EP3087323B1 - Fuel nozzle, burner having such a fuel nozzle, and gas turbine having such a burner - Google Patents

Description

The invention relates to a burner with a premixing chamber and with a fuel nozzle for two fuels. Furthermore, the invention relates to a gas turbine with such a burner. Furthermore, the invention relates to a fuel nozzle for two fuels.

In gas turbines, a burner is typically provided with a premixing chamber in which a particular gaseous fuel is mixed with air to subsequently burn the resulting mixture. The efficiency of the gas turbine and the formation of undesirable emission products, in particular nitrogen oxides are essentially dependent on the mixing of the fuel with the air.

In particular, in a natural gas-powered gas turbine, the natural gas is often injected in the radial direction, that is perpendicular to the flow direction of the air (so-called jet-in-crossflow method). As a result, a suitable mixing of natural gas and air can be achieved.

For mixing are furthermore, for example, from the DE 44 26 351 A1 so-called vortex generators known. There, a combustion chamber is disclosed, which consists essentially of a first and downstream in the flow direction second stage. In this case, the first stage on the head side a mixer for forming a fuel / air mixture and the outflow side of the mixer vortex generators are available. These serve, in particular, for the twisting of hot air, which is then conducted into a premixing zone for mixing with fuel and subsequently into a combustion zone of the second stage.

The US 2002/014078 discloses, for example, a burner with a fuel lance with radially aligned fuel openings and tangentially, ie, circumferentially aligned outlet openings, between which a swirl device for directional twisting of the flow is arranged.

Also the US 5,435,126 A discloses a burner with radial and tangential fuel injection.

In addition, it is known to operate gas turbines with multiple fuels, such as natural gas and hydrogen. The operation can be done either simultaneously with multiple fuels or only with one of the fuels. As a result, in particular the flexibility of the gas turbine is increased, since fuels can be used depending on availability. However, due to the different operating modes, additional requirements are imposed on the gas turbine and its burners.

When using or adding hydrogen, however, there is an increased risk of flashback and auto-ignition compared to the mere use of natural gas. To reduce this risk, it is possible to add a less reactive gas to the hydrogen to form a hydrogen-containing fuel gas, which, however, often has a disadvantageous lower energy density than natural gas. As a result, it is particularly necessary to use different volume flows for the different fuels in a suitable injection concept.

To further reduce the risk of flashback and auto-ignition, it is known to inject the hydrogen-containing fuel gas in the coaxial direction, that is to say in the direction of flow of the air. As a result, in particular an air-side pressure loss is reduced, which is greater when using hydrogen-containing fuel gas due to the larger volume flow than when using natural gas.

From the EP 2 604 919 A1 For example, a fuel nozzle for two fuels is known, comprising an inner tube with radially aligned outlet openings for a first fuel and with an outer tube surrounding the inner tube with axially aligned outlet openings for a second fuel. By means of such a nozzle, it is for example possible to inject a hydrogen-containing fuel gas in the flow direction of the air via the axial outlet openings. To improve the mixing of the fuel gas with the air In addition, a so-called Lobe mixer is provided. The second fuel, for example natural gas is then injected via the radial outlet openings. The disadvantage here is that there is no further optimization possibilities with respect to the mixing in particular of the natural gas and the air.

The object of the invention is to provide an improved burner which is particularly suitable for operation with multiple fuels. Furthermore, a mixture formation in the burner should be improved. Furthermore, a gas turbine to be specified with such a burner. In addition, an improved fuel nozzle is to be specified, which is particularly suitable for multiple fuels.

The object is achieved by a burner nozzle with the features of claim 1, a burner with the features of claim 2 and a gas turbine with the features of claim 11. Advantageous embodiments, developments and variants are the subject of the dependent claims.

For this purpose, it is provided that a burner comprises a plurality of premixing chambers each having a fuel nozzle for two fuels, wherein the fuel nozzle has a extending in a flow direction fuel lance, in which a number of first outlet openings for a first fuel is introduced, and the fuel lance of an outer tube is surrounded, with at least a second outlet opening for a second fuel, the first outlet openings are radially aligned and the second outlet opening axially, wherein between the fuel lance and inside of the premixing chamber, a flow cross-section is formed and wherein a number of vortex generators is arranged on the fuel lance which reduce a flow cross section oriented transverse to the flow direction, wherein at least one vortex generator upstream of the first outlet openings and downstream of the second outlet opening is arranged and the premixing chamber has a cross section and an end and the distance of the first outlet openings from the end of the premixing chamber is at least three times as large as the cross section of the premixing chamber. In particular, the premixing chamber has an air inflow channel in which the fuel nozzle is arranged. Advantageously, air flows in the direction of flow, for mixing with the first and / or second fuel.

The air, the first fuel and the second fuel are hereinafter referred to generally as gases. The application is in principle but not limited to gaseous media. Furthermore, the application is not limited to the following gases, namely natural gas, hydrogen and air.

The fuel lance is advantageously used for the injection of natural gas, which is provided by means of the radial outlet openings for mixing. In this case, radial is understood to mean that the fuel lance extends in the direction of flow, that is to say axially, and radially has a jacket surface in which suitable, for example round, openings are made. As a result, in particular a so-called jet-in-crossflow mixture is realized, in which the fuel is flowed substantially perpendicular to the air.

The outlet openings are preferably distributed in a common position in the axial direction and uniformly in the circumferential direction of the fuel lance. Alternatively, however, another suitable arrangement is chosen. For example, outlet openings are arranged at several positions in the axial direction one behind the other.

Also in the flow direction, ie in the axial direction extends the outer tube surrounding the fuel lance. In this case, the outer tube surrounds the fuel lance in the axial direction preferably only partially, that is, the fuel lance is in the flow direction. This makes it possible, in particular, to arrange the radial outlet openings outside a region of the fuel lance covered by the outer tube, which in particular improves the mixing with air. Alternatively, however, the radial outlet openings are covered by the outer tube or there are both covered, as not covered outlet openings available.

The outer tube is preferably used for axial injection of the second fuel, for example hydrogen or a hydrogen-containing fuel gas. Due to the axial injection, it is in particular possible to inject a fuel by means of a larger volume flow compared to natural gas. Advantageously, furthermore, an air-side pressure loss, as may possibly occur in the case of radial injection, can be reduced or avoided altogether.

To improve a mixing of two or all of the gases with one another, at least one vortex generator is provided, that is to say arranged in the burner. By means of the vortex generator, the mixing can be achieved, in particular, by reducing a flow cross-section of at least one of the gases at at least one position along the flow direction.

For example, the air flows in the flow direction at a first position, a first surface, which is oriented transversely, that is substantially perpendicular to the flow direction. The first surface corresponds to the flow cross-section at the first position. For example, a vortex generator is now arranged at a second position downstream of the first position, which opposes the air with an additional blocking surface, whereby the second surface through which the air flows at the second position is smaller than the first surface. In other words, the flow area is smaller at the second position than at the first position. By way of example, the vortex generator is a surface which is set in relation to the flow direction. It points the vortex generator suitably has a contour, preferably at least one edge, for generating turbulence. These are used in particular for mixing the now swirled gas with a second gas. Expediently, this improves the mixing of the first and / or the second fuel with the air and / or the mixing of the fuels with one another. Overall, therefore, the arrangement of the vortex generator in a multi-fuel nozzle efficient mixing of the gases in operation due to the generated turbulence is achieved, regardless of the respective mode, which gas is currently used as fuel.

In the burner according to the invention at least one vortex generator is mounted on the fuel lance. In particular, when using the vortex generator for turbulence of the fuel injected by the fuel lance first fuel advantageously the vortex generator is adapted to the requirements of this fuel. When exchanging the first fuel and thus possibly changed requirements for mixing with air, it is thereby possible in particular to replace the turbulizer by exchanging the fuel lance at the same time.

Furthermore, in the burner according to the invention, at least one vortex generator is arranged upstream of the radial outlet openings and downstream of the axial outlet opening. This makes it possible, in particular, to achieve turbulence of the air and / or of the second fuel without the vortex generator directly influencing the flow of the first fuel. It is understood by direct influence that the respective vortex generator is affected by the gas influenced by this.

Finally, the premixing chamber of the burner according to the invention has a cross section and an end, wherein with a view to a good mixing of fuel and air, the distance of the first outlet openings from the end of the premixing chamber at least three times as large as the cross section of the premixing chamber. This ensures that the length of the route, on which fuel and air can mix, is sufficiently large.

In a preferred embodiment, the fuel lance and the outer tube are arranged concentrically. In particular, the fuel lance and the outer tube are designed substantially cylindrical and have a common longitudinal axis. The outer tube is preferably formed as a tube with an annular profile transverse to the longitudinal axis. Appropriately, the longitudinal axis extends in the flow direction. In particular, the second fuel and the air flow in each case in the flow direction. In other words, the air and the second fuel are flowed in or injected axially. In contrast, the first fuel is preferably injected radially.

In a suitable embodiment, at least one vortex generator is wedge-shaped. It is understood by wedge-shaped that the vortex generator has a surface which extends obliquely to the axial direction and in particular obliquely to the flow direction. For example, the surface is rectangular. Alternatively, the surface is triangular, with one side of the triangle extending transversely to the flow direction. The two remaining sides either run in or against the flow direction to a tip of the triangle. In particular, wedge-shaped is also understood to mean tetrahedral.

Instead of a wedge-shaped configuration, other geometric shapes are still suitable. Also, the vortex generator is possibly composed as a solid body or of different surface elements or formed in several parts. It is essential that by means of the vortex generator of the flow cross-section in the flow direction is adjustable, in particular to produce turbulence in the flow of the gas flowing the vortex generator. It will Under adjustable in particular understood that the exact design and orientation of the Wirbelträgers is determined during its manufacture and assembly.

In an advantageous embodiment, at least one turbulizer is attached to the outer tube. In this case, the vortex generator is either externally mounted on the outer tube, in particular for turbulence of the air flowing there suitably along, or inside the outer tube, for turbulence of the second fuel preferably flowing therealong.

In a further advantageous embodiment, the premixing chamber comprises an inner wall, on which at least one vortex generator is mounted. In this way, in particular, a turbulence substantially independent of the fuel nozzle can be achieved.

In a further advantageous embodiment, at least one vortex generator is arranged downstream of the radial outlet openings. In other words, at least one vortex generator is arranged downstream of any outlet openings, as a result of which this vortex generator influences in particular each of the inflowing gases, that is, in particular, swirls.

Several or all of the above-mentioned embodiments relating to the positioning of the vortex generators are combined in a further advantageous embodiment. As a result, in particular, the corresponding advantages are combined. For example, at least one vortex generator is arranged downstream of the axial outlet opening and upstream of the radial outlet openings and on the fuel lance. Alternatively or additionally, for example, a plurality of vortex generators are arranged in the axial direction at different positions on the fuel lance.

Furthermore, it is possible to advantageously arrange a plurality of vortex generators in groups, for example in series, in axial Direction one behind the other or offset; or in a plane, that is, in particular both side by side (for example, in the circumferential direction) and in succession. It is also possible that several vortex generators advantageously have different geometries and / or dimensions.

Preferably, a plurality of vortex generators are arranged at approximately the same position in the axial direction and along a circumferential direction with respect to the longitudinal axis. For example, a plurality of vortex generators are arranged on the circumference of the outer tube such that all lying in the direction of rotation between adjacent vortex generators distances are equal.

In particular, it is possible to favorably influence the pairwise turbulence of the various gases by suitable combination of a plurality of, in particular different vortex generators. For example, a number of vortex generators are mounted on the outer tube for entangling the air and for improved mixing with hydrogen injected axially downstream therefrom. To further optimize the turbulence of natural gas with air, for example, vortex generators are mounted downstream of the radial outlet openings.

In an advantageous development, the outer tube has an end region which is designed as a lobe mixer and comprises a number of lamellae. These extend in particular in the flow direction and as radially formed folds. This results transversely to the longitudinal axis, in particular a star-shaped cross section (or a star-shaped profile). In the circumferential direction, a gap is formed between each two slats through which in particular the flow cross-section of the air downstream is advantageously increased.

The lamellae each have a vertex in the radial direction, which extends substantially in the axial direction. This means in particular that the radial distance between vertex and longitudinal axis in the flow direction is substantially constant. In particular, the outer tube has an outer sheath and the vertexes of the lamellae are substantially aligned with the outer sheath. It is possible that a slight inclination or slope is provided in the axial direction.

A mixing of the second fuel with air is advantageously achieved in that it follows a flow in the flow direction, which breaks off at the end of the end region. In particular, the star-shaped cross section of the end region has at the end a contour line which is elongated with respect to the outer tube (and correspondingly star-shaped). This advantageously provides a larger edge in comparison to the circumference of the outer tube for stalling.

In a suitable development, the end region is twisted or twisted in such a way that the lamellae and thus also the apices extend in a spiral around the longitudinal axis. This makes it possible to additionally twist the air flowing along the lamellae and thus to achieve improved mixing.

In a further suitable development, a number of lamellae are additionally designed as vortex generators. For this purpose, these lamellae are in particular formed such that their vertices are formed as inclined in the axial direction surfaces. In other words, the distance from the apex of a lamella to the longitudinal axis changes in the direction of flow. Preferably, the distance in the flow direction is continuously increased. As a result, in particular an employed surface is provided with an edge in such a way that by means of this a turbulence in the manner of a vortex generator can be achieved.

In an advantageous development, at least one vortex generator is arranged in an intermediate space between two lamellae. The space mentioned here corresponds to the already mentioned above space between two adjacent in the direction of rotation of the outer tube fins. In particular, it is possible by this arrangement to produce vortex generators with comparatively large side surfaces, that is, in comparison to, for example, arranged on an annular tube without lobe mixer vortex generators. As a result, the turbulence can be advantageously influenced.

Conveniently, a combination of the vortex generators mentioned above with one of the above-mentioned concepts for the injection of the second fuel allows an improved mixture of the gases involved. Advantageously, the mixture is improved both with simultaneous injection of first and second fuel (for example natural gas and hydrogen) and in a single operation, that is to say when injecting only one fuel (for example natural gas or hydrogen).

Preferably, a gas turbine comprises a burner having one or more of the above features, thereby providing the above-mentioned advantages. In addition, such a gas turbine is in particular more efficient and advantageously has a lower emission of pollutants.

A fuel nozzle according to the invention for two fuels has a fuel lance extending in a flow direction. In this a number of first outlet openings for a first fuel is introduced. The fuel lance is surrounded by an outer tube with at least one second outlet opening for a second fuel, wherein the first outlet openings are radially aligned and the second outlet opening axially, wherein a number of vortex generators is arranged on the fuel lance. At least one vortex generator is arranged upstream of the first outlet openings and downstream of the second outlet opening.

FIG 1

in einer Seitenansicht einen Brenner mit einer Brennstoffdüse für zwei Brennstoffe und mehreren auf der Brennstoffdüse angebrachten Wirbelerzeugern,

FIG 2

den Brenner gemäß FIG 1 mit einer alternativen Brennstoffdüse und einer Vormischkammer, an der innenwändig mehrere Wirbelerzeuger angebracht sind,

FIG 3 bis 17

weitere Ausführungsbeispiele der Brennstoffdüse gemäß FIG 1, wobei die Brennstoffdüse in den Figuren 3, 6, 9, 12 und 15 jeweils in Seitenansicht dargestellt ist, in den Figuren 4, 7, 10, 13 und 16 jeweils in Vorderansicht und in den Figuren 5, 8, 11, 14 und 17 jeweils in einer perspektivischen An-sicht, und

FIG 18 bis 23

jeweils ein Ausführungsbeispiel eines Wirbelgenerators in einer perspektivischen Ansicht.

Embodiments of the invention will be explained in more detail with reference to a drawing. Show:

FIG. 1

in a side view of a burner with a fuel nozzle for two fuels and a plurality of attached to the fuel nozzle vortex generators,

FIG. 2

according to the burner FIG. 1 with an alternative fuel nozzle and a premixing chamber, on which internally several vortex generators are mounted,

FIGS. 3 to 17

Further embodiments of the fuel nozzle according to FIG. 1 , wherein the fuel nozzle is shown in Figures 3, 6, 9, 12 and 15 respectively in side view, in the FIGS. 4 . 7 . 10 . 13 and 16 each in front view and in the Figures 5 . 8th . 11 . 14 and 17 each in a perspective view, and

FIGS. 18 to 23

in each case an embodiment of a vortex generator in a perspective view.

A schematic representation of a burner 2, in particular for a gas turbine 4, respectively show the 1 and 2 , The burner 2 in this case comprises a premixing chamber 6, which is followed by a combustion chamber 8 in the flow direction S. In the exemplary embodiment shown here, two fuels and air are injected into the premixing chamber 6 during operation. For injecting the fuel is a fuel nozzle 10, which extends in the flow direction S. The air is flown in through a fuel inlet duct 12 surrounding the fuel nozzle 10 in the flow direction S.

The fuel nozzle 10 comprises a fuel lance 14 and an outer tube 16 surrounding it, the fuel lance 14 projecting in the flow direction S and with respect to the outer tube 16. The fuel lance 14 and the outer tube 16 are in The embodiment shown here is designed substantially cylindrical, that is, these have transversely to the flow direction S a circular or annular cross-section. In particular, the fuel lance 14 and the outer tube 16 are arranged concentrically and accordingly have a common longitudinal axis L, which extends in the flow direction S.

The fuel lance 14 has a number of radial outlet openings 18. These are circular in the embodiment shown here and arranged in a common position in the axial direction, ie in the flow direction S. In this case, the outlet openings 18 are distributed in a circumferential direction U and in particular uniformly. The radial outlet openings 18 are used in particular for the injection of the first fuel, for example natural gas.

The outer tube 16 has a larger diameter than the fuel lance 14, whereby in the axial direction a particular annular, axial outlet opening 20 is realized. By means of this, the second fuel is injected into the premixing chamber 6. That is, the second fuel in particular flows around the fuel lance 14.

In FIG. 1 is mounted on the fuel lance 14 a number of vortex generators 22. These are arranged downstream of the axial outlet opening 20 and upstream of the radial outlet openings 18. The vortex generators 22 are of tetrahedral design in the exemplary embodiment shown here (cf. FIG. 20 ).

FIG. 1 shows that the premixing chamber 6 has a cross section 50 and an end 52 and the distance of the first outlet openings 18 from the end 52 of the premixing chamber 6 is at least three times as large as the cross section 50 of the premixing chamber 6.

In an alternative or additional embodiment according to FIG. 2 are the vortex generators 22 according to FIG. 1 attached internally to the premixing chamber 6. In this case, the vortex generators 22 are arranged at a position downstream of the radial outlet openings.

In both in the 1 and 2 illustrated embodiments, the vortex generators 22 each have a respect to the flow direction S salaried surface 24, which is triangular here and counter to the flow direction S to the longitudinal axis L tapers. This arrangement is also referred to as forward directed. In an alternative, not shown embodiment, however, the vortex generators 22 are directed backwards, that is rotated by 180 ° such that the surface 24 in the flow direction S to the longitudinal axis L tapers.

In particular, in each case two edges 26 are formed by the surface 24, on which in particular a turbulence is generated during operation. In addition, in particular by the premixing chamber 6 and the elements arranged therein as well as transversely to the flow direction S, a flow cross-section Q is defined, which is changed by the vortex generators 22 in the flow direction S. For example, in FIG. 1 the flow cross-section Q is defined at a first position P1 by the premixing chamber 6 and the fuel lance 14. At this first position P1, the flow cross-section Q is in particular greater than at a second position P2 at which the vortex generators 22 are arranged in the exemplary embodiment shown here. Advantageously, it is possible by suitable design of the vortex generator 22 to adjust the flow cross-section Q and thus to influence in particular the mixing of the gases suitable.

The FIGS. 3 to 17 schematically show further embodiments of a fuel nozzle 14. This show the FIG. 3 . 6 . 9 . 12 and 15 each of the fuel nozzle 14 in a side view and to each of the gases clarified by arrows Inlet direction 28, 30, 32. In this case, the first fuel in the inflow direction 28 is flowed in radially and the second fuel and the air are flowed axially in the inflow directions 30, 32. Due to the axial inflow, in particular the general flow direction S is predetermined in the premixing chamber 6, which also essentially follows the first fuel at a sufficient distance from the radial outlet openings 18.

The FIG. 4 . 7 . 10 . 13 and 16 each show the corresponding fuel lance 14 in front view, the FIG. 5 . 8th . 11 . 14 and 17 each show the corresponding fuel lance 14 in a perspective view.

The in the 3 to 5 illustrated embodiment of the fuel nozzle 10 includes a number of forward oriented tetrahedral vortex generators 22, which are mounted downstream of the axial outlet opening 20 and upstream of the radial outlet openings 18 on the fuel lance 14. In this case, the vortex generators 22 each have a height H which is selected here in such a way that the vortex generator 22 extends further in the radial direction than the outer tube 16. This is particularly evident in FIG FIG. 4 shown. As a result, it is possible, in particular, to supply the vortex generators 22 directly with air and to vortex them.

The FIGS. 6 to 8 show the fuel nozzle 10 with mounted on the outer tube 16 vortex generators 22. These are oriented here forward and are flown by the air flowing around the outer tube 16. By contrast, the fuel lance 14 has no vortex generators 22.

The FIGS. 9 to 11 show the fuel nozzle 10 with a designed as a lobe mixer end portion 34. For this purpose, a number of six blades 36 is formed in the end region 34 here. These give a star-shaped cross-section, such as out FIG. 10 becomes clear. FIG. 10 continues to show that the lamellae 36 do not substantially project beyond the outer tube 16 in the radial direction.

The lamellae 36 each have a vertex 38 extending in the axial direction and, in particular, are evenly spaced in the circumferential direction U by intermediate spaces 40. At the end 42 of the outer tube 16, the lamellae 36 form a star-shaped contour 44, by which in particular a number of outlet channels 46 is realized. The axial outlet opening 20 therefore comprises six outlet channels 46 in the exemplary embodiment shown here.

As the FIGS. 10 and 11 12, the vortex generators 22 mounted downstream of the fuel lance 14 may either follow or be offset from one of the exit channels 46 in the flow direction S. Of the four vortex generators 22 present here, for example, two vortex generators 22A are arranged in an imaginary extension of outlet channels 46 and two vortex generators 22B are arranged in an imaginary extension of intermediate spaces 40. By means of a particularly so designed mixed arrangement, it is possible to use the respective vortex generator 22 either primarily for swirling the air flowing through a gap 40 or primarily for swirling the flowing through an outlet channel 46 second fuel.

The FIGS. 12 to 14 show an embodiment in which the outer tube 16 of the fuel nozzle 10 in the end region 34 has a number of four fins 36 here, which are simultaneously designed as a vortex generator 22. The respective apex 38 of a lamella 36 is designed as an employed surface 24 and has two edges 26 delimiting the substantially triangular surface 24. These extend downstream of the longitudinal axis L away. The end region 34 has a number of outlet channels 46 for the second fuel corresponding to the number of vortex generators 22.

Furthermore, in the exemplary embodiment shown here, the radial outlet openings 18 are arranged substantially directly downstream of the outer tube 16. A respective radial outlet opening 18 is arranged either in an imaginary extension of an intermediate space 40 or in an imaginary extension of an outlet channel 46.

An alternative embodiment with both vortex generators 22 and fins 36 in the end region 34 of the outer tube 16 is in the FIGS. 15 to 17 shown. In each case, a vortex generator 22 is arranged in the intermediate space 40 between two adjacent lamellae 36. The vortex generators 22 are formed in the embodiment shown here to the end 42 of the outer tube 16, that is, in particular the vortex generators 22 are aligned in the radial direction with the end 42 of the outer tube 16. Contrary to those in the FIGS. 12 to 14 shown turbulators 22 have in the FIGS. 15 to 17 vortex generator 22 shown at the end no outlet channels 46.

The FIGS. 18 to 23 each show an embodiment of a vortex generator 22. In this case, the actual design is not limited to the embodiments shown here.

The FIGS. 18 and 19 each show one with respect to a flow direction S employed triangular or rectangular surface 24. Die FIG. 20 and 21 show similarly configured vortex generator 22, but these are formed here as a solid body and have corresponding side surfaces 48. In contrast, those in the FIGS. 22 and 23 shown turbulators 22 each have two, in particular separately manufactured side surfaces 48, which are employed with respect to the flow direction S. In the FIGS. 18 to 23 the vortex generators 22 are respectively oriented forward with respect to the flow direction S. Alternatively, however, the vortex generators 22 are oriented backwards, that is, rotated by 180 ° with respect to the flow direction S (the arrow indicating the flow direction S in FIG the FIGS. 18 to 23 then points in the opposite direction).

Claims (11)

1. Burner nozzle (10) for two fuels, wherein the fuel nozzle (10) has a fuel lance (14) extending in a direction of flow (S) into which a number of first outlet orifices (18) for a first fuel are introduced, and the fuel lance (14) is surrounded by an outer pipe (16) with at least one second outlet orifice (20) for a second fuel, wherein the first outlet orifices (18) are oriented radially and the second outlet orifice (20) is oriented axially, wherein a number of vortex generators (22) are arranged on the fuel lance (14),
   characterized in that at least one vortex generator (22) is arranged upstream of the first outlet orifices (18) and downstream of the second outlet orifice (20).
2. Burner (2) having a plurality of premixing chambers (6) each with a fuel nozzle (10) according to Claim 1, wherein a flow cross section (Q) is formed between the fuel lance (14) and the inside of the premixing chamber (6) and wherein the vortex generators (22) arranged on the fuel lance (14) reduce the flow cross section (Q) oriented transversely of the direction of flow (S),
   characterized in that the premixing chamber (6) has a cross section (50) and an end (52) and the distance between the first outlet orifices (18) and the end (52) of the premixing chamber (6) is at least three times as great as the cross section (50) of the premixing chamber (6).
3. Burner (2) according to Claim 2,
   characterized in that the fuel lance (14) and the outer pipe (16) are arranged concentrically.
4. Burner (2) according to one Claims 2 and 3,
   characterized in that at least one vortex generator (22) is of wedge-shaped configuration.
5. Burner (2) according to one of Claims 2 to 4,
   characterized in that at least one vortex generator (22) is mounted on the outer pipe (16).
6. Burner (2) according to one of Claims 2 to 5,
   characterized in that at least one vortex generator (22) is arranged downstream of the radial outlet orifices (18).
7. Burner (2) according to one of Claims 2 to 6,
   characterized in that at least one vortex generator (22) is mounted on the internal walls of the premixing chamber (6).
8. Burner (2) according to one of Claims 2 to 7,
   characterized in that the outer pipe (16) comprises an end region (34) which is configured as a lobe mixer and comprises a number of lobes (36).
9. Burner (2) according to the preceding claim,
   characterized in that a number of lobes (36) are configured as vortex generators (22).
10. Burner (2) according to one of the two preceding claims,
    characterized in that at least one vortex generator (22) is arranged in an interspace (40) between two lobes (36).
11. Gas turbine (4) having a burner (2) according to one of Claims 2 to 10.

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