EP2927594B1 - Combustion chamber of a gas turbine - Google Patents

Description

The invention relates to a combustion chamber of a gas turbine with an outer combustion chamber wall and attached to the inside of the outer combustion chamber wall shingles.

It is known from the prior art to introduce air into the combustion chamber interior radially from the outside by means of admixing holes or mixing air holes. In this case, individual, discrete admixing holes are always used, which are distributed in a suitable manner on the circumference of the combustion chamber. The Zumischlöcher are usually arranged in one or more rows on the circumference of the combustion chamber.

The supply of mixed air serves to optimize the combustion in the combustion chamber. In particular, the best possible blocking and mixing of the fuel gases with the admixed air should take place in order to control and minimize NOx emissions.

The constructions known from the prior art have the disadvantage that due to the discrete, individual arrangement of the admixing holes, not maximum blocking and best mixing of the admixing air with the combustion gases is possible. Thus, the maximum possible reduction of NOx emissions is not possible. A disadvantage of the known constructions is further shown that any arrangement of the individual discrete Zumischlöcher to each other and in particular an arbitrary spacing of the Zumischlöcher to each other due to the mechanical structure of the combustion chamber outer wall and the shingles are not possible.

From the GB 543 918 A is a combustion chamber previously known, which is constructed of conical, nested elements. The conical mating surfaces form a small gap through which cooling medium can be inserted. GB 543 918 A discloses a combustion chamber according to the preamble of claim 1. Other similar combustion chambers are characterized by US 4,773,227 A . FR 1 036 218 A and DE 11 79 422 B disclosed.

The invention has for its object to provide a combustion chamber of a gas turbine, which avoids the disadvantages of the prior art with a simple structure and simple, cost-effective manufacturability and allows optimized supply of mixed air.

According to the invention the object is achieved by the combination of features of claims 1 or 2, the dependent claims show further advantageous embodiments of the invention.

According to the invention it is thus provided that the combustion chamber in a central region, with respect to the flow direction, a extending around the entire circumference of the combustion chamber wall slot which divides the outer combustion chamber wall and the shingles and can be supplied by the mixed air.

According to the invention thus results in the decisive advantage that the NOx emissions can be reduced in the maximum possible way by the optimized supply of mixed air. It is particularly favorable that the circumferential slot can be provided with an equal effective flow area for air mixing, as known from the prior art Zumischlöcher.

According to the invention it is provided that the combustion chamber is divided by the slot in a front part and a rear part. The term "front and rear part" always refers to the direction of flow through the combustion chamber.

The slit provided in accordance with the invention may be formed in a straight line around the entire circumference, that is, with a constant width. It is also possible to make this wavy, be it with the same width or variable width. As a result, an adaptation to the arrangement of the individual, distributed around the circumference of the annular combustion chamber burner is possible. In a further embodiment variant it can be provided that the slot can be provided with a width which varies around the circumference, for example by bulges and constrictions in the circumferential direction.

Since, according to the invention, the combustion chamber is divided into a front part and a rear part, the front part and the rear part of the combustion chamber are each mounted separately. The storage is preferably carried out by means of combustion chamber arms. These have in a preferred embodiment of the invention flow openings in order to optimize the flow of air. The cross sections of the flow openings are preferably larger than the total cross section of the slot.

It is understood that the storage of the shingles on the outer combustion chamber wall can be done in different ways. It is possible to use bolts for this, as shown in the prior art. However, it is also possible to manufacture the front and rear parts of the combustion chamber wall in one piece by means of additive methods (laser deposition welding method or the like). In any case, it is ensured that between the shingle and the outer combustion chamber wall there is a cooling air gap in order to provide in a known manner an impingement cooling and an effusion cooling can. The inventive construction can also be applied for single-walled combustion chambers (without shingles).

In a particularly favorable development of the invention it is provided that the front part and the rear part of the combustion chamber wall can change their distance during thermal expansion and thermal contraction. Thus, it is possible to vary the width of the slot, depending on the temperature of the combustion chamber. Thus, in the cold state, the width of the circumferential slot may be greater by a greater distance of the side walls of the slot, as in the hot state. Thus, the supply of admixed air is increased in the cold state of the combustion chamber, at the same time less cooling air for the combustion chamber walls. When hot, this is then reversed, the circumferential slot will have a smaller width. As a result, a variable geometry for air introduction and thus a significant reduction in NOx emissions for colder operating points and operating conditions of the combustion chamber is possible.

Fig. 1

eine schematische Darstellung eines Gasturbinentriebwerks gemäß der vorliegenden Erfindung;

Fig. 2

eine vereinfachte Seiten-Schnittansicht einer Brennkammer gemäß dem Stand der Technik;

Fig. 3

eine Seitenansicht, analog Fig. 2, eines ersten Ausführungsbeispiels;

Fig. 4

eine Darstellung, analog Fig. 3, eines zweiten Ausführungsbeispiels;

Fig. 5

eine Darstellung, analog den Fig. 3 und 4, eines weiteren Ausführungsbeispiels;

Fig. 6 bis 8

schematische Darstellungen der Ausgestaltung des erfindungsgemäßen Umfangsschlitzes;

Fig. 9 und 10

Ansichten, analog Fig. 5, mit der Verdeutlichung eines kalten und eines heißen Betriebszustands,

Fig. 11 und 12

Darstellungen, analog den Fig. 6 und 8, im kalten und im heißen Betriebszustand,

Fig. 13 und 14

Erfindungsgemäße Ausgestaltungsvarianten, analog Fig. 9 und 10, und

Fig. 15 und 16

Darstellungen im heißen und kalten Betriebszustand der Ausführungsbeispiele der Fig. 13 und 14 in analoger Darstellung zu dem Fig. 11 und 12.

In the following the invention will be described by means of an embodiment in conjunction with the drawing. Showing:

Fig. 1

a schematic representation of a gas turbine engine according to the present invention;

Fig. 2

a simplified side sectional view of a combustion chamber according to the prior art;

Fig. 3

a side view, analog Fig. 2 , a first embodiment;

Fig. 4

a representation, analog Fig. 3 , a second embodiment;

Fig. 5

a representation analogous to Fig. 3 and 4 , another embodiment;

Fig. 6 to 8

schematic representations of the embodiment of the circumferential slot according to the invention;

FIGS. 9 and 10

Views, analog Fig. 5 , with the illustration of a cold and a hot operating state,

FIGS. 11 and 12

Representations, analogous to 6 and 8 , in cold and hot conditions,

FIGS. 13 and 14

Embodiment variants according to the invention, analogously FIGS. 9 and 10 , and

FIGS. 15 and 16

Representations in the hot and cold operating state of the embodiments of the FIGS. 13 and 14 in an analogous representation to the FIGS. 11 and 12 ,

The gas turbine engine 110 according to Fig. 1 is a generalized example of a turbomachine, in which the invention can be applied. The engine 110 is formed in a conventional manner and comprises in succession an air inlet 111, a fan 112 circulating in a housing, a medium pressure compressor 113, a high pressure compressor 114, a combustion chamber 115, a high pressure turbine 116, a medium pressure turbine 117 and a low pressure turbine 118 and a Exhaust nozzle 119, which are all arranged around a central engine center axis 101.

The intermediate pressure compressor 113 and the high pressure compressor 114 each include a plurality of stages, each of which includes a circumferentially extending array of fixed stationary vanes 120, commonly referred to as stator vanes, which are radially inwardly of the engine casing 121 in an annular manner Flow channel through the compressors 113, 114 protrude. The compressors further include an array of compressor blades 122 projecting radially outward from a rotatable drum or disc 125 coupled to hubs 126 of high pressure turbine 116 and intermediate pressure turbine 117, respectively.

The turbine sections 116, 117, 118 have similar stages, comprising an array of fixed vanes 123 projecting radially inward from the housing 121 into the annular flow passage through the turbines 116, 117, 118, and a downstream array of turbine blades 124, projecting outwardly from a rotatable hub 126. The compressor drum or compressor disk 125 and the vanes 122 disposed thereon and the turbine rotor hub 126 and turbine blades 124 disposed thereon rotate about the engine centerline 101 during operation.

The Fig. 2 shows a combustion chamber according to the prior art in a simplified sectional view. The combustion chamber has a combustion chamber outer wall 1 and a heat shield 2, a combustion chamber head 3 and a burner seal 4. On the inside of the combustion chamber outer wall 1 shingles 9 are arranged, which are integrally connected with studs 7, which in turn are secured from the outside by means of nuts 8. The presentation of impingement cooling holes and effusion cooling holes was omitted for the sake of simplicity.

In the front region, the combustion chamber in a known manner on a top plate 6. Around the circumference of the combustion chamber, a plurality of individual, discrete admixing holes 5 are formed in the combustion chamber outer wall 1 and the shingles 9, through which mixing air is introduced.

The storage of the combustion chamber by means of an outer Brennkammerarms and an inner Brennkammerarms 11 and an outer Brennkammerflansches 12 and an inner Brennkammerflansches 13. The reference numeral 14 denotes an outer combustion chamber housing, while an inner combustion chamber housing is provided with the reference numeral 15. At the outlet of the combustion chamber, an outer turbine housing 16 and an inner turbine housing 17 are shown schematically.

The Fig. 3 to 5 show each different design variants of the combustion chamber. At the in Fig. 3 In particular, it can be clearly seen that the combustion chamber is divided into a front part and a rear part. The division is made by a circumferentially extending admixing slot 18, which passes through both the combustion chamber outer wall 1 and the shingle 9 and extends around the entire circumference. Thus, it is possible to uniformly and effectively supply admixing air 19, as shown by the arrows. In a single-wall combustion chamber formation consisting only of the combustion chamber outer wall 1 without shingles the admixing slot 18 separates the combustion chamber wall analogously in a front and a rear half.

In the Fig. 3 shown combustion chamber is mounted at its front part and its rear part in each case by means of separate outer combustion chamber arms 10. These have flow openings 20 in order to ensure an optimized cooling air flow. The two outer combustion chamber arms 10 are fastened with their outer combustion chamber flanges 12 to the outer combustion chamber housing 14 and the outer turbine housing 16. The inner attachment is analogous to the known from the prior art embodiment, in addition, a connection 21 between the combustion chamber and the inner combustion chamber 11 takes place.

The design variant of Fig. 4 with respect to the storage on the outer combustion chamber housing 14 and on the outer turbine housing 16. The two outer combustion chamber flanges 12 are secured by means of an intermediate housing 24.

At the in Fig. 5 In the embodiment shown, the bearing of the rear part of the combustion chamber with its outer combustion chamber flange 12 takes place between the intermediate housing 24 and the outer turbine housing 16, while the front part of the combustion chamber is mounted above the combustion chamber head 3 and an outer combustion chamber arm 10.

The Fig. 6 to 8 show in a schematic view design variants of the mixing slot 18. Die Fig. 6 shows a design variant in which the Admixing slot 18 is formed in a straight line with the same width. According to Fig. 7 a uniform width of the admixing slot 18 is provided. However, this is formed wavy around the circumference. The Fig. 8 shows a design variant of the admixing slot 18, in which this has around the circumference wider areas and bottlenecks.

The Fig. 9 to 12 show a development in analog representation too Fig. 5 , It shows the Fig. 9 a cold or colder operating condition while the Fig. 10 shows a hot operating condition. In the cold operating condition, a larger width of the admixing slot 18 is present, as in the FIGS. 11 and 12 analogous to the embodiments of 8 and 6 is shown in the left half of the picture. At elevated temperature (hot operating state), the parts of the combustion chamber expand, as shown by the arrows 25. This reduces the width of the admixing slot 18. This is compared in the FIGS. 11 and 12 shown in the right half of the picture. Thus, it is possible to supply a larger volume of mixed air during cold operation to reduce NOx emissions for colder operating points.

The FIGS. 13 and 14 show simplified sectional views in analogous representation to the FIGS. 9 and 10 , In a modification to the embodiment of FIGS. 9 and 10 in which the edges of the admixing slot 18 are formed straight and are arranged directly opposite each other, the embodiment of the FIGS. 13 and 14 an embodiment in which the walls of the portions of the combustion chamber overlap, as in the FIGS. 15 and 16 is shown. The two overlapping areas are each provided with a slot or with holes. The overlap results in the cold state ( Fig. 15 ) a smaller overlap, which results in a total of a smaller width of the admixing slot 18. In a hot operating condition ( Fig. 16 ), the overlap is greater, as seen from the upper half of the Fig. 16 is apparent. This results in a wider effective admixing slot 18. Also in this embodiment, the slot geometry in the circumferential direction can be rectilinear or wavy or formed with a changing cross section. The Fig. 13 to 16 Thus, an embodiment which, in contrast to the embodiment of the Fig. 9 to 12 acts as the width of the mixing slot widens from cold to hot operating condition.

The invention thus enables an ideal blocking / mixing of the admixing air 19 with the fuel gases in the combustion chamber volume 23. By the circumferential slot 18, which is formed in the combustion chamber wall 1 and the shingle 9, the admixing air is supplied in an optimal manner, so that the NOx emissions be minimized. The circumferential slot preferably has the same effective flow cross-section or the same through-flow area as comparable admixing holes 5 according to the prior art (see FIG. Fig. 2 ).

As described, the combustion chamber according to the invention divides into two parts. Therefore, according to the invention, a suspension concept is described in which the parts of the combustion chamber are suitably fixed to the inner and outer combustion chamber housings and to the turbine housing. This is done, as explained, by additional combustion chamber arms 12. These can be attached in any way to the combustion chamber or connected to this, for example by one-piece design, by welding, by screwing or in a similar manner.

LIST OF REFERENCES:

1

Combustion chamber outer wall

2

heat shield

3

bulkhead

4

Brenner seal

5

Zumischlöcher

6

headstock

7

studs

8th

mother

9

shingle

10

outer combustion chamber arm

11

inner combustion chamber arm

12

outer combustion chamber flange

13

inner combustion chamber flange

14

outer combustion chamber housing

15

inner combustion chamber housing

16

outer turbine housing

17

inner turbine housing

18

Zumischschlitz

19

admixed air

20

Flow openings

21

Connection combustion chamber - inner combustion chamber arm 11

22

Combustion chamber annulus

23

combustion chamber volume

24

intermediate housing

25

expansion

101

Engine centerline axis

110

Gas turbine engine / core engine

111

air intake

112

fan

113

Medium pressure compressor (compressor)

114

High pressure compressor

115

combustion chamber

116

High-pressure turbine

117

Intermediate pressure turbine

118

Low-pressure turbine

119

exhaust nozzle

120

vanes

121

Engine casing

122

Compressor blades

123

vanes

124

turbine blades

125

Compressor drum or disc

126

Turbinenrotornabe

127

outlet cone

Claims (6)

1. Combustion chamber of a gas turbine, wherein the combustion chamber has in a center area, relative to the flow direction, an admixing slot (18) extending around the entire circumference of the combustion chamber and dividing the combustion chamber into a front part and a rear part for the supply of mixing air, wherein the front part of the combustion chamber and the rear part of the combustion chamber are mounted separately, characterized in that the combustion chamber has an outer combustion chamber wall (1) with tiles (9) attached to the inner side of said wall, and that the front part and the rear part of the combustion chamber have walls, wherein areas if these walls overlap and wherein the overlapping areas of the walls are each provided with a slot or with holes.
2. Combustion chamber of a gas turbine with a combustion chamber wall (1) of the single-wall design, wherein the combustion chamber has in a center area, relative to the flow direction, an admixing slot (18) extending around the entire circumference of the combustion chamber and dividing the combustion chamber wall (1) into a front part and a rear part for the supply of mixing air, wherein the front part of the combustion chamber and the rear part of the combustion chamber are mounted separately, characterized in that the front part and the rear part of the combustion chamber have walls, wherein areas if these walls overlap and wherein the overlapping areas of the walls are each provided with a slot or with holes.
3. Combustion chamber in accordance with one of the Claims 1 or 2, characterized in that the slot (18) is designed straight or wavy or with a varying cross-section around the entire circumference.
4. Combustion chamber in accordance with one of the Claims 1 to 3, characterized in that the front part of the combustion chamber and the rear part of the combustion chamber are mounted by means of combustion chamber arms (10, 11) having through-flow openings (20).
5. Combustion chamber in accordance with one of the Claims 1 to 4, characterized in that the mounting of the front part and of the rear part of the combustion chamber is designed to vary the width of the slot (18) in the event of thermal expansion or contraction.
6. Combustion chamber in accordance with Claim 5, characterized in that the width of the slot (18) is variable.

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