Combustion chamber, head of combustion chamber and fuel air premixer

Abstract

A fuel air premixer can prevent tempering and explosion and comprises an air inlet pore plate, a fuel air inlet pore plate, an air outlet pore plate and a fuel air inlet pipe. The fuel air inlet hole plate is arranged on the downstream of the air inlet hole plate, and the air outlet hole plate is arranged on the downstream of the fuel air inlet hole plate. A fuel and air mixing cavity is formed between the air inlet pore plate and the fuel inlet pore plate; a fuel gas collecting cavity is formed between the fuel gas inlet pore plate and the gas outlet pore plate; the air inlet direction of the air inlet holes points to the fuel and air mixing cavity from the upstream side of the air inlet hole plate. The gas inlet direction of the fuel gas inlet hole points to the upstream side of the fuel gas inlet hole plate from the fuel gas collecting cavity; the fuel and air mixing cavity communicates with a plurality of air outlet pipes; the fuel gas inlet pipe is communicated with the fuel gas collecting cavity; the gas outlet pipe penetrates through the fuel gas inlet pore plate and the gas outlet pore plate, and the drift diameter of the gas outlet is smaller than that of the gas inlet. A combustion chamber head includes the fuel air premixer. A combustion chamber includes the combustion chamber head.

Description

Technical Field

[0001] The invention relates to a combustion chamber and a head thereof, and a fuel-air premixer, and in particular to a combustion chamber and a head thereof, and a fuel-air premixer of an aircraft engine or a gas turbine. Background Art

[0002] In order to achieve the goals of carbon peak and carbon neutrality, the extensive use of clean energy in the aviation transportation industry has become a future development trend. Since hydrogen combustion is clean and renewable. Using hydrogen as aviation fuel is one of the effective ways to achieve zero carbon emissions. Compared with hydrocarbon fuels, hydrogen has a higher combustion temperature, a faster flame propagation speed, and a wider potential for stable operation. At the same time, hydrogen combustion also brings hazards such as a wide explosion range and a strong explosion power. Pure hydrogen combustion will face higher NOx emissions, spontaneous combustion and flashback, flammability and explosion problems. If hydrogen is used as the only fuel in the combustion chamber of an aircraft engine, it is necessary to design a hydrogen fuel combustion organization form to achieve emission reduction, stable and safe combustion.

[0003] Theoretically, the only product of hydrogen combustion is water, which is a clean energy source. However, due to the high temperature generated during the hydrogen combustion process, N2 and O2 in the air undergo high-temperature oxidation reactions, thereby producing pollutants such as nitrogen oxides (NOx). Therefore, reducing the emission of pollutants from hydrogen combustion is to reduce the emission of NOx. Studies have shown that when the combustion temperature of the main combustion zone exceeds 1800K, the emission of NOx will rise sharply. Therefore, for hydrogen fuel combustion chambers, the lower the combustion temperature of the main combustion zone, the better. In fact, the combustion temperature of the main combustion zone is the highest when the fuel / air ratio reaches the chemically appropriate ratio. When the fuel / air ratio of the main combustion zone moves toward a lean or rich state, the combustion temperature becomes lower and lower. Therefore, the hydrogen / air ratio should be far away from the chemically appropriate ratio, and the use of rich hydrogen + lean hydrogen combustion to organize combustion can effectively reduce NOx emissions. Summary of the invention

[0004] An object of the present invention is to provide a fuel-air premixer which can effectively prevent the occurrence of flashback and explosion.

[0005] Another object of the present invention is to provide a combustion chamber head including the fuel-air premixer, which can effectively reduce NOx emissions.

[0006] Another object of the present invention is to provide a combustion chamber.

[0007] According to one aspect of the present invention, a fuel-air premixer for a combustion chamber head includes an air intake orifice plate having an air intake hole, a fuel intake orifice plate having a fuel intake hole, an outlet orifice plate, and a fuel intake pipe; wherein the fuel intake orifice plate is arranged downstream of the air intake orifice plate, and the outlet orifice plate is arranged downstream of the fuel intake orifice plate; a fuel-air mixing chamber is constructed between the air intake orifice plate and the fuel intake orifice plate; a fuel collecting chamber is constructed between the fuel intake orifice plate and the outlet orifice plate; an air intake direction of the air intake hole points from the upstream side of the air intake orifice plate to the fuel-air mixing chamber; an air intake direction of the fuel intake hole points from the fuel collecting chamber to the upstream side of the fuel intake orifice plate; the fuel-air mixing chamber is connected to a plurality of outlet pipes; the fuel intake pipe is connected to the fuel collecting chamber; the outlet pipe passes through the fuel intake orifice plate and the outlet orifice plate, and the diameter of the air outlet is smaller than the diameter of the air inlet.

[0008] In one embodiment, the air inlet hole is circular and extends perpendicular to the air inlet plate.

[0009] In one embodiment, the fuel inlet hole is circular and extends perpendicularly to the fuel inlet hole plate, and the diameter of the air inlet hole is larger than the diameter of the fuel inlet hole.

[0010] In one embodiment, one of the air inlet holes overlaps with at least one of the fuel inlet holes through the center of the fuel inlet orifice plate in the axial direction of the fuel-air premixer.

[0011] In one embodiment, the gas passage of the gas outlet pipe is conical.

[0012] In one embodiment, the fuel intake pipe sequentially passes through the radial middle portion of the air intake hole plate, the radial middle portion of the fuel intake hole plate and then connects to the fuel collecting cavity.

[0013] According to another aspect of the present invention, a combustion chamber head comprises any one of the fuel-air premixers described above, and a peripheral air intake duct surrounding the fuel-air premixer; wherein the fuel-air premixer is used to provide a fuel-rich flame, and the peripheral air intake duct adds air to the fuel-rich flame by providing a peripheral swirl flow channel to quench and dilute the fuel-rich flame.

[0014] In one embodiment, the peripheral air intake duct comprises a swirler arranged at the air intake.

[0015] In one embodiment, the swirler includes an inclined air intake hole provided on the end wall of the air intake side of the peripheral air intake duct, and inclined air intake holes provided on the inner wall and the outer wall of the air intake side of the peripheral air intake duct, respectively.

[0016] In one embodiment, the peripheral air intake duct further comprises a contraction tube wall protrudingly disposed at an air outlet relative to an end surface of the fuel-air premixer.

[0017] A combustion chamber according to another aspect of the present invention comprises any one of the above-mentioned combustion chamber heads, and a flame tube connected to the downstream side of the combustion chamber head.

[0018] According to an embodiment of the present invention, air and fuel are mixed in a counter-attack manner, which has a good mixing effect and can effectively prevent spontaneous combustion and backfire. In addition, along the direction of air flow, the ventilation aperture in the fuel-air premixer decreases step by step, which can effectively prevent spontaneous combustion, backfire and explosion. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The above and other features, properties and advantages of the present invention will become more apparent through the following description in conjunction with the accompanying drawings and embodiments, in which:

[0020] Figure 1 It is a schematic diagram of the structure of an aircraft engine;

[0021] Figure 2 It is a schematic diagram of the structure of the combustion chamber;

[0022] Figure 3 It is a schematic diagram of the combustion chamber head structure;

[0023] Figure 4 is along Figure 3 Sectional view along line AA;

[0024] Figure 5 It is a partial cross-sectional view of the fuel-air premixer. DETAILED DESCRIPTION

[0025] Reference will now be made in detail to embodiments of the present invention, one or more examples of which are illustrated in the accompanying drawings. Each example is provided to explain the present invention, not to limit the present invention. In fact, it will be apparent to those skilled in the art that various modifications and variations may be made in the present invention without departing from the scope or spirit of the present invention. For example, a feature illustrated or described as part of one embodiment may be used together with another embodiment to produce yet another embodiment. Therefore, the present invention is intended to cover these modifications and variations within the scope of the appended claims and their equivalents.

[0026] The terms "upstream" and "downstream" refer to relative directions relative to the flow of a fluid in a fluid path. For example, "upstream" refers to the direction from which the fluid is flowing, and "downstream" refers to the direction toward which the fluid is flowing.

[0027] Figure 1The main structure of a civil aviation engine is shown, including a fan 1, a low-pressure compressor 2, a high-pressure compressor 3, a combustion chamber 4, a high-pressure turbine 5, a low-pressure turbine 6, and a casing 7. The fan 1 can be understood as a compressor with one or several long blades. After the air flows through the fan 1, it is divided into two paths: one is the inner flow, the air continues to be compressed by the compressor 3, and is mixed and burned with the fuel in the combustion chamber 4. The gas expands through the high-pressure turbine 5, the low-pressure turbine 6 and the nozzle. The gas is discharged from the tail nozzle at a high speed to generate thrust. The flow path is through the low-pressure compressor 2, the high-pressure compressor 3, the combustion chamber 4, the high-pressure turbine 5, and the low-pressure turbine 6, and the gas is discharged from the nozzle. The other path is the outer flow. After the fan 1, the air is directly discharged into the atmosphere through the outer duct or discharged from the nozzle together with the inner gas. In the combustion chamber 4, hydrogen fuel and air are mixed and burned, and the high-temperature and high-pressure gas formed expands the high-pressure turbine 5 to do work, providing kinetic energy for the engine.

[0028] Figure 2 A part of the cut-away combustion chamber structure is shown, which is a cross-sectional view cut along the engine axial direction at a position within a 360-degree range, for example, a cross-sectional view at the 12 o'clock position. The combustion chamber 4 includes a combustion chamber head 8, a combustion chamber casing 9, a combustion chamber flame tube 10, and a fuel intake pipe 11. The combustion chamber casing 9 is a load-bearing structure, and the combustion chamber outer flame tube 10 is a high temperature and high pressure resistant structure. Fuel 12 enters the combustion chamber head 8 through the fuel intake pipe 11 to participate in combustion. Air 13 enters from the combustion chamber inlet.

[0029] Figure 3 and Figure 4 The combustion chamber head structure is shown. The combustion chamber head 8 includes a fuel-air premixer 16 located in the middle and a peripheral air intake duct 17. The fuel-air premixer 16 and the peripheral air intake duct 17 are concentrically assembled.

[0030] like Figure 5As shown, the fuel-air premixer 16 for the head of the combustion chamber includes an air intake orifice plate 29 having an air intake hole 24, a fuel intake orifice plate 30 having a fuel intake hole 25, an outlet orifice plate 31, and a fuel intake pipe 11. The fuel intake orifice plate 30 is arranged downstream of the air intake orifice plate 29, and the outlet orifice plate 31 is arranged downstream of the fuel intake orifice plate 30. A fuel-air mixing chamber 33 is constructed between the air intake orifice plate 29 and the fuel intake orifice plate 30. A fuel collecting chamber 32 is constructed between the fuel intake orifice plate 30 and the outlet orifice plate 31. The intake direction of the air intake hole 24 points from the upstream side of the air intake orifice plate 29 to the fuel-air mixing chamber 33, and the "upstream" here is referenced to the air flow direction. The intake direction of the fuel intake hole 25 points from the fuel collecting chamber to the upstream side of the fuel intake orifice plate, and the "upstream" here is referenced to the flow direction of the fuel-air mixed gas. The fuel-air mixing chamber 33 is connected to a plurality of outlet pipes 26 . The fuel inlet pipe 11 is connected to the fuel collecting chamber 33 . The outlet pipe 26 penetrates the fuel inlet orifice plate 30 and the outlet orifice plate 31 , and the diameter of the outlet port 28 is smaller than the diameter of the inlet port 27 .

[0031] The fuel 12 enters the fuel collecting chamber 32 through the fuel inlet pipe 11, and then enters the fuel-air mixing chamber 33 through the fuel inlet hole 25. The air 13 enters the fuel-air mixing chamber 33 through the air inlet hole 24 to be fully premixed with the fuel 11, and the fuel-air equivalence ratio is greater than 1. The premixed fuel-air mixture enters the flame tube 10 through the outlet pipe 26 to form a fuel-rich flame. The diameter of the air inlet 27 of the outlet pipe 26 is greater than the diameter of the air outlet 28 of the outlet pipe 26. The air flow velocity increases step by step from upstream to downstream, and the air pressure decreases step by step, which can effectively prevent the occurrence of flashback and explosion. The combustion chamber head 8 adopts a central graded combustion organizational structure, the center is premixed hydrogen-rich combustion, generating a hydrogen-rich flame 14, and the periphery is an air intake duct, generating swirl air 15, which is used to quickly quench and dilute the hydrogen-rich flame 14, thereby achieving hydrogen-poor combustion. From hydrogen-rich combustion to hydrogen-poor combustion, the equivalence ratio is far away from the chemically appropriate ratio, which can effectively control the temperature of the combustion zone, thereby reducing NOx emissions. In the fuel-air premixer in the middle, air and fuel are mixed in a counter-mixing manner, which has a good mixing effect and can effectively prevent spontaneous combustion and flashback. When the fuel is pure hydrogen or hydrogen-rich fuel, the above technical effect is more obvious.

[0032] like Figure 5 As shown, the air inlet hole 24 is circular and extends perpendicular to the air inlet hole plate 29.

[0033] The fuel inlet hole 25 is circular and extends perpendicularly to the fuel inlet hole plate 30. The diameter of the air inlet hole 24 is larger than the diameter of the fuel inlet hole 25, which further increases the air flow velocity from upstream to downstream and reduces the air pressure step by step.

[0034] like Figure 4As shown, an air inlet hole 24 overlaps with at least one fuel inlet hole 25 in the axial direction of the fuel-air premixer to enhance the counter-impact mixing effect.

[0035] like Figure 5 As shown, the gas passage of the gas outlet pipe 26 is tapered, and the flow area of ​​the gas passage gradually decreases from the air inlet to the air outlet, which increases the air flow velocity and reduces the gas pressure while reducing the resistance of the fluid flow. In the central fuel-air premixer, the fuel-air mixture equivalence ratio is higher than the chemical proper ratio, and the hydrogen-rich mixture is ejected and burned through the tapered hole, and the flame is not easy to break away, which has strong combustion stability. And along the air flow direction, the ventilation aperture in the fuel-air premixer decreases step by step, which can effectively prevent spontaneous combustion, backfire and explosion.

[0036] like Figure 5 As shown, the fuel intake pipe 1 passes through the radial middle part of the air intake hole plate 29 and the radial middle part of the fuel intake hole plate 30 in sequence and then connects to the fuel collecting cavity 32. After the fuel enters the fuel collecting cavity 32, it is transmitted radially from the middle part to the inside and outside, which is conducive to relatively uniform transmission of air pressure and improves the mixing effect of fuel and air.

[0037] like Figures 2 to 4 As shown, the peripheral air intake duct 17 includes a swirler arranged at the air inlet. The swirler provides a swirling airflow of air to promote the full mixing of air and fuel. The use of swirling air to quickly quench and dilute the hydrogen-rich flame can shorten the flame tube length and reduce the combustion chamber space.

[0038] In the embodiment shown in the figure, the swirler includes an inclined air intake hole 22 arranged on the end wall 20' on the air intake side of the peripheral air intake duct 17, an inclined air intake hole 23 arranged on the inner wall 20 on the air intake side of the peripheral air intake duct 17, and an inclined air intake hole 21 arranged on the outer wall 18 on the air intake side of the peripheral air intake duct 17. By inclining these inclined holes in the same rotation direction, a rotating flow of the air flow can be generated.

[0039] like Figure 3 As shown, the peripheral air intake duct 17 also includes a contraction tube wall 19 protruding from the end face of the air outlet relative to the fuel-air premixer 16. The contraction tube wall 19 forces the air swirl to converge toward the center, quickly quenches and dilutes the hydrogen-rich flame 14, thereby achieving hydrogen-lean combustion.

[0040] According to the embodiment of the present invention, when the fuel is hydrogen fuel, the following effects can be achieved:

[0041] (1) The central stage hydrogen combustion organization mode is adopted, the central stage is hydrogen-rich combustion, and a large amount of air is added to the hydrogen-rich flame through the peripheral flow channel to make the equivalence ratio lower than the chemical appropriate ratio, thereby achieving hydrogen-lean combustion. Hydrogen-rich + hydrogen-lean combustion can effectively reduce NOx emissions;

[0042] (2) Using swirl air to quickly quench and dilute the hydrogen-rich flame can shorten the flame tube length and reduce the combustion chamber space;

[0043] (3) In the central hydrogen / air premixer, air and hydrogen are mixed in a counter-mixing manner, which has a good mixing effect and can effectively prevent spontaneous combustion and flashback;

[0044] (4) In the central hydrogen / air premixer, the hydrogen / air mixture equivalence ratio is higher than the chemically appropriate ratio, the hydrogen-rich mixture is ejected through the tapered hole for combustion, the flame is not easy to separate, and has strong combustion stability;

[0045] (5) Along the direction of air flow, the ventilation aperture in the hydrogen / air premixer decreases step by step, which can effectively prevent spontaneous combustion, backfire and explosion.

[0046] Although the present invention is disclosed as above with preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art may make possible changes and modifications without departing from the spirit and scope of the present invention. Therefore, any modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention shall fall within the protection scope defined by the claims of the present invention.

Claims

1. A fuel-air premixer for a combustion chamber head, characterized in that: include: an air inlet aperture plate having air inlet apertures, a fuel inlet orifice plate having fuel inlet holes, Vent plate, and Fuel intake pipe; Wherein, the fuel inlet orifice plate is arranged downstream of the air inlet orifice plate, and the air outlet orifice plate is arranged downstream of the fuel inlet orifice plate; A fuel-air mixing chamber is constructed between the air intake hole plate and the fuel intake hole plate; A fuel collecting cavity is formed between the fuel air inlet plate and the air outlet plate; The air intake direction of the air intake hole is directed from the upstream side of the air intake hole plate to the fuel-air mixing chamber; The fuel inlet hole has an inlet direction pointing from the fuel collecting cavity to the upstream side of the fuel inlet hole plate; The fuel-air mixing chamber is connected to a plurality of air outlet pipes; The fuel intake pipe is connected to the fuel collecting chamber; The air outlet pipe passes through the fuel air inlet orifice plate and the air outlet orifice plate, and the diameter of the air outlet is smaller than the diameter of the air inlet.

2. The fuel-air premixer according to claim 1, characterized in that The air inlet hole is circular and extends perpendicularly to the air inlet hole plate.

3. The fuel-air premixer according to claim 1 or 2, characterized in that: The fuel inlet hole is circular and extends perpendicularly to the fuel inlet hole plate. The diameter of the air inlet hole is larger than the diameter of the fuel inlet hole.

4. The fuel-air premixer according to claim 1 or 2, characterized in that: One of the air inlet holes overlaps with at least one of the fuel inlet holes through the center of the fuel inlet orifice plate in the axial direction of the fuel-air premixer.

5. The fuel-air premixer according to claim 1 or 2, characterized in that: The gas passage of the gas outlet pipe is conical.

6. The fuel-air premixer according to claim 1 or 2, characterized in that: The fuel intake pipe sequentially passes through the radial middle portion of the air intake hole plate, the radial middle portion of the fuel intake hole plate and then is connected to the fuel collecting cavity.

7. A combustion chamber head, characterized in that: include: A fuel-air premixer as claimed in any one of claims 1 to 6, and a peripheral air intake duct surrounding the fuel-air premixer; The fuel-air premixer is used to provide a fuel-rich flame, and the peripheral air intake duct adds air to the fuel-rich flame by providing a peripheral swirl flow channel to quench and dilute the fuel-rich flame.

8. The combustion chamber head according to claim 7, characterized in that The peripheral air intake duct includes a swirler arranged at the air intake.

9. The combustion chamber head according to claim 8, characterized in that The swirler comprises an inclined air intake hole arranged on the end wall of the air intake side of the peripheral air intake duct, and inclined air intake holes respectively arranged on the inner wall and the outer wall of the air intake side of the peripheral air intake duct.

10. The combustion chamber head according to claim 8, characterized in that The peripheral air intake duct further comprises a contraction tube wall which is protrudingly arranged at an air outlet relative to an end surface of the fuel-air premixer.

11. A combustion chamber, characterized in that: include A combustion chamber head according to any one of claims 7 to 10, and a flame tube connected to the downstream side of the combustion chamber head.

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