GAS TURBINE WITH ANNULAR HEAT SHIELD
A gas turbine includes a supporting structure which concentrically surrounds a hot gas path and is shielded with respect to the hot gas path by an annular heat shield (15′), which heat shield (15′) includes a multiplicity of segments which are arranged one behind the other in a circumferential direction and which in each case butt against one another in the circumferential direction so as to form a gap, seals (16′), being arranged for sealing off the gaps between the segments butting against one another, the seals having thin elongate sealing strips (23), which are accommodated in corresponding sealing slots (19), delimited transversely with respect to the longitudinal direction by a wall (25), in the mutually opposite end faces of the segments of the heat shield (15′) which butt against one another. Vibrationally-induced rubbing through of the wall is inhibited or prevented by the frictional surface between the wall (25) and the sealing strips (23) being markedly enlarged with respect to the end face (22) of the sealing strip (23).
This application is a Continuation of, and claims priority under 35 U.S.C. § 120 to, International application no. PCT/EP2007/050944, filed 31 Jan. 2007, and claims priority therethrough under 35 U.S.C. §§ 119, 365 to Swiss application no. No. 00350/06, filed 6 Mar. 2006, the entireties of which are incorporated by reference herein.
BACKGROUND1. Field of Endeavor
The present invention relates to gas turbines.
2. Brief Description of the Related Art
Feather seals or strip seals between adjacent segments in the hot gas path have been known for a long time in gas turbines (U.S. Pat. No. 3,752,598).
It is known, furthermore, where intersecting seals are concerned, to provide, between the segments, separate angled transition seals sealing off the intersection points (U.S. Pat. No. 5,154,577).
Finally, U.S. Pat. No. 5,655,876 (
Gas turbines already in use, such as, for example, the ALSTOM's gas turbines of type GT24/26, have an internal structure, such as is illustrated in the form of details in
The seal 17 prevents cooling air from flowing through the gaps between the segments into the hot gas path 12. The seal 16, conversely, prevents hot gases from flowing out of the hot gas path 12 through the gaps between the segments. The pressure drop across the seal 16 is low. The associated sealing strip 20 therefore lies loosely in the corresponding sealing slots 18 of the segments butting against one another (
When the sealing strip 20 vibrates in the sealing slots 18 (see the double arrow in
One of numerous aspects of the present invention includes a segment seal for a gas turbine, which can avoid the disadvantage of known seals and is distinguished particularly in that piercing of the wall of the sealing slot by the vibrating strip seal is avoided or at least greatly delayed in a simple way.
Another aspect of the present invention includes the marked enlargement of the frictional surface between the wall and the sealing strips with respect to the end face of the sealing strip. What is achieved thereby is that the material-stripping effect of the friction is reduced, and piercing of the end wall of the sealing slots, by the sealing strip moving to and fro in the slot, is prevented or at least considerably delayed.
Yet another aspect includes that the sealing strips have, at their end facing the wall, an angled end portion, the outside of which forms the contact surface with the wall. The angled portion provides in a particularly simple way a considerably larger contact surface for the frictional contact of the sealing strip with the wall.
An exemplary embodiment can include that, at the ends of the sealing slots, angled slot extensions are provided, into which the sealing strips engage with their angled end portions.
The slot extensions may in this case be angled at right angles. They may, however, also be angled at an angle of 90°±δ0<δ<δ≦20° being applicable.
A simplified embodiment of this slot configuration includes the slot extensions designed as slot portions intersecting the sealing slots.
The invention will be explained in more detail below with reference to exemplary embodiments, in connection with the drawing in which:
If the sealing slot 19, 27 is sufficiently wide, the angled end portion 24, 30 can be introduced, without the slot geometry having to be changed. In order to allow larger contact surfaces, it is advantageous to provide, at the ends of the sealing slots 19, 27, angled slot extensions 28, 33 which receive the angled end portion 24, 30 of the sealing strip 23, 29. In the exemplary embodiment of
In the exemplary embodiment of
According to
- 10 Gas turbine
- 11 Supporting structure
- 12 Hot gas path
- 13 Moving blade
- 14 Guide vane
- 15, 15′, 15″ Heat shield (segmented)
- 16, 16′, 16″, 17 Seal (strip or feather seal)
- 18, 19, 27 Sealing slot
- 20, 23, 29 Sealing strip
- 21 End wall (sealing slot)
- 22 End face (sealing strip)
- 24, 30 End portion (angled)
- 25, 31 Wall (slot extension)
- 26, 32 Contact surface (end portion)
- 28, 33 Slot extension
While the invention has been described in detail with reference to exemplary embodiments thereof, it will be apparent to one skilled in the art that various changes can be made, and equivalents employed, without departing from the scope of the invention. The foregoing description of the preferred embodiments of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed, and modifications and variations are possible in light of the above teachings or may be acquired from practice of the invention. The embodiments were chosen and described in order to explain the principles of the invention and its practical application to enable one skilled in the art to utilize the invention in various embodiments as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the claims appended hereto, and their equivalents. The entirety of each of the aforementioned documents is incorporated by reference herein.
Claims
1. A gas turbine comprising:
- a supporting structure which concentrically surrounds a hot gas path;
- an annular heat shield configured and arranged to shield the supporting structure from the hot gas path, the heat shield comprising a plurality of segments circumferentially arranged one behind the other and circumferentially abutting against one another to form gaps, each pair of abutting segments including opposing faces;
- sealing slots in each of the plurality of segments, the slots transversely delimited with respect to the longitudinal direction by a wall portion of each segment, the sealing slots positioned in said opposing faces of abutting segments;
- seals configured and arranged to seal off the gaps between the segments, said seals comprising thin elongate sealing strips positioned in said sealing slots; and
- an enlarged frictional surface between said wall portion and said sealing strip configured and arranged to reduce friction between said wall and said sealing strip, and to inhibit the frictionally-induced piercing of the wall by the sealing strip.
2. The gas turbine as claimed in claim 1, wherein the sealing strips have, at an end facing the wall, an angled end portion the outside of which end portion forms a contact surface with the wall.
3. The gas turbine as claimed in claim 2, further comprising:
- angled slot extensions at the ends of the sealing slots into which the sealing strips engage with their angled end portions.
4. The gas turbine as claimed in claim 3, wherein the slot extensions are angled at right angles.
5. The gas turbine as claimed in claim 3, wherein the slot extensions are angled at an angle of 90°±δ, 0<δ≦20°.
6. The gas turbine as claimed in claim 3, wherein the slot extensions comprise slot portions intersecting the sealing slots.
Type: Application
Filed: Aug 12, 2008
Publication Date: Feb 5, 2009
Inventors: Peter Marx (Birmenstorf), James Robert Wise (Valrico, FL), Marcel Koenig (Wettingen)
Application Number: 12/189,976
International Classification: F01D 11/00 (20060101);