DE102004016462A1 - Coolable wall structure for especially gas turbine has cooling medium passing through passages formed in core and parallel to one another and parallel to inner and outer shells - Google Patents

Abstract

The coolable wall structure (12) for the bounding of a hot gas path or hot gas chamber (11), especially in a gas turbine, is a sandwich structure and has an inner shell (13) exposed to the hot gas path or chamber, an outer shell (14), and a core (15) interconnecting and supporting the shells with a space between. A cooling medium passes through a number of passages (20) located side by side in the core and parallel to one another and parallel to the shells. An independent claim is included for a gas turbine, of especially a power plant, provided with the aforesaid wall structure.

Description

technical area

The The present invention relates to a coolable wall structure for confinement a hot gas path or hot gas room, especially in a gas turbine. The invention also relates to a gas turbine, in particular a power plant, with such a wall structure Is provided.

State of technology

A Gas turbine, especially in a power plant for electricity production is used contains Areas exposed to hot gases during operation of the gas turbine. Such hot gas paths or hot gas rooms are located For example, in a combustion chamber of the gas turbine and in the Turbine stages and in an exhaust pipe at the outlet of the gas turbine. These are hot gas paths and hot gas rooms of Wall structures limited in the operation of the gas turbine extremely high thermal Exposed to stress and in particular cooled. For example, find these wall structures are attached to guide vanes or rotor blades or combustion chamber or diffuser panels. In the design of such wall structures have to at least two conflicting requirements are met.

To the one leads the cooling the wall structure to a temperature gradient within the wall structure, which in turn induces thermal stresses. Thermal stresses to lead However, to a high load on the wall structure and reduce their life. To the thermal stresses as possible Therefore, trying to keep the wall structure as small as possible thin too choose, to reduce the associated temperature gradient.

To the others require cooling the wall structure by means of a cooling fluid in any case a pressure gradient along the wall structure to drive the respective cooling medium. From this results in a pressure difference, which as a base load always on the wall structure acts and due to the high temperatures to a visco-plastic Deformation of the material and thus damage to the wall structure to lead can. To creep such deformations at a desired Pressure to keep within acceptable limits, is for the Wall structure one possible large wall thickness required.

consequently the pressure load of the wall structure requires a minimum wall thickness, while the thermal load of the wall structure a maximum wall thickness requires. It follows for the construction cooled Wall structures a relatively narrow window for the design of the wall thickness, that by the mentioned wall thickness minimum value and the said wall thickness maximum value is limited. Understandably Here is the desire to expand this relatively narrow interpretation window.

Basically it possible for this to increase the rigidity of a flat wall by that in The wall ribs are integrated, which the load capacity of the Improve wall structure. Such ribs, the appropriate to the cooled Side of the wall structure should be attached, however, lead to a locally elevated Temperature gradients, the locally relatively high thermal stresses triggers, and although mainly at the joints between ribs and wall.

alternative it is basically also possible, the the hot gases to hold exposed wall structure on a cooled support structure, which is sufficiently stiff so that there are no creep deformations occur. Critical here is the transmission of the attacking compressive forces between the hot wall structure and the cold support structure. Here must the power path with the utmost care and relatively high effort to be extremely extreme here high punctiform Avoid stress in one of the two structures.

presentation the invention

Here The invention aims to remedy this. The invention, as in the claims is employed dealing with the problem, for a wall structure of the type mentioned an improved embodiment in particular, on the one hand a comparatively high rigidity has and in the other hand, only relatively small thermal stresses occur.

According to the invention this Problem with the objects the independent one claims solved. Advantageous embodiments are the subject of the dependent Claims.

The invention is based on the general idea of constructing the wall structure as a sandwich structure, which comprises an inner shell, an outer shell and a core arranged therebetween and permeable by the cooling medium. The main advantage of the sandwich wall structure is seen in the fact that the two shells, which form the outer sides or outer skins of the wall structure, each for themselves can have extremely small wall thicknesses, which leads only to very low thermal stresses. In addition, the core of the sandwich wall structure which separates the two shells from each other can also be configured so that in it or in the entire wall structure can not build high voltages. The stiffness of the sandwich wall structure is determined essentially by the thickness of the wall structure, which results essentially (except for the wall thicknesses of the shells) from the distance between the two shells.

One Another advantage of the inventively designed wall structure can also be seen in the fact that the core to flow through with the cooling medium what is a directed cooling flow within the wall structure and in particular along its inner shell, the hot gas space or the hot gas path is exposed. In this way, the inner shell can be cooled directly, which reduces their thermal load. For cooling, for example, a gaseous Cooling medium, such as As air or steam, or a liquid cooling medium, such as. Water, be used. The respective cooling requirement is aimed according to the particular application and according to the materials selected for the sandwich wall structure.

Basically there it for the required mass flow of the cooling medium two ways to cooling the sandwich wall structure. On the one hand, the entire cooling medium mass flow are passed through the core, wherein the flow-through areas are formed of the core in a corresponding manner. For example can be a directed flow of the core can be achieved along the wall structure. On the other hand the cooling medium also so led be that only a part of the cooling medium mass flow is guided through the core, while the remaining mass flow z. B. acts on the outer shell to the cooling. In this procedure, a gradual change in temperature from the hot Inner shell to the cold outer shell be achieved whose temperature gradient in terms of thermal stability the sandwich structure is tuned.

According to one advantageous embodiment, the Materials for Inner shell, outer shell and Kern selected be that the inner shell has a smaller coefficient of thermal expansion has a smaller coefficient of thermal expansion than the core and the core has as the outer shell. This construction leads In addition, the inner shell is less when the temperature increases strong expands than the core and this less strong than the outer shell. As in the operation of the wall structure of the inner shell to the outer shell a temperature gradient is present, through this design a certain Compensation can be achieved, which reduces thermal stresses.

Corresponding In a particularly advantageous development, the temperature expansion coefficients of materials for Inner shell, outer shell and core so as to be at a predetermined location for the wall structure Be adjusted in case of application adjusting temperature gradient that in this application, thermal stresses within the wall structure at least partially or substantially completely compensated. By the proposed construction can thus be thermal stresses essentially avoid or at least within the wall structure to a big one Reduce part. this leads to an elevated one Life of the wall structure.

Further important features and advantages of the invention will become apparent from the Dependent claims, from the drawings and from the associated description of the figures the drawings.

Short description the drawings

preferred embodiments The invention are illustrated in the drawings and in the following description explains where like reference numerals refer to the same or similar or functionally identical components. Show, respectively schematically

1 a greatly simplified, schematics-like schematic diagram of a gas turbine according to the invention, which is equipped with a wall structure according to the invention,

2 to 5 Sectional views and perspective views of the wall structure according to the invention in different embodiments.

Ways to execute the invention

Corresponding 1 includes a gas turbine 1 , in particular a power plant, at least one compressor 2 , a combustion chamber 3 as well as a turbine 4 , About a fresh gas line 5 Fresh gas reaches the compressor 2 and is condensed in it. The compressed fresh gas passes through a first connecting line 6 to the combustion chamber 3 in addition, via a fuel supply 7 Fuel is supplied. After the combustion chamber 3 is via a second connection line 8th compressed and hot exhaust of the turbine 4 fed, in which the combustion gases are expanded. The expanded exhaust gases are via an exhaust pipe 9 from the turbine 4 led away. The turbine 4 drives a common wave 10 the compressor 2 at. Usually the turbine drives 4 over the wave 10 In addition, a generator not shown here for generating electricity.

The gas turbine 1 contains several hot gas paths or hot gas rooms 11 , for example in the combustion chamber 3 in the second connection line 8th in the turbine 4 and in the exhaust pipe 9 , At least one of these hot gas paths or hot gas rooms 11 can at least partially through a wall structure 12 limited according to the invention, that is, the wall structure 12 is at one of the respective hot gas path or hot gas space 11 facing inside during operation of the gas turbine 1 charged with hot gases. In addition, the gas turbine includes 1 a cooling device, not shown, which drives a cooling medium, in particular a cooling gas or a cooling liquid, and thus the said wall structures 12 applied.

2 to 5 now show exemplary embodiments of the inventive wall structure 12 without claiming to be exhaustive. According to the invention, the wall structure 12 designed as a sandwich structure and accordingly has an inner shell 13 , the respective hot gas path or hot gas space 11 is exposed, and an outer shell 14 at one of the hot gas path or hot gas space 11 opposite side of the wall structure 12 is arranged, as well as a core 15 that is between the two shells 13 . 14 is arranged, the two shells 13 . 14 spaced apart, the two shells 13 . 14 connects to each other, the two shells 13 . 14 supported one another and can be flowed through by the cooling medium. The flowability with the cooling medium is in 2 symbolized by circles with inside cross that with 16 are designated and represent a directed away from the viewer, standing perpendicular to the drawing plane flow direction. Essential for the wall structure according to the invention 12 is that a total wall thickness 17 the wall structure 12 is significantly larger than a single wall thickness 18 the inner shell 13 and a single wall thickness 19 the outer shell 14 , For example, the total wall thickness 17 five to ten times larger than the respective single wall thickness 18 respectively. 19 ,

Typically, the two shells exist 13 . 14 each of a flat sheet material, while the core 15 the distance between the two shells 13 . 14 bridged with the formation of cavities and thereby designed so that there is a relatively high rigidity for the composite. In the embodiments shown here, the core is 15 each designed so that it is between the shells 13 . 14 a variety of channels 20 formed. These channels 20 extend parallel to each other and parallel to the shells 13 . 14 , The channels 20 are thus along the shells 13 . 14 arranged side by side. Preference is given to the variants shown here, in which the channels 20 between the cups 13 . 14 are arranged in one layer. In principle, embodiments are also conceivable in which the channels 20 between the cups 13 . 14 are arranged in two or more layers, ie in the thickness direction one behind the other.

In the embodiments of the 2 . 4 and 5 is the core 15 made of a sheet material, which also has a relatively small single wall thickness 21 and is here exemplarily quadrangular, in particular trapezoidal bent or folded. In this way arise on both sides of the core 15 alternately to the inner shell 13 and to the outer shell 14 open channels 20 , As a result, each of these channels 20 a channel wall portion formed by a shell portion. For the trapezoidal cross sections of the channels shown here 20 is in each case the long side of the parallel sides of the respective trapezoidal cross-section through the respective shell 13 respectively. 14 educated.

Instead of the quadrangular or trapezoidal fold shown here, the sheet material for the production of the core 15 for example, be wavy, zigzag or triangular bent or folded. Furthermore, it is clear that the core 15 can also be made of several mutually joined sheet materials, as well as the shells 13 . 14 ,

Due to the design of the core 15 can the rigidity of the wall structure 12 be determined. Decisive influence here is the total wall thickness 17 that with the help of the respective core 15 is determined. Important for a high rigidity and strength of the wall structure 12 is also the largest possible support or contacting the core 15 with the two bowls 13 . 14 , In the embodiments of the 2 . 4 and 5 a large-area contact is achieved in each case on the short sides of the mutually parallel sides of the trapezoidal cross-sections. At the same time, the core 15 in these contact zones flat with the shells 13 . 14 be connected, for example in the form of solder joints. The large-area contact between the core 15 and the bowls 13 . 14 is also beneficial in avoiding thermal stresses within the core 15 ,

Particularly favorable for the stiffness and for the thermal resistance of the wall structure 12 has proven an embodiment in which at least 25% to 50% of the outer shell 14 facing surface of the inner shell 13 with the core 15 contacted or connected. Alternatively or additionally, it is also appropriate that at least 25% to 50% of the inner shell 13 facing surface of the outer shell 14 with the core 15 contacted or connected.

While in the embodiments of 2 . 4 and 5 the core 15 made of a flat sheet material shows 3 a Variant in which the core 15 from a plurality of mutually parallel and adjacent pipes 22 is made. Because the pipes 22 Touch each other, also results in a high stiffness for the sandwich structure. Furthermore, the pipes extend 22 inevitably along the shells 13 . 14 and are firmly connected to these, whereby attention is paid here to a flat support or connection. The individual channels 20 are preferably in the pipes 22 educated. Basically, it is also possible in the between adjacent pipes 22 and the bowls 13 . 14 resulting gaps to pass the cooling fluid.

With the help of the channels 20 can be within the sandwich structure or in the core 15 the wall structure 12 a directed, so given flow through the wall structure 12 be achieved with the respective cooling medium. Basically, it can be provided that accordingly 5 adjacent channels 20 by common channel walls or abutting channel walls, such as in 3 are present, communicate with each other through communicating. This is achieved according to 5 z. B. through connection openings 23 , which are introduced into the channel walls.

5 also shows a possibility of the cooling medium from the outer shell 14 here in the channels 20 of the core 15 contribute. The wall structure possesses this 12 a supply section indicated here by a curly bracket 24 on the outer shell 14 , In this feeder section 24 owns the outer shell 14 a plurality of feed openings 25 through which one of the hot gas path or hot gas space 11 remote outside area 26 with the channels 20 is communicatively connected. In other words, that's about the outdoors 26 the feeding section 24 the outer shell 14 supplied cooling medium can through the feed openings 25 into the channels 20 penetrate and through the channels 20 spread and so the core 15 flow through. Through a targeted spatial arrangement and distribution of the channels 20 then can the respective wall structure 12 be cooled intensively.

Analogous to the feed section 24 can the outer shell 14 at another, not shown here point a correspondingly constructed discharge section containing corresponding discharge openings, through which the channels 20 again with the outdoor area 26 to be able to communicate. If this allows the respective installation situation, the cooling medium can be the channels 20 of the core 15 also fed to the front side and / or be removed from these.

Corresponding 4 At least one of the bowls can 13 . 14 , here both bowls 13 . 14 be made of several individual track sections. Accordingly, every shell exists 13 . 14 of several shell sections which abut each other and are joined together at the abutting edges, in particular by welding or soldering. In an expedient embodiment, the individual shell sections are formed by the said welding or soldering connection, which in 4 With 27 is designated, simultaneously with the web of the core 15 connected.

Basically, for the outer shell 14 , the inner shell 13 and the core 15 the same material can be used. Likewise, it is possible the core 15 made of a different material than the shell 13 respectively. 14 , In addition, also the inner shell 13 made of a different material than the outer shell 14 , The for the individual components of the wall structure 12 For example, selected materials may differ from each other in terms of the coefficient of thermal expansion. Preferred is a variant in which the inner shell 13 has a smaller coefficient of thermal expansion than the core 15 , where the core 15 in turn, has a smaller coefficient of thermal expansion than the outer shell 14 , Such a construction comes the thermal load of the wall structure 12 during operation of the gas turbine 1 contrary, as evidenced by the Heißgasbeaufschlagung the inner shell 13 , in the 2 through arrows 28 is indicated, and by the cooling 16 of the core 15 and possibly by a direction indicated by arrows cooling 29 the outer shell 14 in the thickness direction of the wall structure 12 a temperature gradient sets with decreasing from inside to outside temperature values. According to a particularly advantageous embodiment, the temperature expansion coefficients of the materials for the inner shell can now 13 , the outer shell 14 and the core 15 be tuned to a certain temperature gradient, resulting in a preferred application of the wall structure 12 , So for example, in a steady state operation of the gas turbine 1 , sets. The coordination of the coefficients of thermal expansion takes place in such a way that in the stated application, thermal stresses within the wall structure 12 are largely compensated. This has the consequence that the wall structure according to the invention 12 in this application, so for example in a preferred stationary operating state of the gas turbine 1 , is exposed to substantially no thermal stresses, resulting in the life of the wall structure 12 considerably extended.

In operation of the wall structure 12 , so preferably in the operation of the gas turbine 1 , the wall structure becomes 12 cooled, with the aid of a cooling medium mass flow. The size of this Mas senstrom depends on the cooling demand, the wall structure 12 in their respective installation situation. In principle, it is possible for the cooling medium mass flow supplied to the respective wall structure to pass completely through the core 15 So through its channels 20 to lead. The temperature gradient through the inner shell 13 can be very big. In another cooling principle, it may be provided, only a part of the available cooling medium mass flow through the core 15 or through its channels 20 while with the remaining cooling medium mass flow the outer shell 14 at the of the hot gas path or hot gas room 11 opposite outside, so in the outdoor area 26 is charged. In such a cooling principle, a weaker temperature gradient for the total wall thickness 17 be achieved, what the wall structure 12 spares.

1

gas turbine

2

compressor

3

combustion chamber

4

turbine

5

Fresh gas line

6

first connecting line

7

fuel supply

8th

second connecting line

9

exhaust pipe

10

drive shaft

11

Plenum / hot gas path

12

wall structure

13

inner shell

14

outer shell

15

core

16

Coolant flow in 15

17

Total wall thickness of 12

18

Single wall thickness of 13

19

Single wall thickness of 14

20

channel

21

Single wall thickness of 15

22

pipe

23

connecting opening

24

feeding section

25

supply openings

26

outdoors

27

Welding or solder

28

Heißgasbeaufschlagung

29

Kühlmediumbeaufschlagung

Claims (17)

Coolable wall structure for limiting a hot gas path or hot gas space ( 11 ), in particular in a gas turbine ( 1 ), wherein the wall structure ( 12 ) is designed as a sandwich structure and one of the hot gas path or hot gas space ( 11 ) exposed inner shell ( 13 ), an outer shell ( 14 ) and one of the shells ( 13 . 14 ) spaced apart, interconnecting and abutting core ( 15 ) of a cooling medium parallel to the shells ( 13 . 14 ) can be flowed through. Wall structure according to claim 1, characterized in that the core ( 15 ) between the shells ( 13 . 14 ) a plurality of juxtaposed channels ( 20 ) parallel to each other and parallel to the shells ( 13 . 14 ). Wall structure according to claim 2, characterized in that the channels ( 20 ) between the shells ( 13 . 14 ) are arranged in one layer. Wall structure according to claim 2 or 3, characterized in that each channel ( 20 ) to at least one of the shells ( 13 . 14 ) is open, so that there is a shell portion forms a channel wall portion. Wall structure according to claim 4, characterized in that the core ( 15 ) consists of at least one wavy or zigzag or triangular or quadrangular or trapezoidal curved or folded sheet material. Wall structure according to one of claims 1 to 3, characterized in that the core ( 15 ) of a plurality of juxtaposed and parallel to each other and parallel to the shells ( 13 . 14 ) running pipes ( 22 ) consists. Wall structure according to one of claims 1 to 6, characterized in that adjacent channels ( 20 ) are communicating with each other through common or adjacent channel walls. Wall structure according to one of claims 1 to 7, characterized in that one of the hot gas path or hot gas space ( 11 ) outside ( 26 ) in a feed section ( 24 ) of the outer shell ( 14 ) and / or in a discharge section of the outer shell ( 14 ) through the outer shell ( 14 ) through the channels ( 20 ) is communicatively connected. Wall structure according to one of claims 1 to 7, characterized in that the outer shell ( 14 ) with feed openings ( 25 ) is designed such that the opposite region of the inner shell ( 13 ) is cooled to impact. Wall structure according to one of claims 1 to 9, characterized in that inner shell ( 13 ) in particularly exposed areas passage openings to the hot gas space ( 11 ) has a film cooling of the inner shell ( 13 ) to effect. Wall structure according to one of claims 1 to 10, characterized in that at least one of the shells ( 13 . 14 ) consists of several shell sections which are connected to each other and / or to the core ( 15 ) by welding or soldering joints ( 27 ) are connected. Wall structure according to one of claims 1 to 11, characterized in that - the core ( 15 ) is made of a different material than the shells ( 13 . 14 ) and / or - that the inner shell ( 13 ) is made of a different material than the outer shell ( 14 ). Wall structure according to one of claims 1 to 12, characterized in that the materials for inner shell ( 13 ), Outer shell ( 14 ) and core ( 15 ) are selected so that the inner shell ( 13 ) has a smaller coefficient of thermal expansion than the core ( 15 ) and the core ( 15 ) has a smaller coefficient of thermal expansion than the outer shell ( 14 ). Wall structure according to one of claims 1 to 13, characterized in that the temperature expansion coefficients of the materials for inner shell ( 13 ), Outer shell ( 14 ) and core ( 15 ) are adjusted to a temperature gradient which occurs in the respective application, that in this application thermal stresses within the wall structure ( 12 ) are at least partially or substantially completely compensated. Wall structure according to one of claims 1 to 14, characterized in that the core ( 15 ) with both shells ( 13 . 14 ) is connected and / or contacted over a large area. Wall structure according to one of claims 1 to 15, characterized in that - at least 25% to 50% of the outer shell ( 14 ) facing surface of the inner shell ( 13 ) with the core ( 15 ) is contacted and / or connected, and / or - that at least 25% to 50% of the inner shell ( 13 ) facing surface of the outer shell ( 14 ) with the core ( 15 ) is contacted and / or connected. Gas turbine, in particular a power plant, with at least one hot gas path and / or at least one hot gas space ( 11 ), which at least partially by a wall structure ( 12 ) is limited according to one of claims 1 to 14, whose core ( 15 ) during operation of the gas turbine ( 1 ) is flowed through with a cooling medium.