9 and with relevant side seal 17.

[0088] The additional part 16 is inwardly provided with lobes 25 having holes 26 for matching with holes 27 provided in the rotor cover support 6.

[0089] Reference is made to FIGS. 7 and 8 that are sectional schematic views of an element of the sealing arrangement according to different embodiments of the invention.

[0090] In particular, to FIGS. 7 and 8 show details of the bulkhead 5.

[0091] In FIG. 7, the outer portion of the bulkhead 5 ends upstream with the honeycomb seal 12 and the vane tooth 13 outwardly faces the liner 4.

[0092] In FIG. 8, the outer portion of the bulkhead 5 continues also at the honeycomb seal 12 and the vane tooth 13 is located between the honeycomb seal 12 and the bulkhead 5.

[0093] According the embodiment of FIG. 8, the wall cooling passage 14 extends up to the vane platform 2.

[0094] Reference is made to FIGS. 9A to 9F that are sectional schematic views of six different design variants of the embodiment of sealing arrangement of FIG. 3.

[0095] In the previous described figures, the flat dogbone 3 is reported having a vertical development with a first inner edge 18 and a second outer edge 20.

[0096] However, according the invention the flat dogbone 3 can extend between the rotor cover support 6 and the bulkhead 5 with different orientations.

[0097] FIG. 9A discloses an embodiment wherein the flat dogbone 3 is horizontal (or parallel to the main flow M) and the first edge becomes an upstream edge 18 whereas the second edge becomes a downstream edge 20, In this embodiment the seal arrangement is not provided with the honeycomb seal 12.

[0098] FIG. 9B discloses an embodiment similar to FIG. 9A wherein the vane platform 2 is not provided with the vane tooth 13.

[0099] FIG. 9C discloses an embodiment similar to FIG. 9A wherein the seal arrangement is provided with the honeycomb seal 12.

[0100] FIG. 9D discloses an embodiment similar to FIG. 9C wherein the vane tooth 13 penetrates at least in part the honeycomb seal 12.

[0101] FIG. 9E discloses an embodiment similar to FIG. 9D wherein the flat dogbone 3 seal is vertical or orthogonal to the main flow M (as reported in FIG. 2) to define a inner 18 and an outer 20 edge.

[0102] FIG. 9F discloses an embodiment similar to FIG. 9D wherein the flat dogbone seal 3 is vertical, or orthogonal to the main flow M. As disclosed in FIG. 9A-9F, and according the invention, side seals are foreseen in circumferential direction in order to reduce the leakage, which is state of the art.

[0103] Reference is made to FIGS. 10A to 10D which are sectional schematic views of the sealing arrangement according to the invention in subsequent steps of a method of installing.

[0104] At the starting point of FIG. 10A, the liner 4 is separated from the vane 2. The curved dogbone 7 is kept in position by the fixing plate 9. The flat dogbone 3 has the outer edge 20 arranged in the relevant bulkhead groove 21 whereas the inner edge 18 is free outside the rotor cover support groove 11.

[0105] In this configuration, the flat dogbone 3 can be tilted to set the inner edge 18 in a suitable position for entering the rotor cover support groove 11.

[0106] Once the inner edge 18 has engaged the cover rotor support groove 11, configuration disclosed in FIG. 10B, by an advancing movement of the liner 4 along the main flow M the flat dogbone inner edge 18 goes deeper in the support groove 11 whereas the flat dogbone 3 starts a tilting rotation towards a vertical disposition (see FIG. 10C).

[0107] At the end of the advancing movement of the liner 4, when the vane tooth 13 is near to the honeycomb seal 12, the flat dogbone 3 is in the correct vertical position as disclosed in FIG. 10D.

[0108] Reference is made to FIGS. 11A to 11C that are sectional schematic views of the sealing arrangement according to the invention and show movements thereof in three different operating conditions.

[0109] As previously described, the double dogbone arrangement according a embodiment of the invention allows to reduce the leakage and compensates both axial and radial movement of the interface during the operation condition.

[0110] Finally, reference is made to FIGS. 11 and 12 that are schematic prospective views of a sealing arrangement according to another embodiment of the invention.

[0111] As previously described, the rotor cover support portion having the groove 11 and the step 24 can be provided as an additional part 16 suitable to be fixed to an existing rotor cover support.

[0112] However, according the invention the gas turbine unit can be provided with a rotor cover support 6 having the above groove 11 and the step 24.

[0113] FIGS. 11 and 12 discloses an example of such modified rotor cover support 6 directly produced with the groove 11 and the step 24.

[0114] Although the invention has been explained in relation to its preferred embodiment(s) as mentioned above, it is to be understood that many other possible modifications and variations can be made without departing from the scope of the present invention. It is, therefore, contemplated that the appended claim or claims will cover such modifications and variations that fall within the true scope of the invention.