A short-distance recirculation hydrogen combustion chamber device and its combustion organization method

Abstract

This invention relates to the field of micro-mixing hydrogen combustor structure technology, and more particularly to a short-distance recirculation hydrogen combustor structure based on micro-mixing combustion technology. Its features include an outer casing for the combustor, a hydrogen intake ring, and a flame tube. The flame tube comprises a flow guiding structure, a flame tube head, a flame tube head expansion section, a flame tube mixing section, a flame tube turning section, and a flame tube tail. The flame tube head is provided with air and hydrogen intake ports; the flame tube head mixing section is provided with mixing holes; the flow guiding structure effectively regulates the complex air recirculation, improving the mixing effect; the flame tube head adopts a single-row intake port design to ensure stable combustion and reliable ignition; the hydrogen and air ports are arranged perpendicularly to avoid flame adhesion to the wall and wall erosion. The head expansion section reduces flow losses; the turning section guides airflow deflection; and the tail expansion section achieves thermal diffusion and smooth deceleration, ensuring a uniform outlet temperature field and meeting the stringent requirements of the turbine inlet.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of micro-mixed hydrogen combustion chamber structure. BACKGROUND

[0002] Under the background of the "double carbon" strategy, hydrogen fuel is considered as an effective way to reduce aircraft greenhouse gas and harmful gas emissions and reduce dependence on fossil fuels due to its green, efficient and renewable characteristics. Compared with traditional aviation kerosene, hydrogen fuel has the characteristics of high calorific value, strong reactivity, low ignition energy, wide flammable range and fast combustion speed, which not only helps to achieve fast and efficient combustion, but also provides the possibility for significantly shortening the axial length of the combustion chamber and developing short and compact combustion chambers. In addition, hydrogen fuel combustion is clean, which can significantly reduce harmful substance and greenhouse gas emissions, and is conducive to promoting the lightweight design and overall performance improvement of the aero-engine, making it have better startability, lower fuel consumption and higher unit thrust.

[0003] Most of the existing hydrogen combustion chamber structures are improved from traditional gas turbine combustion chambers, and it is difficult to achieve coordination between combustion efficiency, pollutant emission, outlet temperature uniformity and total pressure recovery coefficient and other key performance indicators. And in the application scenario strictly limited by the overall machine size, due to the significant shortening of the axial length of the combustion chamber, the mixing time of fuel and air is insufficient, the combustion reaction area is limited, the flame is difficult to stabilize, and the fuel cannot be completely burned in a short distance. SUMMARY

[0004] The purpose of the present application is to avoid the shortcomings of the prior art and provide a short-distance backflow hydrogen combustion chamber device and a combustion organization method based on micro-mixed combustion technology. A part of the air enters the head of the flame tube to organize diffusion combustion, and a safe and stable head flame source is provided by reducing the head combustion equivalence ratio. After the fuel and air are mixed, they enter the expansion section to slow down, so that the flame speed decreases, thereby shortening the flame length. Another part of the air enters the flame tube through the mixing hole to supplement the combustion, and the high-temperature area of the flame is cooled to reduce the high-temperature area, thereby reducing the emission of nitrogen oxides. After the combustion is completed, the high-temperature gas enters the turning section, and through sufficient heat diffusion and flow mixing in this section, the temperature distribution of the outlet cross section tends to be uniform, meeting the temperature field requirements of the turbine inlet.

[0005] To achieve the above purpose, the technical scheme adopted by the present application is as follows: a short-distance backflow hydrogen combustion chamber device, characterized in that it comprises a combustion chamber outer casing, a hydrogen gas inlet ring and a flame tube, the hydrogen gas inlet ring and the hydrogen gas inlet pipeline are arranged on the combustion chamber outer casing, and the flame tube is arranged in the combustion chamber outer casing; the flame tube comprises a flow guide structure, a flame tube head, a flame tube head expansion section, a flame tube mixing section, a flame tube turning section and a flame tube tail, the flame tube head is provided with air inlet holes and hydrogen inlet holes; the mixing section of the flame tube head is provided with a mixing hole; The combustion chamber outer casing divides the air into inner and outer rings after the air enters the combustion chamber inlet from the compressor, the inner ring air cools the flame tube wall surface, and the outer ring air enters the flame tube through the mixing hole, is discharged from the combustion chamber outlet after combustion, and a part enters the flame tube head through the flow guide structure.

[0006] Further, the flame tube is in a U-shaped structure, the hydrogen inlet ring and the hydrogen inlet pipeline are arranged corresponding to the hydrogen inlet hole on the flame tube, and the air inlet hole is further arranged on the flame tube head.

[0007] Further, the flow guide structure comprises three flow guide plates, the first flow guide plate is a straight plate fixed on the outer wall surface of the flame tube head, the second flow guide plate is in a U-shaped structure, one end of the U-shaped structure is fixed at one third of the flame tube head, and the other end is between the flame tube head and the combustion chamber outer casing, and the third flow guide plate is in a quarter circular arc structure and is fixed on the inner wall surface of the flame tube head.

[0008] Further, the flame tube head is in a circular ring structure, the air inlet hole is arranged on the ring surface of the flame tube head, the outer diameter of the circular ring structure of the flame tube head is 94mm-98mm, the inner diameter is 82mm-86mm, and the total air inlet area of the air inlet hole is 700mm 2 The corresponding inlet area can be adjusted according to the ratio of the ring surface area to the total inlet area, the air inlet hole is in a rectangular structure with a round chamfer, and the air inlet hole is arranged in a circumferential average single row.

[0009] Further, the air inlet hole is in a single hole structure, the air inlet hole is uniformly distributed along the circumferential direction of the ring surface of the flame tube head, and there are 48 air inlet holes, each air inlet hole has an area of 14.6mm, and the air inlet hole is designed in a rectangular hexagon, a triangle, an ellipse, a long circle and an arch shape with a round chamfer.

[0010] Further, the hydrogen inlet ring is divided into an inner ring and an outer ring, the outer ring injects hydrogen into the flame tube from above the combustion chamber through the hydrogen inlet pipeline, the inner ring injects hydrogen into the flame tube from the tail of the combustion chamber through the hydrogen inlet pipeline, the wall thickness of the hydrogen inlet ring is greater than twice the wall thickness of the flame tube, and the hydrogen in the hydrogen inlet ring is injected into the head of the flame tube through the hydrogen inlet hole.

[0011] Further, the hydrogen inlet pipeline is divided into upper and lower parts, hydrogen is transported to the hydrogen inlet ring through the hydrogen inlet pipeline, the hydrogen inlet hole corresponding to the air inlet hole is distributed along the circumferential direction of the flame tube head, there are 48 hydrogen inlet holes, the hydrogen injection direction of the hydrogen inlet hole is perpendicular to the air flow, and vertical incidence mixing is formed; the hydrogen inlet pipeline connects the combustion chamber outer casing and the hydrogen inlet ring and is used for injecting hydrogen into the hydrogen inlet ring from the outside; the diameter of the hydrogen inlet hole ranges from 0.4mm to 0.6mm. Further, the flame tube head expansion section is located behind the flame tube head structure, the flame tube head expansion section is a gradually expanding arc surface, and the expansion width is not more than 50% of the width of the flame tube head ring surface; The flame tube mixing section is provided behind the flame tube expansion section, the mixing holes on the flame tube mixing section are divided into two parts, one part is provided on the outer wall surface of the flame tube and is perpendicular to the axis of the flame tube, and the other part is arranged on the inner wall surface of the flame tube expansion section and is parallel to the axis of the flame tube, the mixing hole air inlet area is 70% of the total air inlet hole area; the flame tube mixing section provides sufficient space for the mixed gas to organize combustion, and introduces secondary air through the mixing hole; the flame tube turning section is located behind the mixing section and guides the airflow direction to turn; after the airflow is turned through the flame tube turning section, the airflow flows into the flame tube tail section; the flame tube tail section is a gradually expanding section, and the cross-sectional area gradually increases from front to back, until the outlet of the combustion chamber.

[0012] The application also provides a combustion organization method of the short-path backflow type hydrogen combustion chamber. After the air enters the combustion chamber inlet from the compressor, the air is divided into inner ring airflow and outer ring airflow by the combustion chamber outer casing; the inner ring airflow cools the flame tube wall surface; the outer ring airflow is divided into two paths, one path enters the flow guide structure, and the other path enters the flame tube mixing section through the mixing hole; The outer ring airflow entering the flow guide structure passes through two U-shaped flow channels formed by the first flow guide plate, the second flow guide plate and the third flow guide plate arranged in sequence, completes 180° turning, changes the airflow direction to be perpendicular to the direction of the flame tube head, eliminates the backflow area generated by airflow turning, and guides the airflow to flow close to the wall surface, and the turned air enters the flame tube head horizontally through the air inlet hole; At the same time, the hydrogen is transported to the hydrogen inlet hole through the hydrogen inlet ring to be injected into the flame tube head in a direction perpendicular to the air flow, so that the hydrogen jet has a high momentum ratio and deeply mixes in the air mainstream core area to avoid flame wall sticking; the hydrogen inlet ring is divided into an inner ring and an outer ring, the outer ring injects hydrogen into the flame tube from the top of the combustion chamber through the hydrogen inlet pipeline, the inner ring injects hydrogen into the flame tube from the tail of the combustion chamber through the hydrogen inlet pipeline, the wall thickness of the hydrogen inlet ring is greater than twice the wall thickness of the flame tube to ensure that the hydrogen is uniformly transported to each hydrogen inlet hole at equal pressure and to ensure the structural strength to avoid leakage and hydrogen embrittlement; The hydrogen-air mixed gas completing mixing enters the flame tube head expansion section, the expansion section is a gradually expanding arc surface structure, the expansion width is not more than 50% of the width of the flame tube head ring, the flow area gradually increases, the airflow smoothly decelerates, the fuel residence time increases, the local flow loss is reduced, the flame length is controlled, and the preliminary combustion is completed; Furthermore, the combustion gas enters the mixing section of the flame tube, and secondary air is introduced through the mixing holes. The total air intake area of ​​the mixing holes is 65-75% of the total air intake area. The mixing holes on the outer wall are arranged at a distance of 8-12 mm from the flame tube expansion section, and are perpendicular to the flame tube axis. The incoming air cools, dilutes, and supplements combustion in the high-temperature core area. The mixing holes on the inner wall are arranged on the inner wall of the flame tube expansion section, and are parallel to the flame tube axis. The incoming air forms an air film on the wall surface, reducing the flame tube wall temperature and preventing wall erosion. After combustion, the high-temperature gas enters the deflection section of the flame tube. The inner and outer walls of the deflection section are both U-shaped structures. The inner wall is optimized based on streamlines, allowing the airflow to smoothly adhere to the wall and complete a 180° deflection, suppressing flow separation and vortex, and controlling the total pressure loss to above 93%. The gas that has completed its reversal enters the tail of the gradually expanding flame tube, where the cross-sectional area gradually increases from front to back. The airflow slows down smoothly, the temperature field becomes more homogenized, and finally it is discharged from the combustion chamber outlet.

[0013] The beneficial effects of this invention are as follows: The short-distance recirculation hydrogen combustion chamber device effectively regulates the complex air recirculation through its guiding structure, eliminating the recirculation zone caused by directional deflection, allowing air to enter the head horizontally. This not only reduces the total pressure loss caused by the recirculation zone but also ensures vertical mixing of fuel and air, improving the mixing effect. The flame tube head adopts a single-row air inlet design, avoiding uneven flow distribution and ensuring stable combustion and reliable ignition. The hydrogen and air inlets are arranged vertically, combined with small-diameter, high-momentum-ratio injection, enhancing the mixing intensity and preventing flame adhesion to the wall and wall erosion. The head expansion section reduces flow loss, increases the total pressure recovery coefficient, and increases the combustion space. Subsequent secondary air is supplied through mixing holes to cool and dilute the high-temperature zone, control combustion intensity and flame length, and effectively suppress nitrogen oxide generation. The deflection section guides airflow deflection, and the tail expansion section achieves thermal diffusion and smooth deceleration, ensuring a uniform outlet temperature field and meeting the stringent requirements of the turbine inlet. Attached Figure Description

[0014] Figure 1 This is a cross-sectional structural diagram of the present invention; Figure 2 This is a structural diagram of the air intake hole arrangement of the present invention; In the diagram: 1. Combustion chamber inlet; 2. Flame tube; 3. Flow guide structure; 4. Flame tube head; 5. Air inlet; 6. Hydrogen inlet pipeline; 7. Hydrogen inlet ring; 8. Hydrogen inlet port; 9. Flame tube head expansion section; 10. Flame tube mixing section; 11. Mixing port; 12. Flame tube turning section; 13. Flame tube tail; 14. Combustion chamber outlet; 15. Combustion chamber outer casing. Detailed Implementation

[0015] The principles and features of the present invention are described below with reference to the accompanying drawings. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0016] To achieve the above objectives, the present invention provides the following specific embodiments: Example 1: As Figure 1 As shown, the short-distance recirculation hydrogen combustion chamber device is characterized by including an outer combustion chamber casing 15, a hydrogen inlet ring 7, and a flame tube 2. The hydrogen inlet ring 7 and the hydrogen inlet pipe 6 are disposed on the outer combustion chamber casing 15, and the flame tube 2 is disposed inside the outer combustion chamber casing 15. The flame tube 2 consists of a flow guiding structure 3, a flame tube head 4, a flame tube head expansion section 9, a flame tube mixing section 10, a flame tube turning section 12, and a flame tube tail 13. The flame tube head 4 is provided with an air inlet 5 and a hydrogen inlet 8. The flame tube head mixing section 10 is provided with a mixing hole 11. The outer casing 15 of the combustion chamber divides the air into inner and outer rings after the air enters the combustion chamber inlet 1 from the compressor. The inner ring air cools the wall of the flame tube 2, while part of the outer ring air enters the flame tube 2 through the mixing hole 11 and is discharged from the combustion chamber outlet 14 after combustion. Another part enters the flame tube head 4 through the guide structure 3.

[0017] Furthermore, the flame tube 2 has an overall U-shaped structure, and the hydrogen inlet ring 7 and the hydrogen inlet pipe 6 are correspondingly arranged with the hydrogen inlet hole 8 on the flame tube 2; an air inlet hole 6 is also provided on the flame tube head 4.

[0018] Furthermore, the flow guiding structure 3 includes three guide plates. The first guide plate is a straight plate, fixed to the outer wall of the flame tube head 4. The second guide plate is a U-shaped structure, with one end fixed at one-third of the distance from the flame tube head and the other end between the flame tube head and the outer casing of the combustion chamber. The third guide plate is a quarter-circle arc structure, fixed to the inner wall of the flame tube head. The three guide plates form two U-shaped flow channels, the core function of which is to guide the air to complete a 180° turn, making its direction perpendicular to the flame tube head 4, avoiding uneven flow distribution. The three guide plates eliminate the backflow area caused by the airflow turn and make the air enter the air inlet 5 horizontally, perpendicular to the hydrogen flow direction from the hydrogen inlet ring 8 into the flame tube head 4. In addition, the U-shaped flow channel can effectively sort out the large backflow area caused by the high air velocity, guide the airflow to flow close to the wall, thereby significantly suppressing flow separation and reducing the total pressure loss caused by it.

[0019] Furthermore, the flame tube head 4 has a circular structure, and the air inlet 5 is arranged on the annular surface of the flame tube head 4; the outer ring diameter of the air inlet 5 is 94 mm, the inner ring diameter is 81 mm, and the total air inlet area is 700 mm².2 The air intake 5 is a rectangular structure with rounded corners, and the air intake 5 is arranged in a single row on a circumferential average. Furthermore, the air inlet 5 is a single-hole structure, with 48 air inlets 5 evenly distributed circumferentially along the circumferential surface of the flame tube head 4. Each air inlet has an area of ​​14.6 mm. If the structural dimensions change, the air inlet area and the number of circumferentially distributed holes can be adjusted according to this ratio. This arrangement is conducive to achieving efficient layout in a compact space, making full use of the limited radial and axial dimensions of the flame tube head while increasing the total pressure recovery coefficient. The air inlet 5 is designed with rounded chamfers in the form of rectangular hexagons, triangles, ellipses, oblong shapes, and arches. The rounded chamfer structure enhances the mixing intensity of fuel and air and effectively blocks flow field interference from adjacent nozzles, ensuring that each injection unit forms an independent and stable small diffusion flame, further leveraging the advantages of micro-mixing combustion technology.

[0020] Furthermore, the hydrogen intake ring 7 is divided into inner and outer rings. The outer ring injects hydrogen into the flame tube 2 from above the combustion chamber through the hydrogen intake pipe 6, while the inner ring injects hydrogen into the flame tube 2 from the rear of the combustion chamber through the hydrogen intake pipe 6. The wall thickness of the hydrogen intake ring 7 is greater than twice the wall thickness of the flame tube. The hydrogen inside the hydrogen intake ring is injected into the head of the flame tube through the hydrogen intake port. The annular structure and internal flow channel design of the hydrogen intake ring 7 ensure that hydrogen can be delivered at equal pressure and relatively uniformly to each hydrogen intake port 8. At the same time, the thicker wall design ensures structural strength and avoids leakage, hydrogen embrittlement, and other phenomena.

[0021] Furthermore, the hydrogen inlet pipe 6 is divided into upper and lower parts. Hydrogen is transported to the hydrogen inlet ring 7 via the hydrogen inlet pipe 6. Forty-eight hydrogen inlet holes 8, corresponding to the air inlet holes, are distributed circumferentially along the head of the flame tube. The injection direction of the hydrogen inlet holes 8 is perpendicular to the airflow, forming vertical incident mixing. The hydrogen inlet pipe 6 connects the outer casing 15 of the combustion chamber to the hydrogen inlet ring 7, allowing external hydrogen injection into the ring 7. The diameter of the hydrogen inlet holes 7 ranges from 0.4mm to 0.6mm. This design creates a strong shear layer, greatly promoting rapid mixing of hydrogen and air at the microscale. Simultaneously, the small diameter of the hydrogen nozzles ensures a high momentum ratio in the hydrogen jet. The high momentum ratio of the hydrogen jet provides sufficient penetrating power, allowing it to penetrate deep into the core area of ​​the mainstream airflow for mixing, effectively avoiding flame adhesion to the wall due to insufficient momentum, and fundamentally reducing the risk of wall erosion. After being thoroughly mixed with air, hydrogen enters the expansion section 9 at the head of the flame tube.

[0022] Furthermore, the flame tube head expansion section is located behind the flame tube head structure. The flame tube head expansion section is a gradually expanding arc surface, and the expansion width does not exceed 50% of the width of the flame tube head annular surface. This design can smooth the airflow, reduce local flow losses, and help improve the total pressure recovery coefficient. Secondly, by increasing the flow area, the airflow is slowed down, providing more sufficient residence time for the fuel and ensuring more complete combustion in a compact space. The reduction in flow velocity helps to slow down the flame propagation speed, thereby controlling the flame length.

[0023] The mixing section of the flame tube is located after the expansion section of the flame tube. The mixing holes on the mixing section are divided into two parts: one part is located on the outer wall of the flame tube, perpendicular to the flame tube axis, and the other part is located on the inner wall of the expansion section, parallel to the flame tube axis. The air inlet area of ​​the mixing holes is 70% of the total area of ​​the air inlet holes, ensuring the head air equivalence ratio and sufficient mixing intensity. The mixing section 10 of the flame tube provides sufficient space for the mixed air to organize combustion and introduces secondary air through the mixing holes 11. The turning section of the flame tube is located in the area after the mixing section that guides the airflow direction to turn. After the airflow turns through the turning section, it flows into the tail of the flame tube. The tail of the flame tube 13 is a gradually expanding section. The cross-sectional area of ​​the gradually expanding structure increases from front to back until the combustion chamber outlet.

[0024] The mixing holes 11 are divided into two parts, evenly distributed on the inner and outer walls of the flame tube. The number of holes can be adjusted according to usage requirements. The mixing holes on the outer wall are located 10mm away from the expansion section of the flame tube, a distance that can also be adjusted according to usage requirements. Their direction is perpendicular to the flame tube axis. The air entering through these mixing holes supplements the combustion gas, allowing unburned fuel to continue reacting and improving overall combustion efficiency. On the other hand, this cooler air directly cools and dilutes the high-temperature core area formed by combustion, effectively reducing the range of the high-temperature zone and lowering the local peak temperature. This not only helps reduce the formation of nitrogen oxides but also further shortens the flame length, allowing combustion to be completed within a shorter axial distance. The mixing holes on the inner wall are distributed on the inner wall of the expansion section of the flame tube, parallel to the flame tube axis. The air entering through these mixing holes forms an air film on the wall surface, reducing the flame tube wall temperature and preventing wall erosion.

[0025] After the fuel and oxidizer are fully combusted and mixed in the mixing section 10 of the flame tube, they enter the turning section 12. Both the inner and outer walls of the turning section have a U-shaped structure, and the inner wall has been optimized based on streamlines to allow the airflow to smoothly and closely adhere to the wall for turning, minimizing flow separation and vortices caused by changes in flow direction. This achieves a 180° airflow reversal while keeping the total pressure loss at a low level. After passing through the turning section 12, the airflow completes the crucial flow direction change and then enters the tail section 13 of the flame tube.

[0026] The tail section 13 of the flame tube features a gradually expanding profile, providing ample space for thermal diffusion and mixing of the high-temperature combustion gas. During this process, the airflow is smoothly decelerated, further homogenizing the temperature field. Ultimately, the combustion chamber outlet section achieves a highly uniform temperature distribution, fully meeting the turbine inlet's requirements for temperature distribution and velocity, fundamentally avoiding thermal stress concentration and lifespan reduction caused by uneven turbine heating. The fully mixed and homogenized combustion gas is then discharged from the combustion chamber outlet 14.

[0027] Example 2: The present invention also provides a combustion organization method for a short-pitch recirculation hydrogen combustion chamber, characterized by comprising the following steps: After air enters the combustion chamber inlet 1 from the compressor, it is divided into inner ring airflow and outer ring airflow by the outer casing 15 of the combustion chamber. The inner ring airflow cools the wall of the flame tube 2. The outer ring airflow is divided into two paths, one of which enters the guide structure 3 and the other enters the flame tube mixing section 10 through the mixing hole 11. The outer ring airflow entering the guide structure 3 passes through two U-shaped channels formed by the first guide plate, the second guide plate and the third guide plate arranged in sequence, and completes a 180° turn, so that the airflow direction becomes perpendicular to the flame tube head 4, eliminating the backflow area generated by the airflow turn and guiding the airflow to flow close to the wall. The air that has completed the turn enters the flame tube head 4 horizontally through the air inlet 5. Simultaneously, hydrogen is delivered to the hydrogen inlet hole 8 via the hydrogen inlet ring 7 and injected into the flame tube head 4 in a direction perpendicular to the air flow, giving the hydrogen jet a high momentum ratio and allowing it to penetrate deep into the core area of ​​the mainstream air for mixing, thus avoiding flame adhesion to the wall. The hydrogen inlet ring 7 is divided into inner and outer rings. The outer ring injects hydrogen from the top of the combustion chamber to the flame tube 2 through the hydrogen inlet pipe 6, while the inner ring injects hydrogen from the tail 13 of the combustion chamber to the flame tube 2 through the hydrogen inlet pipe 6. The wall thickness of the hydrogen inlet ring 7 is greater than twice the wall thickness of the flame tube 2 to ensure equal pressure and uniform delivery of hydrogen to each hydrogen inlet hole 8, and to ensure structural strength, avoiding leakage and hydrogen embrittlement. The mixed hydrogen-air gas enters the expansion section 9 at the head of the flame tube. The expansion section 9 has a gradually expanding arc surface structure, and the expansion width does not exceed 50% of the width of the annular surface of the flame tube head 4. The flow area gradually increases, the airflow is smooth and decelerated, the fuel residence time increases, local flow loss is reduced, the flame length is controlled, and the initial combustion is completed. Furthermore, the combustion gas enters the mixing section 10 of the flame tube, and secondary air is introduced through the mixing holes 11. The total air intake area of ​​the mixing holes 11 is 65-75% of the total area of ​​the air intake holes 5. The mixing holes 11 on the outer wall are arranged at a distance of 8-12 mm from the expansion section 9 of the flame tube, and the direction is perpendicular to the axis of the flame tube 2. The air entering cools, dilutes, and supplements combustion in the high-temperature core area. The mixing holes 11 on the inner wall are arranged on the inner wall of the expansion section 9 of the flame tube, and the direction is parallel to the axis of the flame tube 2. The air entering forms an air film on the wall, which reduces the wall temperature of the flame tube 2 and prevents wall erosion. After combustion, the high-temperature gas enters the flame tube turning section 12. The inner and outer walls of the turning section 12 are both U-shaped structures. The inner wall is optimized based on the streamline, and the airflow smoothly adheres to the wall to complete a 180° turnback, suppressing flow separation and vortex, and controlling the total pressure loss to above 93%. The gas that has completed its reversal enters the tail section 13 of the gradually expanding flame tube, where the cross-sectional area gradually increases from front to back. The airflow slows down smoothly, the temperature field becomes more uniform, and finally it is discharged from the combustion chamber outlet 14.

[0028] This invention achieves a high-efficiency, short-distance hydrogen combustion chamber structure through a multi-process design involving flow guidance, vertical micro-mixing, co-combustion, wall cooling, streamlined deflection, and uniform temperature diffusion. Air is divided into two parts: a head intake and a mixing orifice intake. The flow guidance device achieves vertical air deflection and flow field shaping, laying the foundation for efficient mixing. Hydrogen and air are injected perpendicularly, and combined with a high momentum ratio design, rapid and uniform mixing is achieved, improving combustion efficiency at the source and eliminating flame adhesion to the wall. The expansion section and mixing section of the flame tube head jointly complete the efficient combustion of fuel, while the design of the mixing orifice avoids the risk of flame tube wall erosion. The streamlined surface design of the flame tube bend section ensures a high total pressure recovery coefficient during combustion and reversal airflow organization. The expansion design of the flame tube tail section provides the necessary space and time for temperature field homogenization, ensuring that the outlet temperature non-uniformity meets the turbine inlet requirements.

[0029] This invention ultimately controls the temperature distribution within the flame tube, ensuring a good temperature distribution coefficient while also achieving high combustion efficiency and a good total pressure recovery coefficient, thus realizing a short-distance recirculation hydrogen combustion chamber structure capable of stable combustion.

[0030] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A short-distance reflux hydrogen combustion chamber device, characterized in that, It includes an outdoor combustion chamber, a hydrogen inlet ring, and a flame tube. The hydrogen inlet ring and hydrogen inlet pipeline are installed on the outdoor combustion chamber, and the flame tube is installed inside the outdoor combustion chamber. The flame tube consists of a flow guiding structure, a flame tube head, a flame tube head expansion section, a flame tube mixing section, a flame tube turning section, and a flame tube tail. The flame tube head is provided with an air inlet and a hydrogen inlet. The flame tube head mixing section is provided with a mixing hole. The outer casing of the combustion chamber divides the air into inner and outer rings after the air enters the combustion chamber from the compressor. The inner ring air cools the flame tube wall, while part of the outer ring air enters the flame tube through the mixing hole, is discharged from the combustion chamber outlet after combustion, and part of the outer ring air enters the flame tube head through the guide structure.

2. The short-distance recirculation hydrogen combustion chamber device as described in claim 1, characterized in that, The flame tube has an overall U-shaped structure, and the hydrogen inlet ring and hydrogen inlet pipe are set to correspond to the hydrogen inlet holes on the flame tube; an air inlet hole is also provided on the head of the flame tube.

3. The short-distance recirculation hydrogen combustion chamber device as described in claim 1, characterized in that, The flow guiding structure includes three flow guiding plates. The first flow guiding plate is a straight plate and is fixed to the outer wall of the flame tube head. The second flow guiding plate is a U-shaped structure, with one end fixed at one-third of the distance from the flame tube head and the other end between the flame tube head and the outer casing of the combustion chamber. The third flow guiding plate is a quarter-circle arc structure and is fixed to the inner wall of the flame tube head.

4. The short-distance recirculation hydrogen combustion chamber device as described in claim 1, characterized in that, The flame tube head has a circular ring structure, with air intake holes arranged on the ring surface of the flame tube head; the outer diameter of the circular ring structure of the flame tube head is 94mm-98mm, and the inner diameter is 82mm-86mm; the total air intake area of ​​the air intake holes is 700mm². 2 The air intake is a rectangular structure with rounded corners, and the air intake is arranged in a single row evenly around the circumference.

5. The short-distance recirculation hydrogen combustion chamber device as described in claim 1, characterized in that, The air inlet is a single-hole structure, with 48 air inlets evenly distributed around the circumference of the flame tube head. Each air inlet has an area of ​​14.6 mm. The air inlet shapes are designed as rectangular hexagons, triangles, ellipses, oblongs, and arches with rounded corners.

6. A short-distance recirculation hydrogen combustion chamber device as described in claim 1 or 2, characterized in that, The hydrogen intake ring is divided into inner and outer rings. The outer ring injects hydrogen into the flame tube from above the combustion chamber through the hydrogen intake pipe, while the inner ring injects hydrogen into the flame tube from the rear of the combustion chamber through the hydrogen intake pipe. The wall thickness of the hydrogen intake ring is more than twice the wall thickness of the flame tube. The hydrogen inside the hydrogen intake ring is injected into the head of the flame tube through the hydrogen intake port.

7. The short-distance recirculation hydrogen combustion chamber device as described in claim 1, characterized in that, The hydrogen intake pipeline is divided into upper and lower parts. Hydrogen is transported to the hydrogen intake ring through the hydrogen intake pipeline. There are 48 hydrogen intake holes distributed circumferentially along the head of the flame tube, corresponding to the air intake holes. The injection direction of the hydrogen intake holes is perpendicular to the air flow, forming a vertical incident mixing. The hydrogen intake pipeline connects the outer casing of the combustion chamber to the hydrogen intake ring, and is used to inject hydrogen into the hydrogen intake ring from the outside. The diameter of the hydrogen intake holes ranges from 0.4mm to 0.6mm.

8. The short-distance recirculation hydrogen combustion chamber device as described in claim 1, characterized in that, The flame tube head expansion section is located behind the flame tube head structure. The flame tube head expansion section is a gradually expanding arc surface, and the expansion width does not exceed 50% of the width of the flame tube head annular surface.

9. A short-distance recirculation hydrogen combustion chamber device as described in any one of claims 1-8, characterized in that, The mixing section of the flame tube is located after the expansion section of the flame tube. The mixing holes on the mixing section are divided into two parts: one part is located on the outer wall of the flame tube, perpendicular to the flame tube axis, and the other part is located on the inner wall of the expansion section, parallel to the flame tube axis. The air inlet area of ​​the mixing holes is 70% of the total area of ​​the air inlet holes. The mixing section provides sufficient space for the mixed air to organize combustion and introduces secondary air through the mixing holes. The turning section of the flame tube is located in the area after the mixing section that guides the airflow direction to turn. After the airflow turns through the turning section, it flows into the tail of the flame tube. The tail of the flame tube is a gradually expanding section, and the cross-sectional area of ​​the gradually expanding structure increases from front to back until the combustion chamber outlet.

10. A combustion organization method for a short-distance recirculation hydrogen combustion chamber as described in any one of claims 1-8, characterized in that, Includes the following steps: After air enters the combustion chamber inlet from the compressor, the outer casing of the combustion chamber divides the air into inner and outer ring airflows. The inner ring airflow cools the flame tube wall. The outer ring airflow is divided into two paths: one path enters the guide structure, and the other path enters the mixing section of the flame tube through the mixing hole. The outer ring airflow entering the guide structure completes a 180° turn through two U-shaped channels formed by the first guide plate, the second guide plate and the third guide plate arranged in sequence, so that the airflow direction becomes perpendicular to the flame tube head, eliminating the backflow area generated by the airflow turn and guiding the airflow to flow close to the wall. The air that has completed the turn enters the flame tube head horizontally through the air inlet. Meanwhile, hydrogen is delivered to the hydrogen inlet via the hydrogen inlet ring and injected into the head of the flame tube perpendicular to the airflow, giving the hydrogen jet a high momentum ratio and allowing it to penetrate deep into the core area of ​​the mainstream airflow for mixing, thus avoiding flame adhesion to the wall. The hydrogen inlet ring consists of inner and outer rings. The outer ring injects hydrogen into the flame tube from the top of the combustion chamber through the hydrogen inlet pipe, while the inner ring injects hydrogen into the flame tube from the rear of the combustion chamber through the hydrogen inlet pipe. The wall thickness of the hydrogen inlet ring is more than twice the wall thickness of the flame tube to ensure isobaric and uniform delivery of hydrogen to each hydrogen inlet and to ensure structural strength, preventing leakage and hydrogen embrittlement. The blended hydrogen-air mixture enters the expansion section at the head of the flame tube. The expansion section has a gradually expanding arc surface structure, and the expansion width does not exceed 50% of the width of the annular surface at the head of the flame tube. The flow area gradually increases, the airflow is smooth and decelerated, the fuel residence time increases, local flow loss is reduced, the flame length is controlled, and the initial combustion is completed. Furthermore, the combustion gas enters the mixing section of the flame tube, and secondary air is introduced through the mixing holes. The total air intake area of ​​the mixing holes is 65-75% of the total air intake area. The mixing holes on the outer wall are arranged at a distance of 8-12 mm from the flame tube expansion section, and are perpendicular to the flame tube axis. The incoming air cools, dilutes, and supplements combustion in the high-temperature core area. The mixing holes on the inner wall are arranged on the inner wall of the flame tube expansion section, and are parallel to the flame tube axis. The incoming air forms an air film on the wall surface, reducing the flame tube wall temperature and preventing wall erosion. After combustion, the high-temperature gas enters the deflection section of the flame tube. The inner and outer walls of the deflection section are both U-shaped structures. The inner wall is optimized based on streamlines, allowing the airflow to smoothly adhere to the wall and complete a 180° deflection, suppressing flow separation and vortex, and controlling the total pressure loss to above 93%. The gas that has completed its reversal enters the tail of the gradually expanding flame tube, where the cross-sectional area gradually increases from front to back. The airflow slows down smoothly, the temperature field becomes more homogenized, and finally it is discharged from the combustion chamber outlet.

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