EP1420208A1 - Combustion chamber - Google Patents

Abstract

Combustion chamber (4) for a gas turbine comprises a combustion chamber wall (24) provided on the inside with a lining formed by a number of thermal shield elements (26). Each thermal shield element forms with the combustion chamber wall an inner chamber (27) loaded with a coolant (K) and containing a coolant distributor connecting a coolant feed line to a number of coolant outlet openings. An Independent claim is also included for a gas turbine comprising the above combustion chamber. Preferred Features: The coolant outlet openings are dimensioned so that the sum of the cross-sectional areas of all the coolant outlet openings of a coolant distributor is less than the cross-sectional area of the appropriate coolant feed line.

Description

The invention relates to a combustion chamber for a gas turbine, the combustion chamber wall of which is provided on the inside with a lining formed by a number of heat shield elements, the or each heat shield element forming an interior to which a coolant can be applied.
The invention further relates to a gas turbine with such a combustion chamber.

Combustion chambers are part of gas turbines, which in many Areas for driving generators or work machines be used. The energy content becomes one Fuel for generating a rotational movement of a turbine shaft used. The fuel is used by burners in the combustion chambers connected to them burned, whereby from compressed air is supplied to an air compressor. By the combustion of the fuel becomes one under high pressure standing working medium with a high temperature. This working medium is downstream of the combustion chambers Turbine unit guided where it is working relaxed.

A separate combustion chamber can be assigned to each burner be, the working medium flowing out of the combustion chambers be brought together before or in the turbine unit can. Alternatively, the combustion chamber can also be used in such a way mentioned annular combustion chamber design, in which a plurality, especially all, of the burners in a common, usually annular combustion chamber open.

When designing such gas turbines in addition to achievable performance usually a particularly high efficiency a design goal. An increase in efficiency can basically be used for thermodynamic reasons by increasing the outlet temperature, with which the working medium from the combustion chamber and into the Turbine unit flows. Therefore temperatures of around Desired 1200 ° C to 1500 ° C for such gas turbines and also achieved.

At such high temperatures of the working medium, however the components and parts exposed to this medium exposed to high thermal loads. To still at high Reliability a comparatively long lifespan It is usually necessary to ensure the affected components a design with particularly heat-resistant materials and cooling the affected components, in particular the combustion chamber, necessary. To thermal tension of the material to prevent the life of the components limited, the aim is usually one if possible to achieve uniform cooling of the components.

The combustion chamber wall is usually on the inside lined with heat shield elements that with special heat-resistant protective layers can be provided, and through the actual combustion chamber wall be cooled. For this purpose, usually also a "baffle cooling" designated cooling process used. In the Impact cooling becomes a coolant, usually cooling air, through a variety of holes in the combustion chamber wall Heat shield elements supplied so that the coolant in the Essentially perpendicular to the combustion chamber wall, outside surface bounces. That through the cooling process heated coolant is then removed from the interior, the combustion chamber wall with the heat shield elements forms, dissipated.

However, the manufacture of such a cooling system can be very difficult be elaborate because to achieve the most uniform possible Cooling the heat shields very many holes in the Combustion chamber wall with a comparatively small cross section are needed, which can be very time-consuming and costly. In particular, the requirements for manufacturing the Drilling required tools very high, because the cooling air holes are relatively long compared to their cross-section, since the wall of the combustion chamber wall for reasons of stability must be of sufficient strength. Furthermore can it with a large number of cooling air holes that in their Total have a high surface area, causing friction and turbulence come when the coolant is supplied. this leads to to an increased coolant pressure loss in the coolant circuit, which adversely affects the efficiency of the combustion chamber effect.

The invention is therefore based on the object of a combustion chamber of the type mentioned above, which at comparative simple design for a particularly high system efficiency suitable is. Furthermore, a gas turbine is said to have the above-mentioned combustion chamber.

With regard to the combustion chamber, this object is achieved according to the invention solved by the assigned to the respective heat shield element Inside each a coolant distributor arranged is, via which a coolant supply line with a A plurality of coolant outlet openings is connected.

The invention is based on the consideration that for one a particularly high system efficiency a reliable and in particular area-wide application of the heat shield elements should be guaranteed with coolant. Also at the apparatus can consistently comply with this requirement Effort and in particular the manufacturing effort kept low by the multitude of the previously provided Coolant holes replaced by a simplified system become. To keep the cooling effect high to maintain and on the other hand to simplify the supply, is a division of the coolant flow path into individual partial paths only as close as possible to the one to be cooled Heat shield element, i.e. particularly far at the end of the flow path, intended. The coolant distributors fulfill these functions.

To the effect of impact cooling when using the coolant distributor to increase the outlet openings of the Coolant distributor appropriately dimensioned such that the sum of their cross-sectional areas of all outlet openings is smaller than the cross section of the coolant supply line. This reduction in cross-section in the direction of coolant flow there is advantageously a nozzle effect, at which the exit velocity of the coolant at the outlet openings and thus the Impact cooling effect on the heat shield elements improved.

A suitable branching of the coolant flow in the coolant distributor to achieve the coolant distributor be designed such that a downstream of the feed line Distribution space branches into several distribution arms, which the cooling air through their end openings to the intended positions on the heat shield elements to lead. To the coolant in the coolant distributor distribute in a particularly simple manner, this has but preferably an approximately rotationally symmetrical Distribution room on that to the coolant supply line connected. The cross section of the coolant distributor for the flow of the coolant advantageously aerodynamically selected by the cross section in Coolant flow direction from the cross section of the supply line continuously expands so that the maximum cross section on Distribution room is reached. The is expediently Distribution room closed by a cover plate, which for Formation of the coolant outlet openings with a number of Holes is provided. In this design, in its entirety reminiscent of a "shower head" is a reliable one Distribution of the coolant using only a special one allows a small number of components.

In an advantageous embodiment, the coolant outlet openings have in sum the smallest cross section within of the coolant distributor so that only in the area the coolant outlet openings a comparatively increased Pressure drop in the coolant occurs.

Around the wall body of the coolant distributor with the cover plate to seal with sufficient tightness and strength, this is expediently welded to the wall body. The coolant distributor formed from the wall body and the cover plate can be particularly easy to assemble be screwed into the combustion chamber housing. To do the torque transmission necessary for screwing on particular to allow simple way, the cover plate is preferred on its outer wall with a number of recesses provided, in the corresponding locking lugs if necessary of an assembly tool can intervene.

To a coolant distributor on the combustion chamber wall with the To connect the coolant supply line, it is expedient with a thread at the opening of the coolant supply line screwed. The coolant distributor can advantageously on this type of attachment during assembly or time-saving installation or replacement during maintenance work become.

The coolant heated up after the cooling process becomes expedient through holes in the combustion chamber wall from the interior between the heat shields and the combustion chamber wall in derived a coolant discharge system. By the shape and one suitable arrangement of the coolant distributor, the one ensures sufficient distance between the coolant distributors, the heated cooling air can pass through the gaps between the coolant distributors to the openings of the bores located on the combustion chamber wall stream. To ensure even cooling of the combustion chamber to ensure the return holes are constant Relationship to the number of coolant distributors over the the entire length of the combustion chamber is preferably evenly distributed, so the coolant in all the return holes evenly with an approximately the same return temperature can be derived.

To drain the coolant out of the holes, these open expediently in a number of substantially parallel collecting channels running to the direction of flow of the working medium, through which the coolant can be removed. advantageously, can be achieved by an almost straight positioning the return holes with a one-sided collecting channel the cooling air is derived from several return holes become.

For a particularly high overall efficiency of the combustion chamber advantageously the heat input into the coolant for the actual energy conversion process in the combustion chamber recovered. This is advantageously a feed those heated during the combustion chamber cooling as a coolant cooling air used is provided in the combustion chamber, the preheated cooling air being exclusive or additional Combustion air can serve. To the outflow Coolant in this sense the combustion process in the Feeding the combustion chamber, each collecting duct is preferred on the output side connected to a collecting room, which in turn is upstream of the combustion chamber. About this can the coolant through a throttle device with the remaining compressor mass flow mixed and the combustion process are fed.

The above-mentioned combustion chamber is preferably a component a gas turbine.

The advantages achieved with the invention are in particular in that through the use of coolant manifolds a large area even with only a small manufacturing effort and comprehensive application of the heat shield elements is made possible with coolant. In addition, the coolant pressure drop kept low when cooling the combustion chamber so that the system efficiency of the combustion chamber elevated. The low coolant pressure drop can in particular can also be achieved because the cooling air distributor only need few feed holes in the combustion chamber wall and keep pressure loss low by choosing a suitable shape. The use of a number of coolant manifolds can uniform cooling with low coolant pressure loss ensure that the coolant is supplied via a coolant distributor the coolant is only shortly before the impingement cooling on the heat shield elements from a larger coolant supply line into several smaller coolant outlet openings branched. This ensures that the coolant is only a short distance with a relatively low Cross-section flows, so that the coolant pressure loss is limited.

Due to the technically simple construction of the coolant distributor and by screwing to the combustion chamber wall is also a simple and inexpensive manufacture and assembly of the Cooling system possible. The cooling air discharge system ensures through the discharge holes and parallel to the flow direction of the working medium running channels even discharge of the heated cooling air, so that uniform cooling of the combustion chamber can be achieved can. In addition, the combustion process takes place via the collecting channels supplyable heated cooling air the system efficiency the combustion chamber further improved.

Fig. 1

einen Halbschnitt durch eine Gasturbine,

Fig. 2

einen Schnitt durch eine Brennkammer,

Fig. 3

im Schnitt einen Ausschnitt der Brennkammerwand,

Fig. 4

im Schnitt und in der Draufsicht einen Kühlmittelverteiler,

Fig. 5

im Schnitt eine Aufsicht auf einen Ausschnitt der Brennkammerwand,

Fig. 6

im Schnitt einen Ausschnitt der Brennkammerwand,

Fig. 7

im Schnitt einen Ausschnitt eines Brenners und einer Brennkammer.

An embodiment is explained in more detail with reference to a drawing. In it show:

Fig. 1

a half-section through a gas turbine,

Fig. 2

a section through a combustion chamber,

Fig. 3

on average a section of the combustion chamber wall,

Fig. 4

in section and in plan view a coolant distributor,

Fig. 5

on average a top view of a section of the combustion chamber wall,

Fig. 6

on average a section of the combustion chamber wall,

Fig. 7

in section a section of a burner and a combustion chamber.

The same parts have the same reference symbols in all the figures Mistake. The gas turbine 1 according to FIG. 1 has a compressor 2 for combustion air, a combustion chamber 4 and one Turbine 6 for driving the compressor 2 and one not shown generator or a work machine. To are the turbine 6 and the compressor 2 on a common, turbine shaft also referred to as a turbine rotor 8 arranged with which the generator or the working machine is connected, and about its central axis 9 is rotatably mounted. The kind of an annular combustion chamber Executed combustion chamber 4 is with a number of burners 10 for the combustion of a liquid or gaseous Fuel.

The turbine 6 has a number of with the turbine shaft 8 connected, rotatable blades 12. The blades 12 are arranged in a ring shape on the turbine shaft 8 and thus form a number of rows of blades. Farther The turbine 6 comprises a number of fixed guide vanes 14, which is also ring-shaped with the formation of Guide vane rows attached to an inner housing 16 of the turbine 6 are. The blades 12 serve to drive the turbine shaft 8 by transfer of momentum from the turbine 6 working medium flowing through M. The guide vanes 14 serve in contrast to the flow of the working medium M between seen two in the flow direction of the working medium M. successive rows of blades or blade rings. A successive pair from a wreath of Guide vanes 14 or a row of guide vanes and from one Wreath of blades 12 or a row of blades is also referred to as the turbine stage.

Each guide vane 14 has one which is also referred to as a blade root Platform 18, which is used to fix the respective guide vane 14 on the inner housing 16 of the turbine 6 as a wall element is arranged. The platform 18 is a thermal comparison heavily loaded component that the outer boundary a heating gas channel for the one flowing through the turbine 6 Working medium M forms. Each blade 12 is analog Way over a platform 20 also referred to as a blade root attached to the turbine shaft 8.

Between the spaced platforms 18 of the guide vanes 14 of two adjacent rows of guide vanes is a respective guide ring 21 on the inner housing 16 of the Turbine 6 arranged. The outer surface of each guide ring 21 is also hot, flowing through the turbine 6 Working medium M exposed and in the radial direction from the outer end 22 of the blade opposite to it 12 spaced by a gap. The one between neighboring Guide rings 21 arranged guide vane rows serve in particular as cover elements that cover the inner wall 16 or other housing installation parts before a thermal Overuse by the flowing through the turbine 6 protects hot working medium M.

The combustion chamber 4 is so-called in the exemplary embodiment Annular combustion chamber designed in which a variety of in Arranged circumferentially around the turbine shaft 8 Burners 10 open into a common combustion chamber space. To is the combustion chamber 4 in its entirety as an annular Designed structure that positioned around the turbine shaft 8 is.

To further clarify the design of the combustion chamber wall 24, the combustion chamber 4 is shown in section in FIG. 2, which is toroidal around the turbine shaft 8 continues. As can be seen in the illustration, the Combustion chamber 4 has an initial or inflow section, in the end of the outlet of the associated burner 10 flows. Seen in the direction of flow of the working medium M. the cross section of the combustion chamber 4 then narrows, where the emerging flow profile of the working medium M is taken into account in this area. On the output side the combustion chamber 4 has a curvature in longitudinal section on, through which the outflow of the working medium M from the Combustion chamber 4 in one for a particularly high pulse and Energy transfer to the following downstream first row of blades is favored.

To achieve a comparatively high efficiency the combustion chamber 4 for a comparatively high temperature of the working medium M from about 1200 ° C to 1500 ° C. This also applies to these operating parameters, which are unfavorable for the materials to enable a comparatively long operating time is the combustion chamber wall 24 on the working medium M facing side with one made of heat shield elements 26 formed lining provided. Any heat shield element 26 is particularly heat-resistant on the working medium side Protective layer. Because of the high temperatures inside the combustion chamber 4 is also for the heat shield elements 26 a cooling system is provided. The cooling system is based on the principle of impingement cooling, in which cooling air as a coolant under sufficiently high pressure on a Blown a large number of points on the component to be cooled becomes.

The cooling system is simple in construction for reliable, Comprehensive exposure to the heat shield elements 26 with cooling air and also for a particularly low one Coolant pressure drop designed. For this, the heat shield elements 26 from the outside through the cooling air K cooled by a number of im from each heat shield element 26 and the combustion chamber wall 24 formed interior 27 arranged coolant distributors 28 on the surface of the respective heat shield element 26 is passed.

To further clarify the execution of the cooling for the heat shield elements 26 is a section in FIG. 3 in section the combustion chamber wall 24 shown. Like this one Are recognizable are a number of Coolant distributor 28 over the entire area of the respective Heat shield element 26 distributed for uniform cooling to ensure. The coolant K flows through one assigned coolant supply line 29 in the respective Coolant distributor 28. The coolant K through a number of coolant outlet openings 30 to the Surface of the heat shield element 26 passed where this with the coolant K is cooled by impingement cooling. The holes for the coolant supply lines 29 are in production to attach the combustion chamber 4 easily and in a time-saving manner, since there is only one for each coolant distributor 28 Coolant supply line 29 is required.

The respective coolant distributor 28 is due to its shape for a particularly low coolant pressure drop designed. To do this, the coolant flows through the Coolant distributor 28 by a rotationally symmetrical, in the exemplary embodiment according to FIG. 4 cylindrical distributor space 34 distributed to the coolant outlet openings 30.

Alternatively, as shown in FIG. 4, the Coolant supply line 29 for the coolant flowing through K streamlined with a continuously widening Cross section connected to the distributor space 34 his. The distributor space 34 is closed by a cover plate 36, which is a number of holes to form the Contains coolant outlet openings 30. For easy manufacturing of the coolant distributor is the cover plate 36 with the Wall 37 of the coolant distributor 28 welded. To one easy installation in the combustion chamber inner wall by screwing to enable, the cover plate 36 also for a Torque transmission from a customized tool a number of recesses on its outer wall.

As can also be seen in the illustration according to FIG. 4, have the coolant outlet openings 30 of the coolant distributor 28 in total a smaller cross section than the coolant supply line 29 of the coolant distributor 28. This leads to the flow of the coolant K through the Coolant distributor 28 to a nozzle effect and associated therewith to an increased outlet speed of the coolant K at the coolant outlet openings 30, whereby the effect of the impingement cooling on the heat shield elements 26 increased.

The coolant distributor 28 is for a particularly stable attachment designed on the combustion chamber wall 24, which at the same time for quick assembly and easy interchangeability Maintenance work is suitable. The coolant distributor 28 is with a thread 38 on the coolant inlet side with the Screwed combustion chamber wall 24.

The one that occurs when cooling the heat shield elements 26 Heating of the coolant K flowing through for the thermodynamic Efficiency in a favorable way for the actual It is intended to make the combustion process usable return the heated coolant K to the burners 10 and the combustion process in the combustion chamber 4 as exclusive or supply additional combustion air. Around the heated coolant K from the interior 27 between the respective heat shield element 26 and the combustion chamber wall 24 Routing to the burners 10 is a coolant discharge system intended. This coolant discharge system is designed to the coolant K uniformly at approximately the same Derive temperature over the entire surface of the combustion chamber 10, a uniform temperature profile over the heat shield elements 26 and to ensure the combustion chamber wall 24.

For this purpose, the heated coolant K is replaced by a number of Coolant return bores 40 in the combustion chamber walls 24 the interior 27 between the combustion chamber wall 24 and the heat shield elements 26, as shown in FIGS. 2, 5 and 6 is shown. The coolant K can pass through the gaps between the coolant distributors 28 to the openings the coolant return holes 40 flow. Are there the coolant return holes 40 in the same ratio as the coolant distributors 28 evenly on the combustion chamber wall 24 distributed so that a uniform coolant removal and thus a uniform temperature profile of the combustion chamber 10 can be guaranteed.

As can be seen in the illustration according to FIG. 6, one opens Coolant return hole 40 in a substantially parallel to the flow direction of the working medium M. Coolant return duct 42 through which the coolant K in Direction of the burner 10 is derived. A number of Return bores 40 are positioned in such a straight line that that multiple coolant return holes 40 in one common coolant return duct 42 open, so that this acts as a collection channel for back-flowing coolant.

Around the coolant K the combustion process of a burner 10 to supply, the respective coolant return duct 42 opens on the burner side into a collecting space assigned to a burner 10 44, as can be seen in FIG. 7. Not for them Combustion chamber cooling used air flow from the compressor 2 is fed to the burner via a throttle 45.

LIST OF REFERENCE NUMBERS

1

gas turbine

2

compressor

4

combustion chamber

6

turbine

8th

turbine shaft

9

central axis

10

burner

12

blades

14

vanes

16

inner housing

18

platform

20

blade

21

guide ring

22

outer end

24

combustion chamber wall

26

Heat shield elements

27

inner space

28

Coolant distributor

29

coolant supply line

30

Coolant outlet opening

34

distribution space

36

cover sheet

37

wall

38

thread

40

Coolant return holes

42

Coolant return channel

44

plenum

M

working medium

K

coolant

Claims (9)

Combustion chamber (4) for a gas turbine (1), the combustion chamber wall (24) on the inside with one of a number of heat shield elements (26) formed lining is provided, the or each heat shield element (26) with the combustion chamber wall (24) one with a coolant (K) Interior (27) forms in which a coolant distributor (28) is arranged, via which a coolant supply line (29) with a plurality of coolant outlet openings (30) connected is. Combustion chamber according to claim 1, wherein the coolant outlet openings (30) are dimensioned such that the Sum of the cross-sectional areas of all coolant outlet openings (30) of a coolant distributor (28) is smaller than the cross-sectional area of the assigned coolant supply line (29). Combustion chamber according to claim 1 or 2, the coolant distributor (28) one to the assigned coolant supply line (29) connected, approximately cylindrical distribution space (34), which on its the respective heat shield element (26) side facing the coolant outlet openings (30) supporting cover plate (36) is provided. Combustion chamber according to Claim 3, in which the cover plate (36) on an associated wall (37) of the respective coolant distributor (28) is welded on. Combustion chamber according to one of claims 1 to 4, wherein the or each coolant distributor (28) in the area of each assigned coolant supply line (29) with the combustion chamber wall (24) is screwed. Combustion chamber according to one of claims 1 to 5, wherein the or each interior (27) with a number of holes a coolant discharge system is connected. Combustion chamber according to claim 6, wherein the holes on the output side in a number of substantially parallel to Flow direction of the working medium (M) in the combustion chamber aligned coolant return channels (42) open. The combustor of claim 7, wherein each coolant return duct (42) on the output side with a burner (10) associated collecting space (44) is connected. Gas turbine (1) with a combustion chamber according to one of the claims 1 to 8.

Images