Micro-swirl flow nozzle and combustion chamber for pure hydrogen fuel based on spiral structure

Abstract

The present invention provides a micro-swirl flow nozzle and combustion chamber for pure hydrogen fuel based on a spiral structure, comprising: the micro-swirl flow nozzle includes a plurality of micro-mixing units, the micro-mixing units include an air channel and two fuel injection holes, the fuel injection holes are located on the end wall of the air channel, the two fuel injection holes are distributed at both ends of the diameter of the air channel and the injection direction is along the radial direction of the air channel; the plurality of micro-mixing units are distributed in an array; the air channels of the plurality of micro-mixing units are all in a spiral linear structure around the central axis of the micro-swirl flow nozzle. The application of this technical solution can provide a micro-swirl flow nozzle and combustion chamber for pure hydrogen fuel based on a spiral structure, which can be used to organize pure hydrogen combustion more efficiently and solve the problems of unstable combustion, flashback and high NOx emissions in the use of existing hydrogen fuel combustion technology.

Description

Technical Field

[0001] The present invention relates to the fields of aviation engines and gas turbines, and in particular to a micro-mixed swirl nozzle of a pure hydrogen combustion chamber and a combustion chamber. Background Art

[0002] With growing global attention to environmental protection and sustainable development, reducing carbon emissions has become a pressing task for the aerospace industry. The combustion of traditional aviation fuel produces large amounts of greenhouse gases such as carbon dioxide, contributing to climate change and environmental pollution. Hydrogen energy, due to its high energy density and environmental friendliness, has become a research priority. Hydrogen energy not only significantly reduces the carbon footprint of aircraft but also promotes energy transition and innovation in aviation technology, possessing enormous potential for application.

[0003] However, there are significant differences in the combustion characteristics of hydrogen and traditional aviation kerosene. The transition from kerosene fuel to hydrogen fuel is not just a matter of changing fuels, but also involves comprehensive combustion chamber design and technological upgrades. Hydrogen has low ignition energy, which makes flashbacks more likely to occur in the combustion chamber. The high-altitude flame speed of hydrogen makes the combustion process more intense and rapid, increasing pressure fluctuations and oscillations in the combustion chamber, making the combustion unstable, reducing combustion efficiency, and making it more susceptible to thermal stress and thermal fatigue. At the same time, due to the wide flammability range and high adiabatic flame temperature of hydrogen fuel, unstable combustion can easily lead to the generation of local high-temperature hot spots, increased thermal NOx generation, and high NOx emissions. The technical challenges brought about by these hydrogen fuel combustion characteristics are currently difficult problems that need to be overcome. Summary of the Invention

[0004] The purpose of the present invention is to overcome the deficiencies in the above-mentioned prior art and provide a pure hydrogen fuel micro-swirling flow nozzle and combustion chamber based on a spiral structure to more efficiently organize pure hydrogen combustion and solve the problems of unstable combustion, flashback and high NOx emissions in the use of existing hydrogen fuel combustion technology.

[0005] In order to solve the above technical problems, the present invention provides a micro-mixing swirl flow nozzle for pure hydrogen fuel based on a spiral structure, which is characterized in that it includes: the micro-mixing swirl flow nozzle includes a plurality of micro-mixing units, the micro-mixing unit includes an air channel and two fuel injection holes, the fuel injection holes are located on the end wall of the air channel, the two fuel injection holes are distributed at both ends of the diameter of the air channel and the injection direction is along the radial direction of the air channel; the plurality of micro-mixing units are distributed in an array; the air channels of the plurality of micro-mixing units are all in a spiral linear structure around the central axis of the micro-mixing swirl flow nozzle.

[0006] In a more preferred embodiment, the cross-sectional diameter of the air channel is 4mm-8mm, the length of the air channel is consistent with the thickness of the micro-mixing swirl nozzle, which is 15mm-30mm, the center spacing between the micro-mixing units is 1.5 times to 3 times the cross-sectional diameter of the air channel, and the diameter of the micro-mixing swirl nozzle is 60mm-100mm.

[0007] In a more preferred embodiment, the helical pitch of the helical structure of the air passage is 150 mm-300 mm.

[0008] In a more preferred embodiment, the fuel injection hole has a diameter of 0.4 mm to 0.8 mm and is 2 mm away from the outlet of the air passage.

[0009] In a more preferred embodiment, the micro-swirling flow nozzle includes a built-in fuel delivery gas path, and the fuel delivery gas path is connected to the fuel injection hole.

[0010] In a more preferred embodiment, the fuel delivery air path is equidistant from each of the air channels, the fuel delivery air path comprises a plurality of annular air paths, the annular air paths are concentrically arranged at intervals, the micro-mixing unit is distributed between two adjacent annular air paths, and the two fuel injection holes of the micro-mixing unit are respectively connected to two adjacent annular air paths; the annular air path located in the outermost circle is a regular hexagon, and the annular air path located in the inner circle is an annular tube structure, which is a hexagon and is in the form of a wavy line composed of multiple arcs of equal radius; two adjacent annular air paths are connected by an equal number of connecting channels; the annular air path located in the outermost circle includes a hydrogen fuel inlet.

[0011] In a more preferred embodiment, the plurality of micro-hybrid units are divided into a plurality of micro-hybrid unit groups in a regular hexagonal pattern around the central axis. There are a total of 37 micro-hybrid units, which are divided into four micro-hybrid unit groups in a regular hexagonal pattern, with one micro-hybrid unit distributed at the center of the circle, and 6, 12, and 18 micro-hybrid units offset toward the periphery, respectively.

[0012] In a more preferred embodiment, the annular gas path has a width of 1.5mm-3mm and a depth of 10mm-20mm; the diameter of the fuel injection hole is 0.4mm-0.8mm; and the connecting channel has a width of 1.5mm-3mm and a depth of 5mm-10mm.

[0013] The present invention also provides a combustion chamber, comprising the micro-swirling flow nozzle of pure hydrogen fuel based on a spiral structure.

[0014] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0015] The present invention provides a micro-mixing swirl nozzle and combustion chamber for pure hydrogen fuel based on a spiral structure. The advantages of the nozzle are that the fuel mixing process is dispersed to each micro-mixing unit, and the spiral structure of the air channel generates a swirl in the combustion chamber. Both of these make the fuel and air mix more evenly, thereby effectively organizing the combustion of pure hydrogen, improving combustion efficiency, avoiding the generation of local high-temperature hot spots, and facilitating thermal protection and reducing thermal NOx generation.

[0016] The micro-mixing unit can rectify and accelerate the incoming air to match the high-level flame speed of hydrogen fuel, which can effectively suppress the combustion backfire phenomenon;

[0017] The diameter of the micro-mixing swirl nozzle is between 60mm and 100mm, but since the micro-mixing unit is divided into multi-circle micro-mixing unit groups, the number of unit groups can be increased or decreased according to actual usage needs to meet the requirements of structural size and combustion intensity. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is an axial cross-sectional view of a micro-swirling flow nozzle and a combustion chamber of pure hydrogen fuel based on a spiral structure of the present invention;

[0019] Figure 2 Schematic diagram of the flow field in the combustion chamber of the present invention after the pure hydrogen fuel passes through the micro-swirling flow nozzle;

[0020] Figure 3 Schematic diagram of a three-dimensional micro-swirling flow nozzle for pure hydrogen fuel of the present invention;

[0021] Figure 4 This is a cross-sectional view of the micro-swirling flow nozzle structure of pure hydrogen fuel of the present invention;

[0022] Figure 5 This is a hydrogen fuel gas path layout diagram of a micro-mixed swirl nozzle for pure hydrogen fuel of the present invention;

[0023] Figure 6 This is a layout diagram of the fuel injection holes of the micro-mixing unit of the micro-mixing swirl nozzle for pure hydrogen fuel of the present invention. DETAILED DESCRIPTION

[0024] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0025] See Figures 1-6 The present invention provides a pure hydrogen fuel micro-swirl flow nozzle and combustion chamber based on a spiral structure, wherein the combustion chamber includes an air inlet channel 100, a combustion chamber wall 200, the micro-swirl flow nozzle 300, a flame tube 400, a combustion chamber and a combustion chamber outlet 500, wherein the combustion chamber wall 200, the flame tube 400 and the air inlet channel 100 can be designed and modified according to the actual working conditions and usage requirements of the combustion chamber, and are not limited to the current structure.

[0026] The micro-mixing swirl nozzle 300 includes multiple micro-mixing units 31, each of which includes an air channel 311 and two fuel injection holes 312. The fuel injection holes 312 are located on the end wall of the air channel 311. The two fuel injection holes 312 are distributed at both ends of the diameter of the air channel 311, and the injection direction is along the radial direction of the air channel 311. The multiple micro-mixing units 31 are distributed in an array. The air channels 311 of the multiple micro-mixing units 31 are all spirally arranged around the central axis of the micro-mixing swirl nozzle 300.

[0027] In this embodiment, the micro-swirl flow nozzle 300 is in the shape of a round pancake, and the micro-mixing units 31 are arranged in an array on the micro-swirl flow nozzle 300. The air channels 311 are all spirally arranged around the central axis of the micro-swirl flow nozzle 300. Therefore, after the airflow passes through the micro-swirl flow nozzle 300, it generates a strong centrifugal force in the radial direction while advancing along the axial direction of the combustion chamber, forming a low-pressure area in the central area of ​​the front of the combustion chamber, causing part of the airflow to reflux and form a central reflux area. The fuel injection hole 312 is connected to the air channel 311, and the fuel is injected into the air channel 311 for mixed combustion. Each injection hole is located at both ends of the diameter of the air channel 311 and points to the center of the micro-swirl flow nozzle 300, and is arranged in the radial direction of the air channel 311. When the incoming air passes through the micro-swirl flow nozzle 300, it is evenly divided into multiple small air flows and enters the air channel 311 of each micro-mixing unit 31, and accelerates as the air channel 311 rotates. The single air channel 311 may be circular, or may be elliptical, triangular, or hexagonal.

[0028] In this embodiment, the cross-sectional diameter of the air channel 311 is 4mm-8mm, the length of the air channel 311 is consistent with the thickness of the micro-mixing swirl nozzle 300, which is 15mm-30mm, the center spacing between the micro-mixing units 31 is 1.5 times to 3 times the cross-sectional diameter of the air channel 311, and the diameter of the micro-mixing swirl nozzle 300 is 60mm-100mm. The helical pitch of the spiral structure of the air channel 311 is 150mm-300mm, ensuring that the angles of the air swirl are equal. The fuel injection hole 312 injects hydrogen fuel from its transport pipeline into the air channel 311. To ensure the penetration depth of the fuel, the diameter of the fuel injection hole 312 is 0.4mm-0.8mm and is 2mm away from the outlet of the air channel 311.

[0029] The micro-mixing swirl nozzle 300 includes a built-in fuel transport path, which is connected to the fuel injection hole 312. The fuel transport path is equidistant from each of the air channels 311. The fuel transport path includes multiple annular gas paths 321, which are concentrically spaced. The micro-mixing unit 31 is distributed between two adjacent annular gas paths 321, and the two fuel injection holes 312 of the micro-mixing unit 31 are respectively connected to two adjacent annular gas paths 321. The annular gas paths 321 located in the outermost circle are regular hexagonal, while the annular gas paths 321 located in the inner circle are annular tube structures. The annular tube structures are hexagonal and take the form of a wavy line composed of multiple arcs of equal radius. The adjacent annular gas paths 321 are connected by an equal number of connecting channels 322. The annular gas path 321 located in the outermost circle includes a hydrogen fuel inlet 323.

[0030] The multiple mild-mixing cells 31 are arranged around the central axis in a regular hexagonal pattern, forming several circles of mild-mixing cells 31. There are 37 mild-mixing cells 31 in total, organized into four regular hexagonal circles, with one mild-mixing cell 31 located at the center of the circle, and six, 12, and 18 more cells 31 offset toward the periphery. The annular gas path 321 has a width of 1.5 mm to 3 mm and a depth of 10 mm to 20 mm. The diameter of the fuel injection hole 312 is 0.4 mm to 0.8 mm. The connecting channel 322 has a width of 1.5 mm to 3 mm and a depth of 5 mm to 10 mm.

[0031] Because the fuel injection hole 312 has an extremely small diameter, the cross-sectional area of ​​the fuel delivery path is designed to be much larger than the injection hole cross-section, with a gas path width of 1.5mm-3mm and a depth of 10mm-20mm. After hydrogen fuel enters the hydrogen fuel inlet 323, due to the large flow resistance of the fuel injection hole 312, the hydrogen fuel preferentially fills the entire fuel delivery path, achieving uniform pressure in the gas path, namely, uniform pressure at the injection hole inlet 323. Furthermore, the outer annular gas path 321 is arranged in the form of a regular hexagon, while the inner annular gas path 321 is a ring tube. The hydrogen fuel gas path between the micro-mixing units 31 is a wavy line formed by connecting multiple arcs of equal radius. Six connecting channels 322 are arranged between each gas path, with a width consistent with a normal gas path of 1.5mm-3mm, but a depth limited to the first half of the normal gas path, 5mm-10mm. Since the injection holes have the same length and flow resistance, and the pressure at the injection hole inlet 323 is also the same, the fuel injection amount of each injection hole is consistent, and the hydrogen fuel is ensured to be smoothly transported in the entire fuel delivery gas path.

[0032] Figure 5Shown is the layout of the fuel injection holes 312 of the micro-mixing unit 31 of the micro-swirl nozzle 300 for pure hydrogen fuel. The fuel injection holes 312 connect the fuel transport path and the air channel 311, injecting hydrogen fuel into the air channel 311 for mixing and combustion. To ensure the penetration depth and mixing effect of the hydrogen fuel, the diameter of the fuel injection holes 312 is 0.4mm-0.8mm and is 2mm from the outlet of the micro-swirl nozzle 300. Each fuel injection hole 312 is located at both ends of the diameter of the air channel 311 and points toward the center of the micro-swirl nozzle 300, arranged in the radial direction of the micro-swirl nozzle 300.

[0033] Figure 6 The figure shows a schematic diagram of the flow field in the combustion chamber behind the pure hydrogen fuel micro-swirl nozzle 300. Since the air channel 311 in the micro-swirl nozzle 300 is spiral-shaped around the axis, after the airflow passes through the micro-swirl nozzle 300, it generates a strong centrifugal force in the radial direction while advancing along the axial direction of the combustion chamber, forming a low-pressure area in the central area of ​​the front of the combustion chamber, causing part of the airflow to reflux, forming a central reflux area. In addition, the sudden expansion of the airflow causes a low-pressure area to exist at the corner position, forming an angle reflux area. The reflux airflow will enhance turbulence, increase the heat transfer and material transfer rate, and mix the fuel and air more fully, so that the flame in the reflux area can burn stably and efficiently while the temperature is more uniform, avoiding the generation of local high-temperature hot spots, which is beneficial to thermal protection and reducing thermal NOx generation. The micro-mixing unit 31 rectifies and accelerates the incoming air to match the high-level flow flame speed of the hydrogen fuel, which can effectively suppress the combustion backfire phenomenon.

[0034] The above is only a preferred specific embodiment of the present invention, but the design concept of the present invention is not limited to this. Any technician familiar with this technical field who uses this concept to make non-substantial changes to the present invention within the technical scope disclosed by the present invention shall be deemed to infringe the scope of protection of the present invention.

Claims

1. A micro-swirling flow nozzle for pure hydrogen fuel based on a spiral structure, characterized in that: include: The micro-mixing swirl nozzle includes a plurality of micro-mixing units, each of which includes an air passage and two fuel injection holes. The fuel injection holes are located on the end wall of the air passage, and the two fuel injection holes are distributed at both ends of the diameter of the air passage, and the injection direction is along the radial direction of the air passage. The plurality of micro-mixing units are distributed in an array; the air passages of the plurality of micro-mixing units are all in a spiral structure around the central axis of the micro-mixing swirl nozzle. The micro-mixed swirl flow nozzle includes a built-in fuel transport passage, and the fuel transport passage is connected to the fuel injection hole; The fuel transport passage is equidistant from each of the air passages, and the fuel transport passage comprises a plurality of annular passages, which are concentrically arranged at intervals, the micro-mixing unit being distributed between two adjacent annular passages, and the two fuel injection holes of the micro-mixing unit being respectively connected to two adjacent annular passages; the annular passage located in the outermost circle is in the shape of a regular hexagon, and the annular passage located in the inner circle is in the shape of an annular tube structure, which is in the shape of a hexagon and is in the form of a wavy line composed of multiple arcs of equal radius; two adjacent annular passages are connected by an equal number of connecting passages; the annular passage located in the outermost circle comprises a hydrogen fuel inlet; The cross-sectional diameter of the air channel is 4mm-8mm, and the diameter of the fuel injection hole is 0.4mm-0.8mm.

2. The micro-swirling flow nozzle of pure hydrogen fuel based on a spiral structure according to claim 1, characterized in that: The length of the air channel is consistent with the thickness of the micro-mixing swirl nozzle, which is 15mm-30mm. The center spacing between the micro-mixing units is 1.5 times to 3 times the cross-sectional diameter of the air channel. The diameter of the micro-mixing swirl nozzle is 60mm-100mm.

3. The micro-swirling flow nozzle of pure hydrogen fuel based on a spiral structure according to claim 1, characterized in that: The helical pitch of the helical structure of the air passage is 150 mm to 300 mm.

4. The micro-swirling flow nozzle of pure hydrogen fuel based on a spiral structure as claimed in claim 3, characterized in that: The fuel injection hole is 2 mm away from the outlet of the air passage.

5. The micro-swirling flow nozzle of pure hydrogen fuel based on a spiral structure according to claim 1, characterized in that: The multiple mild hybrid units are divided into several circles of mild hybrid unit groups according to a regular hexagon around the central axis. There are 37 mild hybrid units in total, which are divided into four circles of mild hybrid unit groups according to a regular hexagon, with one mild hybrid unit distributed at the center of the circle, and 6, 12, and 18 mild hybrid units offset to the periphery respectively.

6. A micro-swirling flow nozzle for pure hydrogen fuel based on a spiral structure according to claim 1 or 5, characterized in that: The annular air path has an air path width of 1.5 mm to 3 mm and an axial depth of 10 mm to 20 mm; the connecting channel has an air path width of 1.5 mm to 3 mm and an axial depth of 5 mm to 10 mm.

7. A combustion chamber, characterized in that: The invention comprises a micro-swirling flow nozzle of pure hydrogen fuel based on a spiral structure as claimed in any one of claims 1 to 6.

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