Axial staged combustion two-stage combustor with micro mixing pipe

Abstract

The invention provides an axial staged combustion two-stage combustor with micro mixing pipes, and relates to the technical field of combustion of gas turbines. The straight blade type combustor body expands and extends gradually, a fuel cavity is defined between the outer side wall and the inner side wall of the straight blade type combustor body, and a diffusion cavity is defined by the inner side wall of the straight blade type combustor body; a fuel hole communicated with the two cavities is formed in the inner side wall of the fuel cavity; a plurality of through micro-mixing pipes perpendicular to the section of the blade are arranged in the diffusion cavity, the two ends of each micro-mixing pipe correspond to the air inlet side and the air outlet side, and spray holes are formed in the pipe walls of the micro-mixing pipes; and the inner side wall converges towards the diffusion cavity at the downstream of the micro-mixing pipe to form a convergence channel. Fuel is evenly distributed through two-stage pressure relief of the fuel cavity and the diffusion cavity, air rectification and preliminary mixing are achieved through the micro mixing pipe, secondary enhanced mixing and pneumatic tempering suppression are achieved through the convergence channel, the combustion stability is remarkably improved, NOx emission is reduced, and support is provided for wide-working-condition safe and clean operation of the high-power gas turbine.

Description

Technical Field

[0001] This invention relates to the field of gas turbine combustion technology, and in particular to an axial staged combustion two-stage burner with a micro-mixing tube. Background Technology

[0002] With increasingly stringent environmental regulations, reducing NOx emissions has become a core objective in gas turbine combustor design. Modern heavy-duty gas turbines commonly employ lean premixed combustion technology to suppress thermal NOx formation, with axial staged combustion being an advanced solution: the primary combustion zone maintains flame stability under most operating conditions, while the secondary combustion zone starts under high-temperature, high-load conditions, achieving complete fuel combustion and controlling combustion temperature through afterburning. The performance of the secondary burner directly determines the stability and emission levels of axial staged combustion, requiring rapid and uniform mixing of fuel and air in the high-speed mainstream while ensuring stable flame anchoring. Existing secondary nozzles generally employ circular or elliptical cross-section structures. This design easily creates a cylindrical turbulence effect downstream, potentially leading to uneven air intake in the primary burner and inducing a large-area backflow zone upstream of the primary burner, significantly increasing the risk of backfire in the primary burner and affecting combustion stability and operational safety.

[0003] To address the issues of low mixing efficiency and high risk of backfire, existing technologies propose an improved scheme of setting up micro-mixing tubes inside the secondary burner to improve the mixing effect of fuel and air through micro-scale mixing. However, existing secondary burners using micro-mixing tubes still have the following shortcomings: (1) The micro-mixing tube structure design is imperfect, lacking optimization in terms of quantity, arrangement, and nozzle position, resulting in uneven mixing, uneven outlet concentration field, and obvious local high-temperature zones, limiting further reduction of NOx; (2) Insufficient fuel injection uniformity, due to unreasonable diffuser or fuel distribution structure, the fuel flow distribution of each micro-mixing tube is uneven, affecting combustion uniformity and increasing the risk of local backfire; (3) Lack of backfire protection structure, the outlet section of the micro-mixing tube lacks a convergence channel design, failing to form an aerodynamic barrier, and the flame root is close to the inside of the tube, making it prone to backfire during load fluctuations, threatening structural safety.

[0004] Existing patent CN118463179A discloses a micro-mixer burner and an axial air staged combustion system, which improves the radial support stability of the mixing tube through positioning columns and stabilizing mechanisms, avoiding radial bending problems caused by airflow blowing. However, this patent also does not include a backfire protection design for the outlet structure of the micro-mixing tube, and cannot solve the technical problems of uneven fuel mixing and high risk of backfire.

[0005] Existing patent CN121557483A discloses a multi-angle microtube staged combustion swirl gas burner, which achieves uniform fuel injection through a multi-angle fuel distribution device and introduces recirculated flue gas through a mixing tube flare and an arc-shaped air sleeve suction port. However, this solution does not optimize for the interference of the secondary burner on the flow field of the primary burner in axial staged combustion, nor does it solve the technical defect of lacking a backfire protection structure at the outlet of the micro-mixing tube.

[0006] In summary, there is an urgent need for a technology that can overcome the problems of uneven fuel mixing, insufficient backfire protection, and significant interference with the flow field of the first-stage burner in existing technologies, so as to achieve efficient and uniform mixing of fuel and air, stable flame anchoring, and overall safety and low emission targets for the combustion chamber. Summary of the Invention

[0007] Based on the current state of technology, this invention proposes an axially staged combustion two-stage burner with a micro-mixing tube to address the problems of uneven combustion, high NOx emissions, high risk of backfire, and significant flow field interference inherent in existing two-stage burners. Compared with existing technologies, this invention achieves a dual improvement in combustion stability and efficiency, as well as a synergistic reduction in NOx and CO emissions, providing key technical support for the clean and safe operation of high-parameter, high-power gas turbines across a wide range of operating conditions.

[0008] To achieve the above objectives, the first aspect of this invention proposes an axially staged combustion two-stage burner with a micro-mixing tube, the specific technical solution of which is as follows: An axially staged combustion two-stage burner with a micro-mixing tube, comprising: The burner body is a straight blade-shaped structure that gradually expands along the combustion chamber axis, including a blade-shaped outer sidewall and a blade-shaped inner sidewall; The fuel chamber is a closed cavity located on the outer periphery of the burner body, formed by the outer wall of the blade-shaped outer side and the inner wall of the blade-shaped outer side; a fuel inlet is provided at one end of the outer wall of the blade-shaped outer side on the upstream side; The diffuser chamber is a closed cavity formed by the inner wall of the blade-shaped structure, located in the middle of the burner body and adjacent to the fuel chamber; multiple fuel holes are opened on the inner wall of the blade-shaped structure to connect the fuel chamber and the diffuser chamber; Multiple micro-mixing tubes are disposed within the diffuser chamber and penetrate the burner body perpendicular to the blade cross-section, with their two ends corresponding to the air intake side and the air outlet side, respectively; spray holes are provided on the tube wall of the micro-mixing tube.

[0009] Furthermore, the flow cross-section of the fuel chamber gradually increases along the combustion chamber axis, forming a primary pressure relief chamber for the fuel.

[0010] Furthermore, the flow cross-section of the diffuser chamber gradually increases along the combustion chamber axis, and the volume of the diffuser chamber is greater than the volume of the fuel chamber, forming a secondary pressure relief chamber for the fuel.

[0011] Furthermore, the diffuser chamber is configured as multiple sections, arranged in segments along the length of the burner body, with each segment having a different chamber diameter.

[0012] Furthermore, the fuel holes are located on both sides and the downstream end of the inner wall of the blade, and the number of fuel holes at the downstream end is less than the number on both sides.

[0013] Furthermore, the nozzle is located at one end of the micro-mixing tube near the air intake side.

[0014] Furthermore, the nozzles are distributed on the wall of the micro-mixing tube in the form of single holes, symmetrical double holes, or circumferential multiple holes.

[0015] Furthermore, the ratio of the diameter of the nozzle to the inner diameter of the micro-mixing tube is 0.2-0.5.

[0016] Furthermore, the inner diameter of the micro-mixing tube is 2-8 mm; the ratio of the length to the inner diameter of the micro-mixing tube is 5-20.

[0017] Furthermore, the multiple micro-mixing tubes are arranged in an array, and the ratio of the spacing between adjacent micro-mixing tubes to the inner diameter of the micro-mixing tubes is 1.2-2.0.

[0018] Furthermore, the blade-shaped inner wall converges towards the diffuser in the downstream section of the micro-mixing tube outlet to form a convergence channel, and the cross-sectional area of ​​the convergence channel gradually decreases along the airflow direction.

[0019] Furthermore, the convergence angle of the convergence channel is greater than 10°.

[0020] Furthermore, the convergence angle of the convergence channel is 15°-30°.

[0021] To achieve the above objectives, a second aspect of the present invention provides a gas turbine combustion chamber, the specific technical solution of which is as follows: A gas turbine combustion chamber includes a primary burner and a secondary burner arranged sequentially along an axial direction, wherein the secondary burner is the aforementioned axially staged combustion secondary burner with a micro-mixing tube.

[0022] Furthermore, there are multiple secondary burners, which are evenly arranged around the circumference of the combustion chamber. The minimum flow area between adjacent secondary burners is the throat cross-sectional area A2. The cross-sectional area of ​​the channel downstream of the secondary burner is the downstream cross-sectional area A1. The downstream cross-sectional area A1 is equal to or less than the throat cross-sectional area A2.

[0023] By applying the above-described technical solution of the present invention, at least the following technical effects are achieved: 1. This invention, by setting a convergence channel downstream of the micro-mixing tube and designing the convergence angle of the channel to be greater than 10°, allows the fuel-air mixture to undergo secondary acceleration and enhanced mixing before injection. This design significantly shortens the residence position of the flame root within the micro-mixing tube and forms a high-speed aerodynamic barrier at the outlet, effectively blocking the path of flame propagation into the micro-mixing tube. Therefore, this invention can significantly reduce the risk of backfire under low-load conditions or when there are localized abnormal fuel concentrations, thus significantly improving the safety and stability of combustion chamber operation.

[0024] 2. This invention utilizes the micro-mixing tube as both the inlet channel for secondary air and the airflow rectification structure. Before entering the secondary combustion zone, the air is regulated and guided by multiple parallel micro-mixing tubes, forming a uniform velocity and pressure field. This design avoids the cylindrical turbulence effect that easily occurs downstream of traditional circular nozzles, ensuring uniform airflow distribution in the secondary combustion zone, thereby achieving a uniform distribution of the combustion temperature field and laying the foundation for low-NOx combustion.

[0025] 3. This invention employs a fuel chamber design with a gradually increasing flow area, allowing the fuel to undergo its first diffusion and depressurization within the chamber. Subsequently, the fuel enters a larger diffusion chamber through fuel orifices for a second depressurization, achieving uniform fuel pressure and flow rate along the flow path. The uniformly mixed fuel is then injected axially into each micro-mixing tube through nozzles, forming a uniform premixed gas with air. Through the synergistic effect of two-stage depressurization and multi-point injection, this invention effectively eliminates the problems of uneven fuel distribution and localized rich combustion zones commonly found in traditional structures, significantly reducing the risk of incomplete combustion.

[0026] 4. This invention achieves highly uniform mixing of fuel and air at the microscale through initial mixing within the micro-mixing tube and secondary enhanced mixing within the convergence channel, suppressing the generation of localized high-temperature hotspots at the source. Simultaneously, uniform fuel distribution and stable flame anchoring ensure complete combustion. Therefore, this invention can simultaneously reduce emissions of nitrogen oxides (NOx) and carbon monoxide (CO), meeting increasingly stringent environmental regulations.

[0027] 5. This invention employs a straight-blade two-stage burner structure, combined with the flow acceleration effect of the downstream converging channel, ensuring that the fuel-air mixture ejected from the two-stage burner is injected into the combustion chamber in a uniform and directional manner, avoiding disturbance to the intake air of the upstream first-stage burner. This design effectively eliminates the interference of traditional two-stage burners on the flow field of the first-stage combustion zone, ensuring flame stability and uniformity of the outlet temperature field in the first-stage combustion zone, and achieving synergistic optimization of the two-stage combustion zones and overall performance improvement.

[0028] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0029] The accompanying drawings, which form part of this specification, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 A schematic diagram of the structure of an axial staged combustion two-stage burner with a micro-mixing tube proposed in this invention is shown; Figure 2 An installation schematic diagram of an axially staged combustion two-stage burner with a micro-mixing tube proposed in this invention is shown; Figure 3 A cross-sectional schematic diagram of an axially staged combustion two-stage burner with a micro-mixing tube proposed in this invention is shown; Figure 4 A schematic diagram of the throat cross-section structure of a gas turbine combustion chamber proposed in this invention is shown.

[0030] Figure label: 10- Blade-shaped outer wall; 20- Blade-shaped inner wall; 11- Fuel inlet; 21- Fuel hole; 30- Micro-mixing tube; 31- Nozzle. Detailed Implementation

[0031] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0032] The present invention will be further described in detail below with reference to specific embodiments, which should not be construed as limiting the scope of protection claimed by the present invention.

[0033] To address the problems of uneven combustion, high NOx emissions, high risk of backfire, and significant interference with the flow field in the primary combustion zone in existing technologies, this invention proposes an axially staged combustion two-stage burner with micro-mixing tubes. By employing a straight-blade body and incorporating multiple parallel micro-mixing tubes as air rectification channels, a fuel chamber with gradually increasing flow area and a fuel diffuser chamber connected to the micro-mixing tubes are constructed on the outer side of the blades, forming a uniform fuel injection structure with pressure relief. A convergence channel with a large convergence angle is located downstream of the micro-mixing tubes, achieving microscopic uniform mixing of fuel and air and suppressing aerodynamic backfire, thereby improving combustion stability and reducing pollutant emissions.

[0034] According to a first aspect of the present invention, an axially staged combustion two-stage burner with a micro-mixing tube is proposed, see reference. Figures 1-3 As shown, the secondary burner is a straight-blade structure extending axially along the combustion chamber, including an outer blade-shaped outer wall 10 and an inner blade-shaped inner wall 20. The outer blade-shaped outer wall 10 and the inner blade-shaped inner wall 20 enclose a fuel chamber, while the inner blade-shaped inner wall 20 encloses a diffuser chamber. Multiple micro-mixing tubes 30 are arranged within the diffuser chamber, extending perpendicularly to the blade cross-section, with their two ends corresponding to the air inlet and outlet of the burner, respectively. Multiple fuel holes 21 are formed on the inner blade-shaped inner wall 20, each connecting the fuel chamber and the diffuser chamber. Each micro-mixing tube 30 has a spray nozzle 31 on its wall for injecting fuel into the micro-mixing tube 30 to mix with air.

[0035] For details, please refer to Figure 1 and Figure 2 As shown, the secondary burner is an overall straight-blade structure extending axially along the combustion chamber. It has a gradually expanding shape with a smaller cross-section at one end and a larger cross-section at the other, along the airflow direction. The smaller cross-section end faces the upstream primary burner, and the larger cross-section end faces the downstream combustion chamber outlet. A fuel inlet and fuel pipe interface 11 are provided at the smaller cross-section end for connecting to an external fuel source, through which fuel enters the burner. The fuel chamber is formed by the outer blade-shaped outer wall 10 and the inner blade-shaped inner wall 20, creating a closed cavity structure extending along the blade height direction (i.e., perpendicular to the combustion chamber axial direction). The flow area of ​​the fuel chamber gradually increases axially, forming a diffuser structure from the fuel inlet end near the primary burner to the closed end away from the primary burner. The fuel chamber receives and accommodates fuel from the fuel pipe, and the gradually increasing flow area reduces the fuel flow velocity and restores static pressure within the chamber, achieving the first diffusion and depressurization of the fuel. This lays the foundation for pressure uniformity in subsequent uniform distribution to each micro-mixing tube 30.

[0036] For details, please refer to Figure 1 and Figure 2 As shown, the diffuser chamber is enclosed by a blade-shaped inner wall 20, forming a closed cavity structure extending along the blade height direction. The diffuser chamber is connected to the fuel chamber through multiple fuel holes 21 formed on the blade-shaped inner wall 20. Preferably, the volume of the diffuser chamber is set to be larger than the volume of the fuel chamber to form a secondary decompression space for the fuel. After the fuel enters the diffuser chamber through the fuel holes 21, the fuel flow velocity further decreases and the static pressure further recovers as the flow cross-section of the diffuser chamber gradually increases along the fuel flow direction, achieving a second diffusion and decompression of the fuel. After two decompressions, the fuel forms a uniform pressure field distribution within the diffuser chamber, ensuring uniform injection into each micro-mixing tube 30 through the nozzle 31.

[0037] For details, please refer to Figure 1 and Figure 2 As shown, there are multiple micro-mixing tubes 30, which are arranged in a direction perpendicular to the blade cross-section within the diffuser cavity. That is, the micro-mixing tubes 30 extend along the blade height direction, with their two ends corresponding to the air inlet side and the air outlet side, respectively. Preferably, the multiple micro-mixing tubes 30 are arranged in an array, with each micro-mixing tube 30 parallel to each other and with uniform spacing.

[0038] The micro-mixing tube 30 has nozzles 31 on its wall, preferably located at the end of the micro-mixing tube 30 near the intake side. After the fuel is evenly distributed in the diffuser chamber, it is injected into the micro-mixing tube 30 through the nozzles 31, where it undergoes preliminary mixing with the air entering from the intake side to form a uniform fuel-air premixed gas. The premixed gas is transported downstream along the micro-mixing tube 30 and finally ejected from the outlet side of the micro-mixing tube 30 to enter the combustion chamber for combustion. By positioning the nozzles 31 close to the intake side, the fuel and air obtain a longer mixing path within the micro-mixing tube 30, further improving the mixing uniformity.

[0039] The micro-mixing tube 30 serves as a channel for air to enter the secondary combustion zone and also rectifies the incoming air. Multiple parallel-arranged micro-mixing tubes 30 ensure a uniform airflow field as the air exits the micro-mixing tube 30, laying the foundation for stable combustion and a uniform temperature field downstream.

[0040] As an optimized implementation, the number and arrangement of the micro-mixing tubes 30, as well as the diameter and distribution of the nozzles 31, can be adaptively designed according to the rated load and fuel type of different gas turbine models to meet the combustion requirements under different operating conditions. The diffuser can also be provided with multiple cavity structures of different diameters along the blade length direction to achieve segmented and uniform fuel depressurization, further improving the uniformity of fuel distribution and combustion stability.

[0041] Optionally, the inner diameter D of the micro-mixing tube 30 is 5-10 mm. The ratio of the length L to the inner diameter D of the micro-mixing tube 30, L / D, is 15-50 to ensure sufficient flow development within the tube and achieve thorough mixing of fuel and air.

[0042] Optionally, the ratio of the distance S between adjacent micro-mixing tubes 30 to the inner diameter D of the micro-mixing tube 30, S / D, is 0.5-2, to ensure sufficient airflow space between each micro-mixing tube 30, while avoiding adverse interference between adjacent jets.

[0043] Optionally, the diameter d of the nozzle 31 can be optimized according to the fuel flow rate and injection pressure drop. The ratio d / D of the nozzle 31 diameter to the inner diameter D of the micro-mixing tube 30 is 0.2-0.5. The distribution of the nozzles 31 on the upper end of the wall of the micro-mixing tube 30 can be configured as a single hole, a double hole symmetrical arrangement, or a multi-hole circumferentially distributed arrangement to optimize the spatial distribution of fuel within the micro-mixing tube 30.

[0044] Optionally, the diffuser chamber can be configured with multiple segments of different diameters along the blade length to achieve segmented and uniform fuel depressurization. The diffuser chamber can be divided into 2-4 segments, with the diameter of each segment gradually increasing from the fuel inlet end to the closed end, to ensure smooth pressure recovery along the blade and avoid uneven fuel distribution caused by local pressure surges. Through the segmented depressurization design, the uniformity of fuel distribution along the blade height within the diffuser chamber can be further improved, thereby enhancing the fuel distribution consistency among the micromixing tubes 30.

[0045] The above design parameters can be optimized and matched according to the specific gas turbine model, rated power, operating conditions and fuel composition to achieve the best combustion stability, the lowest pollutant emissions and the widest backfire safety margin.

[0046] For details, please refer to Figure 3 As shown, a convergence channel is provided at the downstream end of the micro-mixing tube 30, that is, near the burner outlet side. The convergence channel is formed by the blade-shaped inner sidewall 20 extending converging towards the diffuser chamber in the downstream section of the micro-mixing tube 30 outlet end, so that the cross-sectional area of ​​the convergence channel gradually decreases along the airflow direction, forming a convergence structure with a gradually decreasing cross-sectional area. One end of the convergence channel is connected to the outlet end of the micro-mixing tube 30, and the other end is the outlet of the secondary burner, used to inject the fuel-air mixture into the combustion chamber.

[0047] Optionally, the convergence angle α of the convergence channel is greater than 10°, and preferably, the convergence angle α is 10°-30°. The convergence angle α is defined as the angle between the centerline of the convergence channel and the wall of the convergence channel.

[0048] After the fuel-air mixture, initially mixed by the micro-mixing tube 30, enters the convergent channel, the reduced flow area leads to increased airflow velocity and enhanced turbulence, resulting in a secondary, intensified mixing of fuel and air, further improving the uniformity of the mixture. Simultaneously, the high-speed airflow generated at the outlet of the convergent channel forms an effective aerodynamic barrier against flame propagation into the micro-mixing tube 30, significantly suppressing backfire and ensuring safe and stable operation of the combustion chamber over a wide operating range.

[0049] In summary, this invention provides an axially staged combustion two-stage burner with a micro-mixing tube. Through the coordinated design of a straight-blade body, fuel chamber, diffuser chamber, micro-mixing tube, and convergent channel, a complete fuel-air mixing and flow control system is constructed. After entering the fuel chamber through the fuel inlet, the fuel undergoes its first diffusion and depressurization in the gradually expanding structure. Subsequently, it enters the larger diffuser chamber through the fuel orifice, completing a second diffusion and depressurization, achieving uniform fuel distribution along the blade height direction. The homogenized fuel is then injected into the micro-mixing tube through the nozzle, where it undergoes preliminary mixing with the air rectified by the micro-mixing tube. After entering the convergent channel, the premixed air is accelerated and further mixed in the gradually narrowing flow channel, finally being injected into the combustion chamber at a uniform and high speed to participate in combustion. This invention ensures uniform fuel distribution through a two-stage depressurization structure, ensures uniform airflow through the rectification effect of the micro-mixing tube, and achieves backfire suppression and enhanced mixing through the aerodynamic acceleration of the convergent channel. This effectively solves the problems of uneven combustion, high NOx emissions, high risk of backfire, and significant interference with the flow field of the primary combustion zone in the prior art, and significantly improves the operational stability, safety, and environmental performance of the combustion chamber.

[0050] According to a second aspect of the present invention, a gas turbine combustion chamber is provided, comprising a primary burner and a secondary burner arranged sequentially along an axial direction, wherein the secondary burner is an axially staged combustion secondary burner with a micro-mixing tube as described in the first aspect of the present invention.

[0051] Specifically, there are multiple secondary burners, evenly arranged along the circumference of the combustion chamber. (See reference...) Figure 4 As shown, an airflow channel is formed between two adjacent secondary burners, and its minimum flow area is the throat cross-sectional area A2. (See reference...) Figure 3 As shown, the cross-sectional area of ​​the channel located downstream of all secondary burners along the combustion chamber axis is the downstream cross-sectional area A1. In this embodiment, the downstream cross-sectional area A1 is designed to be equal to or slightly smaller than the throat cross-sectional area A2. This design ensures that when the airflow passing through the throat between adjacent secondary burners enters the downstream channel, the flow area does not expand or slightly shrinks, thereby maintaining an accelerated or uniform flow state and avoiding adverse pressure gradients, boundary layer separation, and recirculation zone formation caused by sudden expansion of the flow area.

[0052] By precisely controlling the variation of the flow channel area, this invention effectively avoids airflow separation while ensuring airflow, significantly improving airflow stability and providing a reliable guarantee for the stable and efficient operation of the combustion chamber. Simultaneously, a stable airflow field contributes to the uniform mixing and complete combustion of the fuel-air mixture, further reducing pollutant emissions.

[0053] The above are merely several specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

[0054] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes the element.

[0055] It should be noted that, in the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

Claims

1. An axially staged combustion two-stage burner with a micro-mixing tube, characterized in that, include: The burner body is a straight blade-type structure that gradually expands along the combustion chamber axis, including a blade-type outer sidewall (10) and a blade-type inner sidewall (20). The fuel chamber is a closed cavity located on the outer periphery of the burner body, formed by the blade-shaped outer sidewall (10) and the blade-shaped inner sidewall (20); a fuel inlet (11) is provided at one end of the blade-shaped outer sidewall (10) on the upstream side. The diffuser chamber is a closed cavity formed by the blade-shaped inner sidewall (20), located in the middle of the burner body and adjacent to the fuel chamber; a plurality of fuel holes (21) are opened on the blade-shaped inner sidewall (20) for connecting the fuel chamber and the diffuser chamber; Multiple micro-mixing tubes (30) are disposed in the diffuser chamber and penetrate the burner body perpendicular to the blade cross section, with their two ends corresponding to the air intake side and the air outlet side, respectively; spray holes (31) are opened on the tube wall of the micro-mixing tubes (30).

2. The axially staged combustion two-stage burner with a micro-mixing tube according to claim 1, characterized in that: The flow cross-section of the fuel chamber gradually increases along the axial direction of the combustion chamber, forming a primary pressure relief chamber for the fuel.

3. The axially staged combustion two-stage burner with a micro-mixing tube according to claim 1, characterized in that: The flow cross section of the diffuser chamber gradually increases along the axial direction of the combustion chamber, and the volume of the diffuser chamber is greater than the volume of the fuel chamber, forming a secondary pressure relief chamber for the fuel.

4. The axially staged combustion two-stage burner with a micro-mixing tube according to claim 3, characterized in that: The diffuser chamber is configured as multiple sections, arranged in segments along the length of the burner body, with each segment having a different chamber diameter.

5. The axially staged combustion two-stage burner with a micro-mixing tube according to any one of claims 1-4, characterized in that: The fuel holes (21) are provided on both sides and downstream of the inner wall (20) of the blade type, and the number of fuel holes (21) at the downstream end is less than the number on both sides.

6. The axially staged combustion two-stage burner with a micro-mixing tube according to claim 1, characterized in that: The nozzle (31) is located at one end of the micro-mixing tube (30) near the air intake side.

7. The axially staged combustion two-stage burner with a micro-mixing tube according to claim 6, characterized in that: The nozzles (31) are distributed on the wall of the micro-mixing tube (30) in the form of single holes, symmetrical double holes, or circumferential multi-holes.

8. The axially staged combustion two-stage burner with a micro-mixing tube according to claim 6, characterized in that: The ratio of the diameter of the nozzle (31) to the inner diameter of the micro-mixing tube (30) is 0.2-0.

5.

9. The axially staged combustion two-stage burner with a micro-mixing tube according to claim 6, characterized in that: The inner diameter of the micro-mixing tube (30) is 5-10 mm; the ratio of the length to the inner diameter of the micro-mixing tube (30) is 15-50.

10. The axially staged combustion two-stage burner with a micro-mixing tube according to claim 9, characterized in that: Multiple micro-mixing tubes (30) are arranged in an array, and the ratio of the spacing between adjacent micro-mixing tubes (30) to the inner diameter of the micro-mixing tube (20) is 0.5-2.

0.

11. The axially staged combustion two-stage burner with a micro-mixing tube according to claim 1, characterized in that: The blade-shaped inner wall (20) converges towards the diffuser in the downstream section of the outlet end of the micro-mixing tube (30) to form a convergence channel, and the cross-sectional area of ​​the convergence channel gradually decreases along the airflow direction.

12. The axially staged combustion two-stage burner with a micro-mixing tube according to claim 11, characterized in that: The convergence angle of the convergence channel is greater than 10°.

13. The axially staged combustion two-stage burner with a micro-mixing tube according to claim 12, characterized in that: The convergence angle of the convergence channel is 15°-30°.

14. A gas turbine combustion chamber, comprising a primary burner and a secondary burner arranged sequentially along an axial direction, characterized in that: The secondary burner is the axial staged combustion secondary burner with a micro-mixing tube as described in any one of claims 1 to 13.

15. The gas turbine combustion chamber according to claim 14, characterized in that: There are multiple secondary burners, which are evenly arranged around the circumference of the combustion chamber. The minimum flow area between adjacent secondary burners is the throat cross-sectional area A2. The cross-sectional area of ​​the channel downstream of the secondary burner is the downstream cross-sectional area A1. The downstream cross-sectional area A1 is equal to or less than the throat cross-sectional area A2.

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