Small turbofan engine hydrogen low-pollution combustion chamber and combustion method

Abstract

The invention discloses a small turbofan engine hydrogen low-pollution combustion chamber and a combustion method, the combustion chamber is used for dividing air at an inlet of the combustion chamber into three paths to enter a main combustion area for combustion, and the combustion chamber comprises a main combustion chamber inner casing, an inner flame tube, an outer flame tube and a main combustion chamber outer casing which are sequentially sleeved from inside to outside; a main combustion chamber head is arranged at one end, connected with the inner flame tube, of the outer flame tube; the wall surfaces of the outer flame tube and the inner flame tube at the other end are respectively provided with a large discharge mixing hole and a small discharge mixing hole for air to enter; the head of the main combustion chamber is provided with a hydrogen collecting cavity and a Tesla valve mixer which are connected, one end of the hydrogen collecting cavity is connected with a hydrogen supply pipeline, and the other end of the hydrogen collecting cavity is communicated with a plurality of Tesla valve channels in the Tesla valve mixer. The Tesla valve mixer is utilized, mixing strengthening is achieved on the basis of transverse jet flow and cross jet flow combination, efficient mixing of hydrogen and air is achieved under the constraint of the limited size of the head of the main combustion chamber, hydrogen lean-burn micro-premixed combustion is completed, and emission of nitrogen oxide is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of small turbofan engines, in particular to a small turbofan engine hydrogen low pollution combustion chamber and combustion method. BACKGROUND

[0002] In the new energy combustion technology, the reaction product of hydrogen fuel and air is only water, making hydrogen fuel one of the most potential fuels to achieve zero carbon emission. However, hydrogen molecules have small mass and low jet momentum, which are difficult to fully mix in high-flow and high-speed inlet air flow, resulting in local fuel concentration and local high temperature zone during combustion, which leads to the generation of a large amount of nitrogen oxide pollutants.

[0003] To this end, a hydrogen micro-premixed combustion technology based on micro-channel mixing is proposed, which means that hydrogen and air are premixed in a micro-channel, and the mixed gas is ejected through the same nozzle jet, effectively avoiding the concentration of hydrogen concentration and reducing the formation of local hot spots during combustion, which can achieve extremely low emission of nitrogen oxides. Currently, this technology uses a micro-mixer similar to lean direct injection to achieve micro-premixed combustion, and the mixing methods include jet-crossflow mixing, swirl micro-mixing, porous medium mixing, and screw thread loop mixing. For transverse jet mixing, the hydrogen transverse jet penetration depth is small, which is difficult to achieve efficient mixing in a short distance, resulting in a long nozzle size structure. Micro-swirl mixing can effectively shorten the mixing distance, but it requires a micro-mixing swirl structure, which further increases the complexity of the engine nozzle. SUMMARY

[0004] The purpose of the present application is to provide a small turbofan engine hydrogen low pollution combustion chamber and combustion method, which solves the technical problem of high nitrogen oxide pollutant emission of the hydrogen main combustion chamber of the small turbofan engine in the prior art, and can effectively shorten the size of the combustion chamber head, inhibit the hydrogen backfire problem, and realize the switching of different thermal power conditions of the main combustion chamber.

[0005] The present application solves the above problems by the following technical scheme:

[0006] A small turbofan engine hydrogen low pollution combustion chamber for dividing the combustion chamber inlet air into three paths to enter the main combustion area, comprising: a main combustion chamber inner casing, an inner flame tube, an outer flame tube and a main combustion chamber outer casing which are sequentially sleeved from inside to outside; the outer flame tube and the inner flame tube are connected at one end and are provided with a plurality of main combustion chamber heads in the circumferential direction, and a plurality of igniters are arranged in the main combustion chamber heads; the outer flame tube and the inner flame tube at the other end are respectively provided with a plurality of large mixing holes and a plurality of small mixing holes for air inlet, and the small mixing holes are arranged away from the main combustion chamber heads compared with the large mixing holes; a main combustion area is formed in the middle between the outer flame tube and the inner flame tube;

[0007] The main combustion chamber head has a hydrogen gas collecting cavity and a Tesla valve mixer connected thereto; one end of the hydrogen gas collecting cavity is connected with a hydrogen supply pipeline, and the other end is connected with a plurality of Tesla valve channels in the Tesla valve mixer, so that the hydrogen gas entering the hydrogen gas collecting cavity through the hydrogen supply pipeline is mixed with the air in the Tesla valve channels through transverse jet flow and cross jet flow.

[0008] As a further improvement, the hydrogen supply pipeline is arranged on the outer casing wall of the main combustion chamber.

[0009] As a further improvement, the Tesla valve mixer comprises an outer mixer shell and an inner mixer shell arranged inside and outside, a plurality of Tesla valve channels are formed between the outer mixer shell and the inner mixer shell, a flow guide bluff body is arranged inside the Tesla valve channel, and a gas collecting cavity nozzle is formed on the inner mixer shell to communicate with the hydrogen gas collecting cavity, so that the hydrogen gas in the hydrogen gas collecting cavity is sprayed into the Tesla valve channel.

[0010] As a further improvement, the flow guide bluff body is in a fan-shaped structure, and the circular arc surface, i.e. the trailing edge, of the fan-shaped structure is arranged away from the inlet of the Tesla valve channel, so as to divide the Tesla valve channel into a main flow channel and a secondary flow channel, the hydrogen gas sprayed from the hydrogen gas collecting cavity is mixed with the air in the secondary flow channel through transverse jet flow, at the trailing edge of the flow guide bluff body, the air in the main flow channel and the combustible mixture in the secondary flow channel are mixed again through cross jet flow, and then the mixture is sprayed out through the outlet of the Tesla valve channel.

[0011] As a further improvement, the hydrogen gas collecting cavity comprises an inner hydrogen gas collecting cavity and an outer hydrogen gas collecting cavity arranged inside and outside; the gas collecting cavity nozzle comprises an outer hydrogen gas collecting cavity nozzle communicating with the outer hydrogen gas collecting cavity and an inner hydrogen gas collecting cavity nozzle communicating with the inner hydrogen gas collecting cavity.

[0012] As a further improvement, the outer hydrogen gas collecting cavity nozzle is circular, the inner hydrogen gas collecting cavity nozzle is semicircular, the diameters of the nozzles are 0.3-0.5 mm, and the nozzles are uniformly arranged in the circumferential direction.

[0013] As a further improvement, the hydrogen supply pipeline comprises a mounting seat fixed on the outer casing of the main combustion chamber, the mounting seat is provided with an outer hydrogen gas collecting cavity inlet joint and an inner hydrogen gas collecting cavity inlet joint, the outer hydrogen gas collecting cavity inlet joint is connected with the outer hydrogen gas collecting cavity through an outer hydrogen gas collecting cavity main pipe, and the inner hydrogen gas collecting cavity inlet joint is connected with the inner hydrogen gas collecting cavity through an inner hydrogen gas collecting cavity main pipe.

[0014] As a further improvement, the outer wall of the Tesla valve mixer is provided with a mounting limiting structure.

[0015] As a further improvement, the igniter is arranged symmetrically in the head of the main combustion chamber and is connected to the power supply through two positive and negative power supply lines leading out of the main combustion chamber to the power supply.

[0016] Meanwhile, the application also solves the above problems through the following technical solutions:

[0017] A hydrogen combustion method for a small turbofan engine, characterized by being implemented by a small turbofan engine hydrogen low-pollution combustion chamber according to any one of claims 1-9 to allow air to enter the combustion chamber, the inlet air of the combustion chamber is divided into three paths, and the specific steps include:

[0018] S100, the first path of air flows into the Tesla valve channel of the Tesla valve mixer, mixes with the hydrogen entering the Tesla valve channel through the hydrogen collecting cavity, and then enters the main combustion zone; and when the hydrogen and air premixed combustible gas is sprayed out of the head of the main combustion chamber, the hydrogen lean premixed combustion in the main combustion zone is carried out under the action of the high-temperature ignition source of the igniter, so as to reduce the emission of nitrogen oxides;

[0019] The fuel supply amount of the hydrogen collecting cavity to the main combustion zone can be adjusted according to the power working condition to meet the corresponding fuel demand;

[0020] S200, the second path of air flows into the combustion chamber outer ring cavity formed between the main combustion chamber outer casing and the outer flame tube, and the third path of air flows into the combustion chamber inner ring cavity formed between the main combustion chamber inner casing and the inner flame tube, and the air in the combustion chamber outer ring cavity and the combustion chamber inner ring cavity respectively enters the flame tube through the large mixing holes on the outer flame tube and the inner flame tube to mix and cool with the high-temperature combustion gas, and to adjust the outlet temperature distribution; a small amount of remaining mixed air enters the flame tube through the small mixing holes on the outer flame tube and the inner flame tube to finely adjust the outlet temperature distribution.

[0021] Compared with the prior art, the application has the following advantages and beneficial effects:

[0022] (1) The application uses a Tesla valve mixer to realize mixing enhancement based on the combination of transverse jets and cross jets, realizes efficient mixing of hydrogen and air under the constraint of the limited size of the head of the main combustion chamber, completes hydrogen lean micro-premixed combustion, and reduces the emission of nitrogen oxides.

[0023] (2) The application cancels the main combustion hole of the combustion chamber, only retains the mixing hole, increases the air intake proportion of the head of the main combustion chamber, and increases the outlet flow velocity of the Tesla valve channel, which can limit the backfire problem of the head of the main combustion chamber.

[0024] (3) the present application only supplies fuel to the outer hydrogen gas collecting cavity manifold at low heat power of the main combustion chamber, supplies fuel to the inner and outer hydrogen gas collecting cavity manifold at high heat power, realizes switching of different heat power conditions and matches different thrust working states of the small turbofan engine. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 the structure diagram of the hydrogen low pollution combustion chamber of the present application;

[0026] Figure 2 the structure diagram of the head of the main combustion chamber of the present application;

[0027] Figure 3 the structure diagram of the hydrogen gas collecting cavity of the present application;

[0028] Figure 4 the structure diagram of the hydrogen gas collecting cavity nozzle of the present application;

[0029] Figure 5 the schematic diagram of the inlet and outlet of the Tesla valve channel of the present application;

[0030] Figure 6 the hydrogen supply pipeline schematic diagram of the present application;

[0031] Figure 7 the local hydrogen supply pipeline schematic diagram of the present application.

[0032] The drawings show that: 1, the main combustion chamber outer casing; 2, the main combustion chamber inner casing; 3, the outer flame tube; 4, the inner flame tube; 5, the large mixing hole; 6, the small mixing hole; 7, the main combustion chamber head; 71, the Tesla valve mixer; 711, the Tesla valve channel; 712, the mixer outer shell; 713, the mixer inner shell; 714, the flow guide bluff body; 715, the outer hydrogen gas collecting cavity nozzle; 716, the inner hydrogen gas collecting cavity nozzle; 717, the main flow channel; 718, the secondary flow channel; 719, the Tesla valve channel inlet; 720, the Tesla valve channel outlet; 72, the outer hydrogen gas collecting cavity; 73, the inner hydrogen gas collecting cavity; 74, the mounting limiting structure; 8, the hydrogen supply pipeline; 81, the outer hydrogen gas collecting cavity inlet joint; 82, the inner hydrogen gas collecting cavity inlet joint; 83, the mounting seat; 84, the outer hydrogen gas collecting cavity manifold; 85, the inner hydrogen gas collecting cavity manifold; 9, the igniter; 10, the combustion chamber outer ring cavity; 11, the combustion chamber inner ring cavity; 12, the main combustion zone. DETAILED DESCRIPTION

[0033] With reference to the drawings of the embodiments of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments of the present application, all the other embodiments obtained by a person of ordinary skill in the art without creative effort belong to the protection scope of the present application.

[0034] Embodiment:

[0035] With reference to the drawings of the embodiments of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments of the present application, all the other embodiments obtained by a person of ordinary skill in the art without creative effort belong to the protection scope of the present application. Figures 1-7 As shown in the drawings, a small turbofan engine hydrogen low pollution combustor for dividing combustor inlet air into three paths to enter the main combustion zone 12, comprising: a main combustor inner casing 2, an inner flame tube 4, an outer flame tube 3 and a main combustor outer casing 1 which are sequentially sleeved from inside to outside; the outer flame tube 3 and the inner flame tube 4 are connected at one end and are provided with a plurality of main combustor heads 7 in the circumferential direction, the main combustor heads 7 are provided with a plurality of igniters 9; the other end of the outer flame tube 3 and the inner flame tube 4 are respectively provided with a plurality of large mixing holes 5 and small mixing holes 6 for air entering, the small mixing holes 6 are arranged away from the main combustor heads 7 compared with the large mixing holes 5; a main combustion zone 12 is formed in the middle between the outer flame tube 3 and the inner flame tube 4.

[0036] The main combustor head 7 has a hydrogen gas collecting cavity and a Tesla valve mixer 71 connected thereto; one end of the hydrogen gas collecting cavity is connected with a hydrogen supply pipeline 8, and the other end is connected with a plurality of Tesla valve channels 711 in the Tesla valve mixer 71 to enable hydrogen gas to enter the hydrogen gas collecting cavity through the hydrogen supply pipeline 8 and then to realize mixing and strengthening with air in the Tesla valve channels 711 through transverse jet flow and cross jet flow.

[0037] Among them, the combustor inlet air is divided into three paths to enter the main combustion zone 12: the first path of air flows into the Tesla valve channel 711 of the Tesla valve mixer 71, mixes with hydrogen gas entering the Tesla valve channel 711 through the hydrogen gas collecting cavity, and then enters the main combustion zone 12 to complete combustion; the second path of air flows into the combustor outer annular cavity 10 formed between the main combustor outer casing 1 and the outer flame tube 3, and the third path of air flows into the combustor inner annular cavity 11 formed between the main combustor inner casing 2 and the inner flame tube 4; the air in the combustor outer annular cavity 10 and the combustor inner annular cavity 11 respectively enters the flame tube through the large mixing holes 5, mixes and cools with the high-temperature combustion gas, and adjusts the outlet temperature distribution; and a small amount of mixed air enters the flame tube through the small mixing holes 6 to finely adjust the outlet temperature distribution.

[0038] Specifically, a small turbofan engine hydrogen low pollution combustor comprises a main combustor outer casing 1, a main combustor inner casing 2, an outer flame tube 3, and an inner flame tube 4. The outer flame tube 3 and the inner flame tube 4 are respectively provided with a plurality of rows of large mixing holes 5 and a plurality of rows of small mixing holes 6. The outer flame tube 3 and the inner flame tube 4 are connected at one end and provided with a plurality of main combustor heads 7. The main combustor head 7 is provided with a plurality of igniters 9. The main combustor outer casing 1 is provided with a hydrogen supply pipeline 8 on the wall surface, and the hydrogen supply pipeline 8 is connected with the main combustor head 7 to allow hydrogen to enter the main combustor head 7 through the hydrogen supply pipeline 8.

[0039] The combustor inlet air enters the main combustor outer casing 1 and the main combustor inner casing 2 from the opening of the main combustor outer casing 1 and the main combustor inner casing 2 at the front end of the main combustor head 7. The combustor inlet air is divided into three paths. The first path of air enters the main combustor head 7, mixes with hydrogen, and completes combustion in the main combustion zone 12 formed in the outer flame tube 3 and the inner flame tube 4. Compared with the conventional straight-through annular combustor, the hydrogen Tesla valve low pollution combustor cancels the main combustion hole and only retains a plurality of rows of large mixing holes 5 and small mixing holes 6, thereby increasing the air intake ratio of the main combustor head 7 to 60-70% and increasing the nozzle outlet flow rate of the main combustor head 7 to about 100 m / s, effectively suppressing the risk of backfire in the main combustor head 7. The second path of air flows into the combustor outer annular cavity 10 formed between the main combustor outer casing 1 and the outer flame tube 3, and the third path of air flows into the combustor inner annular cavity 11 formed between the main combustor inner casing 2 and the inner flame tube 4, and enters the flame tube through the large mixing holes 5 on the outer flame tube 3 and the inner flame tube 4, mixes with the high-temperature combustion gas after combustion, and adjusts the outlet temperature distribution to meet the turbine inlet temperature distribution requirements. A small amount of mixed air enters the flame tube through the small mixing holes 6 on the outer flame tube 3 and the inner flame tube 4 to finely adjust the outlet temperature distribution.

[0040] The main combustor head 7 comprises a Tesla valve mixer 71, an outer hydrogen gas collecting cavity 72, an inner hydrogen gas collecting cavity 73, and a mounting limiting structure 74, and the outer wall of the Tesla valve mixer 71 is provided with the mounting limiting structure 74. The inner side of the Tesla valve mixer 71 is connected with the outer hydrogen gas collecting cavity 72 and the inner hydrogen gas collecting cavity 73, and the inner hydrogen gas collecting cavity 73 is arranged on the inner side of the outer hydrogen gas collecting cavity 72. The inner hydrogen gas collecting cavity 73 and the outer hydrogen gas collecting cavity 72 jointly serve as a hydrogen gas collecting cavity.

[0041] Further, the Tesla valve mixer 71 comprises: a plurality of Tesla valve channels 711, a mixer outer shell 712, and a mixer inner shell 713, and the Tesla valve channels 711 are arranged between the inner and outer mixer inner shell 713 and the mixer outer shell 712. The Tesla valve channel 711 is internally provided with a flow guide bluff body 714. The flow guide bluff body 714 is a fan-shaped structure, and the circular arc surface of the fan-shaped structure, i.e. the trailing edge, is arranged away from the inlet of the Tesla valve channel 711, so as to divide the Tesla valve channel 711 into a main flow channel 717 and a secondary flow channel 718. The mixer inner shell 713 is provided with an outer hydrogen gas collecting cavity injection hole 715 on the side close to the outer hydrogen gas collecting cavity 72. The mixer inner shell 713 is provided with an inner hydrogen gas collecting cavity injection hole 716 on the side close to the inner hydrogen gas collecting cavity 73. Each Tesla valve mixer 71 is composed of 15-20 Tesla valve channels 711, the outer hydrogen gas collecting cavity injection hole 715 is circular, the inner hydrogen gas collecting cavity injection hole 716 is semicircular, the hole diameter is 0.3-0.5 mm, the number of the outer hydrogen gas collecting cavity injection hole 715 is 15-20, and the outer hydrogen gas collecting cavity injection hole 715 is uniformly arranged in the circumferential direction. The number of the inner hydrogen gas collecting cavity injection hole 716 is 30-40, and the inner hydrogen gas collecting cavity injection hole 716 is uniformly arranged in the circumferential direction. The Tesla valve channel 711 has a Tesla valve channel inlet 719 and a Tesla valve channel outlet 720, the equivalent diameter of the Tesla valve channel inlet 719 is 3-5 mm, the equivalent diameter of the Tesla valve channel outlet 720 is 2-4 mm, and adjacent Tesla valve channel outlets 720 are spaced apart by 4-6 mm in the circumferential direction; air enters the Tesla valve channel 711 from the Tesla valve channel inlet 719 and is divided into two air flows at the leading edge of the flow guide bluff body 714, and then enters the main flow channel 717 and the secondary flow channel 718 in the Tesla valve channel 711, respectively; in addition, hydrogen is injected from the outer hydrogen gas collecting cavity injection hole 715 and the inner hydrogen gas collecting cavity injection hole 716, respectively, and is mixed with the air in the secondary flow channel 718 by transverse jet flow; at the trailing edge of the flow guide bluff body 714, the air in the main flow channel 717 and the combustible mixture in the secondary flow channel 718 are mixed again by cross jet flow, and then are collected into one path and are injected out through the Tesla valve channel outlet 720. Thus, the mixing of hydrogen and air is strengthened by the combination of transverse jet flow and cross jet flow.

[0042] The igniter 9 is preferably an electric hot plug igniter, which can generate a continuous high temperature of about 800℃ during operation, and can effectively avoid the phenomenon of hydrogen ignition and explosion. The igniter 9 is built in the head part 7 of the main combustion chamber, and the number thereof is preferably 2-4, which are arranged in a circumferential direction. The main combustion chamber is connected with a power supply through two positive and negative power supply lines to realize power supply. When the premixed combustible gas of hydrogen and air is injected into the main combustion chamber head part 7, hydrogen lean premixed combustion is carried out in the main combustion zone 12 under the action of the high-temperature ignition source of the igniter 9, so as to realize the purpose of reducing the emission of nitrogen oxides.

[0043] The hydrogen supply pipeline 8 comprises a mounting seat 83 fixed on the main combustion chamber outer casing 1, and the mounting seat 83 is provided with an outer hydrogen gas collecting cavity inlet joint 81 and an inner hydrogen gas collecting cavity inlet joint 82. The outer hydrogen gas collecting cavity inlet joint 81 is connected with an outer hydrogen gas collecting cavity main pipe 84, and the outer hydrogen gas collecting cavity main pipe 84 is connected with the outer hydrogen gas collecting cavity 72. The inner hydrogen gas collecting cavity inlet joint 82 is connected with an inner hydrogen gas collecting cavity main pipe 85, and the inner hydrogen gas collecting cavity main pipe 85 is connected with the inner hydrogen gas collecting cavity 73.

[0044] When the hydrogen combustion chamber works in a low heat power working condition, the hydrogen gas only supplies fuel to the outer hydrogen gas collecting cavity main pipe 84 through the outer hydrogen gas collecting cavity inlet joint 81, then enters the outer hydrogen gas collecting cavity 72, and finally is sprayed out through the outer hydrogen gas collecting cavity injection hole 715, thereby meeting the fuel demand of the turbofan engine from ignition starting to slow working state. When the hydrogen combustion chamber works in a high heat power working condition, the hydrogen gas simultaneously supplies fuel to the outer hydrogen gas collecting cavity main pipe 84 and the inner hydrogen gas collecting cavity main pipe 85 through the outer hydrogen gas collecting cavity inlet joint 81 and the inner hydrogen gas collecting cavity inlet joint 82, then simultaneously enters the outer hydrogen gas collecting cavity 72 and the inner hydrogen gas collecting cavity 73, and finally is sprayed out through the outer hydrogen gas collecting cavity injection hole 715 and the inner hydrogen gas collecting cavity injection hole 716, thereby meeting the fuel demand of the turbofan engine from slow to maximum thrust state.

[0045] Embodiment 2

[0046] A small turbofan engine hydrogen combustion method is realized by the small turbofan engine hydrogen low-pollution combustion chamber as described in Embodiment 1, so as to make air enter the combustion chamber. The inlet air of the combustion chamber is divided into three paths, and the specific steps comprise:

[0047] S100, the first path of air flows into the Tesla valve channel 711 of the Tesla valve mixer 71, is mixed with hydrogen gas entering the Tesla valve channel 711 through the hydrogen gas collecting cavity, and then enters the main combustion zone 12. When the hydrogen gas and the air premixed combustible gas are sprayed out of the main combustion chamber head 7, the hydrogen gas lean premixed combustion is carried out in the main combustion zone 12 under the action of the high-temperature ignition source of the igniter 9, so as to realize the reduction of nitrogen oxide emission.

[0048] The fuel supply amount of the hydrogen gas collecting cavity to the main combustion zone 12 can be adjusted according to the power working condition, so as to meet the corresponding fuel demand. Specifically, when the hydrogen low-pollution combustion chamber works in a low heat power working condition, the hydrogen gas only supplies fuel to the main combustion zone 12 through part of the hydrogen gas collecting cavities of the main combustion chamber head 7, thereby meeting the fuel demand of the turbofan engine from ignition starting to slow working state. When the hydrogen combustion chamber works in a high heat power working condition, the hydrogen gas simultaneously supplies fuel to the main combustion zone 12 through all the hydrogen gas collecting cavities, thereby meeting the fuel demand of the turbofan engine from slow to maximum thrust state.

[0049] S200, the second airflow flows into the outer annular cavity 10 of the combustion chamber formed between the outer casing 1 and the outer flame tube 3 of the main combustion chamber, and the third airflow flows into the inner annular cavity 11 of the combustion chamber formed between the inner casing 2 and the inner flame tube 4 of the main combustion chamber. The air in the outer annular cavity 10 and the inner annular cavity 11 of the combustion chamber enters the flame tube through the large mixing holes 5 on the outer flame tube 3 and the inner flame tube 4, respectively, to mix with the high-temperature combustion gas after combustion and cool it down, and to regulate the outlet temperature distribution. The remaining small amount of mixed air enters the flame tube through the small mixing holes 6 on the outer flame tube 3 and the inner flame tube 4 to finely regulate the outlet temperature distribution.

[0050] This invention utilizes a Tesla valve mixer to achieve enhanced mixing through a combination of transverse and cross-jet flow. Under the limited size constraints of the main combustion chamber head, it achieves efficient mixing of hydrogen and air, completing lean-burn micro-premixed combustion of hydrogen to reduce nitrogen oxide emissions. Compared to conventional DC annular combustion chambers, the hydrogen Tesla valve low-emission combustion chamber eliminates the main combustion orifice, retaining only the mixing orifice. This increases the air intake ratio at the main combustion chamber head to 60-70% and raises the outlet velocity of the Tesla valve channel to approximately 100 m / s, effectively suppressing backfire at the main combustion chamber head. Under low thermal power conditions, fuel is supplied only to the external hydrogen collection chamber main pipe; under high thermal power conditions, hydrogen is supplied to both the internal and external hydrogen collection chamber main pipes simultaneously. This allows for switching between different thermal power conditions, matching the different thrust operating states of a small turbofan engine.

[0051] The above specific embodiments further illustrate the purpose, technical solution, and beneficial effects of the invention. It should be understood that the above are merely specific embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A low-pollution hydrogen combustion chamber for a small turbofan engine, used to divide the inlet air of the combustion chamber into three paths to enter the main combustion zone (12), characterized in that, include: The main combustion chamber housing (2), inner flame tube (4), outer flame tube (3), and main combustion chamber outer housing (1) are arranged sequentially from the inside to the outside. Several main combustion chamber heads (7) are arranged circumferentially at one end of the outer flame tube (3) and the inner flame tube (4). Several igniters (9) are arranged inside the main combustion chamber heads (7). Several rows of large mixing holes (5) and rows of small mixing holes (6) are respectively arranged on the walls of the outer flame tube (3) and the inner flame tube (4) to allow air to enter. The small mixing holes (6) are located further away from the main combustion chamber heads (7) than the large mixing holes (5). A main combustion zone (12) is formed in the middle between the outer flame tube (3) and the inner flame tube (4). The head of the main combustion chamber (7) has a connected hydrogen gas collection chamber and a Tesla valve mixer (71); one end of the hydrogen gas collection chamber is connected to a hydrogen supply line (8), and the other end is connected to several Tesla valve channels (711) in the Tesla valve mixer (71), so that after the hydrogen enters the hydrogen gas collection chamber through the hydrogen supply line (8), it can be mixed and enhanced with the air in the Tesla valve channel (711) through transverse jet and cross jet.

2. The low-pollution hydrogen combustion chamber of a small turbofan engine according to claim 1, characterized in that, The hydrogen supply pipeline (8) is installed on the wall of the main combustion chamber (1).

3. The low-pollution hydrogen combustion chamber of a small turbofan engine according to claim 1, characterized in that, The Tesla valve mixer (71) includes a mixer outer shell (712) and a mixer inner shell (713) disposed inside and outside the mixer. A plurality of Tesla valve channels (711) are formed between the mixer outer shell (712) and the mixer inner shell (713). A flow guide blunt body (714) is disposed inside the Tesla valve channel (711). A gas collection chamber nozzle communicating with the hydrogen gas collection chamber is formed on the mixer inner shell (713) so that the hydrogen gas in the hydrogen gas collection chamber can be injected into the Tesla valve channel (711).

4. The low-pollution hydrogen combustion chamber of a small turbofan engine according to claim 3, characterized in that, The flow guide blunt body (714) has a fan-shaped structure. The arc surface of the fan-shaped structure, i.e. the trailing edge, is set away from the inlet of the Tesla valve channel (711) so as to divide the Tesla valve channel (711) into a main channel (717) and a secondary channel (718). The hydrogen gas ejected from the hydrogen gas collection chamber is mixed with the air in the secondary channel (718) by transverse jet. At the trailing edge of the flow guide blunt body (714), the air in the main channel (717) and the combustible mixture in the secondary channel (718) are mixed by cross jet again, and then converge into one channel before being ejected through the outlet of the Tesla valve channel (711).

5. The low-pollution hydrogen combustion chamber of a small turbofan engine according to claim 3, characterized in that, The hydrogen gas collection chamber includes an inner hydrogen gas collection chamber (73) and an outer hydrogen gas collection chamber (72) arranged inside and outside; the gas collection chamber nozzle includes an outer hydrogen gas collection chamber nozzle (715) connected to the outer hydrogen gas collection chamber (72) and an inner hydrogen gas collection chamber nozzle (716) connected to the inner hydrogen gas collection chamber (73).

6. The low-pollution hydrogen combustion chamber of a small turbofan engine according to claim 5, characterized in that, The outer hydrogen gas collecting chamber nozzle (715) is circular, and the inner hydrogen gas collecting chamber nozzle (716) is semi-circular. The diameter of the nozzles is 0.3~0.5mm, and they are all evenly arranged along the circumference.

7. The low-pollution hydrogen combustion chamber of a small turbofan engine according to claim 5, characterized in that, The hydrogen supply pipeline (8) includes: a mounting base (83) fixed on the main combustion chamber outer casing (1), the mounting base (83) is provided with an outer hydrogen collection chamber inlet connector (81) and an inner hydrogen collection chamber inlet connector (82), the outer hydrogen collection chamber inlet connector (81) is connected to the outer hydrogen collection chamber (72) through the outer hydrogen collection chamber main pipe (84); the inner hydrogen collection chamber inlet connector (82) is connected to the inner hydrogen collection chamber (73) through the inner hydrogen collection chamber main pipe (85).

8. The low-pollution hydrogen combustion chamber of a small turbofan engine according to claim 1, characterized in that, The Tesla valve mixer (71) has an installation limiting structure (74) on its outer wall.

9. The low-pollution hydrogen combustion chamber of a small turbofan engine according to claim 1, characterized in that, The igniter (9) is symmetrically arranged in the head (7) of the main combustion chamber and is connected to the power supply through two power lines, positive and negative, leading out of the outer casing (1) of the main combustion chamber.

10. A method for hydrogen combustion in a small turbofan engine, characterized in that, This is achieved through a low-emission hydrogen combustion chamber for a small turbofan engine as described in any one of claims 1-9, whereby air is introduced into the combustion chamber, and the inlet air is divided into three paths. Specific steps include: S100, the first air flows into the Tesla valve channel (711) of the Tesla valve mixer (71), mixes with the hydrogen that enters the Tesla valve channel (711) through the hydrogen gas collection chamber, and then enters the main combustion zone (12); and when the hydrogen and air premixed combustible gas is sprayed out of the head (7) of the main combustion chamber, under the action of the high temperature ignition source of the igniter (9), hydrogen lean combustion premixed combustion is carried out in the main combustion zone (12), thereby reducing nitrogen oxide emissions; Furthermore, the amount of fuel supplied by the hydrogen gas collection chamber to the main combustion zone (12) can be adjusted according to the power operating conditions to meet the corresponding fuel demand; S200, the second air flows into the combustion chamber outside the outer casing (1) and the outer flame tube (3) to form the combustion chamber outside the outer casing (1), and the third air flows into the combustion chamber inside the outer casing (2) and the inner flame tube (4) to form the combustion chamber inside the outer casing (2). The air in the combustion chamber outside the outer casing (10) and the combustion chamber inside the outer casing (11) enters the flame tube through the large mixing holes (5) on the outer flame tube (3) and the inner flame tube (4) respectively, so as to mix with the high-temperature gas after combustion to cool it down and adjust the outlet temperature distribution. The remaining small amount of mixed air enters the flame tube through the small mixing holes (6) on the outer flame tube (3) and the inner flame tube (4) to finely adjust the outlet temperature distribution.

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