EP1398462A1 - Gas turbine and transition piece - Google Patents

Abstract

The gas turbine engine has multiple combustion chambers with the effluxes (M) passing through the turbine wheel via transfer ducts (11). Each transfer duct is made as a cast component or from sheet material welded together. The ducts can have coolant channels (24) extending transversely to the flow direction. Each adjacent duct section can have the coolant flowing in an opposite direction.

Description

The invention relates to a gas turbine with a turbine unit, the one flowing out from a number of burners Working medium can be fed, with each burner on the working medium side via a transition component assigned to it is connected to the turbine unit. It continues to affect such a transition component.

Gas turbines are used to drive generators in many areas or used by work machines. The Energy content of a fuel to generate a rotational movement a turbine shaft. The fuel will burned in burners, using an air compressor compressed air is supplied. By burning the Fuel becomes a working medium under high pressure generated with a high temperature. This working medium is in a turbine unit downstream of the burners managed where it relaxes while working.

The burner of the gas turbine can be in the manner of a so-called Annular combustion chamber construction in a common, annular Combustion chamber open from which the working medium of the Turbine unit is fed.

Alternatively, each burner can have an individual one Be assigned combustion chamber, from which the working medium Turbine unit is supplied, with adjacent combustion chambers are kept decoupled from each other on the media side. At this also referred to as "Can Transition Construction" of the combustion chambers, each burner is on the working medium side via an associated transition component with the turbine unit connected. This transition component usually has at its end intended to receive the burner, adapted to its shape, a round cross-section.

The transition piece is at its end opening into the turbine unit however, for one together with the other transition pieces complete filling of the annular passage cross-section designed in the turbine unit. To usually has the transition piece at its turbine end an approximately rectangular or trapezoidal one Cross section on. Therefore, the transition component is common by a in the direction of flow of the working medium a circular to an almost rectangular changing one Cross-section marked. The transition component will usually made of sheet metal.

The production of the transition component in a sheet metal construction However, it can be very complex because the above cross-sectional shape described different metal parts with each other need to be added, which is very time and cost intensive can be. They can also be disadvantageous seams and corners such as the joining process Weld seams have an impact, as they flow through the working medium additional friction on the uneven inside of the transition component can arise, which is disadvantageous affects the efficiency of the gas turbine. The strength of the Transition piece in a construction made of sheet metal is also limited, which leads to a reduction in the life of the Component can lead.

As temperatures of around 1200 ° C to 1500 ° C can occur, the components used, especially the transition component, are cooled to sufficient dimensional stability with a long service life guarantee. The cooling of the transition piece becomes common through a combination of impingement and film cooling realized.

The invention has for its object a gas turbine Above type, especially in "Can - Transition - Construction", specify that with a comparatively simple design is suitable for a particularly high degree of efficiency and moreover has a particularly long lifespan. Furthermore, a particularly suitable transition component can be specified.

With regard to the gas turbine, this object is achieved according to the invention solved by the transition component between the burner and turbine connection executed as a cast part or welded sheet metal part is.

The invention is based on the consideration that to ensure a particularly high system efficiency Shaping the transition component to specifications with regard to a appropriate flow division adapted for the working medium should be. In particular, the should required continuous change in flow cross-section, starting from an approximately circular cross-section towards an approximately rectangular or trapezoidal Cross section, can be provided. To also with such complex requirements for the shape of the molded part the high mechanical life favoring the gas turbine and / or to enable thermal stability, should that Molding targeted with regard to its structural properties designed to comply with these boundary conditions his. This is also with only a limited manufacturing effort possible by using the transition component as a cast part or welded Sheet metal part is executed.

For a particularly effective cooling of the transition component this advantageously provided with coolant channels. These are preferably aligned in the circumferential direction of the component arranged on this. An arrangement of the coolant channels in the circumferential direction has the advantage that through a suitable choice of the local arrangement density of the channels or the size of the local cooling effect Temperature or heating curve adjusted on the transition component can be. Even in the longitudinal direction of the transition component is seen locally different heating an approximately uniform cooling in the longitudinal direction of the whole Transition component reached.

For uniform cooling of the transition component in the circumferential direction neighboring coolant channels can be reached expediently in the opposite direction from the coolant flows through. The coolant heats up as it flows through of the coolant channels through the cooling process increasingly on. The resulting irregularities in the temperature profile in the circumferential direction of the transition component the individual cooling channels can with opposite flow direction therefore kept low or fully compensated become. To an opposite flow direction to ensure the coolant in adjacent coolant channels, is expedient for feeding the coolant channels a corresponding alternating circuit of the Coolant channels with inlet and outlet channels provided.

The coolant channels are preferably as in the wall of the Transition component introduced grooves executed with a Cover plate are closed. With this construction of the coolant channels the grooves can already be cast when the transition component is cast be introduced so that the coolant channels time and cost-saving can be attached.

To when closing a groove with the assigned cover plate To achieve high strength, the cover plate is expedient welded to the transition component. To be there high accuracy and thus a homogeneous coolant channel to obtain, the cover plate preferably has a U-shaped Cross-section, on the upper edges of which the Transition component is welded. The U-shaped cross section of the cover plate has the advantage that the cover plate is due to sufficient expansion space during the welding process deform due to thermal influences of the welding tool can, and therefore a very accurate and homogeneous Cross section of the coolant channel can be reached without cracks. It can also have flat cross-sectional shapes for the cover plate Find application.

To introduce the coolant into the coolant channels and deriving from these is advantageously the coolant channels assigned a common coolant distributor, through which the individual coolant channels with the coolant be supplied. A common distributor has the advantage that the coolant channels are not through individual lines must be supplied with the coolant, which causes a reliable cooling system with a time and cost saving Manufacturing process can be realized.

In the coolant distributor are preferably supply and discharge channels integrated, which is essentially parallel to Flow direction of the working medium are oriented. This On the one hand, arrangement offers the advantage of over the coolant a short distance to the actual coolant channels or to be able to discharge, and on the other hand enables a alternating with respect to the direction of flow of the coolant Wiring the coolant pipes. In addition, at this arrangement of the supply and discharge channels at a suitable Dimensioning also for existing gas turbines In "Can - Transition - Construction" existing supply and discharge connections be used for the coolant supply, so this arrangement is also particularly suitable for retrofitting existing systems is suitable. advantageously, can the coolant distributor with the integrated supply channels cast together during the casting of the transition component become. The circuit for feeding the coolant pipes, especially in the opposite direction of flow, can advantageously also during the casting process be made with. The supply and discharge channels point a suitably chosen course so that the connection side when wiring the coolant channels alternates.

The transition component is expediently via the coolant distributor attached to a support frame. Through the parallel Arrangement of the integrated in the coolant distributor Inlet and outlet channels can be on this part of the cross section the transition component has a particularly high strength be so that when the transition component is fastened at this point the forces acting on the component without further holding structures can be added.

With regard to the transition component itself, the aforementioned Task solved by this is designed as a casting and preferably further developed in the sense of the concepts mentioned above is. The transition component is therefore particularly suitable Dimensions for equipment of a newly manufactured gas turbine or for retrofitting or upgrading already existing gas turbine plants.

The advantages achieved with the invention are in particular in that through the design of the transition component as a cast part or as pressed and welded into shape The geometric transition of the component from a circular to an almost rectangular cross section can be realized particularly precisely because with one Cast the 3-dimensional shape and in particular the change in cross-section made in a smooth transition can be. In the case of a casting, it can also be done with a small amount Weight achieve a comparatively high strength. By a suitable integration of the coolant channels in the Casting is also in every operating state of the gas turbine a suitable application of the Transitional component with coolant and thus a reliable one Component cooling enabled. The transition piece is thus in especially for gas turbines with comparatively high ones Working fluid temperatures can be used and thus favors their efficiency.

Figur 1

einen Halbschnitt durch eine Gasturbine,

Figur 2

ein Übergangsbauteil der Gasturbine nach Figur 1,

Figur 3

im Längsschnitt einen Ausschnitt der Wandung des Übergangsbauteils nach Figur 2,

Figur 4a und 4b

jeweils im Querschnitt einen Kühlmittelverteiler des Übergangsbauteils nach Figur 2.

Figur 5a und 5b

jeweils im Längsschnitt einen Ausschnitt des Kühlmittelverteilers nach Figur 4a und 4b.

An embodiment of the invention is explained in more detail with reference to a drawing. In it show:

Figure 1

a half-section through a gas turbine,

Figure 2

2 shows a transition component of the gas turbine according to FIG. 1,

Figure 3

in longitudinal section a section of the wall of the transition component according to Figure 2,

Figure 4a and 4b

each in cross section a coolant distributor of the transition component according to FIG. 2.

Figure 5a and 5b

each in longitudinal section a section of the coolant distributor according to Figure 4a and 4b.

The same parts are given the same reference symbols in all the figures Mistake.

The gas turbine 1 according to FIG. 1 has a compressor 2 for Combustion air, a number of combustion chambers 4 and one Turbine 6 for driving the compressor 2 and one not shown Generator or a work machine. To are the turbine 6 and the compressor 2 on a common, also arranged as a turbine rotor 8, with which the generator or the work machine is connected, and which is rotatably mounted about its central axis 9 is.

The "Can Transition" type of construction Gas turbine 1 is equipped with a number of burners 10, each of which is assigned an individual combustion chamber 4 is. The combustion chambers 4 are to form an individual Flame or combustion chamber each from an associated Transitional component 11 limits the combustion chambers 4th decoupled from each other on the flow or working medium side holds. A transition component 11 has to accommodate the burner 10 an approximately circular cross section at the end of the burner on while connecting it to the turbine end the turbine has a trapezoidal cross section. Therefore is the transition component 11 in the flow direction of the working medium M from circular to trapezoidal marked changing cross-section.

The turbine 6 has a number of with the turbine shaft 8 connected, rotatable blades 12. The blades 12 are arranged in a ring shape on the turbine shaft 8 and thus form a number of rows of blades. Farther the turbine 6 comprises a number of fixed guide vanes 14, which is also ring-shaped with the formation of Guide vane rows attached to an inner housing 16 of the turbine 6 are. The blades 12 serve to drive the turbine shaft 8 by transfer of momentum from the turbine 6 working medium flowing through M. The guide vanes 14 serve in contrast to the flow of the working medium M between seen two in the flow direction of the working medium M. successive rows of blades or blade rings. A successive pair from a wreath of Guide vanes 14 or a row of guide vanes and from one Wreath of blades 12 or a row of blades is also referred to as the turbine stage.

Each guide vane 14 has one which is also referred to as a blade root Platform 18, which is used to fix the respective guide vane 14 on the inner housing 16 of the turbine 6 as a wall element is arranged. The platform 18 is a thermal comparison heavily loaded component that the outer boundary a heating gas channel for the one flowing through the turbine 6 Working medium M forms. Each blade 12 is analog Way over a platform 20 also referred to as a blade root attached to the turbine shaft 8.

Between the spaced platforms 18 of the guide vanes 14 of two adjacent rows of guide vanes is a respective guide ring 21 on the inner housing 16 of the Turbine 6 arranged. The outer surface of each guide ring 21 is also hot, flowing through the turbine 6 Working medium M exposed and in the radial direction from the outer end 22 of the blade opposite to it 12 spaced by a gap. The one between neighboring Guide rings 21 arranged guide vane rows serve in particular as cover elements that cover the inner wall 16 or other housing installation parts before a thermal Overuse by the flowing through the turbine 6 protects hot working medium M.

To achieve a comparatively high system efficiency the gas turbine 1 is the transition component 11 of each combustion chamber 4 through a suitable choice of shape for the flow pattern of the working medium M flowing through. To one if possible low resistance when flowing through the working medium To reach M, the cross section of the transition component changes 11 continuously in the direction of flow. Around this continuous cross-sectional change with only to consistently comply with comparatively low production costs, the transition component 11 is designed as a cast component. The transition component 11 has due to the cast material high strength and thus a particularly long service life even when used in comparatively adverse operating conditions. The transition component 11 can also as Sheet metal welded part to be executed.

To further clarify the design of the transition component 11 this is shown in FIG. 2 in a suitable view. The transition component 11 is for the in the combustion chamber 4th continuously occurring combustion temperatures designed and in particular designed coolable. To one to achieve effective cooling of the transition component points the transition component 11 several substantially perpendicular to Flow direction of the working medium M and thus in the circumferential direction extending coolant channels 24. Through the course the coolant channels 24 in the circumferential direction can, in particular with a suitable choice of the arrangement density of the coolant channels 24, the cooling effect the temperature curve of the working medium in the transition component 11 under standard operating conditions be adjusted accordingly so that an even Cooling in the longitudinal direction is particularly favored.

Have coolant K to supply the coolant channels 24 the coolant channels 24 via a common coolant distributor 25, which is substantially parallel to the direction of flow of the working medium M on the outer wall of the transition component 11 extends. Through the coolant distributor 25 the coolant K is introduced into the coolant channels 24 and derived from them.

As can be seen in the illustration according to FIG. 3, everyone is Coolant channel 24 from one introduced into the wall of the Groove of the transition component 11 and a final this Cover plate 26 formed. The groove can in particular already be incorporated when casting the transition component 11, so that no further finishing of the wall material is required is. To ensure high strength with this closure of the coolant channel 24, the cover plate 26 welded to the wall of the transition component 11. For one high accuracy during the welding process and to ensure the cover plate 26 has a homogeneous coolant channel 24 thereby a U-shaped cross-section that defines the expansion space with thermal influences of the welding tool for the cover plate 26 limited in the groove. The welding process can therefore deform the cover plate 26, so that a high manufacturing precision is achievable.

As can be seen in the illustration according to FIGS. 4a and 4b, are a supply channel 30 and a in the coolant distributor 25 Discharge channel 32 integrated through which the coolant K in the Coolant channels 24 is supplied and discharged. As also from Figures 4a and 4b show the coolant distributor 25 with the integrated feed channel 30 and the discharge channel 32 cast together with the casting of the transition component 11. To the feed channel 30 and the discharge channel 32 to the To connect the coolant channel 24, the cover plate 26 is on welded its two ends to the coolant distributor 25.

Via the connection point 34 of the coolant distributor 25 the coolant K into the feed channel 30 and out of the discharge channel 32 derived. The positioning of the connection points 34 can in particular meet the requirements of existing ones Adapted gas turbines in "Can - Transition - Construction" be so that the transition component 11 is also particularly for Retrofitting in these gas turbines is suitable.

For uniform cooling of the transition component 11 in the circumferential direction to achieve, flows through the coolant K adjacent Coolant channels 24 in the opposite direction. The result of the cooling process in the coolant channels 24 heating coolants K irregularities the temperature profile of the transition component in the circumferential direction 5 are largely compensated for. As in the illustration 5a and 5b can be seen, is the course of the feed channel 30 and the discharge channel 32 are selected so that when the coolant channels 24 are connected, the connection side alternates to an opposite flow direction of the coolant K of adjacent coolant channels 24 to achieve.

To attach the transition component 11, this is over the Coolant distributor 25 connected to a support frame 36 because through the integrated feed channel running parallel to each other 30 and the discharge channel 32 of the coolant distributor 25 has a particularly high strength, and so on the transition component 11 occurring forces are absorbed can.

LIST OF REFERENCE NUMBERS

1

gas turbine

2

compressor

4

combustion chamber

6

turbine

8th

turbine shaft

9

central axis

10

burner

11

Transitional component

12

blade

14

vane

16

inner housing

18

platform

20

blade

21

guide ring

22

outer end

24

Coolant channel

25

Coolant distributor

26

cover sheet

30

feed

32

discharge channel

34

junction

36

supporting frame

M

working medium

K

coolant

Claims (10)

Gas turbine (1) with a turbine unit, one of a Number of working medium flowing out of burners (10) (M) can be fed, each burner (10) on the working medium side via an assigned one Transition component (11) connected to the turbine unit is, and wherein the transition component (11) as a casting or is designed as a welded sheet metal part. A gas turbine (1) according to claim 1, wherein the or each Transition component (11) with a number of essentially perpendicular to the direction of flow of the working medium (M) aligned coolant channels (24) is provided. Gas turbine (1) according to claim 2, wherein the adjacent coolant channels (24) of the respective transition component (11) for a flow of the coolant (K) in are designed in the opposite direction. Gas turbine (1) according to claim 2 or 3, wherein the coolant channels (24) in the wall of the respective transition component (11) introduced from a cover plate (26) covered grooves are formed. Gas turbine (1) according to claim 4, wherein the respective Cover plate (26) approximately U-shaped in cross section trained and on its upper edges with the Transition component (11) is welded. Gas turbine (1) according to one of claims 2 to 5, in which the coolant channels (24) of the respective Transition component (11) a common coolant distributor (25) is assigned. Gas turbine (1) according to claim 6, in the coolant distributor (25) a supply duct and a discharge duct for coolant (K) are integrated, each in essentially parallel to the flow direction of the Working medium (M) are oriented. Gas turbine (1) according to claim 6 or 7, wherein the coolant distributor (25) to the respective transition component (11) is cast or welded. Gas turbine (1) according to one of claims 6 to 8, in which the or each transition component (11) over its respective coolant distributor (25) on a support frame (36) is attached. Transition component (11) for a gas turbine (1) after a of claims 1 to 9.

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