Center staged combustion chamber head structure applied to NH3 and H2 fuels

Abstract

The invention discloses a center staged combustion chamber head structure applied to NH3H2 fuel, which comprises a pre-combustion stage structure used for mixing H2 and air and a main combustion stage structure positioned on the periphery of the pre-combustion stage structure and used for mixing NH3 and air, and the pre-combustion stage structure utilizes an arranged pre-combustion stage fuel injection piece to replace an original venturi tube. An original air atomizing nozzle is changed into circumferential uniform direct injection, H2 generates a backflow area in a pre-combustion-stage air channel, then the turbulence intensity is increased, mixing of H2 and air is better facilitated, backfire prevention of a pre-combustion-stage structure is achieved through additionally-arranged pre-combustion-stage air film holes, then the wall face of a pre-combustion-stage fuel injection piece is prevented from being ablated, and the service life of the pre-combustion-stage fuel injection piece is prolonged. A main combustion stage air channel in the main combustion stage structure is of a contraction and expansion air channel structure, tempering is effectively prevented, meanwhile, mixing of NH3 and air is facilitated, and therefore local hot spots of a main combustion area are reduced, temperature distribution is more uniform, combustion efficiency is higher, and emission of thermal NOx is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of aircraft engines, and in particular to a central staged combustion chamber head structure applied to NH3 and H2 fuels. Background Art

[0002] With the rapid development of the global aviation transportation industry, the total amount of pollution emissions from aircraft engines continues to increase. Pollutant emissions are an important issue restricting the development of aircraft engines. The development and utilization of clean alternative energy provides a new solution to the problem of pollutant emissions from aircraft engines. Among them, ammonia (NH3) is a clean energy with high energy density, mature production technology, easy liquefaction, easy storage and transportation, and zero carbon emissions of combustion products. It has significant advantages and great potential in energy and power systems. However, there are still some shortcomings in using NH3 as fuel: the flammability limits of NH3 and air are narrow, the ignition temperature is high, the flame propagation speed is low, the flame temperature and radiation heat transfer are lower than those of hydrocarbon fuel flames, and nitrogen oxide (NOx) emissions limit the clean and efficient application of NH3 fuel. In order to solve this problem, Pure NH3 is difficult to ignite and has poor combustion stability at room temperature and pressure. Technologies to improve NH3 combustion include: mixed combustion with conventional fuels, preheating fuel, preheating air, oxygen-enriched combustion, turbulence enhancement, auxiliary combustion, etc. H2, as a clean energy with high calorific value, fast flame propagation speed, wide flammable limit, and high adiabatic flame temperature, can be used in combination with NH3 to improve the combustion characteristics of NH3. However, H2 itself is difficult to liquefy (liquefy at 20.28K under normal pressure) and has high storage and transportation costs. From the perspective of the development path of hydrogen fuel aircraft, the short-term hydrogen fuel cell engine solution is limited by the energy density of the battery and is difficult to apply to large aircraft. The hydrogen turbine engine technology is still immature, and the hydrogen internal combustion engine solution has only been tested and verified on some small general aviation aircraft in the near future.

[0003] For aircraft engines using new alternative fuels, the combustion chamber head structure and the physical and chemical properties of the fuel must be well matched to achieve a good mixture of fuel and air. The mixing of air and fuel not only affects the temperature distribution uniformity and combustion efficiency of the combustion zone, but also has a crucial impact on the outlet temperature distribution characteristics of the combustion chamber, NOx emissions and other performance. Therefore, the application of new fuels in aircraft engines has put forward new requirements for the traditional combustion chamber head structure. At present, the combustion chamber head structure mostly adopts fuel grading and combustion zoning design, and combines different air atomizing nozzles as a Pre-combustion stage and main combustion stage. The pre-combustion stage is generally composed of a centrifugal nozzle and a first (or multiple) swirler. It mostly adopts an oil-rich diffusion combustion method to improve the ignition performance and widen the stable working boundary of the combustion chamber. The main combustion stage is generally composed of a direct injection nozzle and a first (or multiple) swirler. It mostly adopts a lean premixed combustion method to enhance oil-gas mixing and improve combustion efficiency. The center-staged structure is a more advanced aviation engine combustion chamber structure, in which the pre-combustion stage and the main combustion stage are coaxially designed, the inner layer is the pre-combustion stage, and the outer layer is the main combustion stage. However, the direct use of NH3 and H2 fuels in the traditional center-staged combustion chamber for combustion still has the following shortcomings:

[0004] 1. Due to the low flame propagation of NH3 and the high ignition energy required, when NH3 is mixed with air, the low turbulence intensity and short mixing distance easily lead to difficulty in ignition of NH3;

[0005] 2. Since NH3 has high NOx emissions under lean combustion conditions, the equivalence ratio of the NH3 combustion zone needs to be redesigned to meet low NOx emission standards;

[0006] 3. Due to the high propagation speed of H2 flame, it is easy to cause the risk of flashback. The Venturi pre-liquid film air atomizing nozzle with multi-stage swirler used in the pre-combustion stage of the traditional center-staged combustion chamber is not conducive to the stable combustion of H2, and will increase the risk of flashback and damage the pre-combustion stage structure.

[0007] In summary, as new clean energy sources, direct application of NH3 and H2 in traditional center-staged combustion chambers may cause problems such as poor fuel-air mixing, wall erosion, and low combustion efficiency, which will further affect the combustion chamber outlet temperature distribution characteristics, NOx emission concentration, etc. Therefore, it is necessary to innovate the head structure of the traditional center-staged combustion chamber to match the use of new fuels. Summary of the invention

[0008] In order to solve the above technical problems, the present invention provides a central staged combustion chamber head structure applied to NH3H2 fuel.

[0009] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0010] A central staged combustion chamber head structure for NH3 and H2 fuels, comprising a pre-combustion stage structure and a main combustion stage structure located at the periphery of the pre-combustion stage structure, the main combustion stage structure being used for mixing NH3 and air, comprising a main combustion stage fuel bin and a main combustion stage air passage located at the periphery of the main combustion stage fuel bin, and the diameter of the main combustion stage air passage gradually decreases and then increases in the direction from the intake end to the exhaust end, a plurality of main combustion stage fuel jet holes are evenly arranged on the peripheral side of the main combustion stage fuel bin and in the area opposite to the decreasing diameter of the main combustion stage air passage, the main combustion stage air passage adopts a contraction and expansion air passage structure, which is conducive to the mixing of NH3 and air while effectively preventing the occurrence of backfire; the pre-combustion stage structure is used for mixing H2 and air, comprising a pre-combustion stage air passage and a pre-combustion stage fuel injection piece arranged in the pre-combustion stage air passage, the pre-combustion stage fuel injection piece is arranged along the pre-combustion stage A plurality of precombustion stage air film holes with through ends are provided in the length direction of the precombustion stage air channel, as well as a precombustion stage fuel bunker which is through and in an annular shape at one end near the air inlet of the precombustion stage air channel, the through end of the precombustion stage fuel bunker serves as the precombustion stage fuel inlet, and the precombustion stage fuel injection piece comprises a cylinder, the diameter of the cylinder increases gradually at one end near the air outlet of the precombustion stage air channel to form an injection head, the side surface of the injection head forms a blunt surface based on the side surface of the cylinder, and a plurality of precombustion stage fuel jet holes which penetrate the precombustion stage fuel bunker are evenly provided along the circumferential direction of the blunt surface, so that H2 can be directly injected uniformly in the circumferential direction in the precombustion stage air channel, a reflow zone is generated in the precombustion stage air channel to increase the turbulence intensity, which is beneficial to the mixing of H2 and air, and the precombustion stage air film holes are provided to prevent the backfire of the precombustion stage structure and prevent the wall surface of the precombustion stage fuel injection piece from being ablated.

[0011] The above-mentioned main combustion stage structure also includes a swirler and a cylinder connected to the swirler. The main combustion stage fuel bin is placed inside the cylinder and fixed on the swirler. The swirler has a main combustion stage fuel inlet that passes through the main combustion stage fuel bin. The main combustion stage air channel is formed by the gap between the main combustion stage fuel bin and the cylinder.

[0012] The swirler also has a plurality of main combustion stage air inlets penetrating the main combustion stage air passage, and the passage between the main combustion stage air inlet and the main combustion stage air passage is spiral.

[0013] The above-mentioned pre-combustion stage structure includes a center hole opened at the center of the main combustion stage fuel bin and the swirler and passing through both ends, and the pre-combustion stage fuel injection piece is arranged in the center hole, the pre-combustion stage air channel is formed by the gap between the pre-combustion stage fuel injection piece and the center hole, and the end of the pre-combustion stage air channel close to the swirler is the pre-combustion stage air inlet, and the other end is the pre-combustion stage air outlet.

[0014] The angle formed by the injection direction of the precombustion stage fuel jet hole and the central axis of the precombustion stage fuel injection piece is 60-90°, the opening diameter of the precombustion stage fuel jet hole is 0.4-0.68mm, and the diameter of the precombustion stage air film hole is 0.3-0.6mm.

[0015] Preferably, the diameter of one side of the injection head corresponding to the pre-combustion stage air outlet is 16-20 mm, and differs from the outer diameter of the pre-combustion stage air passage by 4-6 mm.

[0016] Preferably, the cyclone is an axial cyclone, and the swirl intensity Sn=0.7-1.1.

[0017] Preferably, the axial distance of the main combustion stage air passage is in the range of 21-26 mm.

[0018] Preferably, the main combustion stage fuel jet hole is located 3-5 mm above the swirler, and the diameter of the main combustion stage fuel jet hole is 1.5-3 mm.

[0019] Preferably, the narrowest inner diameter of the main combustion stage air passage is 37.8-42.5 mm, and the diameters at both ends are 44-49 mm.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] The present invention optimizes the existing center-staged combustion chamber head structure, and uses a pre-combustion stage fuel injection piece to replace the original venturi in the pre-combustion stage structure, and changes the original air atomizing nozzle into a circumferentially uniform direct injection, so that H2 generates a reflow zone in the pre-combustion stage air channel, thereby increasing the turbulence intensity and being more conducive to the mixing of H2 and air. The pre-combustion stage structure is also protected from backfire by the added pre-combustion stage air film holes, thereby preventing the wall surface of the pre-combustion stage fuel injection piece from being ablated. In the main combustion stage structure, the main combustion stage air channel adopts a contraction-and-expansion air channel structure, which effectively prevents the occurrence of backfire and is also conducive to the mixing of NH3 and air, thereby reducing local hot spots in the main combustion zone, making the temperature distribution more uniform, and improving the combustion efficiency, thereby reducing thermal NOx emissions. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the overall top view of the structure of the present invention;

[0023] Figure 2 It is a schematic diagram of the overall top view of the structure of the present invention;

[0024] Figure 3 It is a cross-sectional structural schematic diagram of the present invention;

[0025] Figure 4 It is a 1 / 4 cross-sectional structural schematic diagram of the present invention.

[0026] Figure markings: 11. Pre-combustion stage fuel injection part, 111. Pre-combustion stage air film hole, 112. Pre-combustion stage fuel bin, 113. Pre-combustion stage fuel inlet, 114. Pre-combustion stage fuel jet hole, 12. Center hole, 13. Pre-combustion stage air channel, 131. Pre-combustion stage air inlet, 132. Pre-combustion stage air outlet, 21. Swirl, 22. Cylinder, 23. Main combustion stage fuel bin, 24. Main combustion stage air channel, 25. Main combustion stage air inlet, 26. Main combustion stage fuel inlet, 27. Main combustion stage fuel jet hole. DETAILED DESCRIPTION

[0027] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with embodiments and drawings. The exemplary embodiments of the present invention and their description are only used to explain the present invention and are not intended to limit the present invention.

[0028] The head structure of the traditional center-staged combustion chamber includes a pre-combustion stage fuel nozzle, a venturi, a pre-combustion stage swirler, a main combustion stage fuel cavity, a main combustion stage fuel nozzle, a main combustion stage swirler, etc. In the pre-combustion stage, the fuel nozzle is placed flush with the throat of the venturi. The fuel sprayed from the pre-combustion stage fuel nozzle forms an oil film on the venturi and spreads out, and the fuel is atomized by the shear of the incoming air; the main combustion stage fuel is generally sprayed out through a ring-shaped multi-point nozzle to pre-evaporate and mix with air in the flow channel. Under ignition and slow-running conditions, the pre-combustion stage supplies fuel alone for diffusion combustion to form a pre-combustion stage flame; under large conditions, the pre-combustion stage and the main combustion stage supply fuel and burn at the same time to ensure reliable combustion efficiency. Since the pre-combustion stage provides fuel combustion during the entire cycle of the engine, the combustion stability of the pre-combustion stage is crucial, and NH3 has poor combustion stability and requires high ignition energy, so it is not suitable for use as a pre-combustion stage fuel. Therefore, H2 is used as the pre-combustion stage fuel and NH3 as the main combustion stage fuel.

[0029] Based on the above principle, this embodiment discloses a central staged combustion chamber head structure for NH3 and H2 fuels, such as Figure 1-4As shown, it includes a pre-combustion stage structure and a main combustion stage structure. The main combustion stage structure is used for mixing NH3 and air, including a swirler 21 and a barrel 22 connected to the swirler 21. A main combustion stage fuel bin 23 fixed on the swirler 21 is provided inside the barrel 22, and a gap is provided between the main combustion stage fuel bin 23 and the barrel 22 to form a main combustion stage air channel 24. One end of the main combustion stage air channel 24 away from the swirler 21 serves as a main combustion stage air outlet, and the diameter of the main combustion stage air channel 24 decreases and then increases in the direction from the air inlet end to the exhaust end. The swirler 21 has a plurality of main combustion stage air inlets 25 that penetrate the main combustion stage air channel 24, and the main combustion stage air inlet 25 is connected to the main combustion stage air inlet 25. The channel between the channels 24 is spiral, so that the main combustion air entering the main combustion air channel 24 can achieve swirl. The swirler 21 also has a main combustion fuel inlet 26 that penetrates the main combustion fuel bin 23, which is used to add liquid NH3 into the main combustion fuel bin 23. A plurality of main combustion fuel jet holes 27 are evenly opened on the peripheral side of the main combustion fuel bin 23 and located in the area where the diameter of the main combustion air channel 24 decreases. NH3 is directly injected into the main combustion air channel 24 by multi-point direct injection. The transverse jet formed by the NH3 injection is mixed with the swirling air. Since the liquid NH3 injection will cause flash boiling, it is more conducive to the mixing of NH3 and air. However, N The high latent heat of vaporization of H3 will lead to a low temperature of the mixed air NH3 in the main combustion stage air channel 24. In order to prevent the local temperature from being too low, on the one hand, the number of the main combustion stage fuel jet holes 27 is increased to enhance the mixing speed of NH3 and air. On the other hand, the distance from the main combustion stage fuel jet hole 27 to the main combustion stage air outlet is increased to enhance the mixing and heat transfer of NH3 and air under the action of the streamwise vortex and the spanwise vortex. Through the above two designs, when NH3 and air reach the main combustion stage air outlet, the concentration and temperature distribution of NH3 and air are uniform. Specifically, the main combustion stage air channel 24 adopts a contraction and expansion air channel structure, which is achieved by contracting the area. The flow rate increases. On the one hand, the flame surface needs to establish a new dynamic balance, which is not conducive to the flame burning upstream and effectively prevents flashback. On the other hand, it causes the Reynolds number to increase, which increases the turbulent pulsation and can enhance the mixing of NH3 and air. The expansion section can reduce the flow rate, so that when the flame propagation speed is low, it can find a new balance and will not cause flameout. This distance also provides support for the mixing of NH3 and air. In summary, the designed main combustion stage air passage 24 is beneficial to the mixing of NH3 and air while effectively preventing flashback, thereby reducing local hot spots in the main combustion zone, making the temperature distribution more uniform and the combustion efficiency higher, thereby reducing thermal NOx emissions.

[0030] The pre-combustion stage structure is used for mixing H2 and air, and includes a pre-combustion stage fuel injection member 11. A central hole 12 with two ends passing through is opened at the center of the main combustion stage fuel bin 23 and the swirler 21. The pre-combustion stage fuel injection member 11 is arranged in the central hole 12, and there is a gap between the pre-combustion stage fuel injection member 11 and the central hole 12 to form a pre-combustion stage air channel 13. One end of the pre-combustion stage air channel 13 close to the swirler 21 is a pre-combustion stage air inlet 131, and the other end is a pre-combustion stage air outlet 132. The pre-combustion stage fuel injection member 11 is arranged in the central hole 12, and there is a gap between the pre-combustion stage fuel injection member 11 and the central hole 12 to form a pre-combustion stage air channel 13. The pre-combustion stage air passage 13 is provided with a plurality of pre-combustion stage air film holes 111 with both ends connected, and a pre-combustion stage fuel bin 112 with one end connected and annular near the pre-combustion stage air inlet 131, the through end of the pre-combustion stage fuel bin 112 serves as the pre-combustion stage fuel inlet 113, the pre-combustion stage fuel injection member 11 comprises a cylinder, and the diameter of the end near the pre-combustion stage air outlet 131 increases gradually to form an injection head, the side surface of the injection head forms a blunt surface based on the side surface of the cylinder, and the blunt surface is uniformly circumferentially A plurality of pre-combustion fuel jet holes 114 penetrating the pre-combustion fuel bin 112 are provided, so that H2 is also injected from the pre-combustion fuel jet holes 114 to the pre-combustion air channel 13 in a multi-point direct injection manner. Specifically, when H2 is injected from the pre-combustion fuel jet holes 114, the lateral jet formed forms a lateral jet with the air flow in the pre-combustion air channel 13, thereby achieving a better mixing effect of H2 and air, thereby reducing local hot spots in the main combustion zone, making the temperature distribution more uniform, and facilitating The improvement of combustion efficiency can also reduce the emission of thermal NOx. Taking into account the fast propagation of H2 flame, its premixed combustion easily increases the risk of flashback. The precombustion stage fuel injection member 11 is provided with a plurality of precombustion stage air film holes 111 with through-holes at both ends along the length direction of the precombustion stage air channel 13. For this purpose, the precombustion stage air film holes 111 opened on the precombustion stage fuel injection member 11 form a flashback channel, thereby realizing the anti-flashback of the precombustion stage structure, and effectively preventing the wall surface of the precombustion stage fuel injection member 11 from being burned.

[0031] In summary, the present invention optimizes the existing center-staged combustion chamber head structure, and uses the pre-combustion stage fuel injection member 11 in the pre-combustion stage structure to replace the original venturi, and changes the original air atomizing nozzle to a circumferentially uniform direct injection, so that H2 produces a reflow zone in the pre-combustion stage air channel 13, thereby increasing the turbulence intensity, which is more conducive to the mixing of H2 and air, and also uses the added pre-combustion stage air film holes 114 to achieve anti-flashback of the pre-combustion stage structure, thereby preventing the wall surface of the pre-combustion stage fuel injection member 11 from being ablated. In the main combustion stage structure, the main combustion stage air channel 24 adopts a contraction and then expansion air channel structure, which effectively prevents the occurrence of flashback while also being beneficial to the mixing of NH3 and air, thereby reducing local hot spots in the main combustion zone, making the temperature distribution more uniform, and improving the combustion efficiency, thereby reducing thermal NOx emissions.

[0032] The present invention optimizes the pre-combustion stage structure and the main combustion stage structure of the head structure of the central staged combustion chamber to make it suitable for the combustion of NH3 and H2 fuels. The optimized pre-combustion stage structure and the main combustion stage structure can be well coupled, the fuel-air mixing efficiency is high, and the combustion is complete, thereby avoiding backfire and flameout, achieving uniform outlet temperature distribution, and realizing stable combustion of NH3 and H2 fuels, thereby improving combustion performance and emission performance.

[0033] The cold flow field and hot field of the combustion chamber under different working conditions are calculated through numerical simulation. The results show that in the cold flow field, the fuel and air have a good mixing effect under different working conditions; in addition, in the hot flow field, the pre-combustion stage flame can stably reside downstream of the pre-combustion stage structure, and no backfire or flameout occurs under the studied working conditions. The NH3 and H2 flames can work stably in a wider working boundary, with uniform outlet temperature distribution (OTDF<0.2, RTDF<0.1) and high combustion efficiency.

[0034] In a specific embodiment, the injection direction of the pre-combustion fuel jet hole 114 forms an angle of 60-90° with the central axis of the pre-combustion fuel injection member 11, forming a transverse jet with the air flow in the pre-combustion air channel 13; the opening diameter of the pre-combustion fuel jet hole 114 is 0.4-0.68mm; the diameter of the pre-combustion air film hole 111 is 0.3-0.6mm; the diameter of the injection head corresponding to the pre-combustion air outlet 131 is 16-20mm, and differs from the outer diameter of the pre-combustion air channel 13 by 4-6mm, so as to prevent the high-temperature flue gas from refluxing and ablating the wall surface of the pre-combustion fuel injection member 11 Appearance; in order to prevent NH3 and air from backfiring into the main combustion stage air channel 24, the main combustion stage air channel 24 is designed to be a structure that first contracts and then expands, and the flow velocity is accelerated by contracting the area. The swirler 21 is an axial swirler, and the swirl intensity Sn=0.7-1.1; the axial distance range of the main combustion stage air channel 24 is 21-26mm; the main combustion stage fuel jet hole 27 is located 3-5mm above the swirler 21; the diameter of the main combustion stage fuel jet hole 27 is 1.5-3mm; the inner diameter of the narrowest part of the main combustion stage air channel 24 is 37.8-42.5mm, and the diameter at both ends is 44-49mm.

[0035] Of course, the present invention may have many other embodiments. Without departing from the spirit and essence of the present invention, technicians familiar with the field may make various corresponding changes and modifications based on the present invention, but these corresponding changes and modifications should all fall within the scope of protection of the claims attached to the present invention.

Claims

1. A central staged combustion chamber head structure for NH3 and H2 fuels, comprising a pre-combustion stage structure and a main combustion stage structure located outside the pre-combustion stage structure, characterized in that: The main combustion stage structure is used for mixing NH3 and air, and comprises a main combustion stage fuel bin (23) and a main combustion stage air passage (24) located outside the main combustion stage fuel bin (23), and the diameter of the main combustion stage air passage (24) decreases and then increases in the direction from the air intake end to the exhaust end, and a plurality of main combustion stage fuel jet holes (27) are evenly provided on the peripheral side of the main combustion stage fuel bin (23) and in the area facing the main combustion stage air passage (24) where the diameter decreases; The precombustion stage structure is used for mixing H2 and air, and comprises a precombustion stage air channel (13) and a precombustion stage fuel injection member (11) disposed in the precombustion stage air channel (13); the precombustion stage fuel injection member (11) is provided with a plurality of precombustion stage air film holes (111) with both ends through-holes along the length direction of the precombustion stage air channel (13), and a precombustion stage fuel bin (112) through-holes and in an annular shape close to one end of the air inlet of the precombustion stage air channel (13); the through end of the precombustion stage fuel bin (112) serves as a precombustion stage fuel inlet (113); the precombustion stage fuel injection member (11) comprises a cylinder, the diameter of the cylinder close to one end of the air outlet of the precombustion stage air channel (13) is gradually increased to form an injection head; the side surface of the injection head forms a blunt surface based on the side surface of the cylinder, and the blunt surface is evenly provided with a plurality of precombustion stage fuel jet holes (114) through-holes of the precombustion stage fuel bin (112) along the circumferential direction.

2. The central staged combustion chamber head structure for NH3 and H2 fuels according to claim 1, characterized in that: The main combustion stage structure also includes a swirler (21) and a cylinder (22) connected to the swirler (21); the main combustion stage fuel bin (23) is placed inside the cylinder (22) and fixed on the swirler (21); the swirler (21) has a main combustion stage fuel inlet (26) passing through the main combustion stage fuel bin (23); and the main combustion stage air passage (24) is formed by a gap between the main combustion stage fuel bin (23) and the cylinder (22).

3. The central staged combustion chamber head structure for NH3 and H2 fuels according to claim 2, characterized in that: The swirler (21) also has a plurality of main combustion stage air inlets (25) penetrating the main combustion stage air passage (24), and the passage between the main combustion stage air inlet (25) and the main combustion stage air passage (24) is spiral.

4. The central staged combustion chamber head structure for NH3 and H2 fuels according to any one of claims 2-3, characterized in that: The pre-combustion stage structure comprises a center hole (12) which is opened at the center of the main combustion stage fuel bin (23) and the swirler (21) and is through-hole at both ends, and the pre-combustion stage fuel injection piece (11) is arranged in the center hole (12), a pre-combustion stage air passage (13) is formed by the gap between the pre-combustion stage fuel injection piece (11) and the center hole (12), and one end of the pre-combustion stage air passage (13) close to the swirler (21) is a pre-combustion stage air inlet (131), and the other end is a pre-combustion stage air outlet (132).

5. The central staged combustion chamber head structure for NH3 and H2 fuels according to claim 4, characterized in that: The angle formed by the injection direction of the pre-combustion stage fuel jet hole (114) and the central axis of the pre-combustion stage fuel injection piece (11) is 60-90°, the opening diameter of the pre-combustion stage fuel jet hole (114) is 0.4-0.68mm, and the diameter of the pre-combustion stage air film hole (111) is 0.3-0.6mm.

6. The central staged combustion chamber head structure for NH3 and H2 fuels according to claim 5, characterized in that: The diameter of one side of the injection head corresponding to the pre-combustion stage air outlet (131) is 16-20 mm, and differs from the outer diameter of the pre-combustion stage air channel (13) by 4-6 mm.

7. The central staged combustion chamber head structure for NH3 and H2 fuels according to claim 6, characterized in that: The cyclone (21) is an axial cyclone, and the cyclone intensity Sn=0.7-1.

1.

8. The central staged combustion chamber head structure for NH3 and H2 fuels according to claim 7, characterized in that: The axial distance of the main combustion stage air passage (24) ranges from 21 to 26 mm.

9. The central staged combustion chamber head structure for NH3 and H2 fuels according to claim 8, characterized in that: The main combustion stage fuel jet hole (27) is located 3-5 mm above the swirler (21), and the diameter of the main combustion stage fuel jet hole (27) is 1.5-3 mm.

10. The central staged combustion chamber head structure for NH3 and H2 fuels according to claim 9, characterized in that: The narrowest inner diameter of the main combustion stage air passage (24) is 37.8-42.5 mm, and the diameters at both ends are 44-49 mm.

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