RU2817776C2 - Gas turbine unit with combustion chamber air bypass - Google Patents

Abstract

FIELD: machine building.

SUBSTANCE: present invention relates to a unit for a gas turbine plant comprising combustion chamber (10), swirler (30), combustion zone (13) located in inner space (11) of combustion chamber (10), and air supply means, by means of which the air flow can enter combustion chamber (10), wherein in the transition area from the air supply means to swirler (30), through which the air can flow, the increased pressure chamber (22) is formed, and the assembly adjacent to plenum chamber (22) comprises swirler (30), combustion chamber (10) and cover (40) covering combustion chamber (10), wherein the assembly comprises air passage (60) as an air bypass of the combustion chamber, which is configured to direct a portion of the air flow entering the assembly by means of a means for supplying air from high-pressure chamber (22) through cover (40) and through swirler (30) past combustion zone (13) into combustion chamber (10) so that air flow (S0), following through air supply means, is divided into main flow (S1), following through swirler (30) to combustion zone (13), and bypass flow (S2) passing by combustion zone (13).

EFFECT: long service life is achieved, despite the presence of an air bypass of the combustion chamber.

14 cl, 2 dwg

Description

This invention relates to gas turbine units with an air bypass of the combustion chamber.

Numerous embodiments of gas turbine installations are known from the prior art, which, in particular, also contain an air bypass for the combustion chamber.

Essentially, a gas turbine is a power generating or propulsion machine in which a fuel or a mixture of air and fuel is burned to produce chemical energy. The main elements of a gas turbine plant are essentially a turbine, a compressor and a combustion chamber located between them.

To generate mechanical energy, air is compressed in a compressor and mixed with fuel in a combustion chamber, where the mixture is ignited or burned in a combustion zone. The resulting combustion products expand in a further turbine.

Depending on the temperature at which the mixture burns in the combustion zone, or the temperature of the flame in the combustion zone, emissions change so that, depending on the combustion temperature, different amounts of nitrogen oxides (NOx), carbon monoxides (CO) and other exhaust gases leave the turbine. gaseous substances.

Since emission values are regulated by law, it is desirable to maintain combustion temperature and thus combustion within an acceptable range. During operation of a gas turbine plant in partial power mode, in which the combustion temperature is unfavorable and thus combustion is incomplete, a combustion chamber air bypass known in the art is often used, by which part of the air moving from the compressor to the combustion chamber , passes the combustion zone.

For this purpose, in the case of known gas turbine installations, it is provided that tubes extend from the outside to the outer high-pressure casing through which air moving from the compressor into the combustion chamber is transported, these tubes passing through the high-pressure casing and the wall of the combustion chamber into the combustion chamber, limiting the combustion chamber.

However, this design has many disadvantages. First of all, high temperature gradients or expansions of the tube itself and the components that are connected by the tube are created due to differences in temperature or operating temperatures of the components, so that an expansion joint is needed to equalize the different expansions of the components. In addition, the service life of the combustion chamber or the entire gas turbine installation is reduced, since additional stresses are created in them as a result of the force applied to the various components being connected. Combustion air bypass systems designed in this manner are also very complex and expensive because, in addition to high temperatures, they are also subject to large pressure drops.

Thus, the objective of this invention is to eliminate the above disadvantages and create a gas turbine installation with a combustion chamber air bypass, the cost of which, despite the presence of an air bypass of the combustion chamber, is low, and the service life of which is long, despite the presence of an air bypass of the combustion chamber.

This problem is solved using a set of distinctive features according to claim 1 of the claims.

According to the invention, there is provided an assembly for a gas turbine installation or a combustion chamber assembly for a gas turbine installation and, in another aspect of the invention, a gas turbine installation comprising such an assembly. The assembly contains a combustion chamber, a swirler, which can also be called a swirl generator, a combustion zone located in the internal space of the combustion chamber, and an air supply means, wherein the air flow moving, in particular, from a compressor located upstream, must enter the chamber combustion using an air supply. In the transition region from the air supply means to the swirler, through which air can flow, a pressure chamber, which may also be referred to as a prechamber, may be provided or formed for air moving into the swirler or through the swirler into the combustion chamber. In addition, the assembly connecting to the air space, the swirler and the combustion chamber, contains a cover covering the combustion chamber, which closes the combustion chamber preferably on one side or both sides and can further be located on the swirler or form a swirler and limit or close the increased pressure chamber from the front. According to the invention, it is additionally provided that the assembly contains a channel for the passage of air as an air bypass of the combustion chamber, which is configured to direct part of the air flow by means of air supply means into the assembly from the increased pressure chamber through the cover and through the swirler past the combustion zone into the combustion chamber . Accordingly, the air flow passing through the air supply means is divided, preferably during operation of the gas turbine installation in partial power mode, into a main flow moving through the swirler into the combustion zone, and a bypass air flow moving through the air passage channel past the combustion zone. By means of an air passage designed in this manner, or an extension of this passage from the plenum through the cover and swirler, only components are connected to the combustion chamber which, during operation of the gas turbine plant, are at the same or initial temperature, so that the air passage or no temperature differences occur on the components connected to it, and accordingly no high temperature and pressure differences are created, so that the performance of the combustion chamber or the combustion occurring in the combustion chamber is improved without taking complex measures, for example installing a compensator, which should be used for this purpose.

Accordingly, in a preferred embodiment, the temperature curve of the air passage and/or the temperature at the connection points of the air passage fluctuates or varies from the inlet side at which air enters the air passage to the exhaust side at which air leaves the passage for air passage, a maximum of 10%, preferably a maximum of 5%, even more preferably a maximum of 1%. Accordingly, it can be provided that the air passage passes only through components such as the cover, the swirler and the wall of the combustion chamber, which during operation have the same or at least similar temperatures, which deviate from each other, for example, by a maximum 10%. By means of an air channel formed, for example, in the form of a tube, only components which during operation have the same or similar temperature and the same or similar material characteristics are connected at least partially, preferably thermally and/or mechanically, so that gradients no temperatures and/or expansions are created on the air passage or along the air passages.

In order to be able to effectively design a channel for the passage of air, another development proposes the formation of a channel by providing a pipeline, at least partially.

Additionally or alternatively, the air passageway may be formed by the lid, at least in part, so that, for example, a section of the air passage passage extending through the lid may be formed integrally with the lid.

In addition, provision can be made for the passage of air to be formed at least partially by the swirler. As with the cap, the swirler or its material may provide an air passage as a single piece. Where, for example, guide vanes or other guide members are provided by which the main flow moving through the swirler is to be swirled as it enters the combustion chamber, they may be designed as hollow members, at least in part, so that the bypass flow can pass through the guide elements, and the bypass flow air could not enter the main flow or was directed separately from it. However, as an option, a pipeline leading to or between the guide elements and a bypass flow can easily be provided.

An advantageous embodiment in particular is that the air passage leads from the pressure chamber through the cover to an outer area, which is preferably located on the side of the cover facing away from the combustion chamber. The air passage is configured to redirect the bypass flow to an external area on the side of the cover facing away from the combustion chamber. In addition, an air passage leads from the outer area through the cover into the swirler, in which the bypass flow preferably remains completely isolated from the main flow. From the swirler, an air passage leads to a section of the combustion chamber that is located in the direction of the main flow after the combustion zone and/or offset from it, so that the air moving by the bypass flow into the combustion chamber cannot enter the combustion zone and, accordingly, it is not involved in combustion. The air passage section leading through the outer region, which may be formed, for example, in the form of a tube, is designed in terms of its length and direction such that from its exit from the lid to its entry into the lid, it substantially maintains its temperature. Alternatively, the air passage can also extend entirely into the lid, but this results in a more complex design and more expensive construction.

In order to be able to regulate and control the air flow through the air passage or the bypass flow rate and thus also the main flow flow, another development also provides for a valve, preferably a proportional valve, to be installed in the air passage. Even more preferably, such a valve is located along a section of the air passage extending into the outer region and/or even into the outer region, whereby the valve can be easily installed and maintained.

For the thermal connection of the lid and the swirler, and preferably also the air passage section passing through them or formed by said components, in another embodiment it is provided that the lid and the swirler are formed integrally with each other or at least as one component.

To enable the bypass flow to be effectively distributed and supplied to the combustion chamber, the air passageway further directs the bypass flow in the embodiment to an annular space formed in the combustion chamber, which annularly surrounds the combustion zone. Preferably, the annular space is adjacent to and is at least partially limited by the wall of the combustion chamber. The position of the annular space from which the air entering with the bypass flow can be annularly distributed and supplied to sections of the combustion chamber adjacent to the annular space is preferably offset towards the combustion zone in the radial direction and/or in the axial direction relative to the axis of rotation or the central axis of the combustion chamber .

When multiple air passages are provided in an embodiment, they may supply air along a corresponding bypass flow in spaces separated from each other into the combustion chamber. For example, multiple annular spaces can also be provided, which in each case partially surround the combustion zone in an annular or semi-annular manner. When a plurality of air passages are provided, each of them preferably follows the described direction and includes a valve for regulating the air flow.

To enable the air distributed by the bypass flow to be effectively directed into the combustion chamber so that the air does not enter the combustion zone and is not entrained in the combustion occurring there, in a similar advantageous embodiment, at least one element is provided in the annular space for the passage of a flow, which can be formed, for example, in the form of an inlet or a nozzle. By means of the flow element, the bypass flow or air moved by the bypass flow enters a section of the combustion chamber located outside the annulus. Preferably, a plurality of flow elements are provided which are arranged annularly at equal distances in the annular space such that the bypass flow annularly flows around the hot gases generated in the combustion zone, preferably without adversely affecting the combustion process in the combustion chamber.

The air supplied to the combustion chamber by the bypass flow can subsequently be supplied together with hot gases that are formed as a result of combustion of the air supplied by the main flow to the combustion zone from the combustion chamber to the turbine.

Accordingly, another preferred embodiment provides that at least one flow element or elements are configured to introduce or force bypass flow into a section of the combustion chamber located outside the annulus such that the bypass flow in the combustion chamber does not pass through the combustion zone or into the combustion zone, and thus the combustion occurring in the combustion zone of the main flow mixture of fuel and air is not affected and preferably not negatively affected. In particular, the bypass flow air entering through the at least one flow element is drawn in by the hot gases generated during combustion and moves towards the turbine.

Preferably, the combustion chamber is a cylindrical combustion chamber such that the combustion chamber is formed in the form of a tube, which is technically referred to as a "tubular combustion chamber". Here, the swirl cap as well as the combustion zone in the combustion chamber are preferably located at the front end or section of the tubular combustion chamber which faces away from the turbine.

In addition, the gas turbine installation or assembly according to a preferred embodiment comprises a high pressure casing or an outer high pressure casing surrounding a spaced combustion chamber, the air supply means being formed by an air space between a combustion chamber wall defining the combustion chamber and the high pressure casing , ring-shaped surrounding the wall of the combustion chamber. Accordingly, the air space preferably also extends around the combustion chamber.

The above-described features can be combined in any way, provided that this is technically possible and that the above-described features do not contradict each other.

Other advantageous embodiments of the invention are given in the dependent claims or shown in detail in the figures together with the description of the preferred embodiment. On the drawings:

in fig. 1 shows a part of the combustion chamber with a high-pressure housing, a swirler and a cover located on it;

in fig. 2 shows part of the high pressure space formed in the combustion chamber.

The drawings are schematic. Identical item numbers in the drawings indicate the same functional or design features.

In fig. 1 shows a part of a gas turbine installation or a gas turbine installation unit, more precisely, a section of the combustion chamber 10, made in the form of a tubular combustion chamber, around which a high-pressure housing 20, a swirler 30 located on the front side of the combustion chamber 10, and a cover are located in a ring-shaped manner in the circumferential direction. 40, covering the combustion chamber 10 from the front side. The node shown in FIG. 1 and consisting of the above components (combustor 10, high pressure housing 20, swirler 30, cover 40) may also be referred to as a combustion chamber assembly, and the actual component in which combustion occurs is referred to as combustion chamber 10.

The air compressed by the upstream compressor moves along the air flow direction S0 through the air space 21, which is defined by the annular arrangement of the high-pressure housing 20 around the combustion chamber 10 and its distance from the combustion chamber wall 12, which surrounds the combustion chamber 10 in the circumferential direction. around its central axis and thus limits the combustion chamber 10 in the radial direction. Accordingly, the air space 21 itself is also formed annularly around the combustion chamber 10. The air flow S0 also moves annularly through the air space 21 from the compressor installed upstream into the pre-chamber of the swirler 30, in which the high-pressure chamber 22 is formed, and in FIG. 1 shows and indicates only one possible flow path as an example. The fact that the flow path shown, by way of example only, refers to both the air flow S0 coming from the compressor, which may also be referred to as the main flow, as well as the main flow S1 and the bypass flow S2, will be explained below.

The air flowing along the direction of the air flow S0 into the increased pressure chamber 22 is divided, at least during operation of the gas turbine unit in the partial power mode, into a main flow S1 and a bypass flow S2 moving through the corresponding opening of the air passage 60 with the help of valve 70. The air moving in the direction of the main flow S1 moves along the swirler 30 and in doing so is vortexed or subject to vortex. Swirled air from the swirler 30, moving or forced in the direction of the main flow S1 into the combustion chamber 10, which has previously and preferably been mixed with fuel in the swirler 30 and/or the space annularly surrounded by the swirler 30 and/or the cover 40, or a mixture of air and The fuel generated by swirling is ignited or burned in the combustion chamber 10, so that combustion is stabilized in the combustion zone 13 in the combustion chamber 10, and the flame burns in the combustion zone 13.

The operating range of the flame and thus the combustion in the combustion zone depends, among other things, on the ratio of air and fuel supplied by the main flow S1. The mixture may also be referred to as the fuel-air mixture.

When combustion chamber 10 is operated too economically, carbon monoxide emissions increase greatly. This limits the operating range of the gas turbine plant to the partial power range. To maintain emissions low and increase the operating range of combustion occurring in combustion zone 13 or combustion chamber 10, it is possible for air moving along air flow direction S0 to pass through passage 60 for air to pass along bypass flow direction S2 after combustion zone 13 by opening or adjusting valve 70 so that less air enters the flame, thereby eliminating carbon monoxide emissions.

According to the invention, in a gas turbine installation or assembly, partially shown in FIG. 1, it is provided that part of the air moving through the air space 21 into the high-pressure chamber 22 of the swirler 30 is discharged through the cover 40, resulting in the creation of a bypass flow S2 passing through the air passage channel 60. The amount of air supplied along the bypass flow direction S2, or the amount of air that is separated from the air moving through the air space 21, is controlled by the valve 70 or the position of the valve 70.

The air following the bypass flow S2 passes through the air passage 60, which is, for example, tubular, from the cap 40 to the valve 70 and back to the cap 40 through the swirler 30 and into the annular space 14 located downstream of the swirler 30.

The annular space 14 is shown in an enlarged view in FIG. 2. The air entering through the air passage 60 into the annular space 14 is introduced or forced into the combustion chamber 10 by at least one flow element 15 so as not to adversely affect the flame or combustion in the zone 13 combustion. With the above arrangement, or with the passage 60 for air passing from the inlet side 61 in or on the pressure chamber 22 to the outlet side 62 in or on the annulus 14 through the cover 40 and swirl 30, only components that have approximately one and the same temperature of the material and are mutually connected even without the air bypass of the combustion chamber formed by the channel 60 for the passage of air. The above arrangement eliminates the disadvantages of most gas turbine units with an air bypass combustion chamber known from the prior art.

The invention is not limited to the preferred examples of the above embodiments. On the contrary, a number of implementations are conceivable that may use the illustrated technical solution even with radically different types of embodiments.

List of item numbers

10 – combustion chamber

11 – internal space of the combustion chamber

12 – wall of the combustion chamber

13 – combustion zone

14 – annular space

15 - element for flow passage

20 – high pressure housing

21 – airspace

22 – high pressure chamber

30 - swirler

40 - cover

60 - channel for air passage

61 - inlet side of the channel for air passage

62 - outlet side of the channel for air passage

70 - valve

S0 – air flow passing through the airspace

S1 – main stream

S2 – bypass flow

Claims (18)

1. An assembly for a gas turbine installation containing a combustion chamber (10), a swirler (30), a combustion zone (13) located in the internal space (11) of the combustion chamber (10), and an air supply means through which the air flow can be supplied into the combustion chamber (10), moreover, in the transition region through which air can flow from the air supply means to the swirler (30), an increased pressure chamber (22) is formed, and the unit adjacent to the increased pressure chamber (22) contains a swirler (30), a combustion chamber (10 ) and a cover (40) covering the combustion chamber (10), characterized in that the assembly contains a channel (60) for the passage of air as an air bypass of the combustion chamber, which is configured to direct part of the air flow entering the assembly through the air supply means from the high-pressure chamber (22), through the cover (40) and through the swirler (30) past the combustion zone (13) into the combustion chamber (10) so that the air flow (S0) following through the air supply means is divided into the main flow (S1) flowing through the swirler (30) into the zone (13 ) combustion, and the bypass flow (S2) passing by the combustion zone (13). 2. The unit according to claim 1, in which the temperature curve of the channel (60) for the passage of air and/or the temperature at the connection points of the channel (60) for the passage of air varies from the side (61) of the inlet on which the air enters the channel (60) for the passage of air, to the exhaust side at which the air leaves the channel (60) for the passage of air, a maximum of 10%. 3. The unit according to claim 1 or 2, in which the channel (60) for the passage of air is at least partially formed by a pipeline. 4. Unit according to any one of paragraphs. 1-3, in which the air passage channel (60) is at least partially formed by the cover (40). 5. Unit according to any one of paragraphs. 1-4, in which the channel (60) for the passage of air is at least partially formed by a swirler (30). 6. Unit according to any one of paragraphs. 1-5, in which the passage (60) for the passage of air extends from the chamber (22) of increased pressure through the cover (40) to the outer area, wherein the channel (60) for the passage of air is configured to deflect the bypass flow (S2) in the outer area on the side of the cover (40) facing away from the combustion chamber (10), wherein the channel (60) for the passage of air passes from the outer area through the cover (40) into the swirler (30) and from the swirler (30) into the section of the combustion chamber (10), which in the direction of the main flow (S1) is located after the zone (13) combustion and/or displaced relative to it. 7. Unit according to any one of paragraphs. 1-6, in which a valve (70) is installed in the channel (60) for air passage, through which the bypass flow rate can be adjusted. 8. Unit according to any one of paragraphs. 1-7, in which the cover (40) and the swirler (30) are formed integrally with each other. 9. Unit according to any one of paragraphs. 1-8, in which the air passage channel (60) directs the bypass flow (S2) into an annular space (14) formed in the combustion chamber (10), which annularly surrounds the combustion zone (13). 10. The unit according to claim 9, in which the annular space (14) has at least one flow passage element (15), through which the bypass flow (S2) passes into the combustion chamber section (10) located outside the annular space (14). 11. The assembly according to claim 10, in which at least one flow element (15) is configured to introduce a bypass flow (S2) into a section of the combustion chamber (10) located outside the annular space so that the bypass flow ( S2) in the combustion chamber (10) does not pass through the combustion zone (13), and, thus, there is no influence on the combustion of the mixture of fuel and air of the main flow (S1), occurring in the combustion zone (13). 12. Unit according to any one of paragraphs. 1-11, in which the combustion chamber (10) is a tubular combustion chamber. 13. Unit according to any one of paragraphs. 1-12, also comprising a high-pressure housing (20) surrounding the combustion chamber (10), wherein the air supply means is formed by an air space (21) between the combustion chamber wall (12) delimiting the combustion chamber (10) and the housing (20 ) high pressure surrounding the wall (12) of the combustion chamber. 14. Gas turbine installation containing a unit according to any one of paragraphs. 1-13.