Fuel staged burner

Abstract

The invention discloses a fuel staged combustor, and relates to the technical field of structural design of combustion chambers of gas turbines. Comprising a nozzle outer wall and a plurality of nozzle microtubes, a gap between the nozzle microtube wall and the nozzle outer wall forms a nozzle fuel cavity, the nozzle fuel cavity is communicated with the nozzle fuel cavity, and the nozzle fuel cavity is communicated with the nozzle fuel cavity. The nozzle fuel cavity is divided into a plurality of areas, and a plurality of air inlet channels are arranged in the connecting pipe. Fuel enters the grading end cover fuel cavity from the fuel inlet pipe, enters different areas of the nozzle fuel cavity from different air inlet channels, is sprayed in from the fuel spraying holes of the nozzle micro-pipe, is mixed with air to form uniform premixed gas, and finally is sprayed out from the micro-pipe outlet. A combustion field with uniform temperature distribution can be formed, meanwhile, the fuel cavities of the grading end cover can be opened in sequence to form various permutation and combination paths, and the combustion mode can be effectively adjusted by adjusting the fuel equivalence ratio of each grade.

Description

Technical Field

[0001] The invention relates to the technical field of gas turbine combustion chamber structure design, and in particular to a fuel staged burner. Background Art

[0003] At present, micro-premixing is usually used to make the fuel and air burn under more uniform and leaner mixing conditions. Although micro-premixed combustion technology has significant advantages in reducing nitrogen oxide (NOx) emissions and improving combustion efficiency, it also has some disadvantages and challenges. Flashback risk: Hydrogen burns quickly and is prone to flashback. Especially under high-speed flow conditions, flashback problems may lead to combustion instability and safety issues. Combustion instability: Hydrogen flames propagate quickly and are prone to combustion instability, including oscillation and resonance. Uneven mixing: Hydrogen has a low density and weak jet penetration, and is easily swept away by high-speed airflow, resulting in the inability of the injected hydrogen to be fully mixed in the large-flow, high-speed inlet airflow. There is a phenomenon of local fuel concentration and over-richness, which brings about the problem of high local equivalence ratio and high-temperature hot spots, and then generates a large amount of NOx. Therefore, it is necessary to develop a combustion technology with flexible fuel grading so that the burner can achieve low-pollution and stable combustion under all operating conditions of the whole machine.

[0004] The existing patent CN113091094B discloses a method for premixing fuel and air in a nozzle of a gas turbine combustion chamber, wherein the nozzle includes a fuel delivery manifold, a fuel flow channel, and a fuel-air premixing tube. The fuel delivery manifold is provided with a plurality of fuel outlets, and each fuel outlet corresponds to at least one fuel flow channel. There are a plurality of fuel-air premixing tubes, and the fuel-air premixing tube is provided with a fuel spray hole. The fuel enters from the fuel delivery manifold, enters the fuel flow channel through the fuel outlet, enters the fuel-air premixing tube through the fuel spray hole, and mixes with the air pre-entered therein to form a mixture, and the mixture is sprayed out from the fuel-air premixing tube. The nozzle and method can ensure that the entire nozzle has good uniformity of premixing of fuel and air. The disadvantage is that there is only one-level fuel distribution, and it is easy to extinguish or the flame stability is poor under low-load conditions, especially when burning hydrogen fuel. The escape of hydrogen fuel after extinguishing the flame is easy to cause safety accidents.

[0005] The existing patent CN118423714A discloses a gas turbine multi-nozzle array fuel-staged burner head, which is composed of a duty class nozzle, a first-level main combustion nozzle, a second-level main combustion nozzle, a combustion chamber end cooling plate, a duty class fuel distribution cavity, a first-level main combustion fuel distribution cavity and a second-level main combustion fuel distribution cavity. It adopts a fuel-staged and zoned nozzle arrangement to increase the load step by step from the inside to the outside; by controlling the area of ​​the air film holes on the cooling plate at the end of the combustion chamber and the area of ​​the lateral air inlet holes, it is ensured that the speed of the cooling air film holes is lower than the nozzle speed, and the inclined opening of the cooling air film holes does not affect the combustion flame; each level of the fuel pipe has an independent fuel distribution cavity for distribution, which ensures the uniformity of distribution and the flexibility of fuel regulation.

[0006] In summary, the above two existing patents have not achieved low-pollution and stable combustion of hydrogen fuel in the combustion chamber of a gas turbine. Summary of the invention

[0007] Based on the above technical problems, the present invention proposes a fuel staged burner to solve the problem that hydrogen fuel cannot burn stably with low pollution in the combustion chamber of a gas turbine in the prior art. The specific technical solution is as follows:

[0008] A fuel staged burner comprises an end cover and a nozzle arranged coaxially adjacent to each other and a plurality of connecting pipes connecting the end cover and the nozzle, wherein a plurality of staged end cover combustion chambers are arranged in the end cover, a plurality of fuel inlet pipes corresponding to the staged end cover fuel chambers are connected to a side of the end cover away from the nozzle, the connecting pipe comprises a plurality of air inlet channels, the nozzle comprises a nozzle outer wall and a plurality of nozzle micro-tubes located inside the nozzle outer wall, a nozzle fuel chamber is formed by a gap between the nozzle outer wall and the tube wall of the nozzle micro-tube, the nozzle fuel chamber is divided into a plurality of zones, and the nozzle micro-tubes are all provided with fuel spray holes.

[0009] Furthermore, an annular end cover fuel cavity is provided on the end cover, and the end cover also includes a plurality of fuel cavity partitions, and the fuel cavity partitions are used to divide the end cover fuel cavity into a plurality of graded end cover fuel cavities.

[0010] Furthermore, the fuel cavity partition includes a plurality of first fuel cavity partitions, and the first fuel cavity partitions are used to radially divide the annular end cover fuel cavity into inner and outer adjacent multi-layer annular end cover fuel cavities.

[0011] Furthermore, the fuel chamber partition also includes a plurality of second fuel chamber partitions, each layer of the annular end cover fuel chamber is provided with the second fuel chamber partition, and the second fuel chamber partition is used to divide each layer of the annular end cover fuel chamber into a plurality of graded end cover fuel chambers along the circumferential direction.

[0012] Furthermore, the cavity capacity of the fuel cavity of the graded end cover increases step by step.

[0013] Furthermore, one end of the connecting tube is connected to the position where the first fuel chamber partition is provided on the end cover, and a connecting tube partition is provided in the connecting tube, and the connecting tube partition is used to divide the connecting tube into multiple air intake channels, and the multiple air intake channels correspond one by one to the multi-layer annular end cover fuel chamber.

[0014] Furthermore, the connecting pipe partition is integrally connected to the first fuel chamber partition.

[0015] Furthermore, the plurality of nozzle micro-tubes are arranged at equal intervals on the inner side of the nozzle outer wall, and the nozzle micro-tubes are arranged along the axial direction.

[0016] Furthermore, the nozzle micro-tube passes through two radial end surfaces of the nozzle outer wall, the nozzle micro-tube includes a micro-tube inlet and a micro-tube outlet, and the fuel spray hole is opened at one end of the nozzle micro-tube close to the micro-tube inlet.

[0017] Furthermore, a gap between the outer wall of the nozzle and the wall of the nozzle microtube forms a nozzle fuel chamber, and the nozzle further comprises a plurality of partition plates, and the partition plates are used to partition the nozzle fuel chamber.

[0018] Furthermore, the partition partition includes a first partition partition, and the first partition partition is used to divide the nozzle fuel chamber into a plurality of fan-shaped nozzle fuel chambers along the circumferential direction, and the fan-shaped nozzle fuel chambers are connected to the connecting pipes one by one.

[0019] Furthermore, the partition partition also includes a plurality of second partition partitions, wherein the second partition partitions are located in the fan-shaped nozzle fuel chamber, and the second partition partitions are used to divide the fan-shaped nozzle fuel chamber radially.

[0020] Furthermore, the second partition partition is integrally connected to the connecting pipe partition.

[0021] Furthermore, a convex curved portion is provided on the nozzle micro-tube, and the fuel spray hole is opened on a convex side of the convex curved portion.

[0022] Based on the above technical solution, compared with the prior art, the present invention has at least the following beneficial effects:

[0023] 1. The fuel-graded burner proposed in the present invention has multiple fuel grades and multiple load-raising paths. The equivalence ratio of different fuel grades can be adjusted to meet safe and stable combustion in the full range of operating conditions.

[0024] 2. The present invention proposes a fuel-staged burner, in which the nozzle body is composed of hundreds of micro-tubes to achieve micro-premixed low-pollution combustion. At the same time, the nozzle micro-tubes are divided into multiple zones, which facilitates the implementation of various fuel staged schemes.

[0025] 3. The fuel-staged burner proposed by the present invention divides a single connecting pipe into multiple channels, which can reduce the number of connecting pipes and interfaces and reduce the impact on the air field.

[0026] 4. The fuel staged burner proposed in the present invention realizes micro-mixing of hydrogen fuel and air, improves the uniformity of fuel and air mixing, avoids excessive local combustion temperature, thereby reducing the emission of nitrogen oxides in the combustion chamber and protecting the environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0028] Figure 1 It is a three-dimensional schematic diagram of a fuel staged burner proposed by the present invention;

[0029] Figure 2 It is a side schematic diagram of a fuel staged burner proposed by the present invention;

[0030] Figure 3 It is a cross-sectional schematic diagram of a fuel staged burner proposed by the present invention;

[0031] Figure 4 It is a cross-sectional schematic diagram of a fuel staged burner proposed by the present invention;

[0032] Figure 5 It is a partial structural schematic diagram of a fuel staged burner proposed by the present invention;

[0033] Figure 6 It is a partial structural schematic diagram of a fuel staged burner proposed by the present invention;

[0034] Figure 7 It is a structural schematic diagram of a nozzle micro-tube in a fuel staged burner proposed by the present invention.

[0035] Figure markings: 100-end cover; 200-nozzle; 300-connecting pipe; 101-104-fuel inlet pipe; 105-107-fuel chamber partition, 108-inner 1st stage end cover fuel chamber; 109-inner 2nd stage end cover fuel chamber; 110-outer 1st stage end cover fuel chamber; 111-outer 2nd stage end cover fuel chamber; 201-nozzle microtube; 202-203-partition partition; 204-inner fuel chamber of nozzle; 205-outer fuel chamber of nozzle; 206-microtube inlet; 207-microtube outlet; 208-fuel spray hole; 301-connecting pipe partition; 302-303-intake channel. DETAILED DESCRIPTION

[0036] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0037] The present invention is further described in detail below in conjunction with specific embodiments. These embodiments should not be construed as limiting the scope of protection claimed by the present invention.

[0038] In order to solve the problem in the prior art that hydrogen / hydrogen-rich fuel cannot be stably burned with low pollution in the combustion chamber of a gas turbine, the present invention proposes a fuel staged burner.

[0039] To achieve the above object, the present invention provides a fuel staged burner. Figure 1-Figure 7 As shown, an embodiment of the fuel staged burner of the present invention is specifically illustrated, and the fuel staged burner includes an end cover 100, a nozzle 200 and a connecting pipe 300, and the end cover 100 and the nozzle 200 are connected by the connecting pipe 300. The outer side of the end cover 100 is connected to the fuel inlet pipe, and a plurality of staged end cover fuel cavities are arranged inside the end cover 100. The nozzle 200 includes a nozzle outer wall and a plurality of nozzle microtubes, and the gap between the nozzle outer wall and the nozzle microtubes forms a nozzle fuel cavity, and the nozzle fuel cavity is divided into a plurality of zones. The connecting pipe 300 is divided into a plurality of air inlet channels. The fuel enters the staged machine gate fuel cavity from the fuel inlet pipe, and enters different zones of the nozzle fuel cavity through different air inlet channels of the connecting pipe.

[0040] The structure of the above-mentioned fuel staged burner will be described in detail below in conjunction with the accompanying drawings.

[0041] In some embodiments, the specific implementation of the end cap 100 is shown in Figure 1-Figure 4 shown.

[0042] See also Figure 1 As shown, the fuel staged burner includes an end cover 100, a nozzle 200 and a connecting pipe 300. The end cover 100 and the nozzle 200 are coaxially arranged adjacent to each other, and the end cover 100 and the nozzle 200 are connected by a plurality of connecting pipes 300. Figure 2 As shown, a plurality of fuel inlet pipes 101 - 104 are connected to a side of the end cover 100 away from the nozzle 200 .

[0043] See also Figure 3 As shown, the end cover 100 is an annular disc component, one side of the annular disc is provided with a raised annular cavity, and the fuel inlet pipes 101-104 are all connected to the side of the annular cavity away from the nozzle 200. The fuel can enter the annular cavity from the fuel inlet pipe, and the annular cavity is the end cover fuel cavity.

[0044] See also Figure 4As shown, fuel cavity partitions 105-107 are provided in the end cover fuel cavity, and the fuel cavity partitions 105-107 divide the end cover fuel cavity into 4 levels of fuel cavity. The first fuel cavity partition 105 radially divides the end cover fuel cavity into an inner ring end cover fuel cavity and an outer ring end cover fuel cavity. The second fuel cavity partition 106 is provided in the inner ring end cover fuel cavity, and divides the inner ring end cover fuel cavity into an inner 1st level end cover fuel cavity 108 and an inner 2nd level end cover fuel cavity 109. The second fuel cavity partition 107 is provided in the outer ring end cover fuel cavity, and divides the outer ring end cover fuel cavity into an outer 1st level end cover fuel cavity 110 and an outer 2nd level end cover fuel cavity 111. The fuel inlet pipe 101 is connected to the inner first-stage end cover fuel cavity 108, the fuel inlet pipe 102 is connected to the inner second-stage end cover fuel cavity 109, the fuel inlet pipe 103 is connected to the outer first-stage end cover fuel cavity 110, and the fuel inlet pipe 104 is connected to the outer second-stage end cover fuel cavity 111.

[0045] Optionally, the first fuel chamber partition 105 is a circular partition, an elliptical partition, a polygonal partition, etc.

[0046] Optionally, the cavity volume of the inner 1st stage end cover fuel cavity 108 is smaller than the cavity volume of the inner 2nd stage end cover fuel cavity 109, the cavity volume of the inner 2nd stage end cover fuel cavity 109 is smaller than the cavity volume of the outer 1st stage end cover fuel cavity 110, and the cavity volume of the outer 1st stage end cover fuel cavity 110 is smaller than the cavity volume of the outer 2nd stage end cover fuel cavity 111.

[0047] The classification of the end cover fuel cavity of the present invention is not limited to the above-mentioned separation scheme, and can also be divided into more levels of fuel cavities. For example, multiple first fuel cavity partitions 105 can be provided to separate the end cover fuel cavity into multiple annular fuel cavities adjacent in the radial direction, and each annular fuel cavity is not limited to being divided into two end cover fuel cavities in the above-mentioned scheme, and can also be divided into multiple end cover fuel cavities, and the cavity volumes of the multiple end cover fuel cavities increase successively.

[0048] In some embodiments, the specific implementation of the connecting tube 300 is shown in Figure 1 , Figure 3 and Figure 4 shown.

[0049] See also Figure 3 As shown, one end of the connecting tube 300 is connected to one side of the annular fuel cavity close to the nozzle 200, and is connected to the position where the first fuel cavity partition 105 is set on the end cover 100, and the other end is connected to the outside of the nozzle 200. A connecting tube partition 301 is set in the connecting tube 300, and the connecting tube partition 301 is connected to the first fuel cavity partition 105. The connecting tube partition 301 divides the connecting tube 300 into two air inlet channels 302 and 303. The air inlet channel 302 is connected to the inner first-stage end cover fuel cavity 108 or the inner second-stage end cover fuel cavity 109, and the air inlet channel 303 is connected to the outer first-stage end cover fuel cavity 110 or the outer second-stage end cover fuel cavity 111.

[0050] See also Figure 1 river Figure 4 As shown, a plurality of connecting pipes 300 are evenly distributed and connected between the end cover 100 and the nozzle 200 to ensure fixed support of the end cover 100 and the nozzle 200 .

[0051] The number of connecting tubes 300 of the present invention is not limited to the number shown in the drawings, and is specifically set according to the grading of the end cover fuel cavity. At the same time, the division of the air intake channel of the connecting tube 300 is not limited to the above scheme, and can be divided into multiple air intake channels by a connecting tube partition. The number of air intake channels depends on the division of the above-mentioned end cover fuel cavity, that is, if the end cover fuel cavity is divided into several end cover fuel cavities along the direction, then the air intake channel is divided into several.

[0052] In some embodiments, the specific implementation of the nozzle 200 is shown in Figure 1 , Figure 5 , Figure 6 and Figure 7 The nozzle 200 comprises a nozzle outer wall, a plurality of nozzle micro-tubes 201, and a plurality of partitions 202-203.

[0053] See also Figure 1 As shown, the outer wall of the nozzle is an annular columnar component, and the circular hole in the middle is a through hole, which is convenient for coaxial fixed installation with the end cover 100. Multiple nozzle microtubes 201 are fixedly arranged at equal intervals on the inner side of the outer wall of the nozzle, and the gap between the tube wall of the nozzle microtube 201 and the outer wall of the nozzle forms a nozzle fuel chamber.

[0054] See also Figure 5 As shown, a plurality of first partition baffles 202 are provided in the nozzle 200. The first partition baffles 202 are radial baffles. The first partition baffles 202 divide the annular cylinder of the nozzle 200 into a plurality of sector annular areas along the circumferential direction, that is, the nozzle fuel chamber is also divided into a plurality of areas, each area is respectively connected to a corresponding connecting pipe 300. A second partition baffle 203 is provided in each sector annular area of ​​the nozzle fuel chamber. The second partition baffle 203 is connected between the two end faces of the nozzle outer wall and the plate surface is perpendicular to the end face of the nozzle outer wall. The connection position of the second partition baffle 203 and the end face is the position where the end face is connected to the connecting pipe 300. The second partition baffle 203 divides each sector annular area along the radial direction, that is, it is divided into the nozzle inner fuel chamber 204 and the nozzle outer fuel chamber 205.

[0055] See also Figure 6 As shown, the second partition partition 203 is connected to the partition 301 in the connecting pipe 300, the air intake channel 302 in the connecting pipe 300 is respectively connected to the fuel cavity 204 inside each nozzle, and the air intake channel 303 is respectively connected to the fuel cavity 205 outside each nozzle.

[0056] The nozzle 200 of the present invention is not limited to the above-mentioned integral cylinder, but may be composed of a plurality of independent fan-shaped or other shaped nozzles. Meanwhile, the partition of the nozzle fuel cavity is not limited to the above-mentioned scheme, and can be partitioned according to the classification of the end cover fuel cavity and actual needs.

[0057] See also Figure 6 As shown, each nozzle micro-tube 201 penetrates the outer wall of the nozzle, a corresponding micro-tube inlet 206 is provided on the end surface of the nozzle outer wall close to the end cover 100, a corresponding micro-tube outlet 207 is provided on the end surface of the nozzle outer wall away from the end cover 100, and a fuel injection hole 208 is provided on the tube wall of the nozzle micro-tube 201. Air is introduced from the micro-tube inlet 206, and the fuel in the nozzle fuel cavity is injected into the nozzle micro-tube 201 from the fuel injection hole 208, and the fuel and air are mixed to form a premixed gas, which is discharged from the micro-tube outlet 207.

[0058] Optionally, a plurality of fuel injection holes 208 may be provided on the nozzle micro-tube 201 .

[0059] Optionally, the flow cross section of the nozzle micro-tube 201 is circular, triangular, elliptical or the like.

[0060] See also Figure 7 As shown, a convex curved portion is provided on the nozzle micro-tube 201, and a fuel injection hole 208 is opened on the convex surface of the convex curved portion. The angle between the opening direction of the fuel injection hole 208 and the opening direction of the micro-tube inlet 206 is 0-60°. The fuel is introduced into the nozzle micro-tube 201 through the fuel through hole 208 of the convex curved portion, and the fuel and the air cross jet are mixed to form a premixed gas. The convex curved portion changes the flow direction of the airflow to form a secondary flow, and the disturbance is strengthened, thereby improving the mixing uniformity of the premixed gas at the micro-tube outlet 207 and reducing NOx emissions.

[0061] When the above-mentioned fuel graded burner provided by the present invention is working, the fuel enters the graded end cover fuel chamber 108-111 in the end cover 100 through the fuel inlet pipes 101-104 on the end cover 100 respectively, so that the fuel can be divided into 4 levels, and then enters the corresponding nozzle fuel chamber through the air intake channel 302 or 303 in the connecting pipe 300 respectively, and the fuel is sprayed into the nozzle microtube 201 from the fuel spray hole 208, and mixed with the air entering from the microtube inlet 206 to form a uniform premixed gas, and finally sprayed out from the microtube outlet 207, thereby forming a combustion field with uniform temperature distribution to ensure low NOx emissions. At the same time, the graded end cover fuel chamber of the present invention can be opened in sequence and enter different areas of the nozzle fuel chamber to form a variety of permutation and combination paths. The fuel graded burner proposed by the present invention can not only meet the fuel demand of the whole machine under wide load conditions, but also can effectively adjust the combustion mode by flexibly adjusting the fuel equivalence ratio of each level to avoid thermoacoustic oscillation, thereby achieving low-pollution stable combustion under all load conditions of the whole machine.

[0062] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

[0063] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0064] It should be noted that, in the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, unless they are contradictory.

Claims

1. A fuel staged burner, characterized in that: It includes an end cover and a nozzle arranged coaxially and adjacently and a plurality of connecting pipes connecting the end cover and the nozzle, wherein a plurality of graded end cover combustion chambers are arranged inside the end cover, a plurality of fuel inlet pipes corresponding to the graded end cover fuel chambers are connected to a side of the end cover away from the nozzle, the connecting pipe includes a plurality of air intake channels, the nozzle includes a nozzle outer wall and a plurality of nozzle micro-tubes located inside the nozzle outer wall, a nozzle fuel chamber is formed by a gap between the nozzle outer wall and the tube wall of the nozzle micro-tube, the nozzle fuel chamber is divided into a plurality of zones, and the nozzle micro-tubes are all provided with fuel spray holes.

2. The fuel staged burner according to claim 1, characterized in that: The end cover is provided with an annular end cover fuel cavity, and the end cover also includes a plurality of fuel cavity partitions, and the fuel cavity partitions are used to divide the end cover fuel cavity into a plurality of graded end cover fuel cavities.

3. The fuel staged burner according to claim 2, characterized in that: The fuel cavity partition includes a plurality of first fuel cavity partitions, and the first fuel cavity partitions are used to radially divide the annular end cover fuel cavity into inner and outer adjacent multi-layer annular end cover fuel cavities.

4. The fuel staged burner according to claim 3, characterized in that: The fuel cavity partition also includes a plurality of second fuel cavity partitions. Each layer of the annular end cover fuel cavity is provided with the second fuel cavity partition. The second fuel cavity partition is used to divide each layer of the annular end cover fuel cavity into a plurality of graded end cover fuel cavities along the circumferential direction.

5. The fuel staged burner according to claim 4, characterized in that: The cavity capacity of the fuel cavity of the graded end cover increases step by step.

6. The fuel staged burner according to claim 3, characterized in that: One end of the connecting tube is connected to the position where the first fuel chamber partition is provided on the end cover. A connecting tube partition is provided in the connecting tube, and the connecting tube partition is used to divide the connecting tube into multiple air intake channels, and the multiple air intake channels correspond one by one to the multi-layer annular end cover fuel chamber.

7. The fuel staged burner according to claim 6, characterized in that: The connecting pipe partition is integrally connected to the first fuel chamber partition.

8. The fuel staged burner according to claim 6, characterized in that: The plurality of nozzle micro-tubes are arranged at equal intervals on the inner side of the nozzle outer wall, and the nozzle micro-tubes are arranged along the axial direction.

9. The fuel staged burner according to claim 8, characterized in that: The nozzle micro-tube passes through two radial end surfaces of the nozzle outer wall, the nozzle micro-tube comprises a micro-tube inlet and a micro-tube outlet, and the fuel spray hole is opened at one end of the nozzle micro-tube close to the micro-tube inlet.

10. The fuel staged burner according to claim 9, characterized in that: A gap between the outer wall of the nozzle and the tube wall of the nozzle microtube forms a nozzle fuel cavity. The nozzle further comprises a plurality of partition plates, and the partition plates are used to partition the nozzle fuel cavity.

11. The fuel staged burner according to claim 10, characterized in that: The partition partition includes a first partition partition, which is used to divide the nozzle fuel cavity into a plurality of fan-shaped nozzle fuel cavities along the circumferential direction, and the fan-shaped nozzle fuel cavities are connected to the connecting pipes in a one-to-one correspondence.

12. The fuel staged burner according to claim 11, characterized in that: The partition partition also includes a plurality of second partition partitions, wherein the second partition partitions are located in the fan-shaped annular nozzle fuel cavity, and the second partition partitions are used to divide the fan-shaped annular nozzle fuel cavity radially.

13. The fuel staged burner according to claim 12, characterized in that: The second partition partition is integrally connected to the connecting pipe partition.

14. The fuel staged burner according to claim 9, characterized in that: The nozzle micro-tube is provided with a convex curved portion, and the fuel spray hole is opened on a convex side of the convex curved portion.

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