Diffusion type combustion chamber head injection structure

Abstract

The invention discloses a diffusion type combustion chamber head injection structure, and belongs to the technical field of hydrogen fuel gas turbines. The inner swirler, the hydrogen fuel conveyor and the outer swirler are sequentially and coaxially arranged from inside to outside; the outer cyclone is an annular cavity and sequentially comprises an outer cyclone inlet, outer cyclone blades, a transition section and a convergence-expansion section in the axial direction, and the convergence-expansion section is composed of a convergence section and an expansion section; the inner cyclone is of a coaxial coupling structure of a blocking body and a cyclone cavity; the hydrogen fuel conveyor is coaxially arranged between the inner swirler and the outer swirler and sequentially comprises a gas supply pipe, a gas collection ring, a distribution gas channel, a gas storage chamber and an injection outlet hole in the axial direction; the rotational flow air of the outer swirler, the rotational flow air of the inner swirler and the non-rotational flow air are mixed in the flame tube in the expansion section to form detached flames to isolate a high-temperature combustion area. The mixing effect of hydrogen fuel and incoming flow air is optimized, the low nitrogen oxide emission capacity is achieved, and the risk that a diffusion type structure device is ablated is effectively avoided.

Description

Technical Field

[0001] The invention belongs to the technical field of hydrogen fuel gas turbines, and in particular relates to a diffusion type combustion chamber head injection structure. Background Art

[0002] As international pollution emission requirements for gas turbines become increasingly stringent, the aim of using traditional kerosene as fuel for power transmission will not be able to meet low emission requirements. Hydrogen, as a valuable clean energy, is full of potential in the future gas turbine market; therefore, it is necessary to develop a combustion chamber head injection structure suitable for pure hydrogen combustion. At present, from the perspective of the mixing method of hydrogen fuel and air, the hydrogen fuel combustion chamber head injection structure is mainly divided into two types: premixed combustion type and diffusion combustion type. Among them, the premixed structure is mainly represented by a lean premixed injection unit, which usually includes a premixing section or a premixing chamber; and the diffusion structure is represented by a lean direct injection unit, which usually only includes a partial transition section.

[0003] However, the existing hydrogen fuel premixed structure generally has a high risk of flashback and spontaneous combustion; in contrast, the diffusion structure itself has good anti-flashback and anti-spontaneous combustion properties and stable combustion. However, the conventional diffusion structure usually only contains a part of the transition section, and the hydrogen fuel and air are mainly mixed in the flame tube. The short mixing time and uneven mixing problems can easily lead to excessive combustion temperature and large thermal nitrogen oxide emissions. At the same time, based on hydrogen as fuel, due to the fast propagation speed of the hydrogen flame, the location of the recirculation zone will be related to whether the hydrogen fuel diffusion structure device is burned by the flame.

[0004] Therefore, the present invention proposes a hydrogen fuel diffusion type combustion chamber head injection structure. Summary of the invention

[0005] Technical issues to be solved:

[0006] In order to avoid the shortcomings of the prior art, the present invention provides a hydrogen fuel diffusion-type combustion chamber head injection structure, which couples a hydrogen fuel conveyor between an outer swirler and an inner swirler, and rationally arranges the hydrogen fuel injection hole space; and adopts a combination of non-swirling air and swirling air, a two-stage swirler to distribute the air flow, and an outlet adopts a convergent-divergent section and other technologies to optimize the mixing effect of hydrogen fuel and incoming air, achieve low nitrogen oxide emission capacity, and effectively avoid the risk of ablation of the diffusion-type structure device.

[0007] The technical solution of the present invention is: a diffusion type combustion chamber head injection structure, an inner swirler, a hydrogen fuel conveyor, and an outer swirler are coaxially arranged from the inside to the outside, respectively passing air and hydrogen fuel into the flame tube for uniform mixing;

[0008] The external cyclone is an annular cavity, which includes an external cyclone inlet, external cyclone blades, a transition section and a convergent-expansion section in sequence along the axial direction, and the convergent-expansion section consists of a convergent section and an expansion section; the convergence angle of the convergent section is 135°, the expansion angle of the expansion section is 45°, and the ratio of the axial length of the expansion section to the convergent section is not less than 1 / 2;

[0009] The inner swirler is a coaxial coupling structure of a blocking body and a swirl chamber; the blocking body is a cylindrical body with a convergent end, and a plurality of non-swirl holes are opened on its end surface along the axial direction; the swirl chamber is an annular cavity including an inner swirl inlet, inner swirl blades, and an inner swirl outlet convergent section in sequence along the axial direction, and a cooling hole connecting the swirl chamber and the flame tube is provided on the convergent wall surface of the inner swirl outlet convergent section; wherein the outlet surface of the non-swirl hole is flush with the throat of the convergent-divergent section of the outer swirler;

[0010] The hydrogen fuel conveyor is coaxially arranged between the inner swirler and the outer swirler, and includes an air supply pipe, an air collecting ring, an air distribution channel, an air storage chamber and an injection outlet hole in sequence along the axial direction; the air collecting ring is an annular cavity connected between the air supply pipe and the air distribution channel; the air storage chamber is an annular cavity connected to the downstream of the air distribution channel, and its end is a convergent outlet section arranged opposite to the convergent section of the outer swirler, and a plurality of injection outlet holes are evenly distributed along the circumferential direction on the end face of the end, and the outlet surface of the injection outlet hole is aligned with the throat of the convergent-divergent section;

[0011] The swirling air of the outer swirler, the swirling air of the inner swirler and the non-swirling air are mixed in the expansion section and the flame tube to form a debonding flame to isolate the high-temperature combustion zone.

[0012] A further technical solution of the present invention is: the number of external swirl blades of the external swirler is 12, the blade angle is 40°, the inner hub diameter of the external swirler is equal to the outer diameter of the air storage chamber, and the swirl air flowing through the external swirler accounts for 60%-67% of the total incoming air volume.

[0013] A further technical solution of the present invention is that the axial length of the transition section exceeds 1 / 2 of the axial length of the inner hub of the outer swirler, so as to adjust the tangential momentum of the swirling air.

[0014] A further technical solution of the present invention is: the outer diameter of the inner cyclone is equal to the inner diameter of the air storage chamber, the non-swirl holes thereon are circular small holes, the ratio of their flow area to the area of ​​the blocking body is 1 / 5-2 / 5, and the non-swirl air volume accounts for 6.5%-10% of the total incoming air volume.

[0015] A further technical solution of the present invention is that two circles of circular cooling holes are opened on the convergent wall surface of the inner cyclone, and the axial direction of the cooling holes is parallel to the axial direction of the outer cyclone.

[0016] A further technical solution of the present invention is that the gas distribution channel of the hydrogen fuel conveyor is composed of four axisymmetric gas delivery pipes, which are used to uniformly convey hydrogen to the gas storage chamber.

[0017] A further technical solution of the present invention is that the diameter of the injection outlet hole of the hydrogen fuel conveyor is 0.5 mm, and it is evenly arranged in two circles in the circumferential direction, the radial distance between the circles is 1 mm, and the radial distance between the inner circle and the central axis of the inner cyclone is 6.5 mm.

[0018] A further technical solution of the present invention is that the effective flow area of ​​the hollow annular cavity of the hydrogen fuel conveyor gas storage chamber is equal to the geometric area of ​​the inner hub of the inner cyclone to ensure the proportion of the non-swirling air volume.

[0019] A further technical solution of the present invention is that the outer swirler, the inner swirler and the fuel conveyor are designed in an integrated manner or are mechanically connected.

[0020] A further technical solution of the present invention is: the non-swirl holes are arranged in 5 circles at equal distances in the radial direction, the number of holes in each circle is 1, 6, 12, 24, and 40 respectively, and the radial distance between the circles is 1.1 mm.

[0021] Beneficial Effects

[0022] The beneficial effects of the present invention are as follows: the present invention adopts lean direct injection combustion organization technology to directly inject hydrogen fuel into the flame tube and mix it with excess swirl air and non-swirl air passing through the inner and outer swirlers; this combustion organization technology combines the low flashback and spontaneous combustion risks of diffusion combustion, and the combustion process is stable and not prone to oscillating combustion. At the same time, it can effectively improve the emission of thermal nitrogen oxides during hydrogen combustion. The specific advantages are analyzed as follows:

[0023] 1. Reduce nitrogen oxide emissions. The external swirler of the present invention connects the transition section with the subsequent convergence-expansion section. The transition section is used to adjust and strengthen the tangential momentum of part of the incoming swirling air, and orderly transport the swirling air to the following convergence-expansion section; by reasonably designing the axial length ratio, convergence angle and expansion angle of the convergence section and the expansion section; the ratio between the expansion section and the convergence section is greater than 1 / 2, the expansion angle is 135°, and the convergence angle is 45°, forming an axially symmetrical shape along the throat, which is beneficial to enhance the mixing effect of the external swirling air and the hydrogen fuel, and the fuel gas entering the flame tube is more uniform, thereby achieving the purpose of reducing nitrogen oxide emissions.

[0024] The gas supply pipe of the present invention delivers hydrogen fuel to the gas collecting ring, and the hydrogen fuel is evenly delivered to the axially symmetrical distribution gas channel. Finally, the hydrogen fuel is ejected from the injection outlet in a circumferentially uniform manner, thereby ensuring the uniformity of hydrogen in the flame tube.

[0025] 2. Avoid device ablation. The inner swirler of the present invention arranges five circles of staggered non-swirl air holes on the inner hub column, reasonably designs the diameter and number of non-swirl holes, adjusts the non-swirl air volume and non-swirl air axial flow rate, and is used to resist the combustion speed of hydrogen fuel flame. When the non-swirl air volume accounts for 6.5%-10% of the total incoming air volume, it can effectively form a detached flame in the flame tube, thereby isolating the high-temperature combustion zone from the hydrogen fuel diffusion-type injection unit structure; and can reasonably ensure sufficient external swirl air and internal swirl air flow to shear the hydrogen fuel to form a uniform combustion gas; the non-swirl air outlet surface is flush with the throat of the convergence-expansion section of the swirler, and is in the same plane as the hydrogen fuel outlet, so as to realize the ability of non-swirl air and swirl air to jointly enhance the mixing of hydrogen fuel in the flame tube, so as to achieve the purpose of avoiding structural device ablation and enhancing hydrogen combustion with a small amount of non-swirl air.

[0026] 3. Improve combustion efficiency. The present invention adopts a layout of non-swirl holes, inner swirlers, fuel conveyors, and outer swirlers from the inside to the outside. The jet air ejected from the non-swirl holes will directly resist the propagation speed of the hydrogen combustion flame, achieve balance at the front edge of the recirculation zone in the center of the flame tube, and stabilize the flame combustion; the inner swirling air expands radially in the flame tube, driving the hydrogen fuel to move toward the periphery, and then further mixes with the swirling air from the outer swirler, and performs turbulent motion in the shear layer formed by the joint action of the inner and outer swirling air; the hydrogen fuel can be mixed with multiple swirling air and non-swirl air at the same time in the expansion section of the outer swirler and the flame tube, so as to achieve the ability to achieve superior combustion of hydrogen fuel. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is an exploded schematic diagram of the head structure of the hydrogen fuel diffusion type combustion chamber of the present invention;

[0028] Figure 2 It is a schematic diagram of the structure of the external cyclone of the present invention;

[0029] Figure 3 is a cross-sectional view of the external cyclone of the present invention;

[0030] Figure 4 It is a front view schematic diagram of the internal cyclone structure of the present invention;

[0031] Figure 5 It is a schematic diagram of the back side of the inner cyclone structure of the present invention;

[0032] Figure 6 is a cross-sectional view of the inner cyclone of the present invention;

[0033] Figure 7 It is a schematic diagram of the structure of the fuel conveyor of the present invention;

[0034] Figure 8is a cross-sectional view of a fuel delivery device of the present invention;

[0035] Fig. 9 It is a schematic diagram of the structure of the gas storage chamber of the present invention;

[0036] Fig.10 This is a cross-sectional view of the assembly structure of the head of the hydrogen fuel diffusion type combustion chamber of the present invention

[0037] Fig.11 This is a schematic diagram of the working process of the hydrogen fuel diffusion type combustion chamber head structure of the present invention (without non-swirl holes)

[0038] Fig.12 This is a schematic diagram of the working process of the head structure of the hydrogen fuel diffusion type combustion chamber of the present invention (with non-swirl holes)

[0039] Explanation of reference numerals: 1-external swirler, 11-external swirling inlet, 12-external swirling blades, 13-transition section, 14-convergent-divergent section, 15-external convergent section, 16-external divergent section, 17-throat, 18-inner hub of external swirler, 2-internal swirler, 21-internal swirling inlet, 22-internal swirling blades, 23-non-swirling hole, 24-blocking body, 25-internal swirling outlet surface, 26-non-swirling hole outlet surface , 27-inner convergent section, 28-cooling hole, 29-inner swirl outlet convergent section, 210-inner swirler inner hub 3-fuel conveyor, 31-air supply pipe, 32-gas collecting ring, 33-distribution air duct, 34-air storage chamber, 35-hydrogen fuel outlet convergent section, 36-non-swirl air inlet, 37-hollow annular cavity, 38-inner wall of air storage chamber, 39-injection outlet, 310-air storage chamber outlet, 311-air delivery pipe. DETAILED DESCRIPTION

[0040] The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, but should not be construed as limiting the present invention.

[0041] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0042] Based on the problems that the conventional hydrogen fuel combustion chamber head injection structure has a low mixing effect on hydrogen fuel and incoming air, a large amount of thermal nitrogen oxide emissions, and a risk of ablation, the present invention provides a diffusion type combustion chamber head injection structure, wherein an inner swirler, a hydrogen fuel conveyor, and an outer swirler are coaxially arranged from the inside to the outside, respectively, to pass air and hydrogen fuel into the flame tube for uniform mixing;

[0043] The external cyclone is an annular cavity, which includes an external cyclone inlet, external cyclone blades, a transition section and a convergent-expansion section in sequence along the axial direction, and the convergent-expansion section consists of a convergent section and an expansion section; the convergence angle of the convergent section is 135°, the expansion angle of the expansion section is 45°, and the ratio of the axial length of the expansion section to the convergent section is not less than 1 / 2;

[0044] The inner swirler is a coaxial coupling structure of a blocking body and a swirl chamber; the blocking body is a cylindrical body with a convergent end, and a plurality of non-swirl holes are opened on its end surface along the axial direction; the swirl chamber is an annular cavity including an inner swirl inlet, inner swirl blades, and an inner swirl outlet convergent section in sequence along the axial direction, and a cooling hole connecting the swirl chamber and the flame tube is provided on the convergent wall surface of the inner swirl outlet convergent section; wherein the outlet surface of the non-swirl hole is flush with the throat of the convergent-divergent section of the outer swirler;

[0045] The hydrogen fuel conveyor is coaxially arranged between the inner swirler and the outer swirler, and includes an air supply pipe, an air collecting ring, an air distribution channel, an air storage chamber and an injection outlet hole in sequence along the axial direction; the air collecting ring is an annular cavity connected between the air supply pipe and the air distribution channel; the air storage chamber is an annular cavity connected to the downstream of the air distribution channel, and its end is a convergent outlet section arranged opposite to the convergent section of the outer swirler, and a plurality of injection outlet holes are evenly distributed along the circumferential direction on the end face of the end, and the outlet surface of the injection outlet hole is aligned with the throat of the convergent-divergent section;

[0046] The swirling air of the outer swirler, the swirling air of the inner swirler and the non-swirling air are mixed in the expansion section and the flame tube to form a debonding flame to isolate the high-temperature combustion zone.

[0047] The above technical solution is further described below in conjunction with the accompanying drawings:

[0048] In one embodiment, referring to Figure 1 As shown, this embodiment is a diffusion type combustion chamber head injection structure, including an outer swirler 1, an inner swirler 2, and a coaxial fuel conveyor 3.

[0049] In one embodiment, referring to Figure 2 , 3As shown, the main part of the external swirler 1 is the external swirling blade 12. Through optimization, the swirl angle of the external swirling blade 12 is 40°, and the swirl direction is clockwise, that is, from the incoming flow direction of the swirling air, the blade rotation direction is the clockwise direction under the usual regulations; the axial length of the inner hub 18 of the external swirler is set to 10mm to ensure the light-proof principle, and the incoming air passing through the swirler 1 is all swirling air without generating a jet; the swirler 1 and the coaxial air storage chamber 34 are ensured to be flush at the inlet surface, and the external swirler 1 and the air storage chamber 34 are mechanically connected.

[0050] It should be noted that the rear end of the swirler blade 12 is a transition section 13, and the inner wall of the transition section 13 is uniformly of equal diameter from front to back; the swirling air passing through the swirling blade 12 adjusts the irregular directional fluctuations in the transition section 13, and enters the convergence-expansion section 14 at the rear end with appropriate tangential momentum; through optimization, the axial length of the transition section 13 is 5 mm, which is maintained at 1 / 2 or more of the axial length of the hub 18 in the swirler; and in the convergence-expansion section 14, the axial length of the convergence section 15 is 5 mm, the convergence angle is 135°, the axial length of the expansion section 16 is 2.5 mm, the expansion angle is 45°, and the ratio of the axial length of the expansion section 16 to the convergence section 15 is maintained at 1 / 2 or more, which can effectively enhance the mixing between the gases.

[0051] In one embodiment, referring to Figure 4 , 5 As shown in 6, the main part of the inner swirler 2 includes inner swirling blades 22. Through optimization, the swirl angle of the inner swirling blades 22 is 38°, and the swirl direction is clockwise, ensuring that the swirl intensity generated by the inner swirling blades is equal to the swirl intensity generated by the outer swirling blades, and the hydrogen fuel is effectively controlled in the shear layer. The inner hub 210 of the inner swirler is a cylinder with an inner convergent outlet section 27. Through optimization, the diameter of the inner hub 210 of the inner swirler is 10mm; its outlet surface 26 is aligned with the throat 17 of the convergent-divergent section of the outer swirler, that is, it is placed near the inlet of the flame tube; a strong jet penetration is formed by non-swirling gas, which effectively resists the high flame combustion speed of the downstream hydrogen, thereby forming a detached flame inside the flame tube, isolating the high-temperature combustion zone from the hydrogen fuel diffusion-type injection unit structure, and effectively avoiding the ablation of the structural device; the inner swirler 2 and the fuel inlet The relative installation between the conveyors 3 can be mechanically connected or integrated. A plurality of non-swirl holes 23 of the same diameter are arranged on the inner cyclone 2. The diameter of the non-swirl hole 23 is optimized to be 0.6 mm. The layout of the holes is arranged 5 circles at equal intervals in the radial direction. The number of the first circle is 1, and the number of the second circle, the third circle, and so on are 6, 12, 24, and 40 respectively. The radial distance between the circles is preferably 1.1 mm, and the non-swirl holes 23 on each circle are evenly arranged in the circumferential direction. The effective flow area of ​​the non-swirl hole 23 is 13.65 mm. 2, and the non-swirl air accounts for 6.5%-10% of the total incoming air volume, achieving the effect of strengthening the fuel gas mixing mainly through the swirl effect of the swirl air, and supplemented by the non-swirl air induced hydrogen.

[0052] In one embodiment, referring to Figure 7 , 8 As shown in Figures 9, the inlet end of the fuel conveyor 3 is an air supply pipe 31, the diameter of the air supply pipe 31 is optimized to 4 mm, its axis is parallel to the axis of the cyclone 1, and from the axial direction, the axis of the air supply pipe 31 is located in the middle of the axes of any two air supply pipes 311 in the distribution air channel 33; the air supply pipe 31 is connected to the air collecting ring 32 through an integrated design, and the interior of the air collecting ring 32 is a hollow cavity, and the cavity height is equal to the diameter of the air supply pipe 31, so as to ensure that the hydrogen is stably transported to the distribution air channel 33 at the other end; through the optimized design, the distribution air channel is mainly composed of four mutually axially symmetrical air supply pipes 311, so as to ensure that the hydrogen enters the air storage chamber 34 in a uniform form. In addition, the main part of the air storage chamber 34 is a larger hollow cavity, and the cavity height of the hollow cavity is larger than the inner tube diameter of the air supply pipe 311, so as to further weaken the axial velocity of the hydrogen flow.

[0053] It is worth noting that, since the main body of the air storage chamber 34 is a hollow cavity for storing hydrogen, the inner wall 38 of the air storage chamber constitutes a flow path for the non-swirl air to enter the non-swirl hole 23. Through optimized design, the effective flow area of ​​the flow path is equal to the geometric area of ​​the inner hub 210 of the inner cyclone, which is equivalent to a round tube with a diameter of 10 mm, so as to minimize the impact on the effective flow area of ​​the rear non-swirl hole, ensuring that the amount of non-swirl air is in an appropriate proportion: 6.5%-10%; the rear end of the air storage chamber 34 is a convergent outlet section 35, whose axial length is preferably 3 mm and the convergence angle is 135°. The convergent outlet section 35 constitutes an expansion flow path for the swirl air coming out of the outer cyclone 1 to pass through, ensuring that part of the swirl Air can be quickly mixed with hydrogen fuel in the expansion section 16 of the convergence-expansion section 14; the injection outlet 39 is arranged on the outlet surface 310 of the air storage chamber, and the injection outlet 39 is preferably selected as a circular injection hole with a diameter of 0.5 mm, and the number of injection holes is 48, presenting a layout with two circles evenly arranged circumferentially; the radial distance between the circles is taken as 1 mm; the side close to the inner swirler 2 is called the inner circle, and the side close to the outer swirler 1 is called the outer circle, wherein the radial distance between the inner circle and the central axis of the inner swirler is 6.5 mm, ensuring that the distance between the injection outlet 39 of the inner circle and the non-swirling air flowing through the non-swirling holes 23 of the inner swirler is closer, which is conducive to making full use of the air entering the flame tube through the spatial layout.

[0054] In one embodiment, referring to Fig.10As shown, the outlet surface 310 of the air storage chamber is also aligned with the throat 17 of the convergent-divergent section, ensuring that after the hydrogen fuel is ejected from the injection outlet 39, it can be quickly mixed with the swirling air from the outer swirler 1, the swirling air from the inner swirler 2, and the non-swirling air in the expansion section 16 to enhance the mixing effect.

[0055] It should be noted that when the structure of the present invention is used, the outer swirler 1, the inner swirler 2 and the fuel conveyor 3 can be designed as an integrated whole according to the needs of the present invention, and are not limited to mechanical connections.

[0056] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention without departing from the principles and intent of the present invention.

Claims

1. A diffusion type combustion chamber head injection structure, characterized in that: The inner swirler, hydrogen fuel conveyor and outer swirler are coaxially arranged from the inside to the outside, respectively passing air and hydrogen fuel into the flame tube for uniform mixing; The external cyclone is an annular cavity, which includes an external cyclone inlet, external cyclone blades, a transition section and a convergent-expansion section in sequence along the axial direction, and the convergent-expansion section consists of a convergent section and an expansion section; the convergence angle of the convergent section is 135°, the expansion angle of the expansion section is 45°, and the ratio of the axial length of the expansion section to the convergent section is not less than 1 / 2; The inner swirler is a coaxial coupling structure of a blocking body and a swirl chamber; the blocking body is a cylindrical body with a convergent end, and a plurality of non-swirl holes are opened on its end surface along the axial direction; the swirl chamber is an annular cavity including an inner swirl inlet, inner swirl blades, and an inner swirl outlet convergent section in sequence along the axial direction, and a cooling hole connecting the swirl chamber and the flame tube is provided on the convergent wall surface of the inner swirl outlet convergent section; wherein the outlet surface of the non-swirl hole is flush with the throat of the convergent-divergent section of the outer swirler; The hydrogen fuel conveyor is coaxially arranged between the inner swirler and the outer swirler, and includes an air supply pipe, an air collecting ring, an air distribution channel, an air storage chamber and an injection outlet hole in sequence along the axial direction; the air collecting ring is an annular cavity connected between the air supply pipe and the air distribution channel; the air storage chamber is an annular cavity connected to the downstream of the air distribution channel, and its end is a convergent outlet section arranged opposite to the convergent section of the outer swirler, and a plurality of injection outlet holes are evenly distributed along the circumferential direction on the end face of the end, and the outlet surface of the injection outlet hole is aligned with the throat of the convergent-divergent section; The swirling air of the outer swirler, the swirling air of the inner swirler and the non-swirling air are mixed in the expansion section and the flame tube to form a debonding flame to isolate the high-temperature combustion zone.

2. A diffusion type combustion chamber head injection structure according to claim 1, characterized in that: The number of the outer cyclone blades is 12, the blade angle is 40°, the inner hub diameter of the outer cyclone is equal to the outer diameter of the air storage chamber, and the cyclone air flowing through the outer cyclone accounts for 60%-67% of the total incoming air volume.

3. The diffusion type combustion chamber head injection structure according to claim 1, characterized in that: The axial length of the transition section exceeds 1 / 2 of the axial length of the inner hub of the outer swirler, and is used to adjust the tangential momentum of the swirling air.

4. The diffusion type combustion chamber head injection structure according to claim 1, characterized in that: The outer diameter of the inner cyclone is equal to the inner diameter of the air storage chamber. The non-swirl holes thereon are circular small holes, and the ratio of their flow area to the blocking body area is 1 / 5-2 / 5. The non-swirl air volume accounts for 6.5%-10% of the total incoming air volume.

5. The diffusion type combustion chamber head injection structure according to claim 1, characterized in that: Two circles of circular cooling holes are opened on the convergent wall surface of the inner cyclone, and the axial direction of the cooling holes is parallel to the axial direction of the outer cyclone.

6. The diffusion type combustion chamber head injection structure according to claim 1, characterized in that: The gas distribution channel of the hydrogen fuel conveyor is composed of four axisymmetric gas delivery pipes, which are used to uniformly convey hydrogen to the gas storage chamber.

7. The diffusion type combustion chamber head injection structure according to claim 1, characterized in that: The diameter of the injection outlet hole of the hydrogen fuel conveyor is 0.5 mm, and it is evenly arranged in two circles in the circumferential direction. The radial distance between the circles is 1 mm, and the radial distance between the inner circle and the central axis of the inner cyclone is 6.5 mm.

8. The diffusion type combustion chamber head injection structure according to claim 1, characterized in that: The effective flow area of ​​the hollow annular cavity of the hydrogen fuel conveyor gas storage chamber is equal to the geometric area of ​​the inner hub of the inner cyclone to ensure the proportion of the non-cyclonic air volume.

9. The diffusion type combustion chamber head injection structure according to claim 1, characterized in that: The outer swirler, the inner swirler and the fuel conveyor are designed in an integrated manner or are mechanically connected.

10. The diffusion type combustion chamber head injection structure according to claim 1, characterized in that: The non-swirl holes are arranged in five circles at equal intervals in the radial direction, the number of holes in each circle is 1, 6, 12, 24, and 40 respectively, and the radial distance between the circles is 1.1 mm.

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