The invention relates to an axial-flow machine, in particular a gas turbine with axial gas flow or an axial compressor, according to the preamble of claim 1.
The efficiency of a continuous flow machine, which is achievable, increases with the permissible temperature of the gas flow. Therefore very high temperatures are desirable. In this context, it is usual that the casing and/or the rotor shaft of the continuous flow machine are shielded from the hot gas flow by heat shield segments. These heat shield segments cover cavities, which communicate with one another and with a cooling air source, so that also at very high gas flow temperatures an effective protection of temperature sensitive components can be achieved.
The heat shield segments on the rotor side can be formed, on the one hand, as part of the base of the rotor blades on the side of the rotor. On the other hand, heat shield segments can also be provided between axially neighboring rotor blade rows, separate from the rotor blade bases.
Between adjacent heat shield segments in the circumferential direction there are inevitably gaps, which extend transverse to the circumferential direction of the rotor shaft each side of a parting plane, which forms the gap center. These gaps can cause a more or less pronounced leak of the cooling air, which flows through the above-mentioned cavities.
The invention addresses the problem of ensuring an effective sealing of the above-mentioned gaps.
In doing so, it should be ensured on the one hand that no cooling air can enter into the gas flow of the continuous flow machine, and on the other hand that no hot gases can flow through the above-mentioned gaps into the cooling air flow.
This problem is solved according to the invention, in that the respective gap is sealed with flat strip-like sealing strips, which are arranged with their longitudinal edges in opposing grooves in the side faces of the heat shield segments, which are facing the parting plane.
A first sealing strip can be arranged accordingly along edges of the side faces of the gap extending parallel to a rotational axis. A further sealing strip can be provided on edges of the side faces, which extend radially with respect to the rotor shaft, so that no cooling air can escape here in the axial direction.
In this way, the gap is sealed against air or gas flows radial or parallel to the rotor axis.
The sealing in the axial direction is particularly desired in the region of the free end faces of the heat shields pointing in the direction of the axial gas flow in the last rotor stage in the direction of flow.
In order to simplify the assembly of the sealing strips which seal the gap in the axial direction, the grooves which receive the sealing strips at the side face of the heat shield adjacent the gap can be accessible from the end face facing the direction of flow, so that the sealing strip can be pushed into the grooves from the said end face. In order to facilitate the assembly, the above mentioned sealing strip can have a recess on its side which faces the direction of flow, into which a flat tool can be inserted which is inserted into the gap, in order to push the sealing strip into the corresponding grooves in the side faces.
The end position of the further sealing strip is preferably formed by providing the grooves, on the side faces of the gap which receive the longitudinal edges of the sealing strip, with a corresponding limited length, whereby the ends of the grooves function as end stops for the sealing strip. According to an especially preferred embodiment the further sealing strip can be secured in its end position by a locking device of the rotary slide valve type, which serves furthermore to fix the heat shield segments adjacent the gap to the rotor shaft, or to fix the rotor blades, connected to the heat shield segments, to the rotor shaft.
Preferred features of the invention can be found in the claims and the following description of the drawings, and will be described in more detail using particularly preferred embodiments the invention.
Protection is sought not only for the combination of features given or shown, but in principle also for any combination of the individual features given or shown.
According to
The bases of the rotor blades 2 are formed as heat shield segments 5 of the rotor shaft between the respective rotor blade 2 and its root 4. That is, they form together a shielding of the rotor shaft 1 from the hot gas flow H. For this purpose the heat shield segments 5 are provided with cavities, which communicate with one another and with a source of cooling air (not shown), so that a cooling air layer forms radially between the hot gas side of the surface of the heat shield segments 5 and the rotor shaft 1. The heat shield segments 5 which are combined with the rotor blades 2 can extend in the axial direction of the rotor shaft 1 into the region of the guide vanes 3. Alternatively, it is also possible to arrange separate heat shield segments 6 in the region of the guide vanes 3, which can have roots 4 similar to the rotor blades 2, and can thus be attached to the rotor shaft 1 in a similar way to the rotor blades 2.
The cavities in the heat shield segments 5 or 6 through which cooling air flows communicate respectively with the cavities in adjacent heat shield segments 5 or 6 in the circumferential direction of the rotor shaft.
Compliment
As can be seen especially in
Because the gap 7 communicates with the cavities in the heat shield segments 5 or 6 provided for cooling air, there is the risk that cooling air can enter the hot gas flow H or that hot gases can escape from the hot gas flow H into the cavities of the heat shield segments 5 or 6 through the gap 7 or through the openings 7′ or 7″, and therefore get dangerously close to the rotor shaft 1.
This undesired gas or air flow is prevented by sealing the openings 7′ or 7″ of the gap 7.
Sealing strips 8′are used to seal the openings 7′. The sealing strips 8′are inserted respectively in the longitudinal direction into the grooves 9′, which are arranged in the side faces of the heat shield segments 5 or 6 at opposite sides of the parting plane which forms the center of the respective gap 7.
Further sealing strips 8″ are arranged in principally the same way in the openings 7″. The further sealing strips 8″ are curved around an axis, which is perpendicular to the longitudinal axis of the sealing strips. The grooves 9″, which receive the further sealing strips are correspondingly curved.
According to
The length of the grooves 9″ which receive the sealing strip 8″ are arranged such that the sealing strip 8′ has a desired end position. This means that the upper end of the groove 9″ in
As can be seen in
Before the assembly of the heat shield segments or of their roots 4 to the rotor shaft, the rotary sliding member 13 can be put in a recess in the rotor shaft in its unlocked position.
Number | Date | Country | Kind |
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2010150607 | Dec 2010 | RU | national |