ASSEMBLY OF A GAS TURBINE WITH COMBUSTION CHAMBER AIR BYPASS

Abstract

An assembly for a gas turbine having a combustion chamber, a swirler, a combustion zone in the combustion chamber, and an air feed. In a transition region from the air feed to the swirler that is flowed through by the air, a plenum is formed and the assembly adjoining the plenum has the swirler, the combustion chamber, and a cover closing the combustion chamber. The assembly has an air conduction channel designed to conduct part of the air flow flowing into the assembly into the combustion chamber, so that the air flow leading through the air feed is divided into a main flow leading through the swirler into the combustion zone and a bypass flow leading past the combustion zone.

Claims

1. An assembly for a gas turbine comprising: a combustion chamber; a swirler; a cover; a combustion zone arranged in an interior space of the combustion chamber; an air feed, via which an air flow is fed to the combustion chamber; a plenum is formed in a transition region that can be flowed through by air from the air feed to the swirler and an assembly adjoining the plenum comprises the swirler and the combustion chamber and the cover closing off the combustion chamber; and an air conduction channel configured as a combustion chamber air bypass, which conducts a part of the air flow flowing into the assembly through the air feed from the plenum through the cover and through the swirler past the combustion zone into the combustion chamber, so that air flow leading through the air feed is divided into a main flow leading through the swirler into the combustion zone and a bypass flow leading past the combustion zone.

2. The assembly according to claim 1, wherein a temperature curve of a temperature of the air conduction channel and/or of a temperature adjoining the air conduction channel varies from an inflow side, on which the air flows into the air conduction channel, to an outflow side, on which the air flows out of the air conduction channel, by maximally 10%.

3. The assembly according to claim 1, wherein the air conduction channel is formed by a tubing, at least in sections.

4. The assembly according to claim 1, wherein the air conduction channel is formed by the cover, at least in sections.

5. The assembly according to claim 1, wherein the air conduction channel is formed by the swirler, at least in sections.

6. The assembly according to claim 1, wherein the air conduction channel leads from the plenum through the cover into an outer region, the air conduction channel diverts a bypass flow in the outer region on a side of the cover facing away from the combustion chamber, and the air conduction channel leads from the outer region through the cover into the swirler and from the swirler into a section of the combustion chamber, which in a flow direction of the air flow is arranged after and/or offset to the combustion zone.

7. The assembly according to claim 1, further comprising: a valve arranged in the air conduction channel, configured to adjust a flow rate of the bypass flow.

8. The assembly according to claim 1, wherein the cover and the swirler are formed integrally with one another.

9. The assembly according to claim 6, wherein the air conduction channel conducts the bypass flow into an annular space formed in the combustion chamber, which annular space surrounds the combustion zone.

10. The assembly according to claim 9, wherein at least one flow body is provided on the annular space, by way of which the bypass flow is conducted into a section of the combustion chamber located outside the annular space.

11. The assembly according to claim 10, wherein the at least one flow body introduces the bypass flow into a section of the combustion chamber located outside the annular space such that the bypass flow in the combustion chamber does not pass through the combustion zone and thus a combustion of a mixture of a fuel and air of the main flow occurring in the combustion zone is not influenced.

12. The assembly according to claim 1, wherein the combustion chamber is a tubular combustion chamber.

13. The assembly according to claim 1, further comprising: a pressure housing surrounding the combustion chamber, wherein the air feed is formed by an air space between a combustion chamber wall delimiting the combustion chamber and the pressure housing annularly surrounding the combustion chamber wall.

14. A gas turbine comprising: a combustion chamber; a swirler; a cover; a combustion zone arranged in an interior space of the combustion chamber; an air feed, via which an air flow is fed to the combustion chamber; a plenum is formed in a transition region that can be flowed through by air from the air feed to the swirler and an assembly adjoining the plenum comprises the swirler and the combustion chamber and the cover closing off the combustion chamber; and an air conduction channel configured as a combustion chamber air bypass, which conducts a part of the air flow flowing into the assembly through the air feed from the plenum through the cover and through the swirler past the combustion zone into the combustion chamber, so that the air flow leading through the air feed is divided into a main flow leading through the swirler into the combustion zone and a bypass flow leading past the combustion zone.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Other advantageous further developments of the invention are characterized in the subclaims or are shown in more detail by way of the figures together with the description of the preferred embodiment of the invention. It shows:

[0027] FIG. 1 is an extract of a combustion chamber with a pressure housing, swirler, and cover arranged thereon; and

[0028] FIG. 2 is an extract of a pressure space formed in the combustion chamber.

DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS

[0029] The figures are exemplarily schematic. Same reference numbers in the figures point to same functional same and/or structural features.

[0030] FIG. 1 shows a part of a gas turbine or of an assembly of a gas turbine and more precisely an extract of a combustion chamber 10 embodied as tubular combustion chamber, about which a pressure housing 20 is annularly arranged in the circumferential direction, and a swirler 30 arranged on the front side of the combustion chamber 10 and a cover 40 closing off the combustion chamber 10 on the front side. The assembly shown in FIG. 1 and consisting of the aforementioned components (actual combustion chamber 10, pressure housing 20, swirler 30, and cover 40) can also be referred to as combustion chamber in their entirety, wherein here the actual component, in which the combustion occurs, is referred to as combustion chamber 10.

[0031] Air compressed through a compressor flow-connected upstream flows along the air flow S0 through the air space 21, which is defined by the annular arrangement of the pressure housing 20 about the combustion chamber 10 or the distance between a combustion chamber wall 12, which surrounds the combustion chamber 10 in the circumferential direction about its centre axis and thereby delimits the combustion chamber 10 in the radial direction. Accordingly, the air space 21 itself is also formed annularly about the combustion chamber 10. The air flow S0 also flows annularly through the air space 21 from the compressor connected upstream to the pre-chamber of the swirler 30 in which the plenum 22 is formed, wherein in FIG. 1 only one possible flow path is exemplarily shown and designated. The fact that the shown flow path is merely exemplarily applies both to the air flow S0 flowing in from the compressor, which can also be referred to as basic flow, and also to a main flow 51 and a bypass flow S2 explained in the following.

[0032] The air flowing along the air flow S0 into the plenum 22 is divided, at least in a part-load operation of the gas turbine, into a main flow S1 and a bypass flow S0 through appropriate opening of the air conduction channel 60 by a valve 70. The air flowing along the main flow S1 flows through the swirler 30 and is swirled in the process or subjected to a swirl. The swirl-affected air out of the swirler 30 flowing or injected along the main flow S1 into the combustion chamber 10, which previously and preferentially was mixed in the swirler 30, and/or a space annularly surrounded by the swirler 30, and/or the cover 40 with a fuel, or the mixture of air and fuel created by way of this, is ignited or combusted in the combustion chamber 10, so that the combustion stabilises in the combustion zone 13 in the combustion chamber 10 and a flame burns in the combustion zone 13.

[0033] The working range of the flame and thus of the combustion in the combustion zone depends among other things on the ratio of the air and fuel fed in via the main flow S1. The mixture can also be referred to as air-fuel mixture.

[0034] When the combustion chamber 10 is operated too lean, the carbon monoxide emissions increase severely. This limits the operating range of the gas turbine in the part load range. In order to keep the emissions low and increase the working range of the combustion occurring in the combustion zone 13 or of the combustion chamber 10 it is possible to conduct the arriving air flowing in along the air flow S0 by opening or adjusting the valve 70 through the air conduction channel 60 along the bypass flow S1 past the combustion zone 13, so that less air is fed to the flame and thus carbon monoxide emissions avoided.

[0035] According to one aspect of the invention, it is provided in the gas turbine or the assembly shown by way of extract in FIG. 1 that a part of the air flowing in through the air space 21 into the plenum 22 of the swirler 30 is discharged through the cover 40 as a result of which the bypass flow S2 passing through the air conduction channel 60 is created. The air volume delivered along the bypass flow S2 or the quantity of air which is split off the air flowing in through the air space 21 is controlled by the valve 70 or a valve position of the valve 70.

[0036] The air flowing along the bypass flow S2 is conducted through the air conduction channel 60 here exemplarily formed tubularly, from the cover 40 to the valve 70 back to the cover 40 through the swirler 30 and into an annular space 14 downstream of the swirler 30.

[0037] The annular space 14 is shown by way of extract and enlarged in FIG. 2. The air delivered through the air conduction channel 60 into the annular space 14 is introduced or injected into the combustion chamber 10 via a or at least one flow body 15 so that the flame or the combustion in the combustion zone 13 is not negatively influenced. By way of this or by way of the course of the air conduction channel 60 from its inflow side 61 in or on the plenum 22 to its outflow side 62 in or on the annular space 14 through the cover 40 and the swirler 30 only components are interconnected which approximately have the same material temperature and which are interconnected even without a combustion chamber air bypass formed by the air conduction channel 60. By way of this, the disadvantages of most gas turbines with combustion chamber bypasses known in the prior art are avoided.

[0038] In its embodiment, according to one aspect of the invention, is not restricted to the preferred exemplary embodiments stated above. On the contrary, a number of versions is conceivable which made use of the shown solution even with fundamentally different types of embodiments.

[0039] Thus, while there have shown and described and pointed out fundamental novel features of the invention as applied to a preferred embodiment thereof, it will be understood that various omissions and substitutions and changes in the form and details of the devices illustrated, and in their operation, may be made by those skilled in the art without departing from the spirit of the invention. For example, it is expressly intended that all combinations of those elements and/or method steps which perform substantially the same function in substantially the same way to achieve the same results are within the scope of the invention. Moreover, it should be recognized that structures and/or elements and/or method steps shown and/or described in connection with any disclosed form or embodiment of the invention may be incorporated in any other disclosed or described or suggested form or embodiment as a general matter of design choice. It is the intention, therefore, to be limited only as indicated by the scope of the claims appended hereto.