EP4121696A1

EP4121696A1 - Pilot cone cooling

Info

Publication number: EP4121696A1
Application number: EP21711744.9A
Authority: EP
Inventors: Christian Beck; Jürgen MEISL; Stefan Reich; Sabrina Isolde Siebelist; Christopher Grandt; Benjamin WITZEL
Original assignee: Siemens Energy Global GmbH and Co KG
Current assignee: Siemens Energy Global GmbH and Co KG
Priority date: 2020-05-15
Filing date: 2021-02-24
Publication date: 2023-01-25
Also published as: EP3910238A1; US11971171B2; US20230184437A1; CN115605712A; WO2021228447A1

Abstract

The invention relates to a pilot cone (1) for use in a burner arrangement (2) having a pilot burner (3). The pilot cone (1) comprises: a casing (4) which widens downstream along a burner axis and has a plurality of cooling air passages (12, 14) passing through it; an inner wall (7) which extends upstream starting from the upstream end of the casing (4); an annular gap (6) which runs along the inner wall (7) on the radially outer side; and a plurality of cooling air openings (10) which establish a connection between the annular gap (6) and the cooling air passages (12, 14). Another wall (8) extends upstream at a distance from the inner wall (7) starting from the casing (4) and delimits the annular gap (6) on the radially outer side, the inner wall (7) having a plurality of holes (9).

Description

description

Pilot cone cooling

The invention relates to a pilot cone for use in a burner arrangement, as well as a burner arrangement. The invention also relates to a method for cooling a pilot cone of a burner assembly.

Providing a central pilot burner with a cone for flame design is a widespread measure. Typically, such a pilot cone is cooled. As a rule, it is provided here that cooling air is guided on the back of the pilot cone or in cooling channels within the pilot cone. It is common here for the cooling air to be directed into the combustion chamber downstream of the pilot cone. This is to be viewed as unfavorable in terms of reducing NO _x emissions. For a high-temperature combustion system, closed cooling with reuse of the cooling air in the pilot burner is necessary.

With closed cooling, the pilot cone is usually cooled by an integrated design with air, which is used as combustion air after the cooling task has been completed. For this purpose, it is known to provide the pilot cone with large-volume cooling channels which finally lead the cooling air as combustion air to the pilot burner.

These designs with internal channels for a volume of air that is significantly larger than necessary for the cooling task, however, can no longer be described as simple. The complex and quite large structures are neither inexpensive to produce, nor can service life goals be easily achieved. Apart from the complexity and costs, the performance values are also unsatisfactory. The object of the invention is to provide a pilot cone in which cooling air and scavenging air consumption are as small as possible and which is at the same time as simple and inexpensive to manufacture as possible. Another object of the invention is to provide a burner arrangement with a pilot cone. Finally, it is an object of the invention to provide a corresponding method for operating such a burner arrangement.

The generic pilot cone is intended for use in a burner arrangement. The pilot cone has a conically shaped jacket which widens downstream along a burner axis. It is provided that a plurality of cooling air passages are arranged in the jacket, by means of which cooling of the jacket is made possible. Furthermore, the pilot cone has an inner wall which extends upstream from the upstream end of the shell. It is provided that an annular gap is arranged along the inner jacket on the radially outer side, through which a cooling air can be supplied. On the jacket adjacent to the annular gap, a plurality of cooling air openings are required, which establish a connection from the annular gap to the cooling air passages. Thus, when the burner arrangement is in operation, cooling air can be guided outside the inner wall through the annular gap and through the cooling air openings and through the cooling air passages, thus cooling the jacket.

To enable an optimal setting of the cooling air flow to ensure adequate cooling of the man means with the lowest possible consumption of cooling air, the invention provides that an outer wall is spaced apart from the inner wall on the radially outer side. This limits the annular gap on the radially outer side and also extends upstream from the jacket. Thus, a targeted cooling air duct to the cooling air openings is opened. Thus, an annular gap is formed on the pilot cone by two arranged on the Man tel, in the circumferential direction upstream he stretching, preferably coaxial, radially inner and radially outer walls, over which the pilot cone for Küh treatment supplied air is distributed according to their use.

In order to be able to optimally adjust the flow of cooling air, it is also provided that more cooling air is supplied through the annular gap than the jacket needs. The compensation and thus the optimal setting of the cooling air flow in the cooling air passages is made possible by providing the inner wall with a plurality of openings. This leads to a division of the air flow supplied through the annular gap, on the one hand, to a flow through the openings and, on the other hand, to a cooling air flow through the cooling air openings into the cooling air passages of the jacket.

By utilizing the design options that additive manufacturing allows, it is possible to manufacture a pilot cone with integrated cooling. The pilot cone is therefore a compact component that can be easily integrated into an existing burner and that enables a long service life. The complexity of the cooling air routing is completely hidden inside the pilot cone and can advantageously be produced using additive manufacturing methods. The cooling air throughput is limited to the air throughput required for cooling, so that more air is available for premixing with the fuel.

For optimal adjustment of the cooling air flow to be guided through passages, it is particularly advantageous if the sum of the cross-sectional areas of all openings is greater than the sum of the cross-sectional areas of all cooling air openings on the man tel of the pilot cone. With the choice of the size of the cross-sectional areas of the openings, the amount of air that is not required for cooling the pilot cone can be separated off. It is also advantageous if the cooling air flow supplied to the jacket can be adjusted by appropriately dimensioning the cooling air openings. It is necessary that the sum of the cross-sections of the cooling air openings is smaller than the sum of the cross-sections of the cooling air passages, which flow parallel to each other.

In a further advantageous embodiment, opening cross-sections of the respective cooling air openings are smaller than the cross-sections of the respective cooling air passages. Thus, in this embodiment, the openings, which quasi represent the inlet openings into the cooling air duct in the pilot cone, are the smallest passages in the system and can intercept particles that could block subsequent cooling channels. They are viewed as an integrated filter device.

In this case, it is provided in a particularly advantageous manner that the number of cooling air openings exceeds the number of cooling air passages which technically flow in parallel. It is thus made possible that the cross section of the individual cooling air openings can be selected to be small in relation to the cross section of the cooling air passages and thus clogging of the cooling air passage by particles is prevented.

In an advantageous embodiment of the invention, an annular distributor is arranged in the jacket of the pilot cone, into which the cooling air openings arranged in the circumferential direction open in order to distribute the cooling air evenly over the circumference of the pilot cone. This ensures that even if individual cooling air openings are blocked, a more or less uniform distribution of the cooling air flow over the cooling air passages can be guaranteed. It is provided that cooling air passages branch off from the distributor.

The arrangement of the pilot cone in the burner arrangement is advantageously made possible if the pilot cone has a centering collar for receiving a pilot burner. It is provided that the centering collar is upstream of the jacket is arranged radially inward of the inner wall. In a particularly advantageous manner, the centering collar forms a cylindrical fitting surface.

For the advantageous fitting of the pilot burner into the centering collar, it is furthermore advantageously provided that an annular groove is arranged between the centering collar and the jacket. This is obviously open to the burner axis.

This also enables the advantageous arrangement of sealing air outlets in the annular groove. The sealing air outlets here form the end of cooling air passages, so that the cooling air fed through the cooling air openings flows out through the sealing air outlets. In this case, these are advantageously distributed equidistantly over the circumference, so that there is a uniform supply of sealing air in the area of the interface between the pilot cone and the pilot burner.

It is also advantageous if the blocking air outlets are aligned at an incline. In this way, on the one hand, a swirling pilot burner flow can be taken into account and, on the other hand, the flow can be applied downstream of the annular groove along the surface of the jacket, or a detachment of the flow is avoided.

An advantageous cooling air duct in the jacket is achieved when downstream first cooling air passages and circumferentially offset upstream second cooling air passages are used, the first cooling air passages being connected to the second cooling air passages via the first transverse passages at the downstream end of the jacket. It is provided that the cooling air is supplied from the cooling air openings to the first cooling air passages, the cooling air flowing back to the upstream end of the jacket after being deflected at the first transverse passages through the second cooling air passages. In the simplest Shape here extend the transverse passages in the circumferential direction Rich.

If there is an advantageous distributor in the jacket, the first cooling air passages begin at the distributor.

If there are sealing air outlets, these are advantageously located at the end of the second cooling air passages.

An advantageous deflection of the cooling air flow at the downstream end of the jacket is made possible if a first transverse passage connects at least two first cooling air passages and at least two second cooling air passages with one another. If at least two first cooling air passages open into a first transverse passage and at least two second cooling air passages branch off from the first transverse passage, there are two advantages. On the one hand, the temperature can be distributed more evenly over the circumference of the pilot cone. On the other hand, if a cooling air passage is clogged, an entire path does not immediately fail, but only the flow in one direction along an individual cooling air passage is disturbed or interrupted, while cooling air can continue to flow adjacent.

In connection with a first transverse passage, two second cooling air passages are arranged adjacent to one another between two first cooling air passages.

To ensure a cooling air flow even if there is a possible restriction in the flow of a first cooling air passage, it is also advantageous if adjacent first cooling air passages that are not connected to one another via a first transverse passage are connected to one another via second transverse passages.

However, it is particularly advantageous if, in the connection via the first transverse passage, two first cooling air passages are are arranged adjacent to one another between two second cooling air passages.

Similarly, to ensure a cooling air flow, even with a possible restriction in the flow of a second cooling air passage, it is further advantageous if adjacent second cooling air passages that are not connected to one another via a first transverse passage are connected to one another via a second transverse passage.

The arrangement of the second transverse passage takes place in the direction of the combustion chamber axis offset upstream to the first transverse passage. Thus, a flow in the second transverse passages is only relevant in those cases when there is a restriction in the flow through the connected cooling air passages.

In an advantageous embodiment, the first and second cooling air passages are round in cross section. With rectangular cooling air passages, larger duct cross-sections can be achieved, but round cooling air passages are more advantageous with regard to material stresses and service life.

To generally reduce the cooling air requirement, it is useful if the inner surface of the jacket of the pilot cone, i.e. the surface on the combustion chamber side, is provided with a thermal insulation layer, as is generally the case.

The additive manufacturing method enables the simple addition of additional features. It can therefore be useful if at least three protruding prongs are arranged on the outside of the Pi lotkonus as a safety catch. This safety catch keeps the pilot cone in the main burner in the unlikely event of an unintentional loosening of the pilot cone.

How the inner wall and - if present - the second wall are actually designed is initially irrelevant. At least in the burner arrangement, the inner wall surrounds the pilot burner in sections as intended. For this purpose, in a preferred embodiment, the inner wall is designed in such a way that it expands upstream from the jacket. This creates a larger installation space for the pilot burner. In this embodiment, the annular gap also inevitably widens upstream, starting from the jacket of the pilot cone. Corresponding to the objectionable arrangement of the second wall - if present - of the first wall, this has a shape correspondingly widening upstream.

The provision of a novel pilot cone enables the implementation of a new burner arrangement according to the invention. This generic first of all comprises a centrally arranged pilot burner extending along a burner axis. A pilot cone is arranged at the downstream end of the pilot burner. Furthermore, the burner arrangement comprises a main burner which comprises a central opening. Inside there is a pilot burner with the pilot cone. According to the invention, the pilot cone here has a shape as described above.

A contact point between the pilot burner and the pilot cone is advantageously designed as a sliding fit. A sliding fit is understood here to be a fit that can be easily joined and also allows different thermal expansions in the direction of the burner axis.

It is particularly advantageous if the design of the contact point allows leakage with a slight flow of cooling air. This prevents a fixed connection between the pilot cone and the pilot burner at the contact point due to excessive thermal loads and / or deposits, which prevents relative displacement, in particular due to different thermal expansions, and leads to thermal stresses can. Furthermore, it is advantageous if the existing sealing air outlets in the pilot cone, in particular in the annular groove, are directed towards an end section of the pilot burner immediately downstream of the contact point. This enables optimal protection of the contact point. The cooling air of the pilot cone is thus used again after the pilot cone has been cooled for flushing at the contact point between the pilot burner and the pilot cone. Otherwise, air would have to be fed separately to this area.

It is advantageous if the annular groove in the pilot cone is partially covered by an end section of the pilot burner. This enables the contact point, in particular the sliding seat, to be in a protected position between the pilot cone and the pilot burner. On the other hand, this creates an annular cavity that promotes further cooling air flow. The supplied cooling air then exits from a sealing air gap between the upstream end of the jacket of the pilot cone and the end section of the pilot burner.

An advantageous fastening of the pilot cone is created when the pilot cone is fastened to a pilot cone carrier. The connection is particularly preferably made to the upstream end of the inner wall. The inner wall can, for example, merge seamlessly into the pilot cone carrier.

Furthermore, it is particularly advantageous if the pilot cone carrier enables the cooling air to be guided at the same time. For this purpose, a cooling air supply runs radially outside the pilot cone carrier, which merges into the annular gap. The pilot cone carrier is formed in a simple and advantageous manner in the form of a cylinder.

To support the main burner, a main burner carrier is advantageously arranged radially outside half of the pilot cone carrier. If there is a cooling air supply radially outside of the pilot cone carrier limits the cooling air supply on the radially outer side of the main burner carrier.

It is advantageous if the outer wall is mounted on the main burner support at its upstream end. Since it can be provided that a fixed connection / assembly takes place or a sliding seat is provided which allows un different thermal expansion.

To utilize the cooling air supplied to the pilot cone through the annular gap as combustion air, an annular chamber is advantageously arranged on the side of the inner wall facing the burner axis, which is fluidically connected to a pilot burner inlet. This means that the amount of air supplied for cooling the pilot cone can be divided into a part necessary for cooling the pilot cone with a flow through the cooling air openings and an excess part with a flow through the openings, which is fed to the pilot burner for combustion.

The object directed to a method is achieved by a method for cooling a pilot cone of a burner arrangement with a pilot burner, wherein the pilot cone comprises a downward-widening jacket and is arranged immediately downstream of the pilot burner and is fluidically connected to it, in which cooling air is in Inside the jacket is guided and cooling air leaving the jacket flushes an interface between the pilot burner and pilot cone.

Cooling air is advantageously supplied in the jacket of the pilot cone via a first cooling air passage and is returned via a second cooling air passage adjacent to the first cooling air passage. First and second cooling air passages are connected to one another in the vicinity of the downstream end of the pilot burner via comparatively short first transverse passages. In particular, the cooling air is guided on the shortest path from the annular distributor at the upstream end to the vicinity of the downstream end of the pilot cone and from returned there by the shortest route. This results in an efficient and as uniform as possible cooling or temperature distribution in the pilot cone.

Furthermore, it is advantageous if, in the case of a blocked second cooling air passage, cooling air is returned via a second cooling air passage adjacent to the blocked second cooling air passage.

The main advantages of the invention are, in particular, a compact pilot cone without stretching restrictions with uniform component temperature and the resulting high component life.

Furthermore, closed air cooling of the pilot cone can be implemented with flushing of the interface between the pilot cone and the pilot burner, in which the cooling air already used to cool the jacket of the pilot cone is used again. It is also particularly advantageous here that the cooling air exiting at the contact point between the pilot cone and the pilot burner can additionally be used as combustion air.

Another advantage is the improved insensitivity to a blockage of cooling air openings or individual cooling air passages and an undiminished guarantee of an advantageous cooling of the jacket of the pilot cone.

The complex internal channel structure is favorably favored by the use of additive manufacturing. The component can therefore be constructed very efficiently in terms of cooling performance and cooling air balance. Another advantage of additive manufacturing is the very short production times.

The invention is explained in more detail by way of example with reference to the drawings. They show schematically and not to scale: 1 shows a perspective view of a pilot cone in longitudinal section;

FIG. 2 shows a detail of the pilot cone from FIG. 1 with the pilot burner arranged therein; FIG.

3 shows a detail of a burner arrangement with the pilot cone from FIG. 1 and a pilot burner and, in sections, a main burner;

FIG. 4 again the pilot cone from FIG. 1 with a section through the second cooling air passages; FIG.

FIG. 5 again the pilot cone from FIG. 1 with a section through the first cooling air passages; FIG.

6 shows a further detailed view of the pilot cone in the area of the cooling air openings and the cooling air breakthroughs;

7 shows the cooling air duct in the jacket of the pilot cone; 8 schematically shows the cooling air duct in the jacket starting from the cooling air openings;

9 schematically shows the cooling air duct in the area of the transverse passages.

In Fig. 1 is a perspective view with an exemplary embodiment for a pilot cone 01 according to the invention shown in longitudinal section. The pilot cone 01 has a jacket 04 widening downstream in a main flow direction of fuel and air. The information upstream always refers to the side opposite to a combustion chamber following the pilot cone, while downstream always refers to the side facing the combustion chamber. An inner surface 16 of the jacket 04 of the pilot cone 01 is provided with a thermal insulation layer 17. A cooling air duct 05 runs inside the jacket 04 (not visible in this view).

From the upstream end of the jacket 11, an inner wall 07 extends upstream, which 07 also expands in the process. In relation to the inner wall 07, the outer wall 08 is located on the radially outer side. Here, an annular gap 06 is formed between the inner wall 07 and the outer wall 08, which is used to guide the cooling air.

In FIG. 2, a section of a burner arrangement with the pilot cone 01 and a pilot burner 03 arranged therein is sketched. On the side facing the burner axis 21 and bordering the inner wall 07 radially outside of the pilot burner 03 there is an annular chamber 26.

What is essential for the invention is the division of the cooling air supplied through the annular gap 06 on the one hand for cooling the jacket 04 and on the other hand for mixing with the combustion air supplied to the pilot burner 03. For this purpose, the inner wall 07 has a plurality of perforations 09 distributed around the circumference, which establish a connection between the annular gap 06 and the annular chamber 26 09. The cooling air duct from the ring gap 06 into the jacket 04 of the pilot cone 01 can be seen from FIG. 6 and will be explained in more detail below.

A centering collar 17 can also be seen at the end of the jacket 04 on the upstream side, in which 17 the pilot burner 03 is mounted in a contact point 23 with a sliding seat.

The contact point 23 allows a relative displacement of the pilot burner 03 relative to the pilot cone 01 and thus prevents thermal stresses. Furthermore, the contact point 23 between the pilot burner 03 and the pilot cone 01 as sliding seats allows the cooling air to leak from the Annular chamber 26 and thus counteracts the two components 01, 03 from sticking to one another in the contact point 23.

An annular groove 30 is located between the contact point 23 and the jacket 04 of the pilot cone. This is partially covered on the radially inner side by an end portion of the pilot burner 03. This forms a circumferential cavity 29. A sealing air gap 28 is located between the end section of the pilot burner 03 and the upstream end of the jacket 04 of the pilot cone 01.

3 shows schematically and by way of example a section of a burner arrangement 02 with a central burner axis 21, comprising a main burner 19 and a pilot burner 03 arranged in the main burner 19. Here, the pilot cone 01 is arranged directly downstream of the pilot burner 03.

The main burner 19 is supported on the radially inner side via a main burner support 22. At the same time, it is provided in this exemplary embodiment that the outer wall 08 of the pilot cone 01 is supported at its 08 upstream end in the main burner support 22 and thus centering takes place.

If there is a complaint about the main burner carrier 22 on the side facing the burner axis 21, there is a pilot cone carrier 25. The inner wall 07 of the pilot cone 01 adjoins the end of the pilot cone carrier 25. At this 07, a plurality of protruding prongs 18 are distributed around the circumference in this exemplary embodiment and are arranged on the outside. These prevent a displacement out of the main burner 19 when the pilot cone 01 is released.

The main burner support 22 and the pilot cone support 25 are designed to be cylindrical in this exemplary embodiment and are arranged coaxially to one another and effect a fluidic separation. This is between the main burner support 22 and the pilot cone carrier 25 forms a cooling air feed 24. The cooling air flowing through the cooling air supply 24 also causes the main burner support 22 to be cooled.

The cooling air supply 24 is optimized in order to generate the flow speed necessary for the heat transfer with a low pressure loss at the same time. The high pressure gradient between the cooling air inlet and outlet of the pilot cone 1 enables efficient cooling with a comparatively low air mass flow.

The outer cooling air supply 24 opens into the annular gap 06 of the pilot cone 01, which 06 is formed by the two coaxial, radially inner and radially outer walls 07, 08 arranged on the jacket 04 and extending in the circumferential direction, upwardly inclined. The radially inner wall 07 is connected to the pilot cone carrier 25 and the radially outer wall 08 is connected to the main burner carrier 22, so that a closed cooling air duct to the pilot cone 01 is formed between the main burner 19 and the pilot burner 03.

From the annular gap 06, the cooling air flows proportionally through the openings 09 in the inner wall 07 into the annular chamber 26 and then to the main flow path of the combustion air supplied to the pilot burner to a pilot burner inlet 27.

The cooling air duct 05 in the jacket 04 of the pilot cone 01 is explained in more detail with reference to FIGS. 4 to 9 - see in particular FIG 9 obviously opens up the structure in the jacket 04 of the pilot cone 01.

Distributed around the circumference near the upstream end of the jacket 04 are a plurality of cooling air openings 10 - see FIGS. 5 and 6, which establish a connection from the annular gap 06 to the cooling air passages 12, 14 in the jacket 04. In the man tel 04 of the pilot cone 01 is an annular distributor 11 arranged, in the 11, the circumferential cooling air openings 10 open. When the burner arrangement 02 is in operation, the air for cooling the pilot cone 01 thus initially flows through a multiplicity of cooling air openings 10, which are distributed 10 in the circumferential direction, into the aforementioned annular distributor 11.

First cooling air passages 12 branch off from the distributor 11 and they extend essentially downstream within the jacket 04 - see FIGS. 5 and 8.

At the downstream end of the jacket 04, the first cooling air passages 12 each open into first transverse passages 13, which extend in the circumferential direction - see FIG. 9. Upstream second cooling air passages 14 branch off from the first transverse passages 13 - see FIG. 4 The exemplary embodiment provides that two adjacent first cooling air passages 12 open into a first transverse passage 13 and two second cooling air passages 14 branch off from the first transverse passage 13.

The first and second cooling air passages 12, 14 are round in cross section as an advantageous and simplest embodiment.

The air therefore flows through the first cooling air passages 12 to the front edge of the pilot cone 01 and flows there via first transverse passages 13 to respective adjacent second cooling air passages 14, which are provided for the return of the air to the interface with the pilot burner 03.

The first and second cooling air passages 12, 14, that is, the leading and return channels, are mutually arranged and adjacent second cooling air passages 14 are connected by second transverse passages 15, in the unlikely event of a blocked cooling passage an albeit reduced flow of cooling air through unblocked To enable sections. This emergency cooling property is intended to counteract further damage to the pilot cone 01 after damage with blocked cooling passages 12, 14, so that more or less uniform cooling can be ensured even if a single cooling air passage 12, 14 is blocked.

The cross-sections of the cooling air openings 10 are selected to be smaller than the cross-sections of the first and second cooling air passages 12, 14 or the first and second transverse passages 13, 15, so that a filter function results at the entrance to the cooling air guide 05.

The second cooling air passages 14 open into the annular groove 30 or into the circumferential cavity 29 at the contact point 23 of the pilot cone 01 with the pilot burner 03 - see FIG. 4 (also FIG. 2). That is, after flowing through the pilot cone 01, the cooling air enters a circumferential cavity 29, which blocks the interface between the pilot cone 01 and the pilot burner 03 against the ingress of hot gas. The cooling air then mixes with the pilot burner flow.

The passages of the second cooling air passages 14 near the exit, referred to as sealing air outlets 32, are arranged equidistantly over the circumference in the annular groove 30 and are oriented in such a way that, when the burner arrangement 02 is in operation, they are inclined in the direction of a swirling pilot burner flow so that the flow is located downstream of the annular groove 30 to effect along the man means 04, or to avoid detachment. As a side effect of the overlap, the blocking air outlets 32 are protected.

The flushing of the sealing air gap 28 at the contact point 23 between the pilot cone 01 and the pilot burner 03, which is necessary for safety reasons, involves reuse of the cooling air. Thus, the cooling is viewed as closed or cooling air-neutral. Due to the high pressure gradient between the cooling air inlet and outlet, a high cooling effect is achieved with a low cooling air mass flow.

Claims

1. Pilot cone (01) for use in a burner arrangement (02), with a jacket (04) which (04) expands downstream along a burner axis and is traversed by a plurality of cooling air passages (12, 14), and with an inner wall (07) which (07) extends upstream from the upstream end of the jacket (04), and with an annular gap (06) which (06) on the radially outer side along the inner wall (07) runs, and with a plurality of cooling air openings (10) which (10) establish a connection from the annular gap (06) to the Kühlluftpassa gene (12, 14), characterized by an outer wall (08) which (08) is spaced from the inner wall (07) extending upstream from the jacket (04) and delimiting the annular gap (06) on the radially outer side, the inner wall (07) having a plurality of openings (09).

2. pilot cone (01) according to claim 1, wherein the sum of the cross-sectional areas of all openings (9) is greater than the sum of the cross-sectional areas of all cooling air openings (10).

3. pilot cone (01) according to claim 1 or 2, wherein the sum of the cross-sectional areas of all cooling air töffnungen (10) is smaller than the sum of the cross-sectional areas of all cooling air passages (12, 14); and / or wherein the cross-sectional area of each individual cooling air opening is smaller than the cross-sectional area of the cooling air passages (12, 14).

4. pilot cone (01) according to one of claims 1 to 3, wherein an annular distributor (11) is arranged in the jacket (4), which (11) is connected to the cooling air openings (10) and to cooling air passages (12), from which (11) in particular first cooling air passages (12) branch off.

5. Pilot cone (01) according to one of claims 1 to 4, wherein a centering collar (17) for receiving a pilot burner (03) is arranged upstream of the jacket (04).

6. pilot cone (01) according to claim 5, wherein a circumferential to the burner axis (21) open annular groove (30) is arranged between the jacket (04) and the centering collar (17).

7. pilot cone (01) according to claim 6, wherein sealing air outlets (32) in connection with cooling air passages (14) are arranged on the annular groove (30), which (32) are inclined in particular such that a proportionately tangential cooling air flow occurs; and / or which (32) in particular form the end of the second cooling air passages (14).

8. Pilot cone (01) according to one of claims 1 to 7, wherein inside the jacket (04) say first cooling air passages (12) downstream and second cooling air passages (14) extend upstream, wherein adjacent cooling air passages say (12, 14) via first transverse passages (13) are interconnected.

9. pilot cone (01) according to claim 8, wherein in each case at least two first cooling air passages (12) and at least two second cooling air passages (14) are connected to one another via a respective first transverse passage (13); or two adjacent first cooling air passages (12) and two second cooling air passages (14) being connected to one another via a respective first transverse passage (13); or wherein two adjacent second cooling air passages and two first cooling air passages are each connected to one another via a first transverse passage.

10. Pilot cone (01) according to claim 9, wherein adjacent cooling air passages (14) (not connected via first transverse passages) are connected to one another via second transverse passages (15) offset upstream of the first transverse passages.

11. Pilot cone (01) according to one of claims 1 to 10, wherein the inner wall (07) and the annular gap (06), and in particular the second wall (08), widen upstream.

12. Burner arrangement (02) with a burner axis comprising a main burner (19) and a pilot burner (03) arranged centrally therein (19) and a pilot cone (01) arranged at the downstream end of the pilot burner (03), characterized by an embodiment according to a of the preceding claims.

13. Burner arrangement (02) according to claim 12, wherein a contact point (23) between the pilot burner (03) and the pilot cone (01), in particular the centering collar (17), is designed as a sliding seat, the contact point in particular having a low cooling air flow allows.

14. Burner arrangement (2) according to claim 13, wherein the annular groove (30) is covered at least in sections by egg nem end portion of the pilot burner (03) and a circumferential cavity (29) is formed.

15. Burner arrangement (02) according to one of claims 12 to 14, wherein the pilot cone (01), in particular the inner wall (07), is attached to a pilot cone carrier (25), wherein in particular a cooling air supply (24) radially outwards. ßerhalb the pilot cone carrier (25) and merges into the annular gap (06).

16. Burner arrangement (2) according to claim 15, wherein a main burner carrier (22) is arranged radially outside of the pilot cone carrier (25), in particular special radially outside of the cooling air supply (24), on which (22) in particular the outer wall (08) is mounted is.

17. Burner arrangement (2) according to one of claims 12 to 16, wherein the openings (09) lead to an annular chamber (09) which (09) is fluidically connected to a pilot burner inlet (27) of the pilot burner (03).