EP2154431B1 - Thermal machine - Google Patents

Description

TECHNICAL AREA

The present invention relates to the field of combustion technology. It relates to a thermal machine according to the preamble of claim 1.

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 the cutout has a turbine housing 11, in which a about an axis 27 rotating rotor 12th is housed. 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 is connected via a hot gas channel 25 with the input of the turbine 13 in connection.

EP599055 describes such a gas turbine.

In the front panel 19 burners 16 are arranged in a ring, which are designed for example as a double cone or EV burner and inject a fuel-air mixture into the combustion chamber 15. 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 fasteners 24 to the combustion chamber 15, 25 and between them and the combustion chamber 15, 25 each have a ring-shaped outer and inner Form cooling channel 22 and 32 respectively. In the cooling channels 22, 32 flows in the opposite direction to the hot gas stream 26 cooling air on the walls of the combustion chamber 15, 25 along in a combustion chamber hood 18 and from there into the burner 16 and as a faceplate 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. 2a ), which allows an upper half of the shell 23, 33 (upper half shell 33a in FIG Fig. 2a ) from the lower half (lower half-shell 33b in FIG Fig. 2a ), for example, to assemble or disassemble the gas turbine rotor 12. The parting plane 29 has correspondingly two parting plane welding seams 30 (FIG. Fig. 2a ), which in the example of the Applicant built gas turbine from Type GT13E2 are located at the height of the machine axis 27 (3 o'clock and 9 o'clock position). As already mentioned, the respective lower and upper half-shells 33a, 33b have to be cooled convectively. To favor the cooling, the already mentioned cooling shirts (CoShirts) 21 and 31 are mounted on the half-shell cold side, which redirect ambient air and cause due to the combustion chamber pressure drop or burner pressure drop across the half-shells and thus cause a convective cooling.

• Sie dichten zwei Plena bzw. Kammern ab;
• Sie müssen untereinander auch dichten (Montage einer Dichtlippe oder Überlappung nötig);
• Sie werden, mit Ausnahme der Trennebene 29, rotationssymmetrisch ausgeführt;
• Sie müssen bei der Montage der Brennkammerhalbschalen in der Trennebene ineinander geführt werden;
• Die Kühlhemden 31 der Brennkammer-Innenschalen 33a,b müssen an der Trennebene 29 "blind" ineinander geführt werden (kein Zugang für eine visuelle Kontrolle der Verbindungsebene, da von den Brennkammer-Innenschalen abgedeckt);
• Sie können Kühllöcher aufweisen (für einen gezielten Kühlluftmassenstrom)
• Sie können Kühllöcher für eine allfällige Prallkühlung aufweisen (für eine gezielte, lokal forcierte Kühlung der Halbschalen);
• Sie müssen keine grossen axialen oder radialen Kräfte aufnehmen;
• Sie sind i.d. Regel nicht selbsttragend, sondern werden auf ein Trägerteil montiert;
• Sie müssen einen grossen axialen und radialen Bewegungsspielraum aufweisen, insbesondere bei transienten Betriebszuständen;
• Sie müssen temperaturfest sein (Zeitfestigkeit - Dauerfestigkeit);
• Sie müssen einfach und kostengünstig herstellbar sein; und
• Sie dürfen im Betrieb keine Eigenschwingungen ausweisen.

The cooling shirts 21, 31 preferably have the following properties and functions:

• They seal off two plena or chambers;
• They must also seal with each other (installation of a sealing lip or overlap necessary);
• They are, with the exception of the parting plane 29, executed rotationally symmetrical;
• They must be guided in the assembly of the combustion chamber half shells in the parting line into each other;
• The cooling shrouds 31 of the combustion chamber inner shells 33a, b must be blindly "nested" at the parting plane 29 (no access for visual control of the joint plane, as covered by the combustion chamber inner shells);
• You may have cooling holes (for a targeted cooling air mass flow)
• They may have cooling holes for possible impingement cooling (for a targeted, locally forced cooling of the half-shells);
• You do not have to absorb large axial or radial forces;
• As a rule, they are not self-supporting but are mounted on a carrier part;
• They must have a large axial and radial range of motion, especially in transient operating conditions;
• They must be temperature-resistant (fatigue strength - fatigue strength);
• They must be easy and inexpensive to produce; and
• You must not identify any natural oscillations during operation.

The inner and outer shell 33 and 23 of a gas turbine such as the GT13E2 are thermally and mechanically stressed during operation. The strength properties of the material of the shells 23, 33 are highly temperature dependent. In order to keep the material temperature below the maximum allowable material temperature level, the shells 23, 33 are convectively cooled. The shape and the high thermal load near the turbine inlet (hot gas channel 25) require, especially in this area a constant high heat transfer on the cooling air side. This is achieved in the outer shell 23 by impingement cooling. On the inner shell 33 space and flow conditions and a seal against a cross-flow for such an impingement cooling are not given. Therefore, a conventional convection cooling is resorted to, in which the intensity of the cooling is increased by reducing the channel height of the cooling channel 32.

The previously used configuration of the inner cooling sleeve 31 of 2 axial plates is on the one hand prone to distance tolerances and other irregularities, e.g. in the flow field before the cooling air inlet into the cooling channel, and on the other hand causes an undesirable reduction of the cooling air mass flow in the region of the smaller of the two axial plates.

PRESENTATION OF THE INVENTION

It is therefore an object of the invention to design a thermal machine of the type mentioned above so that the disadvantages of the previous solutions are avoided and in particular the flow conditions of the cooling air in the cooling channels between the shells and the cooling shirts in terms of intensified cooling significantly improved.

The object is solved by the entirety of the features of claim 1. Essential for the invention is that at least one of the cooling shirts on the Side on which the cooling air enters the cooling channel, to improve the Einströmbedingungen has an outwardly curved, rounded leading edge. Preferably, the at least one cooling shirt in the region of the leading edge is flared bell-shaped or trumpet-like. According to the invention, the inner cooling jacket on the side on which the cooling air emerges from the cooling channel, to reduce the flow losses on an outwardly curved, rounded exit edge. According to another embodiment of the invention, the cooling shirts are composed of individual, in the circumferential direction adjoining Kühlhemdsegmenten, wherein the Kühlhemdsegmente are attached by means of distributed arranged fasteners to the associated shells.

A preferred development is characterized in that the Kühlhemdsegmente overlap each other in pairs in the terminal areas, and that in each case a Kühlhemdsegment a pair is provided in the overlapping region with overlapping elements for a positive connection between the overlapping Kühlhemdsegmenten.

Another embodiment of the invention is characterized in that the fastening elements are arranged in the Kühlhemdsegmenten in the axial direction one behind the other, and that in the axial line with the fasteners additional holes are provided in the Kühlhemdsegmenten, through which to improve the cooling cooling air in the rays from the outside flows into the respective cooling channel. According to the invention, the combustion chamber is divided in a parting plane into an upper half with upper half shells and a lower half with lower half shells. The half shells are interconnected in the parting plane by parting plane welds and have in the region of the parting plane welds deviating from the rotational symmetry shape. The cooling shirts are adapted in the parting plane to the different shape of the shells. Preferably, the entirety of the Kühlhemdsegmente in first Kühlhemdsegmente, which adjoin the parting plane, and second Kühlhemdsegmente, which are outside the parting plane, divided, wherein the first Kühlhemdsegmente to adapt to the different shape of the shells have a raised side edge.

BRIEF EXPLANATION OF THE FIGURES

Fig. 1

den 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. 2a

in einer Prinzipdarstellung am Beispiel der Innenschale die Unterteilung der Brennkammerschalen in einer Trennebene in zwei Halbschalen;

Fig. 3

in einer Seitenansicht den Teil einer Innenschale mit segmentiertem Kühlhemd gemäss einem Ausführungsbeispiel der Erfindung;

Fig. 4

einen vergrösserten Ausschnitt des Ausführungsbeispiels aus Fig. 3 mit der besonderen Ausgestaltung des an die Trennebene angrenzenden Kühlhemdsegments;

Fig. 5

ein nicht an die Trennebene angrenzendes Kühlhemdsegment des Ausführungsbeispiels aus Fig. 3;

Fig. 6

ein an die Trennebene angrenzendes Kühlhemdsegment des Ausführungsbeispiels aus Fig. 3 mit der speziellen Seitenkante;

Fig. 7

in einem Ausschnitt die Anordnung der Überlappungselemente an dem Kühlhemdsegment aus Fig. 5 bzw. 6 und

Fig. 8

den Längsschnitt durch das Kühlhemdsegment aus Fig. 6 in der dort eingezeichneten Ebene VIII-VIII.

The invention will be explained in more detail with reference to embodiments in conjunction with the drawings. Show it

Fig. 1

the 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. 2a

in a schematic diagram of the example of the inner shell, the subdivision of the combustion chamber shells in a parting plane in two half-shells;

Fig. 3

in a side view of the part of an inner shell with segmented cooling shirt according to an embodiment of the invention;

Fig. 4

an enlarged section of the embodiment Fig. 3 with the particular configuration of the Kühlhemdsegments adjacent to the dividing plane;

Fig. 5

a Kühlhemdsegment not adjacent to the parting plane of the embodiment of Fig. 3 ;

Fig. 6

an adjacent to the parting plane Kühlhemdsegment of the embodiment Fig. 3 with the special side edge;

Fig. 7

in a section, the arrangement of the overlapping elements on the Kühlhemdsegment Fig. 5 or 6 and

Fig. 8

the longitudinal section through the Kühlhemdsegment Fig. 6 in the plane VIII-VIII marked there.

WAYS FOR CARRYING OUT THE INVENTION

In Fig. 3 is shown in a side view of the part of an inner shell with segmented cooling shirt according to an embodiment of the invention. For cooling the inner shell 33, an annular cooling channel 32 is formed on the outside of the inner shell 33 by a concentric inner cooling jacket 31 arranged concentrically therewith, in which on the in Fig. 3 Cooling air flows in on the left side, flows to the right and leaves the cooling channel 32 on the right side (see flow arrows in Fig. 3 ). The inner Kühlhemd 31 is composed of individual, extending in the axial direction Kühlhemdsegmenten 34, which overlap each other. In the overlapping area, overlapping elements 36 protruding at the edges on the cooling-shirt segments are welded (see in particular FIG Fig. 7 ), which provide a positive fit between the overlapping segments in the overlap area.

The Kühlhemdsegmente 34 are distributed by means of fasteners 24 which pass through mounting holes 40 in the segments ( Fig. 5 . 6 and 8th ), attached to the associated inner shell 33. The fastening elements 24 are arranged one behind the other in the axial direction. In the axial direction of the fastening elements 24 additional holes 35 are provided in the cooling jacket segments 34 in the wake region of the fastening elements 24, flows through the air from the cooling air inlet. Due to its locally high velocity with respect to the incoming cooling air mass flow, the air jet entering the cooling channel 32 leads to an increase in the heat transfer coefficient and thus to a reduction in the wall temperature of the inner shell 33.

The inner cooling jacket 31 is flared bell-shaped or trumpet-like in the region of the leading edge 37. This rounded "bellmouth-shaped" leading edge 37 of the axially one-piece Kühlluftbleches allows on the one hand to minimize the pressure loss at the cooling air inlet and on the other an (unintended) variation of the heat transfer coefficient by detachment of the cooling air at Kühlkanaleintritt (leading edge 37), as to Example of sharp-edged entries arise to prevent. The achieved by the improved inflow conditions decreases the Verwirbelungsverluste lead to a reduction of the required cooling air mass flow and thus to a more efficient operation of the combustion chamber. The flow direction of the cooling air is opposite to the hot gas flow direction.

The inner shell cooling shirt or inner cooling shirt 31 is further designed so that at its outlet side (trailing edge 38) a new transition radius is selected, which causes a much more favorable, ie, lower, flow loss than the previous configuration. The reduction in the flow loss at this point is compensated by a reduction in the cooling channel height, which in turn leads to an increase in the cooling air side heat transfer and thus leads to a reduction of the average material temperature of the inner shell 33.

• können, müssen aber nicht, als Bleche (Walzmaterial) ausgeführt werden;
• müssen untereinander dichten, Montage einer Dichtlippe oder Überlappung (Überlappungselemente 36) nötig
• werden, mit Ausnahme der an die Trennebene 29 angrenzenden Kühlhemdsegmente 34a, rotationssymmetrisch ausgeführt;
• können Kühllöcher (35) aufweisen (für einen gezielten Kühlluftmassenstrom);
• müssen temperaturfest sein (Zeitfestigkeit - Dauerfestigkeit).

The cooling shirt segments 34:

• may, but need not, be carried out as sheets (rolling stock);
• must seal with each other, mounting a sealing lip or overlap (overlapping elements 36) necessary
• be carried out, with the exception of the adjacent to the parting plane 29 Kühlhemdsegmente 34a, rotationally symmetrical;
• may have cooling holes (35) (for a targeted cooling air mass flow);
• must be temperature resistant (fatigue strength - fatigue strength).

As in Fig. 4 and Fig. 6 can be seen, the Kühlhemdsegmente 34a adjacent to the parting plane 29 on a raised or pulled out side edge 39 on. As a result, the cooling jacket 31 recedes outward in the region of the parting plane weld seams 30 and creates space for a corresponding bulge of the combustion chamber shell 33 in the region of the parting plane weld seam 39.

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

24

fastener

25

Hot-gas duct

26

Hot gas flow

27

axis

29

parting plane

30

Split line weld seam

31

inner cooler shirt

32

inner cooling channel

33

inner shell

33a

upper half shell (inner shell)

33b

lower half shell (inner shell)

34

Cool shirt segment

34a

Cooling jacket segment (parting line)

35

drilling

36

lap element

37

Leading edge (rounded, "bellmouth-shaped")

38

Trailing edge (rounded)

39

Side edge (raised)

40

mounting hole

Claims (7)

1. Thermal machine, especially gas turbine (10), which comprises an annular combustor (15, 25) which is outwardly delimited by an outer shell (23) and an inner shell (33) and through which a hot gas flow (26) flows in the axial direction, wherein the outer shell (23) and inner shell (33) are provided in each case with a concentric cooling shroud (21 or 31) which is attached at a distance on their outer side, forming a cooling passage (22 or 32), through which cooling passage (22 or 32) cooling air can flow in a direction which is opposite to the hot gas flow (26), wherein at least one of the cooling shrouds (21 or 31), on the side on which the cooling air can enter the cooling passage (22 or 32), has an outwardly curved, rounded inlet edge (37) for improving the inflow conditions, that the combustor (15, 25) is split in a parting plane (29) into an upper half with upper half-shells (33a) and a lower half with lower half-shells (33b), characterized in that the half-shells (33a, 33b) are interconnected in the parting plane (29) by parting plane welded seams (30), in that the shells (23, 33) in the region of the parting plane welded seams (30) have a shape which deviates from the axial symmetry, and in that the cooling shrouds (21, 31) in the parting plane (29) are adapted to the deviating shape of the shells (23, 33).
2. Thermal machine according to Claim 1, characterized in that the at least one cooling shroud (21 or 31) is widened out in the region of the inlet edge (37) in a bellmouth-shaped or flared manner.
3. Thermal machine according to Claim 2, characterized in that the inner cooling shroud (31), on the side on which the cooling air discharges from the cooling passage (32), has an outwardly curved, rounded discharge edge (38) for reducing the flow losses.
4. Thermal machine according to one of Claims 1 to 3, characterized in that the cooling shrouds (21, 31) are assembled from individual cooling shroud segments (34, 34a) which adjoin each other in the circumferential direction, and in that the cooling shroud segments (34, 34a) are fastened on the associated shells (23 or 33) by means of fastening elements (24) which are arranged in a distributed manner.
5. Thermal machine according to Claim 4, characterized in that the cooling shroud segments (34, 34a) overlap each other in pairs in the adjoining regions, and in that a cooling shroud segment of a pair is equipped in each case in the overlapping region with overlapping elements (36) for a form-fitting connection between the overlapping cooling shroud segments (34, 34a).
6. Thermal machine according to Claim 4 or 5, characterized in that the fastening elements (24) in the case of the cooling shroud segments (34, 34a) are arranged one behind the other in the axial direction in each case, and in that additional holes (35) are provided in the cooling shroud segments (34, 34a) in axial alignment with the fastening elements (24), through which cooling air flows in in jets from outside into the respective cooling passage (22 or 32) for improving the cooling.
7. Thermal machine according to Claim 4, characterized in that the entirety of the cooling shroud segments (34, 34a) is divided into first cooling shroud segments (34a) which are adjacent of the parting plane (29), and second cooling shroud segments (34) which lie outside the parting plane (29), and in that the first cooling shroud segments (34a) have a raised side edge (39) for adapting to the deviating shape of the shells (23, 33).

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