A hydrogen fuel orthogonal vortex pair high-efficiency blending anti-backfire low-emission burner

Abstract

This invention provides a high-efficiency, low-pollution, orthogonal vortex-pair combustor for hydrogen fuel, comprising a petal-shaped fuel nozzle, a partition plate, and an air guide plate. Hydrogen fuel is ejected through fuel orifices arranged on the petal-shaped fuel nozzle's vortex structure, where it undergoes enhanced mixing with the incoming air. The premixed gas forms vortex pairs of the same size but opposite directions downstream of the vortex trailing edge. With increasing axial distance, the strengthening and breaking up of the orthogonal vortex pairs achieves secondary enhanced mixing of fuel and air. Simultaneously, the axial velocity of the premixed gas remains uniform, eliminating low-speed zones and preventing central backfire. Another portion of the air flows through the annular gap between the partition plate and the air guide plate, altering the spatial distribution of the combustible mixture and air at the burner outlet, thereby preventing boundary layer backfire. This invention achieves highly efficient enhanced mixing, reduces nitrogen oxide emissions during combustion, and suppresses thermoacoustic oscillations while preventing backfire through parameter differentiation and grading of the vortex.

Description

Technical Field

[0001] This invention relates to the field of hydrogen fuel gas turbine combustion chamber technology, and in particular to a hydrogen fuel orthogonal vortex pair high-efficiency blending anti-backfire and low-pollution burner. Background Technology

[0002] Gas turbines using natural gas mixed with hydrogen, or even pure hydrogen, as fuel can gradually reduce carbon emissions from power generation, eventually achieving zero carbon emissions. However, compared to traditional natural gas fuels, gas turbine combustors face numerous challenges when using high-hydrogen-content fuels. Due to the significant technical difficulties in burning high-hydrogen-content or even pure hydrogen fuels, most gas turbines on the market currently have a hydrogen fuel volume adaptability of around 30%. Hydrogen's high flame propagation speed and low ignition delay time pose a risk of backfire; its higher adiabatic flame temperature and rapid heat release at the same equivalence ratio lead to increased nitrogen oxide emissions; simultaneously, these fuel characteristics of hydrogen result in significantly different combustion characteristics, with a unique and compact reaction zone morphology, leading to significant variations in the flame thermoacoustic response. Therefore, it is necessary to consider achieving rapid mixing of fuel and air within limited time and space when designing premixed combustors, improving mixing quality to enhance combustion stability and reduce nitrogen oxide emissions. At the same time, safety during hydrogen fuel combustion must be considered to avoid thermoacoustic oscillations and backfire. Summary of the Invention

[0003] To address the aforementioned technical problems, this invention provides a high-efficiency, low-pollution, orthogonal vortex pair hydrogen fuel blending burner with anti-backfire properties. Under hydrogen fuel combustion conditions, especially under high hydrogen content or even pure hydrogen combustion conditions, it can effectively prevent backfire, reduce nitrogen oxide emissions, and suppress thermoacoustic oscillations, thereby achieving safe, stable, and low-emission combustion in hydrogen fuel gas turbines.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] A high-efficiency, low-pollution, orthogonal vortex-pair hydrogen fuel blending burner with backfire prevention includes: a petal-shaped fuel nozzle, a partition plate, and an air guide plate; the petal-shaped fuel nozzle includes an upstream straight structure and a downstream lobed structure, with a fuel chamber inside; the partition plate includes an inner partition plate and an outer partition plate, adjacent to and coaxially arranged with the petal-shaped fuel nozzle; the air guide plate includes an inner air guide plate and an outer air guide plate, adjacent to the partition plate and coaxially arranged with the petal-shaped fuel nozzle, and the air guide plate and the petal-shaped fuel nozzle are connected through the bottom surface of the burner, wherein the inner air guide plate of the first stage of the burner is connected to the center duty plate;

[0006] Hydrogen-containing fuel flows through fuel ducts arranged on the bottom surface of the burner and enters the fuel chamber in the petal-shaped fuel nozzle. It is then ejected through inner and outer fuel holes asymmetrically arranged in the downstream lobe structure. First, it is intensified to mix with the air flowing in from the annular gap between the petal-shaped fuel nozzle and the partition plate. The resulting premixed gas forms a vortex pair downstream of the lobe trailing edge. The strengthening and breaking of the vortex pair achieves secondary intensified mixing of fuel and air. At the same time, the axial velocity of the premixed gas remains uniform, with no low-speed zone, preventing center backfire. The air flowing through the narrow space between the partition plate and the air guide plate changes the spatial distribution of the combustible mixture and air at the burner outlet to prevent boundary layer backfire. It also controls the rise height of the reaction zone and, combined with the differences in different lobe structures and the staged scheme, suppresses thermoacoustic oscillations.

[0007] Preferably, the grading scheme includes: setting the burner to N stages, satisfying N = 2, 3, 4, 5; the petal-shaped fuel nozzle, two rings of partition plates and two rings of air guide plates constitute the first stage of the burner.

[0008] Preferably, the number of lobes contained in the downstream lobe structure of a ring of lobe-shaped fuel nozzles is n, satisfying 16≤n≤80.

[0009] Preferably, the inner opening angle α and the outer opening angle β of the lobe structure satisfy: 10°≤α≤30°, 10°≤β≤30°.

[0010] Preferably, the number of fuel holes in a single row within a single lobe is p, and the number of fuel holes in a single row outside is q, satisfying 4 ≤ p ≤ 20, 4 ≤ q ≤ 20, and the aperture size d satisfies 0.1 mm ≤ d ≤ 2.0 mm.

[0011] Preferably, the distance L2 between the center position of the inner fuel hole and the outer fuel hole in the downstream first row and the burner end face satisfies 0 ≤ L2 ≤ 5L1, where L1 is the distance between the inner partition plate and the outer partition plate.

[0012] Preferably, the distance L3 between the center position of the inner and outer fuel holes in the first row downstream and the end of the lobe trailing edge satisfies 0 ≤ L3 ≤ L1, where L1 is the distance between the inner and outer partition plates.

[0013] Preferably, both the inner and outer fuel holes are arranged in two rows in a staggered manner. The distance L4 between the two rows of fuel holes should satisfy 1 / 4 L1 ≤ L4 ≤ L1, where L1 is the distance between the inner and outer partition plates.

[0014] Preferably, the wave height L5 of a single lobe satisfies 1 / 5 L1 ≤ L5 ≤ 4 / 5L1, where L1 is the distance between the inner and outer partition plates.

[0015] Preferably, the distance L6 between adjacent partition plates and air guide plates satisfies 0.5 mm ≤ L6 ≤ 3 mm; the distance L7 between the partition plate and the burner end face satisfies 0 ≤ L7 ≤ 10 mm.

[0016] This invention achieves enhanced mixing by setting multiple tiny fuel orifices on the petal-shaped fuel nozzle for cross-mixing with the incoming airflow. Simultaneously, the axial velocity of the premixed gas remains uniform, eliminating low-speed zones and preventing center backfire. Furthermore, the lobe structure not only increases the contact area between the inner and outer bypass airflows under the same outlet area but also induces large-scale vortex structures at the lobe trailing edge, thereby achieving secondary enhanced mixing of fuel and air and reducing nitrogen oxide emissions. The geometric dimensions of the lobe structure control the vortex scale. Therefore, the change in the lobe structure geometry between radial stages offsets the vortex shedding frequency, effectively reducing the problem of thermoacoustic oscillations in the combustion chamber. By placing a partition plate between the air guide plate and the petal-shaped fuel nozzle, the spatial distribution of fuel and air at the burner outlet is altered, ensuring that there are no combustibles in the boundary layer near the burner outlet, thus suppressing boundary layer backfire.

[0017] As can be seen from the above technical solution, the present invention has the following beneficial effects:

[0018] (1) Compared with traditional premixed burners, the fuel nozzle of the burner of the present invention has a lobe structure, which enables the mixture to form vortices of the same size and opposite direction downstream of the lobe trailing edge. The enhancement and breaking process of the vortex pairs realizes the secondary enhanced mixing of fuel and air, thereby reducing NO x emission;

[0019] (2) Compared with traditional premixed burners, the burner of the present invention can suppress the phenomenon of thermoacoustic oscillation in the combustion chamber by changing the geometric dimensions of the lobes between the radial stages and thus staggering the vortex shedding frequency, and by changing the hysteresis time by different axial arrangements of the fuel holes.

[0020] (3) Compared with traditional premixed burners, the burner of the present invention can avoid the occurrence of central backfire by setting multiple tiny fuel holes on the petal-shaped fuel nozzle to cross-mix with the incoming air; at the same time, a partition plate is set between the fuel nozzle and the air guide plate, which can change the spatial distribution of fuel and air at the burner outlet, thereby avoiding boundary layer backfire and raising the reaction zone to improve the safety of the fuel nozzle. Attached Figure Description

[0021] Figure 1 This is a cross-sectional view of a hydrogen fuel orthogonal vortex pair high-efficiency blended backfire-preventing low-pollution burner according to an embodiment of the present invention;

[0022] Figure 2 for Figure 1 The diagram shows a cross-sectional view of the burner's lobe structure along plane AA.

[0023] Figure 3 This is a schematic diagram of a petal-shaped vortex-mixed anti-backfire burner according to an embodiment of the present invention.

[0024] The attached figures are labeled as follows:

[0025] 1-Lobe-shaped fuel nozzle; 2a-Inner partition plate;

[0026] 2b - Outer partition; 3a - Inner air deflector;

[0027] 3b - External air deflector; 4 - Burner bottom surface;

[0028] 5-Lobe structure; 6-Straight structure;

[0029] 7-Lobe trailing edge; 8a-Inner fuel port;

[0030] 8b - External fuel port; 9 - Fuel chamber;

[0031] 10 - Hydrogen-containing fuel; 11 - Fuel conduit;

[0032] 12 - Central duty shift.

[0033] α - Inner angle of the lobe structure; β - Outer angle of the lobe structure; L1 - Distance between the inner and outer partition plates; L2 - Distance between the center positions of the first row of inner and outer fuel holes downstream and the burner end face; L3 - Distance between the center positions of the first row of inner and outer fuel holes downstream and the end of the lobe trailing edge; L4 - Distance between the two rows of inner and outer fuel holes; L5 - Wave height of a single lobe; L6 - Distance between adjacent partition plates and air guide plates; L7 - Distance between the partition plate and the burner end face. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0035] like Figures 1-2As shown, this embodiment of the invention provides a high-efficiency, low-pollution, orthogonal vortex-pair hydrogen fuel blending burner with backfire prevention, comprising: a petal-shaped fuel nozzle 1, a partition plate, and an air guide plate; the petal-shaped fuel nozzle 1 includes an upstream straight structure 6 and a downstream lobed structure 5, with a fuel chamber 9 inside; the partition plate includes an inner partition plate 2a and an outer partition plate 2b, both annular, adjacent to and coaxially arranged with the petal-shaped fuel nozzle 1; the air guide plate includes an inner air guide plate 3a and an outer air guide plate 3b, both annular, adjacent to the partition plate, and coaxially arranged with the petal-shaped fuel nozzle 1, while the air guide plate and the petal-shaped fuel nozzle 1 are connected through the burner bottom surface 4, as shown. Figure 3 As shown, the internal air guide vane 3a of the first stage of the burner is connected to the center value class 12, as... Figure 1 As shown.

[0036] Hydrogen-containing fuel 10 flows through the fuel conduit 11 arranged on the bottom surface 4 of the burner, enters the fuel chamber 9 in the petal-shaped fuel nozzle 1, and is then ejected through the inner fuel hole 8a and outer fuel hole 8b in the downstream lobed structure 5. It first undergoes enhanced mixing with the air flowing in from the annular gap between the petal-shaped fuel nozzle 1 and the partition plate. The resulting premixed gas will form a vortex pair downstream of the lobed trailing edge 7. The enhancement and breaking process of the vortex pair realizes the secondary enhanced mixing of fuel and air.

[0037] The air flowing through the narrow space between the partition plate and the air guide plate changes the spatial distribution of the combustible mixture and air at the burner outlet, which is used to prevent boundary layer backfire and control the rise height of the reaction zone and suppress thermoacoustic oscillations.

[0038] The burner consists of a petal-shaped fuel nozzle 1, two rings of partition plates, and two rings of air guide plates, forming one stage. The burner contains a total of N stages, satisfying N = 2, 3, 4, 5. N is the number of burner stages.

[0039] To ensure sufficient contact area and increase mixing efficiency during secondary blending, while also considering the potential weakening of vortex intensity due to excessive lobes, the downstream lobe structure 5 of the ring-shaped fuel nozzle 1 contains n lobes, satisfying 16 ≤ n ≤ 80. To guarantee blending efficiency while avoiding excessive angles that could lead to flow separation and additional pressure loss, the inner angle α and outer angle β of the lobe structure 5 satisfy 10° ≤ α ≤ 30° and 10° ≤ β ≤ 30°.

[0040] To ensure sufficient contact between fuel and air and improve mixing efficiency, the number of fuel holes 8a in a single row within each lobe is p, and the number of fuel holes 8b in a single row is q, satisfying 4 ≤ p ≤ 20 and 4 ≤ q ≤ 20. The hole diameter d satisfies 0.1 mm ≤ d ≤ 2.0 mm. The distance L2 between the center position of the downstream first row of the inner fuel holes 8a and outer fuel holes 8b and the burner end face satisfies 0 ≤ L2 ≤ 5L1, where L1 is the distance between the inner partition plate 2a and the outer partition plate 2b.

[0041] To ensure mixing efficiency at the combustion chamber outlet, the distance L3 between the center position of the first downstream row of the inner fuel hole 8a and the outer fuel hole 8b and the end of the lobe trailing edge 7 satisfies 0 ≤ L3 ≤ L1, where L1 is the distance between the inner partition plate 2a and the outer partition plate 2b.

[0042] To suppress thermoacoustic oscillations, both the inner fuel orifice 8a and the outer fuel orifice 8b are arranged in two rows in a staggered manner. The spacing L4 between the two rows of fuel orifices should satisfy 1 / 4 L1 ≤ L4 ≤ L1, where L1 is the distance between the inner partition plate 2a and the outer partition plate 2b; the wave height L5 of a single lobe satisfies 1 / 5 L1 ≤ L5 ≤ 4 / 5L1.

[0043] To avoid flow separation and reduce pressure loss, the distance L6 between the adjacent partition plate and the air guide plate satisfies 0.5 mm ≤ L6 ≤ 3 mm; to raise the reaction zone and improve the safety and durability of the nozzle, the distance L7 between the partition plate and the burner end face satisfies 0 ≤ L7 ≤ 10 mm.

[0044] It should be noted that experimental methods not illustrated or described in the accompanying drawings or the main text of the specification are all forms known to those skilled in the art and are not described in detail. Furthermore, the definitions of the various components above are not limited to the specific structures and shapes mentioned in the embodiments; those skilled in the art can easily modify or substitute them, for example:

[0045] (1) The bottom surface of the burner does not have to be manufactured as a whole. It can be split into a semi-circular or fan-shaped base, and then the air guide plate and petal-shaped fuel nozzle of the burner can be installed on it through the connector. As long as the same function can be performed;

[0046] (2) Considering that the volume of the combustion chamber is limited under specific design parameters, the tail edge modification design can be adopted. For example, tail edge oblique cutting, fan-shaped lobes and sawtooth lobes can be used to change the lobes structure, thereby improving the mixing performance within a limited distance. As long as the fuel-air mixing degree at the nozzle outlet meets the requirements.

[0047] (3) In the embodiments of the present invention, the central duty nozzle adopts the form of a multi-nozzle array. In addition, a swirl nozzle can be used as a substitute, as long as it can perform a similar function.

[0048] (4) The hydrogen fuel orthogonal vortex pair high-efficiency blending anti-backfire low-pollution burner referred to in this invention can be installed as a single unit in the combustion chamber or as a burner in the combustion chamber.

[0049] (5) The first stage of the burner mentioned in this invention can be composed of a ring of petal-shaped fuel nozzles or multiple rings of petal-shaped fuel nozzles, as well as a partition plate and an air guide plate, as long as the expected mixing and suppression of thermoacoustic oscillation effects can be achieved.

[0050] (6) The present invention may provide examples of parameters containing specific values, but these parameters need not be exactly equal to the corresponding values, but can be approximated within acceptable error tolerances or design constraints;

[0051] (7) The directional terms mentioned in the implementation, such as “front” and “back”, are only for reference to the direction of the accompanying drawings and are not intended to limit the scope of protection of the present invention.

[0052] In summary, the petal-shaped vortex-pair blending anti-backfire burner provided by this invention fully utilizes the lobe structure and partition plate in the fuel nozzle to improve the safety and durability of the burner during hydrogen fuel combustion. The micro-orifice design of the petal-shaped fuel nozzle and the cross-mixing method with air help enhance blending efficiency while preventing backfire. Simultaneously, the lobe structure in the fuel nozzle allows the air-fuel mixture to form vortices of the same size but opposite direction at the trailing edge of the lobes, thereby achieving secondary enhanced blending of fuel and air and reducing NO₂ levels. X Emissions. By altering the geometric dimensions of the vortex shedding frequency between radial stages and lobes, the generation of thermoacoustic oscillations in the combustion chamber is suppressed. By installing a partition plate between the fuel nozzle and the air guide plate, the spatial distribution of fuel and air at the burner outlet is changed, ensuring that the boundary layer near the burner outlet is free of combustible reactants. This prevents boundary backfire and the lifting of the reaction zone, thereby improving the nozzle's safety and durability.

[0053] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. The above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A high-efficiency, low-pollution, orthogonal vortex pair hydrogen fuel burner with anti-backfire properties, characterized in that, include: The burner comprises a petal-shaped fuel nozzle, a partition plate, and an air guide plate. The petal-shaped fuel nozzle includes an upstream straight structure and a downstream corrugated structure, with a fuel chamber inside. The partition plate includes an inner partition plate and an outer partition plate, which are adjacent to and coaxially arranged with the petal-shaped fuel nozzle. The air guide plate includes an inner air guide plate and an outer air guide plate, which are adjacent to the partition plate and coaxially arranged with the petal-shaped fuel nozzle. The air guide plate and the petal-shaped fuel nozzle are connected through the bottom surface of the burner. The inner air guide plate of the first stage of the burner is connected to the center duty plate. Hydrogen-containing fuel flows through fuel ducts arranged on the bottom surface of the burner and enters the fuel chamber in the petal-shaped fuel nozzle. It is then ejected through inner and outer fuel holes arranged asymmetrically in the downstream lobed structure. First, it is intensified to mix with the air flowing in from the annular gap between the petal-shaped fuel nozzle and the partition plate. The resulting premixed gas forms a vortex pair downstream of the lobed trailing edge. The enhancement and breaking of the vortex pair achieves secondary intensified mixing of fuel and air. The air flowing through the space between the partition plate and the air guide plate changes the spatial distribution of the combustible mixture and air at the burner outlet. The partition plate includes an inner partition plate and an outer partition plate, both of which are annular and arranged coaxially with the petal-shaped fuel nozzle; the air guide plate includes an inner air guide plate and an outer air guide plate, both of which are annular and arranged coaxially with the petal-shaped fuel nozzle, adjacent to the partition plate, and the air guide plate and the petal-shaped fuel nozzle are connected through the bottom surface of the burner; the inner air guide plate of the first stage of the burner is connected to the center duty plate; Set the burner to N stages, satisfying N = 2, 3, 4, 5.

2. The hydrogen fuel orthogonal vortex pair high-efficiency blending anti-backfire low-pollution burner according to claim 1, characterized in that, The petal-shaped fuel nozzle, two rings of partition plates, and two rings of air guide plates constitute the first stage of the burner.

3. The hydrogen fuel orthogonal vortex pair high-efficiency blending anti-backfire low-pollution burner according to claim 1, characterized in that, The downstream lobe structure of a ring-shaped fuel nozzle contains n lobes, satisfying 16 ≤ n ≤ 80.

4. The hydrogen fuel orthogonal vortex pair high-efficiency blending anti-backfire low-pollution burner according to claim 1, characterized in that, The inner opening angle α and outer opening angle β of the lobe structure satisfy: 10° ≤ α ≤ 30°, 10° ≤ β ≤ 30°.

5. A high-efficiency, low-pollution, orthogonal vortex pair hydrogen fuel burner with anti-backfire properties according to claim 1, characterized in that, The number of fuel holes in a single lobe is p, and the number of fuel holes in a single row is q, satisfying 4 ≤ p ≤ 20 and 4 ≤ q ≤ 20. The aperture size d satisfies 0.1 mm ≤ d ≤ 2.0 mm.

6. A high-efficiency, low-pollution, orthogonal vortex pair hydrogen fuel burner with anti-backfire properties according to claim 1, characterized in that, The distance L2 between the center position of the inner fuel hole and the outer fuel hole in the first row downstream and the burner end face satisfies 0 ≤ L2 ≤ 5L1, where L1 is the distance between the inner partition plate and the outer partition plate.

7. A high-efficiency, low-pollution, orthogonal vortex pair hydrogen fuel burner with anti-backfire properties according to claim 1, characterized in that, The distance L3 between the center position of the inner and outer fuel holes in the first row downstream and the end of the lobe tail edge satisfies 0 ≤ L3 ≤ L1, where L1 is the distance between the inner and outer partition plates.

8. A high-efficiency, low-pollution, orthogonal vortex pair hydrogen fuel burner with anti-backfire properties according to claim 1, characterized in that, Both the inner and outer fuel holes have two rows arranged in an alternating manner. The distance L4 between the two rows of fuel holes should satisfy 1 / 4 L1 ≤ L4 ≤ L1, where L1 is the distance between the inner and outer partition plates.

9. A high-efficiency, low-pollution, orthogonal vortex pair hydrogen fuel burner with anti-backfire properties according to claim 1, characterized in that, The wave height L5 of a single lobe satisfies 1 / 5 L1 ≤ L5 ≤ 4 / 5L1, where L1 is the distance between the inner and outer partition plates.

10. A high-efficiency, low-pollution, orthogonal vortex pair hydrogen fuel burner with anti-backfire properties according to claim 1, characterized in that, The distance L6 between adjacent partition plates and air guide plates satisfies 0.5 mm ≤ L6 ≤ 3 mm; the distance L7 between the partition plate and the burner end face satisfies 0 ≤ L7 ≤ 10 mm.

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