EP1630361A1 - Cooling device and method for a gas turbine casing or a combustor - Google Patents

Abstract

The device for the cooling of a gas turbine casing (2) and/or a combustion chamber has a cooling gas supply unit (7), a cooling gas path (10) directed through the casing in its circumferential direction, and a switching unit (13) switchable between a first position, in which it connects the outlet (8) of the cooling gas supply unit to a first casing connection (11) and connects the inlet (9) of the cooling gas supply unit to a second casing connection (12), and a second position in which it connects the outlet of the cooling gas supply unit to the second casing connection and connects the inlet of the cooling gas supply unit to the first casing connection. An independent claim is included for a method for the cooling of the casing of a gas turbine and/or of a combustion chamber of a gas turbine.

Description

Technical area

The present invention relates to a device and a method for cooling a housing of a gas turbine and / or a combustion chamber, in particular the combustion chamber of a gas turbine.

State of the art

The housing of a gas turbine or a gas turbine combustion chamber must be cooled during operation of the gas turbine. For this purpose, it is customary to pass a cooling gas path in the circumferential direction of the housing through the housing. Such a cooling gas path thereby connects a first housing connection, the z. B. serves as a cooling gas inlet, with a second housing connection, which serves for example as a cooling gas outlet. When flowing through the cooling gas path, the cooling gas heats up. Accordingly, the housing has a lower temperature at the cooling gas inlet than at the cooling gas outlet. This means that a circumferential temperature difference is formed in the circumferential direction of the housing. This peripheral temperature difference must not exceed a predetermined maximum value during operation of the gas turbine in order to avoid damage to the housing due to thermal stresses. Furthermore, may Also, an average temperature of the housing does not exceed a predetermined maximum value in order to avoid damage to the housing.

However, it has been found that in a conventional housing cooling between the average temperature and the peripheral temperature difference of the housing is an interaction. If the average temperature is reduced, for example, by lowering the cooling gas temperature at the cooling gas inlet, this automatically leads to an increase in the circumferential temperature difference. Conversely, an increase in the average temperature, z. B. by increasing the Kühlgaseinlasstemperatur, automatically to a reduction in the circumferential temperature difference. In a conventional case cooling, the setting of the peripheral temperature difference and the setting of the average temperature is thus always a compromise of a comparatively large peripheral temperature difference and a comparatively high average temperature.

Presentation of the invention

This is where the invention starts. The invention, as characterized in the claims, deals with the problem of providing a way for the cooling of the housing of a gas turbine or a combustion chamber, which in particular makes it possible to adjust the peripheral temperature difference regardless of the average temperature.

According to the invention, this problem is solved by the subject matters of the independent claims. Advantageous embodiments are the subject of the dependent claims.

The present invention is based on the general idea of changing the peripheral temperature difference by switching the flow direction with which the cooling gas flow passes through the cooling gas path of the housing. By switching the flow direction, the previously used as a cooling gas inlet housing connection to the cooling gas outlet and the previously used as a cooling gas outlet housing connection to the cooling gas inlet. As a result, the hitherto incurred peripheral temperature difference is first reduced and then inverted, provided that the respective switching state is maintained longer. Due to the time interval between successive switching operations with respective flow direction reversal, the circumferential temperature difference can thus be set to quasi arbitrarily small values. In theory, even a peripheral temperature of about 0 ° C can be set. Of crucial importance in the present invention is the fact that the change in the direction of flow has substantially no effect on the average temperature of the housing. By reversing the flow direction, only the temperature distribution in the circumferential direction of the housing changes, while the average temperature of the housing remains constant. The invention thus enables the circumferential temperature difference to be set independently of the average temperature. In this way, it is thus possible to set comparatively low values for both the peripheral temperature and the average temperature.

To realize the invention, a cooling device according to the invention is equipped with a switching device for flow direction reversal, which - depending on switching position - can connect a cooling gas outlet of a cooling gas supply either with the first housing connection or with the second housing connection, so as to connect the respective flow direction through the two housing connections with each other To determine cooling gas path. With the help of such Switching device, the flow direction of the cooling gas in the cooling gas path can be switched very easily, without requiring the operation of the cooling gas supply device must be changed.

Basically, the switching device may have any structure and be equipped in particular with any suitable switching elements, with the help of which the connection between the cooling gas outlet of the cooling gas blower on the one hand and the one or the other housing connection can be switched internally. However, preferred is a switching device that operates with a flap assembly to define and change internal paths with which the cooling gas outlet can be selectively connected to one or the other housing connection. Such a flap assembly has a simple structure, can be realized inexpensively and works reliably.

Other important features and advantages of the present invention will become apparent from the dependent claims, from the drawings and from the associated figure description with reference to the drawings.

Brief description of the drawings

Fig. 1

eine stark vereinfachte Prinzipdarstellung einer Gasturbine, die mit einer erfindungsgemäßen Kühleinrichtung ausgestattet ist,

Fig. 2

eine stark vereinfachte Prinzipdarstellung einer Schalteinrichtung nach der Erfindung bei einer ersten Schaltstellung,

Fig. 3

eine Ansicht in Fig. 2, jedoch bei einer zweiten Schaltstellung,

Fig. 4

ein vereinfachtes Flussdiagramm zur Erläuterung eines Kühlverfahrens nach der Erfindung zur Steuerung einer Umfangstemperaturdifferenz,

Fig. 5

ein Flussdiagramm wie in Fig. 4, jedoch zur Steuerung einer Durchschnittstemperatur.

Preferred embodiments of the invention are illustrated in the drawings and will be described in more detail in the following description, wherein like reference numerals refer to the same or similar or functionally identical components. Show, in each case schematically,

Fig. 1

a greatly simplified schematic representation of a gas turbine, which is equipped with a cooling device according to the invention,

Fig. 2

a greatly simplified schematic diagram of a switching device according to the invention in a first switching position,

Fig. 3

a view in Fig. 2, but at a second switching position,

Fig. 4

a simplified flow chart for explaining a cooling method according to the invention for controlling a circumferential temperature difference,

Fig. 5

a flowchart as in Fig. 4, but for controlling an average temperature.

Ways to carry out the invention

According to FIG. 1, a gas turbine 1 comprises a housing 2, which surrounds the jacket of the gas turbine 1, which is not shown otherwise, in the manner of a shell. It is clear that this housing 2 can also envelop a combustion chamber, not shown, of the gas turbine 1 at the same time or alternatively serve exclusively for the enclosure of a combustion chamber, preferably a gas turbine combustion chamber.

For cooling the housing 2, a cooling device 3 is provided which has a cooling gas fan 4 for driving a cooling gas. As the cooling gas, air is preferably used. Suitably, the cooling gas fan 4 is incorporated into a closed cooling gas circuit 5, in which also a cooler 6 can be arranged. Likewise, it is possible to design the cooling gas circuit 5 open, so that the cooling gas is sucked in from the environment and then expelled back into the environment. Cooling gas fan 4 and cooler 6 each form part of a cooling gas supply device 7, which has a cooling gas outlet 8 and a cooling gas inlet 9. Through the cooling gas outlet 8, the cooling gas passes from In contrast to this, due to the cooling gas inlet 9, the warmed-up cooling gas coming from the housing 2 returns to the cooling gas supply device 7.

In the interior of the housing 2, a cooling gas path 10 is formed, which is guided in the circumferential direction of the housing 2 through the housing 2. In this case, the cooling gas path 10 connects a first housing connection 11 to a second housing connection 12.

The cooling device 3 according to the invention is also equipped with a switching device 13, by means of which the flow direction in the cooling gas path 10 can be reversed. In Fig. 1, a first flow direction 14 is indicated by solid arrows, which adjusts itself in a first switching position of the switching device 13. In contrast, a second flow direction 15, which is opposite to the first flow direction 14, symbolized by broken arrows. The second flow direction 15 adjusts itself in a second switching position of the switching device 13.

The switching device 13 is integrated in the cooling gas circuit 5 in such a way that it connects the cooling gas outlet 8 with the first housing connection 11 and the second housing connection 12 with the cooling gas inlet 9 in the first switching position. In contrast, the switching device 13 connects the cooling gas outlet 8 with the second housing connection 12 and the first housing connection 11 with the cooling gas inlet 9 in its second switching position. This then results in the second flow direction 15.

When the cooling device 3 is operated such that the flow direction of the cooling gas in the cooling gas path 10 remains the same for a long time, that is to say when, for example, the switching device 13 has its first switching position, then that the first flow direction 14 is formed, this has the consequence that along the cooling gas path 10 forms a temperature gradient. At each entry of the cooling gas in the cooling gas path 10, ie the first flow direction 14 on the first housing terminal 11, arises due to the cooling effect of the cooling gas at the periphery of the housing 2, a first temperature T _1, which is referred to hereinafter as the inlet temperature T ₁ , In the course of the cooling gas path 10, the cooling gas is heated, whereby its cooling effect decreases. Accordingly, an exit of the cooling gas path 10, that is to say in the first flow direction 14 at the second housing connection 12, leads to a second temperature T ₂ , which is higher than the inlet temperature T ₁ . The second temperature T ₂ is also referred to below as the outlet temperature T ₂ . The difference between the outlet temperature T ₂ and the inlet temperature T ₁ is referred to below as the circumferential temperature difference △ T: $$\mathrm{\Delta }\mathrm{T}={\mathrm{T}}_2-{\mathrm{<figure-callout\; id="1"\; label="T"\; filenames="imgf0001.png"\; state="\{\{state\}\}">T</figure-callout>}}_1,$$

In order to avoid excessive thermal stresses of the housing 2 in the operation of the gas turbine 1, it is necessary that this peripheral temperature difference .DELTA.T is not greater than a predetermined or predeterminable upper limit .DELTA.T _max . In addition, it may be desirable that this peripheral temperature difference .DELTA.T is not less than a predetermined or predeterminable lower limit .DELTA.T _min . It must therefore apply: $$\mathrm{\Delta }{\mathrm{T}}_{\min }\le \mathrm{\Delta }\mathrm{T}\le \mathrm{\Delta }{\mathrm{T}}_{\mathrm{Max}},$$

In order to vary the circumferential temperature difference .DELTA.T, in the cooling device 3 according to the invention with the aid of the switching device 13, the flow direction in the cooling gas path 10 can be reversed. Before the Flow direction reversal prevails at the inlet of the cooling gas path 10, the lowest housing temperature, while at the outlet of the cooling gas path 10, the highest temperature of the housing 2 is present. After reversing the flow direction, the temperatures at the inlet and at the outlet of the cooling gas path 10 approach each other. This can lead to a zero crossing, in which the temperatures at the entrance and at the exit of the cooling gas path 10 are the same. Furthermore, the temperature ratio between the temperatures at the inlet and at the outlet of the cooling gas path 10 can subsequently also be reversed. By a specific switching back and forth of the flow direction in the cooling gas path 10, a predetermined and in particular comparatively small value for the circumferential temperature difference .DELTA.T can thus be readily set. It is of particular advantage that, as a result of the variation of the circumferential temperature difference ΔT, an average temperature T of the housing 10, which has the housing 2 along its circumference in the middle, does not change substantially. That is, the variation of the circumferential temperature difference ΔT can be performed independently of the average temperature T. The invention also makes it possible to set values for the average temperature T which lie between relatively low limit values, so that in particular: $${\mathrm{T}}_{\min }\le \mathrm{T}\le {\mathrm{T}}_{\mathrm{Max}},$$

In principle, the switching device 13 can be configured in any suitable manner. With reference to FIGS. 2 and 3, only one possible embodiment of such a switching device 13 is explained in more detail below, wherein this is to be done without limiting the generality.

According to FIGS. 2 and 3, the switching device 13 has four terminals, namely a first terminal 16, a second terminal 17, a third terminal 18 and a fourth terminal 19. The first terminal 16 is connected to the cooling gas outlet 8 of the cooling gas supply device 7. The second port 17 is connected to the cooling gas inlet 9 of the cooling gas supply device 7. The third terminal 18 is connected to the first housing terminal 11 of the housing 2, while the fourth terminal 19 is connected to the second housing terminal 12 of the housing 2.

Furthermore, the switching device 13 in the particular embodiment shown here comprises three lines, namely a first line 20, a second line 21 and a third line 22. Furthermore, three openings are provided, namely a first opening 23, a second opening 24 and a third port 25. The first conduit 20 leads from the first port 16 to the third port 18. The second conduit 21 leads from the fourth port 19 to the second port 17. The third conduit 22 leads from the second port 24 to the third port 25. The first Opening 23 connects the first line 20 to the second line 21 and is for this purpose formed, for example, in a common partition wall between the first line 20 and the second line 21. The second opening 24 is formed in the first conduit 20, preferably in one of the first opening 23 opposite wall of the first conduit 20. Accordingly, the third opening 25 is formed in the second conduit 21, preferably in one of the first opening 23rd opposite wall of the second conduit 21st

The switching device 13 is also equipped with a flap assembly, which here comprises three flaps, namely a first flap 26, a second flap 27 and a third flap 28. While the first flap 26 serves to control the first opening 23, can with the second flap 27, the second opening 24 are controlled, and the third flap 28 serves to control the third opening 25th

Fig. 2 shows the first switching position of the switching device 13, while Fig. 3 shows the second switching position of the switching device 13. In the first Switching position closes each flap 26, 27, 28 their associated opening 23, 24, 25. In this way, the first line 20 and the second line 21 are enabled, while the third line 22 is locked. In this switching position, the flap arrangement 26-27-28 thus defines a first path 29 leading from the first connection 16 to the third connection 18 through the first line 20 and a second path 30 leading from the fourth connection 19 to the second connection 17 through the second line 21.

In the second switching position shown in FIG. 3, the flaps 26, 27, 28 are each adjusted so that they open the respectively associated openings 23, 24, 25. At the same time the first flap 26 locks in the second switching position, the first line 20, between the first opening 23 and the second opening 24. In addition, the third flap 28 locks in the second switching position, the second line 21, between the first opening 23rd and the third opening 25. In this way, the flap assembly 26-27-28 may define a third path 31 and a fourth path 32 in the second switching position. While the third path 31 leads from the first port 16 through a portion of the first conduit 20, through the first port 23 and through a portion of the second conduit 21 to the fourth port 19, the fourth path 32 leads from the third port 18 through a portion of the first port Line 20, through the second opening 24, through the third line 22, through the third opening 25 and through a part of the second line 21 to the second terminal 17th

It is also noteworthy that in the case of the flap arrangement 26-27-28 selected here, the three flaps 26, 27, 28 can be adjusted simultaneously by means of a common actuator 33. The switching device 13 shown here thus has a relatively inexpensive structure, which also works very reliable.

According to Fig. 4, the cooling of the housing 2 can be conveniently carried out as follows:

In the initial situation, the switching device 13 has its first switching position, so that the first flow direction 14 is present in the cooling gas path 10. As a result, the first temperature T ₁ at the first housing terminal 11 is smaller than the second temperature T ₂ at the second housing terminal 12. That is, a circumferential temperature difference ΔT is established.

With the help of appropriate, not shown here temperature sensors can be determined at position 34, the current peripheral temperature difference .DELTA.T. Subsequently, at position 35, the check is made as to whether the determined circumferential temperature difference △ T lies within a predetermined value range. If this is the case, "YES" applies and is looped back to temperature measurement 34. If the measured circumferential temperature difference △ T in the query 35 is no longer in the permissible value range, "NO" applies and it is preferably the question at position 36, whether the determined circumferential temperature difference .DELTA.T is greater than the upper allowable limit .DELTA.T _max . If this is the case, "YES" applies and at position 37, the second flow direction 15 is now set to be set. For this purpose, the switching device 13 is actuated for setting its second switching position. As a result, the second temperature T ₂ at the second housing connection 12 drops and the first temperature T ₁ at the first housing connection 11 increases. That is to say, the circumferential temperature difference △ T decreases.

The second flow direction 15 then remains until the peripheral temperature difference △ T falls outside the permissible values at the lower range. Then the query 35 returns the answer _" NO". The subsequent query 36 then also gives the answer _" NO". As a result, the first flow direction 14 is then set again at position 38, by the switching device 13 is actuated in accordance with the setting of the first switching position.

It is clear that the process flow illustrated in FIG. 4 is to be understood only as an example, so that in principle also other processes are conceivable. For example, it may be provided to look at the circumferential temperature difference .DELTA.T only in terms of amount and whenever the measured circumferential temperature difference AT exceeds in magnitude a predetermined or predeterminable limit value .DELTA.T _max to reverse the direction of flow.

Furthermore, it is possible to reduce the circumferential temperature difference ΔT by increasing the switching frequency or to increase it by lowering the switching frequency.

It is essential for the invention that the change in the circumferential temperature difference △ T with the aid of the invention has virtually no influence on the average temperature T, which can be adjusted separately.

By way of example, FIG. 5 shows a conceivable sequence for controlling the average temperature T of the housing 2. At a position 39, the mean temperature, that is to say the average temperature T of the housing 2, is determined. This average temperature T can be formed, for example, by the mean value of the first temperature T ₁ at the first housing connection 11 and the second temperature T ₂ at the second housing connection 12. For this purpose, the sensors for determining the circumferential temperature difference .DELTA.T can be used. However, a plurality of temperature sensors, not shown here, are expediently distributed along the circumference of the housing 2, with which the average temperature T of the housing 2 can be determined.

In a subsequent query 40 is then checked whether the measured average temperature T is in a predetermined or predeterminable range of permissible average temperatures. If this is the case, then "YES" applies, so that it is possible to loop back to the temperature determination 39. If, however, query 40 results in a response _" NO", the query is made at position 41 as to whether the measured average temperature T is greater than the maximum permissible average temperature T _max . If this is the case, then "YES" applies, so that suitable measures for lowering the average temperature T can be initiated at position 42. For example, the funded by the cooling gas path 10 cooling gas mass flow can be increased. For this purpose, z. B. the power of the fan 4 are increased accordingly. Additionally or alternatively, a cooling gas inlet temperature, ie the temperature with which the cooling gas flows into the cooling gas path 10, are lowered. Such a lowering of the cooling gas inlet temperature can be achieved, for example, by increasing the power of the radiator 6.

However, if the query 36 results in a response _" NO", this means that the measured average temperature T is below the desired permissible temperature values, so that the following applies: $$\mathrm{T}<{\mathrm{T}}_{\min },$$

If this is the case, appropriate measures for increasing the average temperature T can be initiated at position 43. For example, the cooling gas mass flow can be reduced for this purpose. Additionally or alternatively, it is also possible to raise the cooling gas inlet temperature.

LIST OF REFERENCE NUMBERS

1

gas turbine

2

casing

3

cooling device

4

Cooling gas blower

5

Gas circuit

6

cooler

7

Cooling gas supply device

8th

Cooling gas outlet of 7

9

Cooling gas inlet of 7

10

Cooling gas path in 2

11

first housing connection of 2

12

second housing connection of 2

13

switching device

14

first flow direction

15

second flow direction

16

first connection of 13

17

second port of 13

18

third connection of 13

19

fourth connection of 13

20

first line in 13

21

second line in 13

22

third line in 13

23

first opening of 13

24

second opening of 13

25

third opening of 13

26

first flap of 13

27

second flap of 13

28

third flap of 13

29

first path in 13

30

second path in 13

31

third path in 13

32

fourth path in 13

33

actuator

34

Position in the flowchart according to FIG. 4

35

Position in the flowchart according to FIG. 4

36

Position in the flowchart according to FIG. 4

37

Position in the flowchart according to FIG. 4

38

Position in the flowchart according to FIG. 4

39

Position in the flowchart according to FIG. 5

40

Position in the flowchart according to FIG. 5

41

Position in the flowchart according to FIG. 5

42

Position in the flowchart according to FIG. 5

43

Position in the flowchart according to FIG. 5

Claims (9)

Device for cooling a housing (2) of a gas turbine (1) and / or a combustion chamber, in particular a gas turbine (1), - with a cooling gas supply device (7), a cooling gas outlet (8), from which during operation of the cooling gas supply device (7) exits a cooling gas flow, and a cooling gas inlet (9), via which during operation of the cooling gas supply means (7) of the cooling gas flow to the cooling gas supply device ( 7) flows back, with a cooling gas path (10) guided through the housing (2) in its circumferential direction and connecting a first housing connection (11) to a second housing connection (12), - With a switching device (13) for flow direction reversal, which connects between a first switching position in which it connects the cooling gas outlet (8) with the first housing connection (11) and the cooling gas inlet (9) with the second housing connection (12), and a second switching position is switchable, in which it connects the cooling gas outlet (8) with the second housing connection (12) and the cooling gas inlet (9) with the first housing connection (11). Cooling device according to claim 1,
characterized, - that the switching device (13) comprises a first port (16) connected to the cooling gas outlet (8), a second port (17) connected to the cooling gas inlet (9), a third terminal (18) connected to the first housing terminal (11) and a fourth terminal (19) connected to the second housing terminal (12), in that the switching device (13) contains a flap arrangement (26-27-28) which, in the first switching position, has a first path (29) leading from the first connection (16) to the third connection (18) and one from the fourth connection (19). to the second terminal (17) leading second path (30) defined and
which in the second switching position defines a third path (31) leading from the first connection (16) to the fourth connection (19) and a fourth path (32) leading from the third connection (18) to the second connection (17). Cooling device according to claim 2,
characterized, - that the switching device (13) comprises a first line (20) leading from the first connection (16) to the third connection (18), a second line (21) leading from the second connection (17) to the fourth connection (19), a first opening (23) which can be controlled by means of a first flap (26) and which connects the first line (20) to the second line (21), a second opening (24) in the first conduit (20) controllable by means of a second flap (27), a by means of a third flap (28) controllable third opening (25) in the second conduit (21) and a third conduit (22) connecting the second opening (24) to the third opening (25), in that the first flap (26) closes the first opening (23) in the first switching position and opens the first opening (23) in the second switching position and the first line (20) between first opening (23) and second opening (24) locks, in that the second flap (27) closes the second opening (24) in the first switching position and opens the second opening (24) in the second switching position, in that the third flap (28) closes the third opening (25) in the first switching position and opens the third opening (25) in the second switching position and the second line (21) between the first opening (23) and the third opening (25) locks. Cooling device according to claim 3,
characterized,
in that a common actuator (33) is provided for the three flaps (26, 27, 28) for the simultaneous adjustment of the flaps (26, 27, 28). Method for cooling a housing (2) of a gas turbine (1) and / or a combustion chamber, in particular a gas turbine, - In which a cooling gas path (10) which is passed through the housing (2) in its circumferential direction and thereby connects a first housing connection (11) with a second housing connection (12), is subjected to a flow of cooling gas, - in which a circumferential temperature difference (.DELTA.T) of the housing (2) measured between one of the one housing connection (12) outlet temperature (T ₂₎ and at the other housing connection (11) measured inlet temperature (T ₁₎ by switching the flow direction of the cooling gas flow in the Cooling gas path (10) is varied. Cooling method according to claim 5,
characterized,
that the circumferential temperature difference (ΔT) is reduced by increasing the switching frequency and increased by lowering the switching frequency. Cooling method according to claim 5 or 6,
characterized,
that the flow direction (14, 15) of the cooling gas flow is always switched when the circumferential temperature difference (.DELTA.T) exceeds a predetermined or predeterminable limit value (.DELTA.T _max) exceeds. Cooling method according to one of claims 5 to 7,
characterized,
in that an average temperature (T) of the housing (2) is varied by varying an inlet temperature of the cooling gas as it enters the cooling gas path (10) and / or by varying a mass flow of the cooling gas supplied to the cooling gas path (10). Cooling method according to claim 8,
characterized,
that the average temperature (T) of the housing (2) by the average of the inlet temperature (T ₁₎ and outlet temperature (T ₂₎ is formed.

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