A micro-mixing pure hydrogen nozzle for a reflow combustion chamber

Abstract

The application discloses a micro-mixing pure hydrogen nozzle for a backflow combustion chamber and relates to the technical field of gas turbines, which comprises a nozzle body, a hydrogen channel arranged axially in the center of the nozzle body, and a first air channel arranged circumferentially around the hydrogen channel, wherein the hydrogen channel is used for feeding hydrogen, and the first air channel is used for feeding air; a first hydrogen jet hole is arranged between the hydrogen channel and the first air channel, the first hydrogen jet hole is used for hydrogen in the hydrogen channel to enter the first air channel, and the first hydrogen jet hole is arranged close to a first air inlet of the first air channel; a second hydrogen jet hole is further arranged on the hydrogen channel, and the opening position of the second hydrogen jet hole corresponds to the first outlet position of the first air channel. The first hydrogen jet hole is used for micro-premixing, the second hydrogen jet hole is used for micro-diffusion, and the combination of the two can reduce nitrogen oxide emission, inhibit backfire, and improve combustion stability and operation safety.

Description

Technical Field

[0001] This invention relates to the field of gas turbine technology, and more particularly to a micro-mixing pure hydrogen nozzle for a recirculation combustion chamber. Background Technology

[0002] Hydrogen, as a clean fuel with zero carbon emissions, has broad application prospects in gas turbines, aero engines, and industrial combustion chambers. However, due to the physicochemical properties of hydrogen, such as its fast flame propagation speed, wide flammability limit range, and low ignition energy, it is prone to problems such as backfire, unstable combustion, concentrated local heat load, and high nitrogen oxide emissions in the combustion chamber nozzle, which seriously restrict the safe and efficient operation of hydrogen combustion equipment.

[0003] The mainstream technology for pure hydrogen combustion is micro-mixing combustion, which mainly includes two categories: micro-premixing and micro-diffusion. Micro-premixing combustion allows fuel and air to mix in advance, which helps reduce pollution emissions, but flame backflow is prone to occur in the premixing channel, and the risk of backfire is significantly higher than with conventional fuels. Micro-diffusion combustion can avoid backfire problems, but the fuel and air mixing is delayed, which can easily form a local fuel-rich zone, resulting in higher combustion temperature and lower combustion efficiency.

[0004] To balance these contradictions, existing technologies attempt to employ a structure combining swirling air intake and fuel jet. Some schemes organize the airflow field through internal and external dual swirlers, while others use a single-stage jet orifice to achieve local premixing. However, existing structures generally have significant limitations: most nozzles only inject fuel into the swirling outlet region, failing to achieve micro-premixing within the air channel; some structures use a central air channel and peripheral fuel supply layout, making it difficult to form a staged and controllable fuel concentration field; and some schemes only set up a single-stage fuel injection, failing to achieve coordinated matching between premixing within the channel and outlet diffusion, making it difficult to simultaneously meet the comprehensive requirements of efficient mixing, suppression of backfire, stable combustion, and low emissions. Summary of the Invention

[0005] In view of the above-mentioned defects or deficiencies in the prior art, the present invention provides a micro-mixing pure hydrogen nozzle for a recirculation combustion chamber.

[0006] To achieve the above objectives, the present invention provides a micro-mixing pure hydrogen nozzle for a recirculation combustion chamber, comprising: The nozzle body, the hydrogen passage axially disposed at the center of the nozzle body, and the first air passage circumferentially surrounding the hydrogen passage, wherein the hydrogen passage is used to introduce hydrogen and the first air passage is used to introduce air. A first hydrogen jet hole is provided between the hydrogen channel and the first air channel. The first hydrogen jet hole is used for hydrogen in the hydrogen channel to enter the first air channel. The first hydrogen jet hole is located near the first air inlet of the first air channel. A second hydrogen jet hole is also provided on the hydrogen channel, and the opening position of the second hydrogen jet hole corresponds to the first outlet position of the first air channel.

[0007] Preferably, it further includes a second air channel that circumferentially surrounds the first air channel and is used to allow air to pass through; The second outlet of the second air passage is located on the same axial side as the first outlet.

[0008] Preferably, the opening directions of the first air inlet of the first air channel and the second air inlet of the second air channel are both arranged circumferentially toward the nozzle body; A first radial vortex is provided at the first air inlet, and a second radial vortex is provided at the second air inlet.

[0009] Preferably, the first hydrogen jet orifice and the second hydrogen jet orifice are arranged circumferentially at intervals along the hydrogen channel.

[0010] Preferably, the first radial cyclone and the second radial cyclone have the same cyclone direction.

[0011] Preferably, the first radial cyclone and the second radial cyclone are arranged alternately in the circumferential direction.

[0012] Preferably, the second hydrogen jet orifice is inclined from the inside out and toward the first outlet.

[0013] Preferably, the outlet end of the nozzle body has an integral outward expansion structure.

[0014] Preferably, the apertures of the first hydrogen jet orifice and the second hydrogen jet orifice are smaller than the critical quenching diameter of hydrogen.

[0015] Preferably, the diameter of the first hydrogen jet orifice is smaller than the space of the second hydrogen jet orifice.

[0016] Based on this, the beneficial effects of the present invention are as follows: 1. This invention, by setting a central hydrogen channel and a circumferentially surrounding first air channel, and setting a first hydrogen jet hole between the two, allows hydrogen to be premixed with air in the first air channel to form micro-premixing, thereby reducing nitrogen oxide emissions; at the same time, through a second hydrogen jet hole corresponding to the first outlet of the first air channel, hydrogen forms micro-diffusion in the outlet area, effectively suppressing backfire; by combining micro-premixing and micro-diffusion, the nozzle can simultaneously achieve the comprehensive effects of low nitrogen oxide emissions, reliable suppression of backfire, and stable and efficient combustion. 2. This invention, by setting up a first air channel, a second air channel, and corresponding first and second radial swirlers, enables two air streams to form swirling airflows rotating in the same direction, jointly constructing a stable and synergistic dual-swirling flow field. Under the centrifugal force of the swirling flow, a low-pressure central recirculation zone is formed in the central region of the nozzle outlet, providing a stable ignition and combustion position for the flame. At the same time, the structure of the two swirlers with the same rotation direction and circumferentially staggered arrangement further enhances the airflow disturbance and shearing effect, significantly improves the mixing uniformity of hydrogen and air, and effectively improves combustion stability. 3. In this invention, the apertures of both the first and second hydrogen jet holes are set to be smaller than the critical quenching diameter of hydrogen. By utilizing the small-hole quenching effect, the flame backflow channel is physically blocked structurally, which can effectively prevent the flame from backflowing into the first air channel and the hydrogen channel and causing backfire, thereby significantly improving the operational safety and structural reliability of the nozzle during operation. Attached Figure Description

[0017] Other features, objects, and advantages of this application will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings: Figure 1 A schematic diagram illustrating the structure of a micro-mixing pure hydrogen nozzle according to one embodiment of the present invention; Figure 2 A schematic cross-sectional view of a micro-mixing pure hydrogen nozzle according to one embodiment of the present invention; Figure 3 This diagram illustrates the usage state of a micro-mixing pure hydrogen nozzle according to one embodiment of the present invention. Explanation of reference numerals in the attached drawings: 10-nozzle body, 20-hydrogen passage, 201-first hydrogen jet orifice, 202-second hydrogen jet orifice, 30-first air passage, 301-first air inlet, 302-first outlet, 303-first radial swirler, 40-second air passage, 401-second air inlet, 402-second outlet, 403-second radial swirler, 50-recirculation combustion chamber, 501-third air inlet, 502-combustion chamber outlet. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0019] The terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. The singular forms "a," "the," and "the" as used in the embodiments of this application are also intended to include the plural forms unless the context clearly indicates otherwise.

[0020] It should be understood that although the terms first, second, third, etc., may be used to describe related structures in the embodiments of this application, these related structures should not be limited to these terms. These terms are only used to distinguish related structures from each other.

[0021] Depending on the context, the word "if" as used here can be interpreted as "when" or "when". Similarly, depending on the context, the phrase "if determined" can be interpreted as "when determined" or "when (the condition or event of the statement) is detected".

[0022] It should be noted that the directional terms such as "upper," "lower," "left," and "right" described in the embodiments of this application are used to describe the angles shown in the accompanying drawings and should not be construed as limiting the embodiments of this application. Furthermore, in the context, it should also be understood that when it is mentioned that an element is formed "upper" or "lower" of another element, it can not only be formed directly "upper" or "lower" of the other element, but also indirectly "upper" or "lower" of the other element through an intermediate element.

[0023] Figure 1 This schematic diagram illustrates the structure of a micro-mixing pure hydrogen nozzle according to one embodiment of the present invention. Figure 2 This schematic diagram shows a cross-sectional view of a micro-mixing pure hydrogen nozzle according to one embodiment of the present invention. Figure 3 This diagram illustrates the usage state of a micro-mixing pure hydrogen nozzle according to one embodiment of the present invention, as shown below. Figure 1-3 As shown, a micro-mixing pure hydrogen nozzle for a recirculation combustion chamber according to the present invention includes: The nozzle body 10, the hydrogen channel 20 axially disposed at the center of the nozzle body 10, and the first air channel 30 circumferentially surrounding the hydrogen channel 20, the hydrogen channel 20 being used to introduce hydrogen and the first air channel 30 being used to introduce air. A first hydrogen jet hole 201 is provided between the hydrogen channel 20 and the first air channel 30. The first hydrogen jet hole 201 is used for hydrogen in the hydrogen channel 20 to enter the first air channel 30, so that the hydrogen is mixed with air in the first air channel 30 in advance to form a micro-premixed gas, thereby achieving more uniform combustion and effectively reducing the generation and emission of nitrogen oxides during combustion.

[0024] Meanwhile, the first hydrogen jet hole 201 is positioned close to the first air inlet 301 of the first air channel 30, so that the hydrogen begins to mix in the early stage of air entering the channel, effectively extending the premixing stroke and improving the mixing uniformity, further optimizing the combustion characteristics, avoiding the formation of local high-temperature fuel-rich zones, and reducing the risk of backfire.

[0025] Furthermore, a second hydrogen jet orifice 202 is provided on the hydrogen channel 20. The opening position of the second hydrogen jet orifice 202 corresponds to the position of the first outlet 302 of the first air channel 30, so that hydrogen is directly injected into the combustion zone in the nozzle outlet area to form micro-diffusion combustion, avoiding flame backflow into the first air channel 30 and effectively suppressing backfire. At the same time, it works in conjunction with the micro-premixed gas to achieve gradient combustion that combines premixing and diffusion, further improving combustion stability and operational safety.

[0026] Furthermore, the micro-mixed pure hydrogen nozzle for the recirculation combustion chamber of the present invention further includes a second air channel 40, which surrounds the first air channel 30 in a circumferential direction. The second air channel 40 is used to introduce air, and the second outlet 402 of the second air channel 40 and the first outlet 302 are located on the same axial side, so that the two air streams can flow out synchronously in the same axial direction.

[0027] Specifically, the opening directions of the first air inlet 301 of the first air channel 30 and the second air inlet 401 of the second air channel 40 are both arranged circumferentially towards the nozzle body 10. A first radial vortex 303 is provided at the first air inlet 301, and a second radial vortex 403 is provided at the second air inlet 401. This arrangement allows the air entering the first air channel 30 and the second air channel 40 to form regular and controllable swirling airflows. The two swirling airflows superimpose and couple at the nozzle outlet to construct a composite swirling flow field, thereby inducing a stable low-pressure recirculation zone in the central region of the nozzle, providing a stable ignition source and reliable flame stabilization support for the flame. At the same time, the inner and outer double-layer swirling airflows form a surrounding shearing and enveloping constraint on the internal hydrogen-air mixture, effectively enhancing the uniformity of hydrogen and air mixing, promoting complete fuel combustion, and significantly improving overall combustion stability and combustion efficiency.

[0028] Furthermore, the first radial swirler 303 and the second radial swirler 403 have the same swirling direction, which can make the inner and outer swirling airflows rotate in the same direction and flow in coordination, avoiding mutual collision and disturbance between the two airflows, maintaining the regularity and stability of the overall flow field, strengthening the overall strength of the composite swirling flow, and facilitating the stable formation of the flame stabilization recirculation zone.

[0029] Furthermore, the first radial swirler 303 and the second radial swirler 403 are arranged alternately in the circumferential direction. This arrangement can break the uniform inertia of the airflow distribution along the circumference of the nozzle body 10, generate stronger airflow disturbance and shear mixing effect, effectively intensify the momentum exchange and micro-mixing between hydrogen and air, make the fuel and air mix more uniform, and improve combustion completeness and combustion efficiency.

[0030] Furthermore, the first hydrogen jet hole 201 and the second hydrogen jet hole 202 are arranged at intervals along the circumference of the hydrogen channel 20, so that the hydrogen in the hydrogen channel 20 can be uniformly sprayed out in a ring shape, effectively avoiding the formation of a fuel-rich zone due to excessively high local hydrogen concentration, while achieving uniform mixing of hydrogen and air throughout the entire area, preventing the generation of local high-temperature hot spots, reducing nitrogen oxide emissions, and improving overall combustion uniformity and combustion stability.

[0031] Furthermore, the second hydrogen jet orifice 202 is inclined from the inside out and toward the first outlet 302, which allows the hydrogen jet to be ejected obliquely along the mainstream airflow direction, conforming to the outlet airflow trend, avoiding the strong airflow from the circumferential jet from interfering with the flow, and effectively improving the mixing effect of hydrogen and air by utilizing the shearing effect of the oblique jet; at the same time, the outlet end of the nozzle body 10 is an integral outward expansion structure, which can form a gradually expanding flow channel, guiding hydrogen and air to diffuse and mix over a large area outside the outlet, realizing gradient diffusion mixing, further widening the combustion area, uniformly distributing fuel concentration, effectively stabilizing the flame shape, and improving combustion uniformity and combustion stability.

[0032] Furthermore, the diameters of the first hydrogen jet orifice 201 and the second hydrogen jet orifice 202 are smaller than the critical quenching diameter of hydrogen. By utilizing the small-hole quenching effect, the backflow propagation path of the flame is physically blocked structurally. This effectively prevents the flame from flowing back into the hydrogen channel 20 through the first hydrogen jet orifice 201 and the second hydrogen jet orifice 202, thus suppressing backfire from the source and improving the operational safety of the nozzle under high-temperature conditions.

[0033] Meanwhile, the diameter of the first hydrogen jet orifice 201 is smaller than that of the second hydrogen jet orifice 202. The smaller orifice diameter makes the hydrogen injection finer and improves the micro-premixing uniformity of hydrogen and air; while the larger orifice diameter enhances the hydrogen injection penetration and facilitates outlet diffusion mixing. The two stages work together to optimize the overall combustion effect.

[0034] Furthermore, the hydrogen concentration of the micro-premixed gas formed in the first air channel 30 is lower than the lower flammability limit of hydrogen, so that the premixed gas in the channel does not have the conditions for self-sustaining combustion. This can prevent the micro-premixed gas from igniting and burning prematurely inside the first air channel 30, completely avoid the risks of backfire and ablation inside the channel, and ensure the long-term stable and reliable operation of the nozzle.

[0035] like Figure 2 , 3As shown, when the micro-mixed pure hydrogen nozzle of the present invention is in operation, outside air enters the cavity through the third air inlet 501 of the recirculation combustion chamber 50, while hydrogen fuel is axially introduced through the hydrogen channel 20; a portion of the air flows through the first radial vortex 303 to form a swirling airflow, which is fully mixed with the hydrogen injected from the first hydrogen jet hole 201 to form a uniform micro-premixed gas, and then flows along the first air channel 30 to the main combustion zone of the combustion chamber; Another portion of the air, after being rectified and swirled by the second radial swirler 403, flows into the mainstream combustion zone along the second air channel 40, where it is entrained and mixed with the diffused hydrogen ejected from the second hydrogen jet hole 202 and the micro-premixed gas flowing out of the first air channel 30, thus providing sufficient combustion air for the combustion process. Meanwhile, the nozzle body 10 adopts an outward expansion structure at the outlet end, which can provide sufficient flow space for the radial diffusion of hydrogen and the formation of the central low-pressure reflux zone. Finally, the fully mixed combustible mixture is ejected from the combustion chamber outlet 502 and burns stably.

[0036] In summary, this invention, by setting a central hydrogen channel 20, a surrounding first air channel 30, and a first hydrogen jet orifice 201 and a second hydrogen jet orifice 202, respectively forms micro-premixed combustion within the channel and micro-diffusion combustion at the outlet, taking into account both low nitrogen oxide emissions and backfire suppression effects; by nesting and circumferentially arranging the first air channel 30, the second air channel 40, and the first radial swirler 303 and the second radial swirler 403 with the same swirling direction and circumferentially staggered, a composite swirling flow field and a central recirculation zone are constructed to enhance hydrogen-air mixing and improve combustion stability; at the same time, by setting the orifice diameters of the first hydrogen jet orifice 201 and the second hydrogen jet orifice 202 to be smaller than the critical quenching diameter of hydrogen, and controlling the premixed gas concentration to be lower than the lower limit of hydrogen flammability, the flame backflow is blocked from the dual effects of structural quenching and concentration-based flame suppression, effectively avoiding the hidden danger of internal backfire and improving the reliability and operational safety of the nozzle.

[0037] The above description is merely a preferred embodiment of this application. Those skilled in the art should understand that the scope of disclosure in this application is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the above-described concept. For example, technical solutions formed by substituting the above features with (but not limited to) technical features with similar functions disclosed in this application.

Claims

1. A micro-mixing pure hydrogen nozzle for a recirculation combustion chamber, characterized in that, include: The nozzle body, the hydrogen passage axially disposed at the center of the nozzle body, and the first air passage circumferentially surrounding the hydrogen passage, wherein the hydrogen passage is used to introduce hydrogen and the first air passage is used to introduce air. A first hydrogen jet hole is provided between the hydrogen channel and the first air channel. The first hydrogen jet hole is used for hydrogen in the hydrogen channel to enter the first air channel. The first hydrogen jet hole is located near the first air inlet of the first air channel. A second hydrogen jet hole is also provided on the hydrogen channel, and the opening position of the second hydrogen jet hole corresponds to the first outlet position of the first air channel.

2. The micro-mixing pure hydrogen nozzle for a recirculation combustion chamber according to claim 1, characterized in that, It also includes a second air passage that surrounds the first air passage and is used to allow air to enter. The second outlet of the second air passage is located on the same axial side as the first outlet.

3. A micro-mixing pure hydrogen nozzle for a recirculation combustion chamber according to claim 2, characterized in that, The opening directions of the first air inlet of the first air channel and the second air inlet of the second air channel are both arranged circumferentially toward the nozzle body; A first radial vortex is provided at the first air inlet, and a second radial vortex is provided at the second air inlet.

4. A micro-mixing pure hydrogen nozzle for a recirculation combustion chamber according to claim 1, characterized in that, The first hydrogen jet orifice and the second hydrogen jet orifice are arranged circumferentially along the hydrogen channel.

5. A micro-mixing pure hydrogen nozzle for a recirculation combustion chamber according to claim 3, characterized in that, The first radial cyclone and the second radial cyclone have the same swirl direction.

6. A micro-mixing pure hydrogen nozzle for a recirculation combustion chamber according to claim 5, characterized in that, The first radial cyclone and the second radial cyclone are arranged alternately along the circumference.

7. A micro-mixing pure hydrogen nozzle for a recirculation combustion chamber according to claim 1, characterized in that, The second hydrogen jet orifice is inclined from the inside out and toward the first outlet.

8. A micro-mixing pure hydrogen nozzle for a recirculation combustion chamber according to claim 1, characterized in that, The outlet end of the nozzle body has an integral outward expansion structure.

9. A micro-mixing pure hydrogen nozzle for a recirculation combustion chamber according to claim 1, characterized in that, The diameters of the first hydrogen jet orifice and the second hydrogen jet orifice are smaller than the critical quenching diameter of hydrogen.

10. A micro-mixing pure hydrogen nozzle for a recirculation combustion chamber according to claim 1, characterized in that, The diameter of the first hydrogen jet orifice is smaller than the diameter of the second hydrogen jet orifice.

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