Burner with burner component having vortex generators

Abstract

The invention is about a burner component (11) for use in a flow channel (02) of a burner (01) of a gas turbine. A component wall (14) extends from a leading edge (12) to a trailing edge (13) and in a transverse direction cross the flow direction from a first wall end (15) to an opposite second wall end (16), wherein vortex generators (17, 18) are arranged on the component wall (14) near the leading edge (12) including a first main vortex generator (17a) at the side facing the first wall end (15) and a second main vortex generator (17b) next to first main vortex generator (17a) and an additional vortex generator (18). Fuel nozzles (19) are arranged downstream to each respective main vortex generator (17). To improve the mixing the additional vortex generator (18) is located between the first main vortex generator (17a) and the first wall end (15) and has a height above the component wall (14) less than the height of the first main vortex generator (17a) and is without a respective fuel nozzle.

Description

[0001] The invention is about a burner, in particular for a gas turbine, having a burner component.

[0002] The task of the burner component is to cause or tc enhance swirling of combustion air with fuel.

[0003] For favourable combustion with the aim of avoiding pollutants as far as possible, it is essential that homogeneous mixing of the fuel in the combustion air takes place before combustion of the fuel. In order to achieve this, various solutions are used in the state of the art. In many cases, these are based on creating a turbulence between the combustion air and the fuel. Although turbulence leads to resistance in the flow, it is generally not possible to achieve the required largely pollutant-free combustion without turbulence.

[0004] In order to mix the combustion air with the fuel, disturbance elements are generally arranged in the flow path to deflect the flow and cause swirling. In many cases, blade-like structures are used for this purpose.

[0005] It is further known to arrange disturbance contours on the surface along the flow path, which cause turbulence of the combustion air. For example, it is known to arrange so-called vortex generators on the wall of the flow channel, which project into the flow channel accordingly.

[0006] A burner according to the preamble of claim 1 is known from IT 2017 0006 1780 A1.

[0007] Regardless of the type of flow pattern and the design of the necessary means for homogeneous mixing of the combustion air with the fuel, it is important to keep the flow resistance as low as possible while still ensuring adequate mixing. It is therefore the task of the present invention to achieve improved mixing with the lowest possible resistance.

[0008] The task is solved by an embodiment of a burner according to the teaching of claim 1.

[0009] Advantageous embodiments are the subject of the sub-claims. The type of burner is initially irrelevant, but is advantageously used in a gas turbine. Here it is obvious that the burner is to be arranged on the upstream side of a combustion chamber. The burner has a flow channel in which combustion air flows in a flow direction from upstream side to downstream side. The direction of the flow of combustion air defines a flow direction. The burner component is arranged within the flow channel of the burner and therefore the flow direction, the upstream side and the downstream side also applies here. Next, a transverse direction is defined as direction cross to the flow direction.

[0010] With the arrangement of the burner component in the flow channel, it has a leading edge at the upstream side and a downstream edge at the downstream side. The leading edge and the trailing edge are meant at respective end of the burner component. The burner component further comprises a component wall extending in the flow direction from the leading edge to the trailing edge. The component wall extends further in the transverse direction from a first wall end to an opposite second wall end. With the arrangement in the flow channel the combustion air flows along the component wall.

[0011] To enhance the mixing of fuel within the combustion air a number of vortex generators are arranged on the component wall protruding into the flow channel. Here, the vortex generators (in the sense of the invention, no matter if others located somewhere else are present) are arranged near the leading edge and spaced apart from each other in the transverse direction. A position near the leading edge is assumed if the respective vortex generator is arranged within an edge portion of 20% of the distance from the leading edge to the trailing edge at the same transversal position.

[0012] Next, the vortex generators have to be divided into a group of main vortex generators and an additional vortex generator. Here, a first main vortex generator is arranged as one of the main vortex generators at the side facing the first wall end. A second main vortex generator is arranged next to the first vortex generator.

[0013] The burner component further comprises a number of fuel nozzles. Here, the fuel nozzles (in the sense of the invention, no matter if others are present somewhere else) are arranged each downstream to a respective main vortex generator. That means there is always the arrangement of a main vortex generator next to the leading edge together with a fuel nozzle downstream of the respective main vortex generator.

[0014] Even the arrangement of a fuel nozzle downstream of a vortex generator is advantage per se, it has been found, that a further improvement of the mixing could be achieved with an additional vortex generator without any fuel nozzle. Here, the additional vortex generator is located between the first wall end and the first main vortex generator. If the size of the additional vortex generator is too big, the improvement by adding the additional vortex generator turns into a disadvantage regarding the mixing of the fuel into the combustion air. Therefore, the height above the component wall of the additional vortex generator needs to be less than the height of the adjacent first main vortex generator.

[0015] The vortex generators can be formed in a different shape, whereby it is advantageous to choose a triangular design with a leading curve on the combustion wall at the upstream side and a trailing curve cross to the combustion wall at the downstream side. Thereby, the height of the vortex generators increases from the upstream side to the downstream side.

[0016] This leads advantageously to a top surface of the vortex generators extending from the leading curve to the free end of the trailing curve. The height of the vortex generator is therefore defined by the distance from the component wall to the free end of the trailing curve. According to the triangular design the vortex generators comprises advantageously further two opposite side surfaces each extending from the trailing curve to one of both ends of the leading curve.

[0017] Regarding the position of the vortex generators (the main vortex generators and the additional vortex generator) near the leading edge it is further advantageous to arrange them at the same position relative to the flow direction. Here, it is in particular advantage, if the trailing edge of each of the vortex generators is located at the same distance to the leading edge (which is assumed, if the distances are within a range of + / -10%).

[0018] Regarding the location of the vortex generators, it is further advantage to arrange them close or at the leading edge. With a given different size of the vortex generators and the preferred arrangement of them with the trailing curve at the same position in flow direction, it is obvious, that advantageously the biggest main vortex generator is arranged in that the distance from the leading edge to at least one leading curve is less than 10% of the distance from the leading edge to the respective trailing curve of the biggest main vortex generator.

[0019] Dependent on the size of the burner component, in particular the width in the transversal direction from the first wall end to the second wall end, it is advantageous to arrange at least three and at most six main vortex generators each with a respective fuel nozzle, which is arranged downstream of the respective main vortex generator. Here, it is in particular advantageous to use four or five main vortex generators. Consequently, a third vortex generator is arranged next to the second vortex generator on the side facing the second wall end and a fourth vortex generator is arranged next to the third vortex generator on the side facing the second wall end. If applicable, a fifth vortex generator is arranged next to the fourth vortex generator on the side facing the second wall end.

[0020] If using a third and in particular a fourth main vortex generator it is advantageous to increase the size starting form the first main vortex generator over the second main vortex generator further, so that the third main vortex generator is bigger than the second main vortex generator and the fourth main vortex generator is bigger than the third main vortex generator.

[0021] Regarding the further concrete position of the additional vortex generator without any fuel nozzle, it is advantageous to arrange this in the middle between the first wall end and the first main vortex generator. This is assumed as given, if the position is within a tolerance of 15% of the distance from the first wall end to the first main vortex generator. It must be noted, that regarding the position of a vortex generator in the transversal direction the centre or trailing curve of the vortex generator is considered.

[0022] With this arrangement of the additional vortex generator at half of the distance from the first wall end to the first main vortex generator it is further advantageous to arrange the first main vortex generator at the half of the distance from the first wall end to the second main vortex generator. Here, it is also assumed, that the preferred position is given if the first main vortex generator is arranged in the middle between the first wall end and the second main vortex generator with a tolerance of 15% of the distance from the first wall end to the second main vortex generator.

[0023] As the impact with this arrangement of the additional vortex generator decreases at each further main vortex generator, it is preferred to arrange the preferred third main vortex generator at a distance to the second main vortex generator of at least 1,2 times and at most 1,5 times the distance between the second main vortex generator and the first main vortex generator.

[0024] Regarding the fuel nozzles, it is advantageous to arrange them close to the respective main vortex generators. Therefore, the distance between the vortex generator and the respective fuel nozzle should be less than half of the length of the vortex generator. It is in particular preferred that the distance from the respective main vortex generator to the centre of the fuel nozzle is less than half of the distance between the leading curve to the trailing curve of the respective main vortex generator.

[0025] The burner component arranged within a flow channel could be designed with a different shape (except the component wall with the vortex generators and the fuel nozzles). But it is advantageous to design the burner component with the shape of a vane. This enables the guidance of the flow of combustion air with a low resistance.

[0026] The inventive burner has a central burner axis and an annular flow channel extending from an upstream side to a downstream side. The flow channel is limited at the radial inner side by an inner flow channel wall and at the radial outer side by an outer flow channel wall. Here, a number of burner components according to the preceding description are arranged within the flow channel. The first wall end of the burner components is attached to the inner flow channel wall and the second wall end of the burner component is attached to the outer flow channel wall. It is obvious, that it is possible to realize the burner component as separate part, which is for example mounted in-between the inner channel wall and the outer channel wall. On the other hand, it is possible to build the burner with the inner channel wall and the outer channel wall and the burner components integrally, e.g. by additive manufacturing. Further options for production are obviously possible to combine the burner component with the inner channel wall and the outer channel wall.

[0027] In the following figures an example for a burner component of the inventive burner is shown. Fig. 1sketches a part of an exemplary burner with burner components; Fig. 2and Fig. 3 shows in a perspective view an exemplary embodiment of the burner component of the inventive burner; Fig. 4sketches in detail a vortex generator with a fuel nozzle.

[0028] In Figure 1 a part of a burner 01 is sketched. This embodiment of an inventive burner 01 comprises a main burner 03 surrounding annular a pilot burner 06. The main burner 03 has an annular flow channel 02, which 02 is defined by an inner channel wall 04 and an outer channel wall 05. Within the flow channel 02 a number of burner components 11 are arranged circumferentially distributed.

[0029] As it could be seen in Figure 2 and Figure 3 the burner component 11 has a shape of a vane with a component wall 14 extending from a leading edge 12 of the burner component to a trailing edge 13 of the burner component. The component wall is further limited by a first side end 15 and opposite by a second side end 16. The direction from the leading edge at an upstream side to the trailing edge 13 at the downstream side defines a flow direction. Cross to the flow direction a transversal direction is defined from the first side end 15 to the second side end 16.

[0030] As it could be seen in the figures, close to the leading edge 12 a number of vortex generators 17, 18 are arranged. Here, there are four main vortex generators 17a, 17b, 17c and 17d. Their size and height increase from a first main vortex generator 17a at the side facing the first wall end 15 over the second main vortex generator 17b to the third main vortex generator 17c. The fourth main vortex generator 17d has against the change from the first main vortex generator 17a to the third main vortex generator 17c a reduced size. In this embodiment the vortex generators 17, 18 are arranged with their downstream end at the same position in flow direction. As a result the third main vortex generator 17c as biggest one is arranged with its upstream end very close to the leading edge 12, whereby the distance to the leading edge 12 increases to the first main vortex generator 17a (and also the fourth main vortex generator 17d with a reduced size).

[0031] The main vortex generators 17 are classified by the fact that downstream to them at each main vortex generator 17a-17d a respective fuel nozzle 19a-19d is arranged. As it could be seen the distance from the fuel nozzles 19 to the respective main vortex generator 17 is much less than the size of the vortex generators 17.

[0032] The improved mixing is achieved by the additional vortex generator 18, which is arranged between the first main vortex generator 17a and the first wall end 15. Against the main vortex generators 17 no fuel nozzle is arranged at the additional vortex generator 18. Further the size of the additional vortex generator 18 is reduced compared to the first main vortex generator 17a.

[0033] In Figure 4 a detailed view of a main vortex generator 17 arranged on the component wall 14 is sketched. As it could be seen the main vortex generator 17 has a triangular shape with a leading curve 22 as transition from a top surface 24 of the main vortex generator 17 to the component wall 14 and a trailing curve 23, which 23 extends cross to the component wall and therefore defining the height of the main vortex generator 17. This leads to two opposite side walls 25 extending from the trailing curve 23 to one of the two opposite ends of the leading curve 22. Downstream to the main vortex generator 17 a fuel nozzle 19 is arranged.

Claims

1. Burner (01), in particular for a gas turbine, with a central burner axis and an annular flow channel (02) with a flow direction from an upstream side to a downstream side, the burner (01) comprising an inner flow channel wall (04) and an outer flow channel wall (05), and at least one burner component (11), wherein the burner component (11) has a leading edge (12) at the upstream side and a trailing edge (13) at the downstream side and a component wall (14), which (14) extends from the leading edge (12) to the trailing edge (13) and in a transverse direction cross the flow direction from a first wall end (15) to an opposite second wall end (16); and wherein the burner component (11) comprises - vortex generators (17, 18), which (17, 18) are arranged on the component wall (14) near the leading edge (12) spaced apart from each other in the transverse direction protruding into the flow channel (02), including a first main vortex generator (17a) at the side facing the first wall end (15) and a second main vortex generator (17b) next to first main vortex generator (17a) and an additional vortex generator (18); and - fuel nozzles (19), each arranged downstream to a respective main vortex generator (17), characterized in that the additional vortex generator (18) is located between the first main vortex generator (17a) and the first wall end (15) and has a height above the component wall (14) less than the height of the first main vortex generator (17a) and is without a respective fuel nozzle.

2. Burner (01) according to claim 1, wherein the vortex generators (17, 18) have a triangular design with a leading curve (22) on the component wall (14) at the upstream side and trailing curve (23) cross to the component wall (14) at the downstream side.

3. Burner (01) according to claim 2, wherein the vortex generators (17, 18) have a top surface (24) extending from the leading curve (22) to the free end of the trailing curve (23) and two side surfaces (25) each extending from one end of the leading curve (22) to the trailing curve (23).

4. Burner (01) according to one of the claims 1 to 3, wherein the vortex generators (17, 18) are arranged at the same position relative to the flow direction.

5. Burner (01) according to claim 4, wherein the vortex generators (17, 18) are arranged close to the leading edge (12).

6. Burner (01) according to one of the claims 1 to 5, comprising at least three and at most six, in particular four or five, main vortex generators (17) each with a respective fuel nozzle (19) arranged downstream.

7. Burner (01) according to claim 6, wherein the size of the second main vortex generator (17b) is bigger than of the first vortex generator (17a) and the size of a third main vortex generator (17c) next to the second vortex generator (17b) is bigger than of the second vortex generator (17b).

8. Burner (01) according to one of the claims 1 to 7, wherein the additional vortex generator (18) is arranged in the middle with a tolerance of 15% between the first wall end (15) and the first main vortex generator (17a) and wherein the first main vortex generator (17a) is arranged in the middle with a tolerance of 15% between the first wall end (15) and the second main vortex generator (17b).

9. Burner (01) according to claim 8, wherein the distance between the third main vortex generator (17c) and the second main vortex generator (17b) is at least 1,2-times and at most 1,5-times the distance between the second main vortex generator (17b) and the first main vortex generator (17a).

10. Burner (01) according to one of the claims 1 to 8, wherein the distance from the trailing curve (23) to the respective fuel nozzle (19) is less than half of the length of the respective main vortex generator (17) in flow direction, in particular is less than half of the respective distance from the leading curve (22) to the trailing curve (23).

11. Burner (01) according to one of the claims 1 to 8, having the shape of a vane.

12. Burner (01) according to one of the claims 1 to 11 wherein more than one of the at least one burner component (11) is provided and wherein the burner components (11) are arranged in the flow channel (02) with the first wall end (15) attached to the inner flow channel (04) wall and the second wall end (16) attached to the outer flow channel wall (05).

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