A secondary burner with adaptively adjustable equivalence ratio and axially staged combustion chamber

Abstract

The present invention provides a secondary burner with adaptively adjustable equivalence ratio and an axially graded combustion chamber, which relates to the technical field of industrial burners, and includes a secondary burner housing, a secondary fuel spray rod and an equivalence ratio adjustment device; the secondary fuel spray rod extends into the flame tube of the combustion chamber, and a fuel spray hole is provided at the end; it also includes a short tube, which surrounds the secondary fuel spray rod, and a plurality of air circulation holes are provided on the side wall of the short tube; the equivalence ratio adjustment device includes a piston sleeve; the outer wall of the piston sleeve is provided with a piston and an air baffle, the piston separates the secondary burner housing into an upper chamber and a lower chamber, and the air baffle is located between the secondary fuel spray rod and the short tube; the piston sleeve moves along the direction of the axis of the secondary fuel spray rod. The present invention realizes adaptive adjustment of the secondary burner intake opening area, thereby adjusting the combustion chamber air distribution.

Description

Technical Field

[0001] The present invention relates to the technical field of industrial burners, in particular to a secondary burner with adaptively adjustable equivalence ratio and an axially graded combustion chamber, which meet the requirements of stable operation and low emission within a wide range of operating conditions. Background Art

[0002] As an efficient and clean combustion technology, the staged combustion technology in the combustion chamber can meet the requirements of low-emission stable combustion chambers in a wide load range of gas turbine combustion chambers, and has received extensive attention and research from various gas turbine manufacturers. Since all the fuel in the combustion chamber of a traditional gas turbine is sprayed into the flame tube by the head swirler, this will result in the combustion chamber being able to meet the emission requirements only within a narrow range of rated loads, and the emission performance can only be sacrificed in order to maintain stable combustion under low load conditions. Staged combustion technology is to introduce air and fuel at different positions in the combustion chamber, including fuel staging and air staging. Commonly used is fuel staging, including radial staging and axial staging. Radial staging means injecting fuel into the flame tube for combustion at different radial positions of the combustion chamber head. Axial staging means introducing fuel into the flame tube at different axial positions of the flame tube. By controlling the fuel supply amount at each level, the equivalence ratio of each level is changed, and then the temperature of each area is controlled, so that the combustion temperature is in a range where the generation of exhaust gases such as NOx, CO, and UHC is relatively low.

[0003] GE sets up multiple groups of burners at the head of the combustion chamber. When the load is low, only one or several groups of burners are supplied with fuel, and the rest are supplied with air only. In order to adapt to a wide range of load changes, the burner structure is complex. In order to stabilize combustion and achieve low emissions, the combustion chamber needs to continuously switch the working burners when the load changes at different times, and the fuel system and control process are complex. Kawasaki Heavy Industries uses axial grading technology to broaden the range of stable and low-emission operation of the combustion chamber. However, the fuel is only adjustable at the rear of the flame tube, and the air flow is not adjustable. Mitsubishi Heavy Industries adopts a bypass valve structure design, and sets a bypass valve on the transition section. When the load of the combustion chamber is low, the bypass valve is opened to bypass part of the air in the combustion chamber directly into the transition section, and does not participate in the combustion of the flame tube, so as to control the equivalence ratio of the combustion area. The bypass valve is close to the outlet of the combustion chamber, and the bypassed air and the combustion flue gas from the flame tube are not mixed evenly, which has a greater adverse effect on the outlet temperature distribution, and the opening and closing of the bypass valve requires an additional actuator to achieve.

[0004] The afterburner of Japan's Kawasaki combustion chamber adopts axial staged combustion, and introduces air and fuel at the rear of the flame tube, but the afterburner adopts radial air intake, which easily causes uneven distribution of air and fuel at the outlet of the afterburner. The bypass valve structure of the combustion chamber of Japan's Mitsubishi Heavy Industries realizes axial air staging, but the bypass valve does not introduce fuel staging.

[0005] The patent with application number CN202011621901.4 provides an adaptively adjustable hydrogen-rich fuel low-emission micro-flame combustion chamber, including a casing, a flame tube, a two-stage adjustable guide vane head, a fuel conduit, and a porous plate. The flame tube is fixed in the casing, and a porous plate, a two-stage adjustable guide vane head, and a fuel conduit are arranged in the casing. The fuel conduit passes through the porous plate to connect the two-stage adjustable guide vane head. The present invention automatically adjusts the angle of the adjustable guide vane in the annular air channel of the combustion chamber head, and can control the position of the flame surface when hydrogen-rich fuels with different hydrogen content ratios are burned, so that the flame will not be blown out, nor will it adhere to the combustion chamber head and burn the head wall, thereby achieving stable, efficient and clean combustion of hydrogen-rich fuels with different hydrogen content ratios, without the existence of a premixing chamber, and avoiding the dangers of flashback, spontaneous combustion and combustion oscillation. Although the invention uses hydrogen-rich fuel to achieve energy conservation and emission reduction, and the angle of the adjustable guide vane is used to change the head air flow rate to achieve the purpose of classification, the structure is relatively complex and can only be divided into two levels.

[0006] At present, no low-emission combustion chamber has been found at home or abroad that can achieve both combustion chamber air flow regulation and fuel regulation on the combustion chamber flame tube and does not require an external actuator of the combustion chamber for regulation. Summary of the invention

[0007] Based on the above problems, the purpose of the present invention is to overcome the shortcomings of the prior art and provide a secondary burner with adaptively adjustable equivalence ratio and an axially graded combustion chamber, which utilizes the secondary burner to achieve fuel staging, thereby achieving energy conservation and emission reduction while maintaining stable operation.

[0008] To achieve the above object, the present invention provides the following technical solutions:

[0009] A secondary burner with adaptively adjustable equivalence ratio comprises a secondary burner housing, a secondary fuel spray bar and an equivalence ratio adjusting device;

[0010] One end of the secondary burner housing is closed by being fixedly connected to the mounting flange, and the other end is fixedly connected to the combustion chamber housing and leads into the combustion chamber;

[0011] The secondary fuel spray rod passes through the mounting flange and extends into the flame tube of the combustion chamber, and a fuel spray hole is provided at the end of the secondary fuel spray rod;

[0012] It also includes a short tube, which surrounds the outer side of the secondary fuel spray rod, and one end of the short tube is connected to the secondary burner shell, and the other end is an outlet section and leads to the flame tube; a plurality of air circulation holes are opened on the side wall of the short tube;

[0013] The equivalence ratio adjustment device includes a piston sleeve sleeved outside the secondary fuel spray rod;

[0014] The outer wall of the piston sleeve is provided with a piston and an air baffle, the piston separates the secondary burner housing into an upper chamber and a lower chamber, the air baffle is composed of a cylindrical surface and a circular ring surface perpendicular thereto, and the air baffle is located between the secondary fuel spray rod and the short tube;

[0015] The piston sleeve moves along the direction of the axis of the secondary fuel spray rod.

[0016] Preferably, the piston is in close contact with the inner surface of the secondary burner shell, the upper chamber is connected to the environment through a pressure-introducing hole, and the outer wall of the air baffle is in close contact with the inner surface of the short tube.

[0017] Preferably, a telescopic compression spring is provided in the upper chamber, and two ends of the compression spring are respectively connected to the mounting flange and the piston.

[0018] Preferably, a limiting ring is further provided at one end of the piston sleeve away from the air baffle.

[0019] Preferably, the secondary burner housing is cylindrical, and a flange is provided at one end of the secondary burner housing connected to the combustion chamber housing, and the inner diameter of the flange is smaller than the outer diameter of the piston.

[0020] Preferably, the secondary fuel spray rod is a hollow tubular structure with one end open, a section of the secondary fuel spray rod extending into the combustion chamber is conical, and the fuel spray hole penetrates the outer wall of the secondary fuel spray rod.

[0021] Preferably, the outer diameter of the secondary fuel spray rod is smaller than the inner diameter of the mounting flange, and the diameter of one end of the secondary fuel spray rod connected to the mounting flange is enlarged to form a connecting disc, and the connecting disc is fixedly connected to the mounting flange.

[0022] Preferably, the pressure-introducing hole leads into a gap formed by the secondary fuel spray rod and the mounting flange.

[0023] Preferably, the length of the air baffle is slightly smaller than the length of the air circulation hole.

[0024] The present invention also provides an axially staged combustion chamber, comprising a secondary burner as described in any one of the above.

[0025] Preferably, it also includes a combustion chamber casing, a flame tube, a main burner and a duty burner;

[0026] An annular cavity channel is formed between the combustion chamber shell and the side wall of the flame tube;

[0027] The secondary burner is arranged on the side of the combustion chamber casing and passes through the combustion chamber casing into the flame tube.

[0028] Preferably, the main burner and the duty burner are both connected to the flame tube;

[0029] The duty burner is provided with a duty fuel inlet, the duty fuel inlet is connected to a duty fuel channel, the duty fuel channel is connected to the flame tube through a duty fuel through hole; a duty air channel is formed between the outer wall of the duty fuel channel and the flame tube, and the duty air channel opens to the annular cavity channel;

[0030] The main-stage burner is provided with a main-stage fuel inlet and a main-stage air passage, wherein the main-stage fuel inlet leads into the main-stage air passage; and both ends of the main-stage air passage are respectively connected with the annular cavity passage and the flame tube.

[0031] Preferably, a main-stage swirl blade is provided at one end of the main-stage air channel communicating with the annular cavity channel; and a duty swirl blade is provided at one end of the duty air channel communicating with the annular cavity channel.

[0032] Compared with the prior art, the present invention has the following advantages:

[0033] 1. The present invention designs a secondary burner with an adaptively adjustable equivalence ratio, comprising a secondary burner housing, a secondary fuel spray rod and an equivalence ratio adjusting device; wherein the piston sleeve of the equivalence ratio adjusting device can move up and down, and since the air baffle at the end of the piston sleeve can block the air circulation hole, the area of ​​the secondary burner intake opening can be adaptively adjusted to adjust the air distribution of the combustion chamber. Therefore, when the combustion chamber is under low load, that is, when the pressure is low, the piston drives the piston sleeve to move downward, at this time, the air baffle reduces the blocking of the air circulation hole, the area of ​​the secondary burner intake opening increases, the proportion of the secondary burner air volume increases, and the corresponding main burner air ratio decreases; when the combustion chamber is under high load, that is, when the pressure is high, the pressure difference between the upper and lower cavities increases, the piston is pushed upward, the area of ​​the secondary burner intake opening decreases, the proportion of the secondary burner air volume is reduced, and the main burner air ratio is increased; it is ensured that the fuel-air ratio of the main combustion area is stable within a reasonable range under different working conditions, the overall combustion stability of the combustion chamber is improved, and the working condition range that can achieve low pollution emissions is broadened at the same time.

[0034] 2. The combination of the equivalence ratio adjustment device structure of the secondary burner in the present invention can automatically adjust the amount of air entering the secondary burner according to the different pressures of the combustion chamber at different loads. No additional control and actuator are required to achieve the adjustment function. The structure is simple and the reliability is high.

[0035] 3. The secondary fuel injection holes of the present invention can be arranged in multiple rows along the spray rod, and the number of fuel injection holes can be increased as the load of the combustion chamber increases. This prevents the fuel and air mixing degree of the secondary burner from changing significantly with the working conditions, which is conducive to stable combustion and reduced NOx emissions. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is a schematic structural diagram of the secondary burner provided by the present invention in the cross-sectional direction;

[0037] Figure 2 It is a structural schematic diagram of the secondary burner in the present invention;

[0038] Figure 3 The present invention is based on Figure 1 The cross-sectional view in the AA direction;

[0039] Figure 4 It is a partial schematic diagram of the pressure-introducing hole of the secondary burner in the present invention;

[0040] Figure 5 (a) is a schematic diagram of the structure of the piston of the secondary burner when it moves to the lower limit position based on Example 1 of the present invention, Figure 5 (b) is based on Figure 5 (a) Cross-sectional view along the BB direction;

[0041] Figure 6 (a) is a schematic diagram of the structure of the piston of the secondary burner when it moves to the upper limit position based on the second embodiment of the present invention. Figure 6 (b) is based on Figure 6 (a) Cross-sectional view along CC direction;

[0042] Figure 7 (a) is a schematic diagram of the structure of the piston of the secondary burner when it moves to the lower limit position based on the second embodiment of the present invention. Figure 7 (b) is based on Figure 7 (a) Cross-sectional view in DD direction;

[0043] Figure 8 It is a structural schematic diagram of a combustion chamber provided by the present invention;

[0044] Reference numerals:

[0045] 1. Combustion chamber; 2. Secondary burner; 3. Main burner; 4. Duty burner; 5. Flame tube;

[0046] 6. Combustion chamber shell; 7. Main stage swirl blades; 8. Duty swirl blades 9. Secondary burner shell;

[0047] 11. Piston sleeve; 12. Piston; 13. Limiting ring; 14. Air baffle; 15. Air circulation hole;

[0048] 16. Mounting flange; 17. Short pipe; 18. Outlet section; 19. Pressure inlet hole; 20. Secondary fuel spray rod; 21. Air rectification hole; 100. Annular cavity channel; 101. Main fuel inlet; 102. Duty fuel inlet; 103. Secondary fuel inlet; 104. Compression spring; 105. Sealing ring; 110. Secondary fuel jet hole. DETAILED DESCRIPTION

[0049] In order to make the purpose and technical solution of the embodiments of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention.

[0050] In the description of the present application, it should be understood that the terms indicating orientation or positional relationships are based on the orientation or positional relationships shown in the drawings and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be understood as a limitation on the present application.

[0051] Embodiment 1

[0052] Figure 1 and Figure 2 The figure shows a schematic diagram of the overall structure of the secondary burner, including a secondary burner housing 9, a secondary fuel spray rod 20 and an equivalence ratio adjustment device.

[0053] The secondary burner housing 9 is fixed on the outer surface of the combustion chamber housing 6. The secondary burner housing 9 is a hollow cylindrical structure, and its cross-sectional shape is similar to an I-shaped structure. One end of the secondary burner housing 9 is closed by being fixedly connected to the mounting flange 16, and the other end is fixedly connected to the combustion chamber housing 6 and passes into the combustion chamber 1.

[0054] It is fixedly connected to the mounting flange 16 by threaded connection, and a flange is provided at one end connected to the combustion chamber housing 6, the inner diameter of the flange is smaller than the diameter of the secondary burner housing 9, and the outer diameter is larger than the diameter of the secondary burner housing 9; the secondary burner housing 9 is fixedly connected to the combustion chamber housing 6 by the flange. A short tube 17 is fixed to the lower surface of the flange, and the short tube 17 is a hollow tubular structure and is located inside the combustion chamber 1. The end of the short tube 17 is close to the outlet section 18 of the secondary burner 2, and the outlet section 18 leads to the inside of the flame tube 5. A plurality of air circulation holes 15 are opened on the side wall of the short tube 17, and the air circulation holes 15 are all located in the area inside the annular cavity channel 100. The air circulation holes 15 can pass the air in the annular channel cavity 100 into the inside of the short tube 17.

[0055] The mounting flange 16 is provided with a through hole, and the secondary fuel spray rod 20 passes through the mounting flange 16, the secondary burner housing 9 and the short tube 17 in sequence, and the secondary fuel spray rod 20 is fixedly connected to the mounting flange 16 by bolts. The end of the secondary fuel spray rod 20 is located in the outlet section 18 or the short tube 17 of the secondary burner 2. The secondary fuel spray rod 20 is a hollow tubular structure with one end open. The end is provided with a secondary fuel jet hole 110, and the head end is provided with a secondary fuel inlet 103. The secondary fuel enters the secondary fuel spray rod 20 through the secondary fuel inlet 103 and finally ejects from the secondary fuel jet hole 110 at the end; preferably, the diameter of the end of the secondary fuel spray rod 20 gradually decreases to form a conical structure, and the secondary fuel jet holes 110 penetrate the outer wall of the secondary fuel spray rod 20 and are evenly distributed on the conical structure.

[0056] The equivalence ratio adjustment device includes a piston sleeve 11 sleeved outside the secondary fuel spray rod 20 . The gap between the piston sleeve 11 and the secondary fuel spray rod 20 is extremely small, and the piston sleeve 11 can move up and down along the axial direction of the secondary fuel spray rod 20 .

[0057] The outer wall of the piston sleeve 11 is provided with a limit ring 13, a piston 12 and an air baffle 14 from top to bottom. The limit ring 13 and the piston 12 are located above the flange, and the air baffle 14 is located inside the short tube 17. The limit ring 13, the piston sleeve 11 and the air baffle 14 are an integrated structure. The limit ring 13 is cylindrical, and the outer diameter of the limit ring 13 is larger than the inner diameter of the mounting flange 16 and smaller than the inner diameter of the secondary burner housing 9. The limit ring 13 and the secondary fuel spray rod 20 are sealed by a sealing ring 105.

[0058] The piston 12 is in close contact with the inner surface of the secondary burner housing 9, isolating the secondary burner housing 9 into an upper chamber and a lower chamber, wherein the upper chamber is connected to the environment through the pressure-introducing hole 19. Figure 4 As shown. A retractable compression spring 104 is provided in the upper chamber, and the two ends of the compression spring 104 are respectively connected to the mounting flange 16 and the piston 12. The compression spring 104 is always in a compressed state during the sliding process of the piston sleeve 11 between the upper and lower limit positions. A sealing ring 105 is provided between the piston 12 and the secondary burner housing 9, and between the piston 12 and the secondary fuel spray rod 20. The sealing ring 105 inside the sleeve can enable the piston sleeve 11 to slide relative to the secondary fuel spray rod 20 while preventing the air in the combustion chamber 1 from leaking from the gap therebetween; the sealing ring 105 outside the piston 12 can enable the piston 12 to slide relative to the inner wall of the secondary burner housing 9 while preventing the air in the combustion chamber 1 from leaking from the gap therebetween.

[0059] The air baffle 14 is composed of a cylindrical surface and a circular ring surface perpendicular thereto, and the air baffle 14 is located between the secondary fuel spray rod 20 and the short tube 17. The cylindrical outer wall of the air baffle 14 is in close contact with the inner surface of the short tube 17 and the length of the air baffle 14 is slightly smaller than the length of the air circulation hole 15. During the movement of the piston sleeve 11, the air baffle 14 will block the air circulation hole 15 to varying degrees, changing the air circulation area. An air rectification hole 21 is provided on the circular ring surface of the air baffle, and the air flowing in from the air circulation hole 15 flows into the end of the short tube 17 through the air rectification hole 21, and then enters the flame tube 5 through the outlet section 18.

[0060] When the piston sleeve 11 moves upward until the limit ring 13 abuts against the mounting flange 16, the piston sleeve 11 cannot move further upward and is located at the upper limit position; when the piston sleeve 11 moves downward until the piston 12 abuts against the flange of the secondary burner housing 9, the piston sleeve 11 cannot move further downward and is located at the lower limit position.

[0061] The working principle of the secondary burner 2 is as follows: Figure 5 As shown, when the combustion chamber 1 is under low load, that is, when the internal pressure of the annular cavity channel 100 is low, under the combined action of atmospheric pressure and spring elastic force, the compression spring 104 will push the piston 12 and drive the piston sleeve 11 to the lower limit position. At the lower limit position, the air baffle 14 does not block the air flow hole 15. At this time, the opening area of ​​the secondary burner 2 is the largest, the corresponding air ratio of the secondary burner is the highest, and the air ratio of the main burner is the lowest. The secondary fuel spray rod 20 is controlled by an external valve to not introduce or introduce a small amount of fuel, such as Figure 1 shown.

[0062] When the combustion chamber 1 is under high load, that is, when the pressure of the annular cavity channel 100 is high, the pressure difference between the upper and lower cavities overcomes the elastic force of the compression spring 104, pushing the piston 12 to the upper limit position. At the upper limit position, the air baffle 14 blocks most of the air flow holes 15. At this time, the opening area of ​​the secondary burner 2 is the smallest, the corresponding air ratio of the secondary burner is the lowest, and the air ratio of the main burner is the highest. At this time, the amount of secondary fuel introduced is the largest. Through this adaptive adjustment, the equivalence ratio of the main combustion zone is maintained within a certain range, and the stability of the main combustion zone and the low NOx generation are maintained.

[0063] An axially staged combustion chamber 1 comprises a secondary burner 2 as described above. Figure 8 As shown, it also includes a combustion chamber casing 6, a flame tube 5, a main burner 3 and a service burner 4; an annular cavity channel 100 is formed between the combustion chamber casing 6 and the side wall of the flame tube 5; the secondary burner 2 is arranged on the side of the combustion chamber casing 6, and the secondary burner 2 is arranged downstream of the main burner 3 along the flow direction of the gas and passes through the combustion chamber casing 6 into the flame tube 5.

[0064] The main burner 3 and the duty burner 4 are both connected to the flame tube 5; the duty burner 4 is provided with a duty fuel inlet 102, the duty fuel inlet 102 is connected to the duty fuel channel, and the duty fuel channel is connected to the flame tube 5 through the duty fuel through hole; a duty air channel is formed between the outer wall of the duty fuel channel and the flame tube 5, and the duty air channel opens to the annular cavity channel 100; the main burner 3 is provided with a main fuel inlet 101 and a main air channel, and the main fuel inlet 101 is connected to the main air channel; the two ends of the main air channel are respectively connected to the annular cavity channel 100 and the flame tube 5. The end of the main air channel connected to the annular cavity channel 100 is provided with a main swirl blade 7; the end of the duty air channel connected to the annular cavity channel 100 is provided with a duty swirl blade 8. The duty flame and the main premixed flame are formed at the outlets of the main burner and the duty burner 4, respectively.

[0065] Embodiment 2

[0066] This embodiment provides a secondary burner 2 with an adjustable equivalence ratio. The structure of the secondary burner 2 is similar to that of the first embodiment. Figure 6 and Figure 7 As shown, compared with the first embodiment, the difference is that the diameter of the end of the secondary fuel spray rod 20 gradually decreases to form a conical structure, and the secondary fuel jet hole 110 penetrates the outer wall of the secondary fuel spray rod 20, and the secondary fuel jet hole 110 is arranged in several rows along the radial direction of the flame tube 5. Several fuel injection holes are arranged circumferentially along the secondary fuel spray rod 20. When the combustion chamber 1 has different loads, that is, pressures, the air baffle 14 is located at different positions. The air baffle 14 can completely or partially block the air inlet while closing all or part of the secondary fuel jet holes 110. At different loads, the fuel jet velocity remains relatively stable, and a relatively stable mixing degree, that is, the fuel concentration distribution of the fuel-air mixture is always maintained. This can effectively maintain low thermoacoustic oscillations and nitrogen oxide emission levels at different loads.

[0067] The above is only an embodiment of the present invention, and its description is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention.

Claims

1. A secondary burner with adaptively adjustable equivalence ratio, characterized in that: It includes a secondary burner housing, a secondary fuel spray bar and an equivalence ratio adjustment device; One end of the secondary burner housing is closed by being fixedly connected to the mounting flange, and the other end is fixedly connected to the combustion chamber housing and leads into the combustion chamber; The secondary fuel spray rod passes through the mounting flange and extends into the flame tube of the combustion chamber, and a fuel spray hole is provided at the end of the secondary fuel spray rod; It also includes a short tube, which surrounds the outer side of the secondary fuel spray rod, and one end of the short tube is connected to the secondary burner shell, and the other end is an outlet section and leads to the flame tube; a plurality of air circulation holes are opened on the side wall of the short tube; The equivalence ratio adjustment device includes a piston sleeve sleeved outside the secondary fuel spray rod; The outer wall of the piston sleeve is provided with a piston and an air baffle, the piston separates the secondary burner housing into an upper chamber and a lower chamber, the air baffle is composed of a cylindrical surface and a circular ring surface perpendicular to the cylindrical surface, and the air baffle is located between the secondary fuel spray rod and the short tube; The piston sleeve moves along the direction of the axis of the secondary fuel spray rod.

2. A secondary burner with adaptively adjustable equivalence ratio according to claim 1, characterized in that: The piston is in close contact with the inner surface of the secondary burner shell, and the outer wall of the air baffle is in close contact with the inner surface of the short tube.

3. The secondary burner with adaptively adjustable equivalence ratio according to claim 1, characterized in that: A retractable compression spring is arranged in the upper chamber, and two ends of the compression spring are respectively connected to the mounting flange and the piston.

4. The secondary burner with adaptively adjustable equivalence ratio according to claim 1, characterized in that: A limiting ring is also provided at one end of the piston sleeve away from the air baffle.

5. The secondary burner with adaptively adjustable equivalence ratio according to claim 1, characterized in that: The secondary burner shell is cylindrical, and a flange is provided at one end of the secondary burner shell connected to the combustion chamber shell, and the inner diameter of the flange is smaller than the diameter of the secondary burner shell.

6. The secondary burner with adaptively adjustable equivalence ratio according to claim 1, characterized in that: The secondary fuel spray rod is a hollow tubular structure with one end open. The section of the secondary fuel spray rod extending into the combustion chamber is in a cone shape, and the fuel spray hole penetrates the outer wall of the secondary fuel spray rod.

7. The secondary burner with adaptively adjustable equivalence ratio according to claim 6, characterized in that: The outer diameter of the secondary fuel spray rod is smaller than the inner diameter of the mounting flange. The diameter of one end of the secondary fuel spray rod connected to the mounting flange is enlarged to form a connecting disc, and the connecting disc is fixedly connected to the mounting flange.

8. The secondary burner with adaptively adjustable equivalence ratio according to claim 7, characterized in that: A pressure-inducing hole is provided on the connecting disc, and the pressure-inducing hole leads into a gap formed by the secondary fuel spray rod and the mounting flange.

9. The secondary burner with adaptively adjustable equivalence ratio according to claim 1, characterized in that: The length of the air baffle is smaller than the length of the air circulation hole.

10. An axially staged combustion chamber, characterized in that: It includes a secondary burner as described in any one of claims 1 to 9; it also includes a combustion chamber casing, a flame tube, a main burner and a service burner; an annular cavity channel is formed between the side walls of the combustion chamber casing and the flame tube; the secondary burner is arranged on the side of the combustion chamber casing and passes through the combustion chamber casing into the flame tube; a number of secondary burners are arranged along the circumference of the combustion chamber casing; the service burner and the main burner are arranged at the end of the flame tube.

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