EP2242955B1 - Gas turbine having an annular combustion chamber and assembly method - Google Patents

Description

Technical area

The present invention relates to the field of thermal machines. It relates to a thermal machine according to the preamble of claim 1 and a method for mounting such a thermal machine.

State of the art

Modern industrial gas turbines (IGT) are usually designed with annular combustion chambers. Most smaller IGTs are designed as so-called "Can Annular Combustors". In an IGT with annular combustion chamber of the combustion chamber is limited by the side walls and the inlet and outlet plane of the hot gas. Such a gas turbine is in the Fig. 1 and 2 shown. The in the Fig. 1 and 2 Gas turbine 10 shown in section has a turbine housing 11 in which a rotor 12 rotating about an axis 27 is accommodated. On the right side of the rotor 12 a compressor 17 is formed for the compression of combustion and cooling air, on the left side of a turbine 13 is arranged. The compressor 17 compresses air which flows into a plenum 14. In the plenary concentric with the axis 27, an annular combustion chamber 15 is arranged, which is closed on the input side by a front plate cooling air 20 cooled front panel 19 and the output side via a hot gas channel 25 with the input of the turbine 13 in connection.

In the front plate 19 burners 16 are arranged in a ring, for example, as a premix burner, as they are preferably made EP-A1-321809 or EP-A1-704,657 emerge, are designed and inject a fuel-air mixture in the combustion chamber 15. The cited documents and the developments derived therefrom form an integral part of this application. The resulting during the combustion of the mixture hot air stream 26 passes through the hot gas channel 25 in the turbine 13 and is relaxed there under work. The combustion chamber 15 with the hot gas channel 25 is outside with a distance surrounded by an outer and inner Kühlhemd 21 and 31, which are fastened by means of fastening elements 24 to the combustion chamber 15, 25 and between them and the combustion chamber 15, 25 each have an outer and inner cooling channel 22 or 32 train. In the cooling channels 22, 32 flows in the opposite direction to the hot gas flow 26 cooling air on the walls of the combustion chamber 15, 25 along a combustion chamber hood 18 and from there into the burner 16 and front plate cooling air 20 directly into the combustion chamber 15th

The side walls of the combustion chamber 15, 25 are carried out either as shell elements or as solid shells (outer shell 23, inner shell 33). When using full shells arises due to the installation, the need for a parting plane (29 in Fig. 4 ff.), which allows an upper half of the shell 23, 33 (the upper part) to be removed, for example to assemble or disassemble the gas turbine rotor 12. The parting plane 29 accordingly has two parting plane welding seams which are located at the height of the machine axis 27 using the example of the gas turbine engine constructed by the applicant.

For the welding of the parting planes 29 on the outer shell 23, access from both the hot gas side and the cooling air side is possible. For the welding of the parting planes on the inner shell 33, access is guaranteed only from the hot gas side (access via a manhole in the turbine housing 11). The separation of a shell in an upper and lower half (Upper and lower part) and the welding after assembly of the rotor 12 is known from the prior art and common practice.

EP 1 847 685 discloses a thermal machine, which comprises a limited by an outer shell and an inner shell to the outside, annular combustion chamber, wherein the outer shell and inner shell are each divided in a parting plane in an upper half and a lower half and which are welded together in the parting plane. US 3,031,844 describes a method for mounting a thermal machine with the essential steps that the connecting element is inserted into one of the halves, in a second step, the two halves juxtaposed, in a third step, a connecting element is retracted into one of the halves of the respective shell , And the connecting element in the final position is firmly connected to the two halves. CH 342 794 also discloses annular combustors which are composed of halves. According to the doctrine of GB 2 434 199 Seam lines between combustion chamber segments are covered by heat shield.

Due to the material properties of the weld seam, which are reduced compared to the base material, and the lack of a thermal barrier coating (TBC Thermal Barrier Coating) on and in the immediate vicinity of the weld seams, the side walls in the region of the parting planes 29 have a reduced strength and service life. The thermally very heavily loaded outer and inner shells 23 and 33 act on the four parting planes (29 and others) with high compressive and tensile stresses. The required service life of outer and inner shells 23 and 33 is typically two so-called service intervals (service intervals). An operating interval describes the time between (re) commissioning of the combustion chamber and the reconditioning of the components. Both shells, the outer and inner shell 23, 33, often begin to break at the beginning and end of the parting plane welding seams during operation.

Presentation of the invention

It is an object of the invention to provide a thermal machine, in particular gas turbine, which avoids the above-mentioned disadvantages of known machines and in particular prevents tearing of the combustion chamber shells to the weld halves connecting the shell halves, and to provide a method for their assembly.

The object is solved by the entirety of the features of the independent claims. It is essential for the invention that an additional mechanical positive connection is provided for receiving tensile and shear forces acting on the parting planes on the parting planes.

In this case, as an additional mechanical positive connection in each case over the dividing plane extending connecting element is provided in the form of a bridge that the outer shell and inner shell at the entrance and / or exit of the combustion chamber have a flange that the connecting elements are arranged on the outside of the flange the flange on the outside has a circumferential groove, and that the connecting elements are inserted into the groove.

By the subsequent installation of (cooled!) Screwed and / or welded, form-fitting bridges in the grooves of the (two) flanges at the location of Trennebenenschweissnähte existing in the art strength deficit can be compensated. The structural bridges absorb the tensile and shear forces occurring at the beginning and end.

The connecting elements can be releasably connected to the two halves of the outer shell or inner shell. In particular, the connecting elements with the two halves of the outer shell or inner shell are then releasably connected by screws or bolts.

However, the connecting elements can also be materially connected, in particular welded, to the two halves of the outer shell or inner shell.

The invention is characterized in that the groove and the connecting elements are formed such that the connecting elements are held by positive engagement in the groove.

According to a further embodiment, the connecting elements have first means for improving the mechanical integrity, wherein throat-shaped incisions are preferably provided as means for improving the mechanical integrity, preferably at the ends.

Another embodiment is characterized in that the connecting elements have second means for improving the mountability, wherein as a means for improving the mountability is preferably provided on the top of a cam.

Another embodiment is characterized in that the connecting elements have third means for improving the cooling of the connecting elements.

According to another embodiment of the invention, the connecting elements fourth means for forming cooling channels between the connecting element and the flange, wherein as a means for forming cooling channels preferably on the bottom of a wavy base is provided.

An embodiment of the inventive method is characterized in that the connecting element is loosely inserted in the first step in the upper half and welded in the final position with the two halves.

Another embodiment is characterized in that the connecting element is inserted into the upper half in its final position in the first step and secured with screws or bolts, and that in the third step, the upper half is positioned with simultaneous retraction of the connecting element on the lower half.

Brief explanation of the figures

Fig. 1

einen Längsschnitt durch eine gekühlte Ringbrennkammer einer Gasturbine nach dem Stand der Technik;

Fig. 2

im einzelnen die Ringbrennkammer aus Fig. 1 mit den aussen befestigten Kühlhemden;

Fig. 3

im Längsschnitt das turbinenseitige Ende der Aussenschale der Brennkammer aus Fig. 1 mit dem angesetzten Flansch;

Fig. 4

im Ausschnitt die an der Trennebene zusammen stossenden Hälften der Aussenschale mit einer am Flansch angeordneten verschraubten Brücke gemäss einem bevorzugten Ausführungsbeispiel der Erfindung;

Fig. 5

den Ausschnitt aus Fig. 4 von einer anderen Richtung betrachtet;

Fig. 6

einen ersten Teilschritt bei der Montage der Brücke gemäss Fig. 4;

Fig. 7

in verschiedenen Teilfiguren (a), (b) und (c) verschiedene Ansichten einer Brücke gemäss Fig. 4;

Fig. 8

im Ausschnitt die an der Trennebene zusammen stossenden Hälften der Aussenschale mit einer am Flansch angeordneten verschweissten Brücke gemäss einem anderen bevorzugten Ausführungsbeispiel der Erfindung;

Fig. 9

den Ausschnitt aus Fig. 8 aus einer anderen Richtung betrachtet;

Fig. 10

in verschiedenen Teilfiguren (a), (b) und (c) verschiedene Ansichten einer Brücke gemäss Fig. 8, und

Fig. 11

in zwei Teilfiguren (a) und (b) unterschiedliche Ansichten einer mit zusätzlichen Kühlmitteln versehenen Brücke ähnlich Fig. 10.

The invention will be explained in more detail with reference to embodiments in conjunction with the drawings. All for the immediate understanding The elements not required by the invention have been omitted. The same elements are provided in the various figures with the same reference numerals. The flow direction of the media is indicated by arrows. Show it

Fig. 1

a longitudinal section through a cooled annular combustion chamber of a gas turbine according to the prior art;

Fig. 2

in detail, the annular combustion chamber Fig. 1 with cooling shirts attached to the outside;

Fig. 3

in longitudinal section, the turbine-side end of the outer shell of the combustion chamber Fig. 1 with the attached flange;

Fig. 4

in the cutout, the halves of the outer shell which abut on the parting plane together with a bolted bridge arranged on the flange according to a preferred embodiment of the invention;

Fig. 5

the cutout Fig. 4 viewed from another direction;

Fig. 6

a first step in the assembly of the bridge according to Fig. 4 ;

Fig. 7

in different sub-figures (a), (b) and (c) different views of a bridge according to Fig. 4 ;

Fig. 8

in the neckline, the halves of the outer shell which abut on the parting plane together with a welded bridge arranged on the flange according to another preferred embodiment of the invention;

Fig. 9

the cutout Fig. 8 viewed from another direction;

Fig. 10

in different sub-figures (a), (b) and (c) different views of a bridge according to Fig. 8 , and

Fig. 11

in two sub-figures (a) and (b) similar views of a provided with additional coolant bridge similar Fig. 10 ,

Ways to carry out the invention

An essential feature of the inventive idea is an additional, mechanical positive connection of the parting plane welding seams between the half shells of the outer shell and / or inner shell of an annular combustion chamber (remark: all following explanations and illustrations relate to the outer shell, but also apply correspondingly to an inner shell). In this case, a bridge is used as an additional connecting element on both sides of the parting plane, preferably in a respective already existing flange. However, this bridge may or may not be designed to continue to permit or permit cooling of the flange portion.

• Die Brücken sind nahezu formschlüssig ausgelegt. Das hat zur Folge, dass diese genau in die jeweilige Flanschgeometrie passen und im Betrieb, aufgrund der thermischen Verformung der Schalen und des Flansches, formschlüssig verklemmen.
• Die Brücken sollen möglichst nahe der "kalten" Schalenaussenwand zu liegen kommen, damit keine weiteren, unnötig hohen Hebelwirkungskräfte entstehen.
• Die Brücken können geschweisst, formschlüssig eingeklemmt oder verschraubt werden.
• Kühlluft kann eingesetzt werden, um die Unterseite der Brücken in unmittelbarer Nachbarschaft der thermisch belasteten Schalenstruktur zu kühlen, um durch die Brücke eine verstärkte Übertragung von Spannungen von der Trennebenenschweissnaht weg zu bewirken.

The structural design is generally subject to the following principles:

• The bridges are designed almost form-fitting. This has the consequence that they fit exactly into the respective flange geometry and jam in the form-locking operation due to the thermal deformation of the shells and the flange.
• The bridges should come as close as possible to the "cold" shell outer wall, so that no further, unnecessarily high leverage forces arise.
• The bridges can be welded, positively clamped or screwed.
• Cooling air may be used to cool the underside of the bridges in the immediate vicinity of the thermally stressed shell structure to cause increased transfer of stresses away from the parting line weld through the bridge.

In a practical embodiment of the inventive idea, the bridge is used on one side, in the upper part of the outer shell, in a flanged groove. The two shells are placed one above the other in the gas turbine (GT) and the bridge is pushed into position or beaten (a cam or a nose on the outer diameter of the bridge can serve as a starting point for a mandrel or hammer.) Once the bridge over the parting line is in position, it is welded at its top with the flange. The geometric design of the flange and the bridge itself allows preferably the cooling air to flow through the flange under the bridge over - and thus to ensure the conditions for a convective cooling.

Instead of the cohesive welding connection between bridge and flange, however, a releasable connection is also conceivable: the bridge is then inserted on one side, in the upper part (in the upper half) of the outer shell, into the flanged groove and positioned with bolts at its destination. The two half shells are placed one above the other in the gas turbine and the bridge is retracted into the lower half shell. As soon as the two half-shells are exactly on top of each other, the bridge can also be secured in the lower half shell (by bolts and / or screws). For better accessibility when welding the parting line, the bridge can also be removed and reused at any time.

The two above-mentioned alternatives (welded or bolted bridge) are to follow the embodiments of the Fig. 4 to 11 be explained. Preferably, the shells 23, 33 of the annular combustion chamber 15, 25 are provided on the burner side and at the turbine end with flanges for connection be used between the combustion chamber and adjacent components. In Fig. 3 shows as an example in longitudinal section the turbine-side end of the outer shell 23 of the combustion chamber 15, 25 from Fig. 1 with the attached flange 28. The flange 28 has on the outside a groove 34 which receives the provided for mechanical relief of the parting plane welds bridges.

In 4 and 5 are - seen from different angles - reproduced in a section at the parting plane 29 colliding halves 23a, 23b of the outer shell 23 with a bolt 34 arranged on the bolted bridge 30 according to a preferred embodiment of the invention. The bridge 30 itself is in different views in Fig. 7a to 7c shown. The bridge 30 is in the form of an elongate planar strip of rectangular cross section having the slightly curved shape of a circular arc segment. The length of the bridge 30 is selected so that on both sides of the parting plane 29 with sufficient distance two mounting holes 36 can be attached, which serve the screw / Verbolzung the bridge 30 with the two welded half-shells 23 a, 23 b. If the bridge 30 is screwed, according to Fig. 4 or 5 corresponding screws 35 used. When assembling the bridge - as already mentioned above - initially according to Fig. 6 screwed to the upper half 23 a of the outer shell, before the half-shells 23 a, 23 b are then merged. The same applies to the inner shell 33.

For a discharge arrangement with a welded bridge, a connecting element 40 is preferably used according to FIG Fig. 8-10 or 11 used. The bridge 40 is in its cross-sectional contour ( Fig. 10b ) of the cross-sectional contour of the flange groove 34 adapted so that the bridge 40 can be positively inserted into the groove 34 and thereby engages with a skirt 37 in an undercut in the groove 34. On the upper side of the bridge 40, a transversely projecting cam 39 is provided in the middle, at which when driving the bridge 40 into the groove 34 with a striking tool can be recognized. On the underside of the bridge 40, a wave-shaped base 38 is formed ( Fig. 10b ), through which between the bridge 40 and groove bottom in the circumferential direction of the flange 28 extending cooling channel. At the ends of the bridge 40 throat-shaped incisions 41, 42 are advantageously arranged, the partially one-sided ( Fig. 10c ) or as a cross ( Fig. 11 ) are incorporated. The radii of curvature of the incisions may vary.

Overall, the novel, positive-locking connecting elements, which act as "structural bridges for the combustion chamber shell parting plane", ensure significantly improved force transmission at the ends of the parting plane.

• Die Brücken (40) können für eine verbesserte mechanische Integrität - verbesserte Kraftflussübertragung, Brechen der Kraftspitzen - an ihren Enden kehlförmige Einschnitte (41, 42) aufweisen;
• die Einschnitte in der Brücke können partiell einseitig oder auch als Kreuz eingearbeitet werden;
• die Radien der gezeigten Einschnitte Fig. 10) können variieren;
• die Wandstärken der beiden gezeigten Brücken (30, 40) können variieren;
• die Brücken können auf der Kühlluftseite zur Steigerung der Kühleffektivität mit Turbulenzrippen ergänzt werden;
• die Brücken könnten auf der Kühlluftseite zur Steigerung der Kühleffektivität mit Prallkühlluft gekühlt werden;
• die Brücken können aus Gründen der besseren Montierbarkeit an der Oberseite einen Nocken (39) aufweisen, um eine vereinfachte Verschiebbarkeit durch Hammerschlag zu erreichen; und
• in der Werkstatt kann für das Verschweissen der Brücken mit dem Flansch jegliche Art von adäquaten Schweissverfahren angewendet werden.

In the context of the invention, different deviations and variants of a basic version are possible:

• The bridges (40) may have throat-shaped cuts (41, 42) at their ends for improved mechanical integrity - improved force flux transfer, breakage of the force peaks;
• the incisions in the bridge can be partially integrated on one side or as a cross;
• the radii of the cuts shown Fig. 10 ) can vary;
• the wall thicknesses of the two shown bridges (30, 40) can vary;
• the bridges can be supplemented with turbulence ribs on the cooling air side to increase the cooling efficiency;
• the bridges could be cooled on the cooling air side to increase the cooling efficiency with impingement cooling air;
• the bridges may have a cam (39) at the top for ease of mounting, for ease of hammer travel; and
• In the workshop, any type of adequate welding procedure can be used to weld the bridges to the flange.

LIST OF REFERENCE NUMBERS

10

gas turbine

11

turbine housing

12

rotor

13

turbine

14

plenum

15

combustion chamber

16

Burner (double cone or EV burner)

17

compressor

18

combustion chamber hood

19

front panel

20

Front plate cooling air

21

outer cooling shirt

22

outer cooling channel

23

outer shell

23a

upper half of the outer shell

23b

lower half of the outer shell

24

fastener

25

Hot-gas duct

26

Hot gas flow

27

axis

28

flange

29

parting plane

30,40

Connecting element (bridge)

31

inner cooler shirt

32

inner cooling channel

33

inner shell

34

groove

35

screw

36

mounting hole

37

skirting

38

Base area (wavy)

39

cam

41.42

Incision (throat-shaped)

Claims (14)

1. Thermal machine, in particular a gas turbine (10), which comprises an annular combustion chamber (15, 25) which is bounded on the outside by an outer shell (23) and an inner shell (33), wherein the outer shell (23) and the inner shell (33) are each split on a separating plane (29) into an upper half (23a) and a lower half (23b), which are welded to one another on the separating plane (29), characterized in that an additional mechanical interlock (30, 40) in the form of a connecting element (30, 40) which extends over the separating plane (29) in a bridge-like manner is provided on the separating planes (29) in order to absorb tensile and shear forces acting on the separating planes (29), in that the outer shell (23) and the inner shell (33) have a flange (28) at the inlet and/or outlet of the combustion chamber (15, 25), and in that the connecting elements (30, 40) are flanges (28) arranged on the outside of one of these outer shells or even inner shells, in that the flange (28) has a circumferential groove (34) on the outside, wherein the connecting elements (30, 40) are inserted into the groove (34), and in that the connecting elements (30, 40) and the groove (34) are designed such that the connecting elements which can be inserted into the groove are held in the groove (34) by an interlock.
2. Thermal machine according to Claim 1, characterized in that the connecting elements (30) are detachably connected to the two halves (23a, 23b) of the outer shell (23) and of the inner shell (33), respectively.
3. Thermal machine according to Claim 2, characterized in that the connecting elements (30) are detachably connected to the two halves (23a, 23b) of the outer shell (23) and inner shell (33), respectively, by means of screws (35) or bolts.
4. Thermal machine according to one of Claims 2 to 3, characterized in that the connecting elements (40) are additionally integrally connected, in particular welded, to the two halves (23a, 23b) of the outer shell (23) and inner shell (33).
5. Thermal machine according to one of Claims 1 to 4, characterized in that the connecting elements (30) have first means (41, 42) in order to improve the mechanical integrity.
6. Thermal machine according to Claim 5, characterized in that the connecting elements (40) have incisions (41, 42) in the form of fillets as means (41, 42) in order to improve the mechanical integrity at the ends.
7. Thermal machine according to one of Claims 1 to 6, characterized in that the connecting elements (40) have second means (39) in order to improve the assembly capability.
8. Thermal machine according to Claim 7, characterized in that the connecting elements (40) have a stud (39) on the upper face as means in order to improve the assembly capability.
9. Thermal machine according to one of Claims 1 to 8, characterized in that the connecting elements (30, 40) have third means in order to improve the cooling of the connecting elements (30, 40).
10. Thermal machine according to one of Claims 1 to 9, characterized in that the connecting elements (40) have fourth means (38) in order to form cooling channels between the connecting element (40) and the flange (28) .
11. Thermal machine according to Claim 10, characterized in that the connecting elements (40) have a corrugated base surface (38) on the lower face, as means in order to form cooling channels.
12. Method for assembly of a thermal machine according to one of Claims 1 to 11, characterized in that, in a first step, the connecting element (30, 40) is inserted into the upper half (23a) of the respective shell (23, 33), which is separated into an upper half (23a) and a lower half (23b), in that, in a second step, the upper and the lower half (23a, 23b) are placed one on top of the other, in that, in a third step, the connecting element (30, 40) is driven into the lower half (23b) of the respective shell (23, 33), and in that the connecting element (30, 40) is connected in an interlocking manner to the upper and the lower half (23a, 23b) in the final position.
13. Method according to Claim 12, characterized in that, in the first step, the connecting element (40) is inserted loosely into the upper half (23a), and is welded to the two halves (23a, 23b) in the final position.
14. Method according to Claim 12, characterized in that, in the first step, the connecting element (30) is inserted into the upper half (23a) at its final position, and is secured by screws (35) or bolts, and in that, in the third step, the upper half (23a) is positioned while the connecting element (30) is driven in on the lower half (23b) at the same time.

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