EP3526520A1

EP3526520A1 - Burner tip having an air channel structure and a fuel channel structure for a burner, and method for producing said burner tip

Info

Publication number: EP3526520A1
Application number: EP18702918.6A
Authority: EP
Inventors: Carl Hockley; Christoph Kiener; Andreas Kreutzer; Matthias SALCHER
Original assignee: Siemens AG
Current assignee: Siemens Energy Global GmbH and Co KG
Priority date: 2017-01-17
Filing date: 2018-01-04
Publication date: 2019-08-21
Also published as: WO2018134058A1; DE102017200643A1; KR20190108126A; JP2020506356A; CN110177976A; CA3050180A1; US20200018483A1

Abstract

The invention relates to a burner tip (19) for installation in a burner (11), wherein the burner tip (19) has a surface (OF) facing a combustion chamber (BR), an air channel structure (21) leading to the surface (OF) and defining an air channel (20), and a fuel channel structure (32) leading to the surface (OF), and wherein the fuel channel structure (32) defines a fuel channel (33), which extends in a surface region (OFB) of the burner tip (19) in a first direction parallel to the surface (OF) and then extends back, at least in part, in a second direction (2R), different from the first direction (1R), in order to cool the surface region (OFB) of the burner tip (19) by a fuel flowing through the fuel channel (33) during operation of the burner tip (19).

Description

description

Burner tip having an air channel structure and a fuel channel structure for a burner and method for producing the burner tip

The present invention relates to a burner tip having an air channel structure and a fuel channel structure, preferably for a burner in a gas turbine. Furthermore, a method, preferably an additive method, for the production of the burner tip is described.

The burner tip is preferably provided for use in a turbomachine, preferably in the hot gas path of a gas turbine. The component further preferably consists of a nickel-base and / or superalloy, in particular a nickel- or cobalt-based superalloy. The alloy may be precipitation hardened or precipitation hardenable.

Burner tips of the construction specified above are known for example from EP 2 196 733 AI. The burner tip described therein can be used, for example, in a gas turbine, wherein the burner tip forms the downstream end of a burner lance, which is arranged in a main duct for combustion air. The burner tip has a double-walled construction, wherein the outer wall forms a heat shield, which is intended to keep emerging heat of combustion away from the inner wall. Therefore, between the outer wall and the inner wall, an annular cavity, so an annular space arranged, which can be flowed through for cooling purposes via openings with air. In the embodiment described, the heat shield must be designed to withstand the heat load due to the combustion taking place in the downstream combustion chamber. Therefore, the outer wall of the burner tip is the limiting factor for the life of the burner tip. The object of the invention is to develop a burner tip of the type specified in such a way that results in an improvement in the life of the component. In particular, to be made possible by the present invention, an improved cooling of the burner tip. It is another object of the invention to provide a method for producing such a burner tip.

The production can be carried out, for example, by casting with a lost core. According to a solution of the above-stated object, however, it is particularly advantageous if an additive manufacturing method is used for the production. In this case, the burner tip can preferably be produced in one piece and with a design that is particularly complex and / or optimized with regard to a cooling effect, wherein the additive manufacturing enables in particular geometrically complex constructions with advantageously large surface area for a heat transfer. In the context of this application, additive manufacturing processes are to be understood as processes in which the material from which a component is to be produced is added to the component during formation. In this case, the component is already produced in its final shape or at least approximately in this shape. The building or starting material is preferably powdery, wherein the material for producing the component is physically solidified by introducing additive energy by the additive manufacturing process. To be able to produce the component, data describing the component (CAD model) are prepared for the selected additive manufacturing process. The data is converted into data of the component adapted to the manufacturing process to produce instructions for the production plant, so that the suitable process steps for the successive production of the component can take place in the production plant. The data are processed in such a way that the geometric data for the respective slices of the construction partly available, which is also referred to as "Slicen".

Examples of additive manufacturing include selective laser sintering (also called SLS for selective laser sintering), selective laser melting (also known as SLM for selective laser sintering)

Melting), the electron beam melting (also EBM for

Electron Beam Melting), which is called laser powder deposition welding (also LMD for laser metal deposition) or cold gas spraying (also GDCS for gas dynamic cold spray).

These methods are particularly suitable for the processing of metallic materials in the form of powders, with which

Construction components can be produced. With the SLM, SLS and EBM, the components are produced in layers in a powder bed. These processes are therefore also referred to as powder bed-based additive manufacturing processes. In each case, a layer of the powder is produced in the powder bed which is then locally melted or sintered by the energy source (laser or electron beam) in those areas in which the component is to be formed. Thus, the component is successively produced in layers and can be removed after completion of the powder bed. With the LMD and GDCS, the powder particles are fed directly to the surface on which a material application is to take place. With the LMD, the powder particles are melted by a laser directly in the point of impact on the surface and thereby form a layer of the component to be produced. In the GDCS, the powder particles are strongly accelerated so that they adhere primarily due to their kinetic energy with simultaneous deformation on the surface of the component. GDCS and SLS have the common feature that the powder particles are not completely melted in these processes. Among other things, this also allows the production of porous structures, if spaces between the Particles are preserved. In the case of the GDCS, melting takes place at most in the edge region of the powder particles, which can melt on their surface due to the strong deformation. With the SLS, care is taken when selecting the sintering temperature that this is below the melting temperature of the powder particles. In contrast, the SLM, EBM and LMD amount of the energy input deliberately so high that the powder particles are completely melted. The object mentioned is achieved by the subject of the independent claims. Advantageous embodiments are the subject of the dependent claims.

One aspect of the present invention relates to a burner tip for installation in a burner, wherein the burner tip has a surface facing a combustion chamber and an air channel structure leading to the surface and defining an air channel and a fuel channel structure leading to the surface. The fuel channel structure defines a fuel channel which extends in a surface region of the burner tip along a first direction parallel to the surface and then at least partially extends back or is bent or deflected in the surface region along a second direction different from the first direction Surface area of the burner tip to cool by a flowing during operation of the burner tip through the fuel channel fuel.

Due to the "back extension" or the curved course of the fuel channel, a cooling effect in the surface area of the burner tip can advantageously be effected by the fuel in a particularly effective manner during operation of the burner tip, for example when using a gas turbine Surface or surface area of the burner tip is no longer reliant on the consumption of compressor air valuable for the efficiency of a turbomachine Saved for this compressor air and the corresponding components are advantageously simplified.

In one embodiment, the fuel channel with several turns runs parallel to the surface and in the surface region. In other words, the fuel channel is preferably deflected several times parallel to the surface or extends according to the deflection. In one embodiment, the fuel channel extends at least partially along an axis of symmetry of the burner tip or a main flow direction in the operation thereof.

In one embodiment, the fuel channel extends from its course along the first direction into an interior of the burner tip. According to this embodiment, an area of the surface (surface area) which is distanced from the surface can advantageously also be cooled during operation of the burner tip. This in turn has an advantageous effect on the life of the entire construction component.

In one embodiment, the first direction includes an angle between 160 ° and 200 °, preferably 180 °, relative to the second direction. This embodiment allows a particularly expedient return or deflection of the fuel channel, as described above.

The term "surface area" preferably describes a structure region of the burner tip in the vicinity of the surface mentioned.

In one embodiment, the fuel channel subsequently, ie after its deflection into the interior of the burner tip, opens into the surface via at least one further change in direction, for example a deflection between 70 ° and 110 °. By this configuration, an efficient cooling in the use of the burner tip and at the same time Advantageous design of the burner tip can be realized, as an efficient cooling by the fuel in the use of the burner tip and at the same time a preheating of the fuel to be fed into the combustion chamber fuel is enabled.

In one embodiment, the fuel channel, after its course along the first direction, and expediently before an orifice into the surface, has an area with an enlarged cross-section, in particular an interaction or collection space. According to this embodiment, a heat transfer from a surface region to a fuel which is located in the collecting chamber or flows through it during operation of the burner tip can be made particularly advantageous. In particular, the increased cross-section provides an increased volume of interaction and heat transfer, thereby effectively increasing a heat capacity (to accommodate the heat applied to the surface during operation of the torch tip).

In one embodiment, the air duct structure comprises a central air duct, which leads to a central outlet opening in the burner tip. In particular, the air duct structure may represent or define said central air duct.

In one embodiment, the burner tip has an inlet region. Preferably, both the air channel and the fuel channel extend coaxially in the inlet region. In other words, air duct structure and fuel channel structure are formed accordingly.

In one embodiment, the fuel channel extends in the inlet region radially outside the air channel. In other words, the fuel channel structure and the air duct structure can be designed accordingly. In one embodiment, the burner tip has a discharge region which is preferably offset along an axis of symmetry (axially). Expediently, the outlet region, from which preferably both an air and a fuel flow can escape, comprises the described surface or the surface region.

In one embodiment, the fuel channel extends in the outlet region at least partially radially within the air channel.

In one embodiment, the fuel channel and the air channel extend nested, entangled or intertwined in order to additionally cool the surface region of the burner tip by an air flow, and not exclusively by a flow of fuel. However, the fuel channel and air channel preferably extend without fluid communication with each other. Alternatively, the air channel and the fuel channel can communicate at least partially fluidly with one another.

In one embodiment, the burner tip is at least largely rotationally symmetrical about the described axis of symmetry.

In one embodiment, the air duct and / or fuel channel extend at least partially along a circumferential direction or tangential direction of the burner tip. In one embodiment, the fuel channel structure, preferably in the outlet region, lamellae, which divide the fuel channel - at least in sections - in a plurality of sub-channels. As a result, it is also advantageously possible to optimize a cooling effect during operation of the burner tip by means of improved heat transfer. The said fins can - as well as other parts of the fuel channel structure or the burner tip - arbitrary shapes have, which may be realized only by additive manufacturing technology under certain circumstances.

In one embodiment, the fuel channel structure forms an annular chamber in the inlet region.

In one embodiment, the fuel channel structure is shaped such that the fuel channel extends along the second direction and before its mouth into the surface through the annular chamber after its course.

In one embodiment, the fuel channel structure has a plurality of fuel channels in the outlet region, which lead via the surface into the combustion chamber or open into said surface. By virtue of this embodiment, an improved and / or more homogeneous cooling of the surface can advantageously be achieved.

In one embodiment, the air duct extends at least partially through the fuel channel, or vice versa. With this configuration, a particularly compact and expedient design of the burner tip can be realized.

In one embodiment, the air duct structure has a multiplicity of air ducts which, for example, open into the surface or lead into the combustion chamber at different exit angles relative to the surface or a surface normal. As a result of this embodiment, an efficient surface or film cooling of the surface can be achieved particularly advantageously.

In one embodiment, the air channel structure and / or the fuel channel structure define channel cross sections which have a cross-sectional shape deviating from a round, in particular circular shape, for example an elliptical or star-shaped cross-sectional shape. With this configuration, advantageously, a heat transfer from the surface to a fuel or to an air flow during operation of the burner tip by a - in the United States equal to a circular cross-section - increased cross-sectional area can be improved and / or optimized.

In one embodiment, the surface is formed by an open-wall wall or wall structure of the burner tip, which defines a plurality of air channels by their porosity. According to this embodiment, therefore, the surface area can be flowed through particularly homogeneously by cooling air in order to effect effective cooling during operation of the burner tip.

In one embodiment, the burner tip is additive or produced by an additive manufacturing process. In one embodiment, the burner tip is made in one piece or in one piece.

Another aspect of the present invention relates to a turbomachine, for example a gas turbine, comprising the described burner tip.

A further aspect of the present invention relates to a method for producing the burner tip, wherein the burner tip is produced in particular as an additive and / or in one piece or can be produced.

Embodiments, features and / or advantages relating in the present case to the burner tip or the turbomachine may also relate to the method or vice versa.

Further details of the invention are described below with reference to the figures.

Figure 1 shows a schematic sectional view of a burner, in which an embodiment of the burner tip according to the invention is installed. FIG. 2 shows a schematic sectional view of a burner tip in an embodiment according to the invention.

FIG. 3 shows a schematic sectional view of a part of the burner tip according to an embodiment of the invention.

FIG. 4 shows a schematic sectional view of a burner tip in a further embodiment according to the invention.

FIG. 5 shows a schematic sectional view of a part of the burner tip according to a further embodiment of the invention.

FIG. 6 shows a schematic sectional view

Embodiment of the method according to the invention.

In the exemplary embodiments and figures, identical or identically acting elements can each be provided with the same reference numerals. The illustrated elements and their proportions with each other are basically not to be regarded as true to scale, but individual elements, for better presentation and / or for better understanding exaggerated thick or large dimensions, be represented.

FIG. 1 shows a burner 11 which has a jacket

12, in which a main channel 13 is formed for air. The jacket 12 is symmetrical about a longitudinal and / or symmetry axis 14 and has in the center of the main channel

13 on a burner lance 15. The burner lance 15 is fixed with webs 16 in the main channel 13. In addition, extending between the burner lance 15 and the shell 12 vanes 17, which impose a twist on the air around the symmetry axis 14, as the indicated air arrows 18 can be seen. The burner lance 15 has a burner tip 19 at the downstream end, which is supplied with air via a central air channel 20 and with a fuel 23 via an annular channel 22 arranged around the air channel 20.

The fuel 23 may be gaseous or liquid. In particular, the fuel may be natural gas, a hydrogen-containing gas or fluid, or another fuel.

The air (see air flow or air duct 20) and the fuel 23 is expelled through openings, not shown in the burner tip and so the air flow from the

Main channel 13 mixed. The air 21 usually cools the burner tip 19 (see below). The burner 11 follows the operating principle of a pilot burner. This can for example be installed in a combustion chamber BR, for example a gas turbine, wherein the combustion chamber BR forms an environment 30 of the burner tip 19 in this case.

FIG. 2 shows a schematic sectional view of a burner tip 19, as described above. In particular, a section along the axis of symmetry 14 is shown. The symmetry axis 14 can likewise mean a rotational symmetry of the burner tip 19.

The burner tip 19 has an inlet region EB. Furthermore, the burner tip 19 on a Austrittsberei AB. The outlet region AB adjoins the inlet region EB along the axis of symmetry 14, or is arranged axially offset from the inlet region EB.

The air channel 20 leads to an outlet opening 24 of the burner tip 19. In this air channel can be housed in operation another burner lance (see below). During operation of the burner tip 19, for example in use in a gas turbine, the burner tip 19 is traversed by air, in particular compressor air, in the air channel 20, in that air enters the air channel 20 in the inlet region EB and leaves it again in the outlet region AB. The air channel 20 is defined by an air channel structure 21.

An air flow is indicated in the operation of the burner tip 19 in Figure 2 by the dashed arrows in the air channel 20.

The burner tip 19 furthermore has a fuel channel structure 32. The fuel channel structure 32 defines a fuel channel 33. A fuel stream is in operation of the burner tip 19 in FIG

2 indicated by the solid arrows in the fuel channel 33.

The fuel channel 33 is arranged radially outside of the air channel 20, so that - during operation of the burner tip 19 - a

Fuel 23 (along the air flow direction) can be guided radially outside the described air flow.

The fuel channel structure 32 may include or define an outer wall 28 of the burner tip 19.

The air channel structure 21 may include or define an inner wall 29 of the burner tip 19. The burner tip 19 or the air channel structure 21 is preferably designed such that the air channel 20 tapers from the inlet region EB into the outlet region AB. After a corresponding conical or tapering course, the air channel structure 21 again defines the air channel 20 parallel to the axis of symmetry 14.

In the figures, in particular FIGS. 2 and 4, no further components are shown in the central air duct 20 for the sake of clarity. In use of the burner nerspitze 19, for example, in operation of a burner tip having corresponding gas turbine (not explicitly marked), expediently further components in this central region of the burner tip 19 are arranged, for example, more ignition and / or oil lances. The components mentioned are essential for the function of the burner 11 and preferably at the same time seal off the central air duct in such a way that an air gap is formed which, during operation of the burner tip, causes a suitable cooling effect of said components and / or the burner tip.

It can also be seen in FIG. 2 that the outer wall also tapers in the exit region AB or extends to the centrally arranged symmetry axis 14. In the outlet region AB, the fuel channel structure 32 is now designed such that the fuel channel 33 initially extends parallel to an outer surface OF of the burner tip 19 or runs parallel to the surface OF. In particular, during operation of the burner tip 19, a fuel stream runs along a first direction 1R parallel to the surface OF.

A surface area which has the surface OF is characterized in this case by the reference symbol OFB. In particular, precisely this surface area OFB, preferably in the exit area AB of the burner tip 19, should be effectively cooled by a fuel 23 guided through the fuel channel structure 32 during operation of the burner tip 19.

After the fuel (compare arrows drawn in the fuel passage 33) runs a certain length along the first direction parallel to the surface OF, the fuel channel is deflected by the geometry of the fuel channel structure 32 along a second direction, so that it is at least partially opposite to the the first direction is retracted or deflected to then leave the surface area OFB of the burner tip 19. In other words, by deflecting the fuel channel in the surface area OFB, it can be efficiently cooled by a fuel during operation of the burner tip 19, since the fuel is initially guided close to the surface in the interior of the component, then deflected, and later - possibly through passed through itself - at a plurality of provided fuel outlets (not explicitly marked in the figures) can be discharged into the combustion chamber BR (see Figure 3 below). Accordingly, the profile of the fuel channel 33 or the geometry of the fuel channel structure 32 may correspond to or resemble the design of a so-called "small bottle." The first direction may describe a direction at least partially or proportionately along the symmetry axis (in the flow direction) or along a corresponding main flow direction The second direction preferably designates a direction which is different, preferably exactly opposite, to the first direction, Preferably, the fuel channel 33 is deflected from the first direction to the second direction in such a way that it follows its course parallel to the first direction In this way, even deeper structures of the surface area can be effectively cooled.

The second direction may also describe a direction parallel to the surface, but preferably opposite to a main flow direction. The second direction may alternatively or additionally continue to run at 90 ° or at some other angle inclined to the first direction.

The burner tip 19 may, based on its axis of symmetry 14, be rotationally symmetrical or approximately rotationally symmetrical. Accordingly, the second direction may be along a circumferential direction of the burner tip 19, for example. Along the circumferential direction (not explicitly marked in the figures), the burner tip 19 in the outlet region AB correspondingly have a plurality of fuel channels 33 which - for example circumferentially arranged equidistantly - over the surface OF in the combustion chamber BR lead (see Figure 3 below). The positions of the fuel outlets correspondingly formed by the mouth of the fuel channels 33 into the surface OF may correspond to a conventional burner tip design.

By virtue of said deflection or retraction, for example by an angle between 160 and 220 ° C., preferably by approximately 180 °, a cooling effect of the surface area OFB can advantageously be relatively cold due to the compressor air used for cooling Fuel, to be improved. In other words, not necessarily compressed air must be taken to cool the component outer surface, but it can be the much cooler fuel gas (about 50 ° C instead of 400 ° C for conventionally used compressed compressed air from the compressor part of a gas turbine (not explicitly shown)) directly be guided under the component surface for cooling in the surface area OFB along.

After the retraction, the fuel channel 33 preferably undergoes a further deflection, for example a deflection between 70 and 110 °, so that it can then open into the surface OF or leave it in the direction of the combustion chamber BR. In other words, the

Fuel is held or collected by the geometry of the fuel channel structure 32 for an improved cooling effect in the surface area OFB, and can then again emerge at a certain exit angle into the combustion chamber BR and burned.

Preferably, the described burner tip 19 is produced by an additive manufacturing process, preferably selective laser Melting (SLM) or electron beam melting (EBM). The additive manufacturing makes it possible in particular to produce components with integrated functions. In particular, it is possible to produce the described burner tip 19 with the described complexity of its channel structures in one piece and without conventionally required heat shields via additive means.

Since the burner tip 19 only has to conduct a single fluid for cooling purposes, under certain circumstances less connections may be required with advantage, as a result of which the manufacture and function of the component can be simplified.

FIG. 2 also shows a region B, in which the fuel channel 33 has an enlarged cross section. This configuration advantageously allows a larger volume of fuel 23 to be "collected" in area B to effect a convenient cooling effect Figure 3 shows a cross-sectional view of a burner tip 19, preferably cut in the surface area OFB (see Figure 2). The outer fuel openings identified by the reference numeral 34 define the shape of the fuel channel 33 (see FIG. 2).

The arrows drawn in FIG. 3 again indicate the course of the fuel channel 33 or of the fuel 23. In particular, - indicated by the arrows - a plurality of fuel channels, in particular distributed over a circumference of the burner tip 19, shown, which are preferably provided, but not visible in the figures 2 and 4. In other words, the fuel channel 33, preferably circumferentially, is divided by one or more fins 39 into a plurality of individual part fuel channels. These plurality of fuel channels or the partial channels indicated by the reference numeral 34 are preferably circumferentially spaced apart (by the fins 39). The partial channels 34 unite - as shown in Figure 3 - extending radially inwardly preferably in a single fuel channel 33 of the burner tip 19. In this way, in the operation of the burner tip 19 continues to advantage with a heat transfer from the structure of the burner tip to a through the fuel channel 33 guided Brennstoffström, and thus the cooling of the burner tip can be improved.

The described geometry of the lamellae can not be realized, in particular, by conventional production methods, and is therefore produced additively and preferably in one piece according to the described teaching, for example by selective laser melting. By way of example, FIG. 3 shows fuel channels 34 or openings with rectangular cross sections. Alternatively, however, other cross-sectional shapes can be used, for example elliptical or star-shaped cross sections, in order to achieve an improved cooling effect through an enlarged surface and thus improved heat exchange during operation of the burner tip 19.

The fuel channel structure 32 can furthermore, in particular in accordance with a rotationally symmetrical design of the burner tip 19, have a (complex-shaped) about its axis of symmetry.

Form ring chamber. The fuel channel structure 32 is furthermore preferably shaped in such a way that the fuel channel 33, after its course along the second direction 2R and before its mouth into the surface OF, extends in the exit region AB through the annular chamber (compare the arrows indicating the fuel 23 in FIG. 2).

In particular, the course of the arrows in FIG. 3 represents precisely the deflection of the fuel in the fuel channel 33 caused by the geometry of the fuel channel structure 32 in order to be able to effectively cool the surface area OFB of the burner tip 19 during operation thereof. Figure 4 shows a sectional view (longitudinal section) of an alternative embodiment of a burner tip according to the invention. In contrast to FIG. 2, the fuel channel 33 runs at least partially radially inside the air channel 20 in the outlet region AB. Furthermore, the fuel channel 33 and the air channel 20 are at least partially interlaced, in order additionally to cool the surface region OFB of the burner tip 19 by an air flow. which results in a further improved cooling effect.

The air channel structure 21 has, in the inlet region EB, openings 25 in the side wall which fluidly connect the (central) air channel 20 with an annular space annularly surrounding the air channel or a plurality of individual air channels.

The individual air ducts 20 mentioned, according to the embodiment of the air duct structure 21, preferably at least partially intersect the course of the fuel duct structure 33.

According to the representation of FIG. 4, said air ducts can furthermore lead into the combustion chamber BR at different exit angles, for example exit angles between 60 ° and 120 ° relative to the surface OF or a corresponding surface normal. The mentioned exit angle of the

For example, fuel channels 33 may vary along the symmetry axis of the burner tip 19. With decreasing exit angles (for example less than 90 °), film cooling on the surface OF of the burner tip 19 can be made stronger or weaker.

Furthermore, the air channel structure 21 and the fuel channel structure 32 can define channel cross sections which have a cross-sectional shape deviating from a round, in particular circular, shape. In particular, the mentioned channel structures can be star-shaped and / or elliptical. All these geometries can be produced in a simple manner with the described additive manufacturing method and thus permit the use of the inventive advantages of the present invention.

In a further embodiment, the surface OF may be formed by an open-porous wall structure (not explicitly marked) that defines a plurality of air channels 20. This geometry can also advantageously be realized by additive manufacturing technology and contribute to improved cooling of the burner tip during operation.

FIG. 5 shows-analogously to the representation of FIG. 3 -a cross-sectional view of the burner tip (cut perpendicular to the axis of symmetry) according to the embodiment of the burner tip described in FIG. In contrast to the representation of FIG. 3, it can be seen in FIG. 5 that additional circular air openings 35 are provided which bring about the cooling effect for the burner tip 19 by air cooling (in addition to the fuel cooling) (compare FIG. The dashed arrows spring from the openings 35 and are intended to indicate an air flow, while the solid arrows - analogous to the representation of Figure 3 - indicate the deflection of the fuel flow according to the present invention.

FIG. 6 shows a detail of how a component 19 according to FIG. 2 or FIG. 4 can be produced by laser melting with a laser beam 37. Shown is the section of a powder bed 36, in which a part of the air duct structure 21 and / or the fuel channel structure 32 is produced. The fuel channel structure 32 is embodied, for example, analogously to the representation of FIG. 2 and preferably has inter alia the lamellae described above (not shown in FIG. 6) and likewise defines the inventive deflection of the fuel channel.

After the finished structure has been fabricated, the powder 36 must be removed from the respective cavities containing the air chamber. nal- or form the fuel channel system or the corresponding channel structures are removed. This can be done for example by suction, shaking or blowing. The invention is not limited by the description based on the embodiments of these, but includes each new feature and any combination of features. This includes in particular any combination of features in the patent claims, even if this feature or this combination itself is not explicitly stated in the patent claims or exemplary embodiments.

Claims

claims

A burner tip (19) for installation in a burner (11), the burner tip (19) defining a surface (OF) facing a combustion chamber (BR) and defining an air channel (20) leading to the surface (OF) Air duct structure (21) and a fuel channel (32) leading to the surface (OF), and wherein the fuel channel structure (32) defines a fuel channel (33) which in a surface area (OFB) of the burner tip (19) along a first direction parallel to the surface (OF) and then in the surface area (OFB) along a second, from the first direction (1R) different direction (2R) at least partially back to the surface area (OFB) of the burner tip

(19) to cool by a in the operation of the burner tip (19) through the fuel passage (33) flowing fuel.

2. burner tip (19) according to claim 1, wherein the

Starting from its course along the first direction (1R), the fuel channel (33) extends into an interior of the burner tip (19) and then opens into the surface (OF) via at least one further change in direction, for example a deflection between 70 ° and 110 ° ,

A burner tip (19) according to claim 1 or 2, wherein the first direction (1R) includes an angle between 160 ° and 200 ° relative to the second direction (1R). 4. burner tip (19) according to any one of the preceding claims, wherein the fuel channel (33) after its course along the first direction (1R) and before an orifice in the surface (OF) has a region (B) with an enlarged cross-section.

5. burner tip (19) according to any one of the preceding claims, wherein the air duct structure (21) has a central Luftka- Nal (20) which leads to a central outlet opening (24) in the burner tip (10).

6. burner tip (19) according to one of the preceding claims, wherein the burner tip (10) has an inlet region (EB), in which both the air duct (20) and the

Fuel channel (33) extend coaxially, and one along an axis of symmetry (14) offset from the inlet region (EB), an outlet region (AB).

7. burner tip (19) according to claim 6, wherein the fuel passage (33) in the inlet region (EB) radially outside of the air passage (20). 8. burner tip (19) according to claim 6 or 7, wherein the

Fuel passage (33) in the outlet region (AB) at least partially radially within the air passage (20).

9. Burner tip (19) according to any one of the preceding claims, wherein the fuel channel (33) and the air channel (20), interlaced to additionally cool the surface area (OFB) of the burner tip (BS) by an air flow. 10. burner tip (19) according to any one of the preceding claims, wherein the fuel passage structure (32) lamellae (39) which divide the fuel passage (33) into a plurality of sub-channels (34). 11. burner tip (19) according to any one of the preceding claims, wherein the fuel channel structure (32) in the inlet region (EB) defines an annular chamber and wherein the fuel channel structure (32) is shaped such that the fuel channel (33) along its course along the second Direction (2R) and before its mouth into the surface (OF) by the annular chamber runs.

12. A burner tip (19) according to any one of the preceding claims, wherein the air passage (20) at least partially through the fuel passage (33) passes therethrough, and wherein the air passage structure (21) has a plurality of air passages (20), which at different exit angles relative to the surface (OF) into the combustion chamber (BR) lead.

13. Burner tip (19) according to any one of the preceding claims, wherein the air channel structure (21) and the Brennstoffka- nalstruktur (32) channel cross-sections define which have a different from a round, in particular circular shape cross-sectional shape.

A burner tip (19) according to any one of the preceding claims, wherein the surface (OF) is formed by an open porous wall structure (40) defining a plurality of air channels (20).

15. Burner tip (19) according to any one of the preceding claims, wherein the burner tip (19) is produced additively in one piece.

16. A gas turbine, comprising a burner tip (19) according to one of the preceding claims.

17. A method for producing a burner tip (19) according to any one of the preceding claims, wherein the burner tip (19) is produced additively in one piece.