Mixing tube, and burner having such a mixing tube

Abstract

The invention relates to a mixing device (31) for use in a burner (21), comprising a connecting element (04) which extends centrally along a central axis, a supporting wall (36) which surrounds the connecting element (04), an outer flow channel (18) which is located between the connecting element (04) and the supporting wall (36), and a plurality of outer swirl vanes (08) which are distributed about the central axis, are connected to the supporting wall (36), and which (08) have an upstream leading edge (14) and a downstream trailing edge (15) which is offset in the circumferential direction. At least a plurality of the outer swirl vanes (08) have fuel nozzles (19) on the respective trailing edge (15) and fuel channels (10a, 10b) leading from a feed opening to the fuel nozzles (19), the supporting wall (36) having a spherical shape on the radially outwardly facing side and a plurality of flushing grooves (38, 39) distributed over the circumference.

Description

Description Mixing tube and burner with such a TECHNICAL DESCRIPTION

[0001] The invention relates to a mixing tube for use in a burner for mixing fuel in combustion air. H BACKGROUND

[0002] Gas turbine burners typically use mixing devices to mix the fuel with the combustion air before it is introduced into a combustion chamber. For this purpose, swirl vanes are arranged in a flow channel, causing turbulence in the flowing combustion air. At least a portion of the fuel is injected into the combustion air at the upstream edge of the swirl vanes.

[0003] A typical design for such a mixing device is disclosed in EP 2233836 B1. The mixing device comprises a central fuel distribution element from which swirl vanes extend radially. Near the leading edge of the swirl vanes, in the area of ​​greatest thickness, radial fuel channels traverse the swirl vanes.

[0004] Directly adjacent to the fuel channels, the swirl vanes contain a number of outlet openings from which the fuel is injected into the combustion air. According to current knowledge, this type of injection is advantageous for achieving the best possible mixture of the fuel in the combustion air.

[0005] Furthermore, the swirl vanes are often arranged in a flow channel, whereby in some embodiments they are mounted displaceably in the flow channel. This leads directly to the problem of unfavorable flow at the radially outer and downstream end of the swirl vanes adjacent to the flow channel.

[0006] On the one hand, designs are known in which the swirl vanes are designed to be free-standing radially outward. However, the remaining gap between the swirl vanes and the flow channel causes undesirable crossflows and eddies, impairing the mixing of the fuel in the combustion air.

[0007] On the other hand, there are designs in which the swirl vanes are connected to a surrounding ring. Consequently, there is no gap between the ring and the swirl vanes, which promotes uniform flow. However, this is disadvantageous if the ring is movably mounted in the flow channel, creating a different gap between the ring and the flow channel.

[0008] It would be obvious to provide a seal between the ring and the flow channel. However, this requires more assembly effort, and ensuring the seal's service life is not without its challenges. SUMMARY OF THE INVENTION

[0009] The object of the present invention is, on the one hand, to achieve the most homogeneous mixture of the fuel in the combustion air and, at the same time, to improve the flow properties of the mixing device.

[0010] The object is achieved by a mixing device according to the invention as defined in claim 1. A burner according to the invention with a corresponding mixing device is specified in claim 14. Advantageous embodiments are the subject of the dependent claims.

[0011] The mixing device comprises a central connecting element (04) and a surrounding support wall, between which an outer flow channel is arranged. The flow channel contains several outer swirl vanes distributed around the central axis. The outer swirl vanes have an upstream leading edge and a downstream circumferentially offset trailing edge.

[0012] Furthermore, it is provided that at least several of the outer swirl vanes have fuel channels leading from a supply opening to fuel nozzles. The fuel nozzles are arranged at the respective trailing edge of the respective outer swirl vane.

[0013] To optimize the flow and mixing without additional sealing, according to the invention several flushing grooves are arranged in the supporting wall, distributed around the circumference. DESCRIPTION OF THE INVENTION

[0014] A generic mixing device is designed for use in a burner. The type of burner is initially irrelevant. At the very least, its use is particularly suitable for a gas turbine burner. Preferably, a gaseous fuel is burned (at least partially).

[0015] The mixing device has a central axis, which is usually aligned parallel to the burner axis. A connecting element extends along the central axis. A supporting wall is arranged surrounding the connecting element. The free space between the connecting element and the supporting wall forms at least one outer flow channel through which combustion air can flow in a flow direction along the central axis during operation of the mixing device.

[0016] The outer flow channel contains several outer swirl vanes distributed around the circumference. The outer swirl vanes extend approximately radially along the center axis from a leading edge at the upstream end of the outer swirl vanes to a trailing edge at the downstream end of the outer swirl vanes. The outer swirl vanes are connected to the support wall.

[0017] Functionally, the outer swirl vanes are designed to generate a circumferential swirl as the combustion air flows past. To achieve this, the trailing edge is preferably positioned offset from the leading edge in the circumferential direction.

[0018] Furthermore, the fuel is supplied, as is typical, at least partially via at least some of the outer swirl vanes. For this purpose, the outer swirl vanes have fuel channels. These begin at a feed opening on the outer swirl vanes and end at fuel nozzles on the surface of the outer swirl vanes. The position of the feed opening is initially irrelevant, provided the fuel supply, its routing through the fuel channels, and its injection into the combustion air are ensured. Advantageous flow conditions without compromising the mixing of the fuel in the combustion air are achieved when the fuel nozzles are arranged at the trailing edge of the outer swirl vanes.

[0019] More preferably, each of the outer swirl vanes has corresponding fuel channels and fuel nozzles.

[0020] It is particularly advantageous to align the fuel nozzles in such a way that the injection occurs approximately in the direction of flow starting from the trailing edge.

[0021] To avoid clamping of the support wall in a mixing tube due to thermal expansion, a minimum clearance is usually provided - corresponding to the expected thermal expansion and the accuracy of the manufacturing.

[0022] According to the invention, the support wall is designed with a spherical outer surface. This simplifies the fit in a mixing sleeve, thus minimizing leakage. Furthermore, the spherical shape ensures a largely constant gap between the support wall and the mixing sleeve, even with slight deviations in the shape of the support wall compared to a mixing sleeve.

[0023] Advantageously, the largest diameter of a spherical support wall is located near the downstream side. Preferably, the distance from the largest diameter to the downstream end of the support wall is at least 0.1 times and at most 0.3 times the length of the support wall in the direction of the central axis.

[0024] An optimization with regard to a uniform flow and at the same time the mixing of the fuel in the passing combustion air can be achieved if, according to the invention, a plurality of flushing grooves are arranged distributed in the circumferential direction on the outer circumference of the supporting wall.

[0025] The purge grooves lead to a predictable flow between the support wall and the mixing tube, which in turn advantageously leads to a more uniform flow and a better mixing of the fuel in the combustion air.

[0026] It is advantageously provided that the central flushing grooves extend from an upstream side to a downstream side along the central axis, preferably in a straight line and / or parallel to the central axis.

[0027] In any case, it is particularly advantageous to arrange the central purge grooves with their downstream end, viewed in the circumferential direction, precisely at the location where the fuel nozzles of the outer swirl vanes are positioned. Thus, the end of each central purge groove is advantageously located in the same circumferential direction as the radially outer end of the outer swirl vane at the trailing edge. This promotes the mixing of the fuel with the combustion air, especially since the targeted leakage air is guided through the central purge grooves in the area of ​​the fuel injection position.

[0028] To stabilize the flow, it can also be advantageous to provide that an adjacent flushing groove is present in the support wall on both sides of a central flushing groove.

[0029] In this case, the two adjacent flushing grooves preferably run parallel to the middle flushing groove.

[0030] It is advantageous if the flushing grooves are open on the downstream side.

[0031] Furthermore, it is advantageous if the central flushing grooves extend over the entire length of the supporting wall and are thus open on both the upstream and downstream sides.

[0032] It can be provided that the adjacent flushing grooves do not start at the upstream end of the supporting wall, but at a slight distance, for example from a distance of 0.1 times the length of the supporting wall.

[0033] To avoid thermal stresses, some of the flushing grooves on the upstream side may also be designed to completely penetrate the supporting wall. In this case, these are preferably the central flushing grooves.

[0034] The homogeneity of the combustion air-fuel mixture is improved when an outer flow channel is separate from an inner flow channel. For this purpose, the advantageous mixing device further comprises a partition wall arranged between the connecting element and the supporting wall. Accordingly, the inner flow channel is located between the connecting element and the partition wall, and the outer flow channel is located between the partition wall and the supporting wall.

[0035] For this purpose, several inner swirl vanes are advantageously arranged in the inner flow channel, distributed around the circumference. The inner swirl vanes extend approximately radially along the central axis from a leading edge at the upstream end of the inner swirl vanes to a trailing edge at the downstream end of the inner swirl vanes. The inner swirl vanes are connected to the connecting element.

[0036] Thus, in the preferred embodiment, several inner swirl vanes are arranged circumferentially in the inner flow channel, and several outer swirl vanes are arranged circumferentially in the outer flow channel. The inner swirl vanes extend from the connecting element to the partition wall, and the outer swirl vanes extend from the partition wall to the supporting wall.

[0037] Functionally, the inner swirl vanes should also generate a circumferential swirl as the combustion air flows past. For this purpose, the trailing edge is preferably arranged offset in the circumferential direction from the leading edge.

[0038] Separating the combustion air flow into an inner flow channel and an outer flow channel is particularly advantageous when opposing swirl is generated in the flow of the inner flow channel and the outer flow channel. To achieve this, the circumferential offset of the trailing edge relative to the leading edge of the inner swirl vanes must be opposite to the offset of the outer swirl vanes.

[0039] Furthermore, the fuel supply is advantageously carried out at least partially via at least some of the inner swirl vanes. For this purpose, the inner swirl vanes have fuel channels. These begin at a supply opening on the inner swirl vanes and end at fuel nozzles on the surface of the inner swirl vanes.

[0040] The position of the supply opening and the position of the fuel nozzles are initially irrelevant, provided the fuel supply, its routing through the fuel channels, and its injection into the combustion air are ensured. Thus, the fuel supply preferably occurs at least partially via at least some of the inner swirl vanes and at least some of the outer swirl vanes.

[0041] More preferably, each of the inner swirl vanes has corresponding fuel channels and fuel nozzles.

[0042] An improvement in the flow conditions without compromising the mixing of the fuel in the combustion air is achieved when the fuel nozzles are arranged at the trailing edge of the inner swirl vanes.

[0043] It is particularly advantageous to align the fuel nozzles in such a way that the injection occurs approximately in the direction of flow starting from the trailing edge.

[0044] The fuel can be supplied to the fuel channels in the swirl vanes from the outside radially via the support wall. This means that the supply opening for the fuel channels of the outer swirl vanes is located in the support wall.

[0045] Particularly preferably, the fuel is supplied to the fuel channels from the radial inside. A fuel guide runs inside the connecting element, with the supply opening of the fuel channels of the inner swirl vanes being arranged on the connecting element.

[0046] To supply the fuel to the fuel channels of the outer swirl vanes, it can advantageously be provided that fuel channels first run through inner swirl vanes and continue in outer swirl vanes.

[0047] Conversely, it is possible to guide the fuel channels of the inner swirl vanes from the radial outside through the outer swirl vanes.

[0048] An opening of the fuel channels at the trailing edge could be achieved simply by extending the fuel channels to the trailing edge without geometric adjustment of the conventional swirl vanes. However, due to the low thickness of the swirl vanes at the trailing edge, this would result in the combustion air passing directly past the trailing edge at the end of such a fuel channel without any clearance.

[0049] In contrast, however, it is advantageous to provide a protective distance from the passing combustion air at the trailing edge surrounding the fuel nozzles. For this purpose, the respective swirl vane has a thickened portion in the area of ​​the fuel channels extending from the fuel nozzles.

[0050] The thickening can be provided on one side of the respective swirl vane. Preferably, a thickening is provided on both sides of the respective swirl vane.

[0051] The respective inner and outer swirl vanes exhibit varying thicknesses. The thickness is determined in the tangential direction and the circumferential direction, respectively. As with a typical blade shape, the thickness initially increases rapidly from the leading edge and then decreases continuously toward the trailing edge.

[0052] The thickening leads to a local increase in the thickness of the swirl vane. This is particularly relevant at the trailing edge in the area of ​​the fuel nozzle. Since the thickness directly at the trailing edge is difficult to determine – particularly depending on the shape of the trailing edge – a cross-section close to the trailing edge is considered to determine the thickening. For this purpose, a position is selected at which the distance to the fuel nozzle is equal to half the thickness of the swirl vane at the position of the thickening. This means that a sphere with a diameter corresponding to the thickness of the swirl vane at the thickening touches the surface of the swirl vane and the fuel nozzle on both sides.

[0053] The thickening in the area of ​​the fuel nozzles to achieve the desired distance between the fuel nozzle and the passing combustion air should not be too small to achieve the desired distance effect. To this end, the swirl vane at the thickening at the fuel nozzle has a thickness locally increased by at least a factor of 1.2 relative to the thickness of the swirl vane adjacent to the thickening. Particularly preferably, the increased thickness is at least 1.5 times the thickness adjacent to the thickening.

[0054] However, the thickening should not be too large, as otherwise the swirl vane would cause unnecessarily high air resistance. Therefore, it is advantageous if the increased thickness of the swirl vane at the thickening at the fuel nozzle is a maximum of three times the thickness adjacent to the thickening. Particularly preferably, the increased thickness is a maximum of three times the thickness adjacent to the thickening at the trailing edge.

[0055] The inner swirl vane, or - if present - the outer swirl vane, can be shaped differently at the trailing edge. On the one hand, it is possible to have it tapered adjacent to the fuel nozzles and the thickened portion. Alternatively, it is possible to provide a rounded trailing edge.

[0056] Preferably, the trailing edge of the inner swirl vane or, if present, the outer swirl vane forms a single plane. Particularly preferably, the trailing edge of the inner swirl vane and the outer swirl vane lie in a common plane. Furthermore, it can be provided that the partition wall and, if present, the supporting wall also end at the plane of the trailing edge.

[0057] Increased flexibility in fuel use is achieved when two different fuels can be supplied. This requires a fuel bore separate from the fuel guide. The fuel bore—which does not necessarily have to be circular and straight with a constant diameter—ends at fuel openings. Preferably, the fuel bore is also located within the connecting element.

[0058] The fuel openings are preferably located in the area of ​​the downstream end of the connecting element.

[0059] The advantageous fuel openings can be arranged in different ways. In a first variant, the connecting element has the fuel guide and the fuel bore in parallel. without any additional component, with the fuel openings located near the downstream end of the connecting element.

[0060] It is particularly preferred if a fuel lance is arranged within the connecting element. In this case, the fuel bore extends within the fuel lance, and the fuel openings are arranged near the downstream end of the fuel lance. In this case, the fuel guide is preferably arranged between the fuel lance and the connecting element.

[0061] In principle, it is possible to assemble the mixing device from various components, the connecting device, the dividing wall and the inner swirl vanes, if present, the supporting wall and the outer swirl vanes.

[0062] Particularly preferred is an integral design in which at least the connecting element, the support wall, and the swirl vanes are manufactured as a single piece. If present, the partition wall as well as the inner and outer swirl vanes form part of the single-piece design. An additive manufacturing process is particularly suitable for this.

[0063] The connecting element, the supporting wall, and—if present—the partition wall and—if present—the fuel lance are preferably formed as rotating bodies. Irrespective of this, a different shape is also possible.

[0064] The mixing device is preferably supplemented by a section for supplying the combustion air and a section for mixing the fuel in the combustion air. For this purpose, the mixing device particularly preferably has a mixing sleeve surrounding the arrangement of the connecting element, the partition wall, and—if present—the supporting wall.

[0065] The mixing sleeve is divided into a feed section arranged upstream of the swirl vanes, a guide section arranged in the area of ​​the swirl vanes, a Mixing section and a homogenization section arranged downstream of the connecting element and - if present - downstream of the fuel lance.

[0066] An air duct for supplying combustion air is arranged in the supply section. The connecting element for supplying fuel is preferably located centrally in the supply section.

[0067] The guide section houses the arrangement of swirl vanes and a support wall. The support wall can be designed as an integral part of the mixing sleeve, thus creating a one-piece design with the mixing tube.

[0068] Preferably, the support wall is mounted within the mixing sleeve in such a way that a relative axial displacement, for example for thermal compensation, is possible.

[0069] On the one hand, a fit can be used for this purpose so that - apart from a negligible leakage - there is no flow between the mixing sleeve and the supporting wall.

[0070] In an alternative design, a gap remains between the supporting wall and the mixing sleeve with a proportional flow of combustion air. SUMMARY OF THE CHARACTERS

[0071] The mixing device 01 serves to mix fuel with combustion air. Figures 1 to 4 show an exemplary embodiment of a mixing device 01.

[0072] In Figure 1, an example of a mixing device 01 is schematically sketched in section, wherein within a mixing sleeve 22 a division into an inner flow channel 17 and an outer flow channel 18 takes place.

[0073] Figure 2 shows an enlarged view of the exemplary Mixing device 01 from Fig. 1 in the area of ​​the flow channels 17, 18.

[0074] In Figure 3, a mixing device 31 according to the invention is sketched in perspective view.

[0075] Figure 4 shows a plan view against the flow direction of the arrangement from Fig. 3.

[0076] Figure 5 shows an example of a burner 21 in which a plurality of mixing devices 01 are used. DESCRIPTION OF THE FIGURES

[0077] The mixing device 01, sketched in Figure 1 as an example in a longitudinal section, has a feed section 23, a guide section 24, a mixing section 25, and a homogenization section 26. The mixing device 01 comprises a mixing sleeve 22 extending along a central axis over its entire length.

[0078] Within the mixing sleeve 22, in the area of ​​the supply section 23, there is an air duct 13 for supplying combustion air. Following this, the air flow divides in the area of ​​the guide section 24 into an inner flow duct 17 and an outer flow duct 18. After fuel is injected, it is mixed with the swirling combustion air in a subsequent mixing duct 16 in the area of ​​the mixing section 25. A favorable homogeneity of the mixture of combustion air and fuel can be achieved by the end of the homogenization section 26.

[0079] The proposed design can be seen in more detail in Figure 2. In this exemplary embodiment, a fuel lance 03 extending along the central axis is arranged centrally, with a fuel bore 11 located inside it. The downstream end of the fuel lance 03 tapers conically, with fuel openings 20 arranged in the conical section at the end of the fuel bore 11. so that fuel can be injected into the surrounding air flow.

[0080] The fuel lance 03 is centrally mounted on a connecting element 04, with a seal or fit between the fuel lance 03 and the connecting element 04 being provided near the downstream end of the connecting element 04. An annular fuel guide 12 extends between the fuel lance 03 and the connecting element 04. The air duct 13 in the supply section 23 is located in an annular manner between the connecting element 04 and the mixing sleeve 22.

[0081] An inner flow channel 17 surrounds the connecting element 04 in a ring shape. This 17 is delimited on the radially outer side by a sleeve-shaped partition 05. Arranged in the inner flow channel 17 are a plurality of inner swirl vanes 07, each extending approximately radially from the connecting element 04 to the partition 05. The inner swirl vanes 07 begin in the flow direction at a respective leading edge 14 and run to a respective associated trailing edge 15. The trailing edge 15 of the inner swirl vanes 07 is arranged offset counterclockwise to the leading edge 14.

[0082] An outer flow channel 18 surrounds the dividing wall 05 in a ring shape. This 18 is delimited on the radially outer side by a sleeve-shaped supporting wall 06. In the outer flow channel 18, a plurality of outer swirl vanes 08 are arranged analogously, each of which extends approximately radially from the dividing wall 05 to the supporting wall 06. The outer swirl vanes 08 begin in the flow direction at a respective leading edge 14 and run to a respective associated trailing edge 15. The trailing edge 15 of the outer swirl vanes 08 is arranged offset clockwise to the leading edge 14.

[0083] Fuel channels 10 run in the inner swirl vanes 07 and the outer swirl vanes 08, with radial fuel channels 10a extending from the fuel guide 12 near the leading edge radially into the inner swirl vanes 07 and the outer swirl vanes 08 and from these 10a starting axial fuel channels 10b along the central axis up to respective Fuel nozzles 19 on the trailing edge 15.

[0084] In this embodiment, it is provided that a slight gap remains between the support wall 06 and the mixing sleeve 22, so that a small part of the combustion air is guided through the gap from the air duct 13 into the mixing duct 16.

[0085] Figure 3 shows an example of an embodiment of the invention for a mixing device 31 in perspective view. Essentially, this embodiment largely corresponds to the example in Figures 1 and 24, except that there is no mixing sleeve.

[0086] The figure shows the arrangement of the inner flow channel 17, the outer flow channel 18 with the inner swirl vanes 07 and the outer swirl vanes 08, the relevant arrangement of the fuel nozzles 19 at the trailing edge 15, and the associated thickening 19 on both sides of the respective swirl vanes 07, 08. As can be seen, the inner swirl vanes generate a flow that is circumferentially opposite to that of the outer swirl vanes 08. The fuel injection from the fuel nozzles 19 is intended to occur approximately parallel to the central axis.

[0087] What is not immediately apparent from the illustration is that the position with the largest diameter 37 of the support wall 36 is located near the downstream end of the support wall 36.

[0088] Furthermore, the support wall 36 has a plurality of purge grooves 38, 39 distributed along the outer circumference. A central purge groove 38 is located in the circumferential direction at the location where the fuel nozzles 19 of the outer swirl vanes 08 are located.

[0089] Adjacent flushing grooves 39 run parallel to the central flushing groove 38 on both sides. In this example, the flushing grooves 38, 39 run parallel to the central axis, wherein it is further provided that the central flushing groove 38 penetrates the support wall 36 on the upstream side.

[0090] For this purpose, Figure 4 again sketches a cross-section through the arrangement transverse to the central axis at a position close to the trailing edge 15. The annular arrangement with the central fuel lance 03 with the fuel bore 11 running therein and the surrounding connecting element 04 can be seen. Below, outside the connecting element 04, there is the inner flow channel 17, which is delimited radially on the outside by the partition wall 05.

[0091] The outer flow channel 18 is located radially outside the partition wall 05, which in turn is bounded radially outward by the support wall 06. In the inner flow channel 17, there are inner swirl vanes 07 connecting the connecting element 04 to the partition wall 05, and in the outer flow channel 18, there are outer swirl vanes 08 connecting the partition wall 05 to the support wall 06.

[0092] As can also be seen, the fuel nozzles 09 are located at the trailing edge, with the thickness of the respective swirl vanes 07, 08 being increased at the fuel nozzles 09.

[0093] In Figure 5, an exemplary burner 21 is sketched in perspective in half section, wherein a plurality of mixing devices are arranged parallel to one another in the burner 21.

Claims

Patent claims 1 . Mixing device (31) for use in a burner (21) comprising - a connecting element (04) extending centrally along a central axis; and - a support wall (36) surrounding the connecting element (04); and - an outer flow channel (18) arranged between the connecting element (04) and the supporting wall (36); and - a plurality of outer swirl vanes (08) arranged distributed around the central axis and connected to the support wall (36), which (08) have an upstream leading edge (14) and a downstream trailing edge (15) offset in the circumferential direction; wherein at least a plurality of the outer swirl vanes (08) have fuel nozzles (19) on the respective trailing edge (15) and fuel channels (10a, 10b) leading from a supply opening to the fuel nozzles (19), characterized in that the support wall (36) has a spherical shape on the radially outward-facing side and a plurality of scavenging grooves (38, 39) arranged distributed around the circumference.

2. Mixing device (31) according to claim 1, wherein the flushing grooves (38, 39) extend from the upstream side to the downstream side; and / or wherein the flushing grooves (38, 39) run along the central axis; and / or wherein the flushing grooves (38, 39) run parallel to the central axis.

3. Mixing device (01) according to claim 1 or 2, wherein, viewed in the circumferential direction, a central flushing groove (38) is arranged at each outflow edge (15) of an associated outer swirl vane (08).

4. Mixing device (31) according to claim 3, wherein an adjacent flushing groove (39), in particular one extending parallel, is arranged on both sides of a respective central flushing groove (38).

5. Mixing device (31) according to one of claims 1 to 4, wherein the flushing grooves (38, 39) are open toward the downstream side; and / or wherein the central flushing groove (38) is open toward the upstream side; and / or wherein the adjacent flushing groove (39) begins at a distance from the upstream side.

6. Mixing device (31) according to one of claims 1 to 5, wherein at least some of the flushing grooves (38, 39), in particular the middle flushing grooves (38), each penetrate the support wall (06) in sections.

7. Mixing device (31) according to one of claims 1 to 6, comprising - a partition wall (05) arranged between the connecting element (04) and the supporting wall (06, 36); and - an inner flow channel (17) arranged between the connecting element (04) and the partition wall (05); and - inner swirl vanes (07) arranged in the inner flow channel (17).

8. Mixing device (31) according to claim 7, wherein the offset from the leading edge (14) to the trailing edge (15) in the circumferential direction is carried out in the inner swirl vanes (07) opposite to the outer swirl vanes (08).

9. Mixing device (31) according to one of claims 1 to 8, wherein the swirl vanes (07, 08) have, starting from the fuel nozzles (19), a thickening (09) on at least one side in sections along the fuel channels (10b).

10. Mixing device (01) according to one of claims 1 to 9, wherein a fuel supply (12) runs within the connecting element (04) and branches from there to the fuel channels (10a).

11. Mixing device (01) according to one of claims 1 to 10, wherein a fuel lance (03) is arranged in the connecting element (04), which (03) has fuel openings (20) at the downstream end and a fuel bore (11) leading to the fuel openings (20).

12. Mixing device (01) according to one of claims 1 to 11, comprising - a mixing sleeve (22) surrounding the support wall (06) and displaceable in the axial direction relative to the support wall (06).

13. Mixing device (01) according to claim 12, wherein the mixing sleeve (22) has a feed section (23) arranged upstream of the swirl vanes (07, 08) and a guide section (24) surrounding the support wall (06) and a conical mixing section (25) arranged downstream of the swirl vanes (07, 08) and a homogenization section (26) arranged downstream of the connecting element (04).

14. Burner (21), in particular of a gas turbine, comprising a plurality of mixing devices (01) arranged adjacent to one another according to one of the preceding claims.

Images