Diffuser and stability augmentation integrated center staged combustor

Abstract

The application relates to the technical field of aero-engines, and provides an expander and expander-stabilizer integrated center staged combustion chamber, wherein the expander comprises: an expander body provided with an expander inlet and an expander outlet on opposite sides, and provided with a gradually expanding flow channel inside; a pair of partitions arranged in the flow channel and arranged along the extension direction of the flow channel, the pair of partitions being arranged on the two sides of the middle streamline in the flow channel and used for separating the flow channel into a middle flow channel, a first side flow channel and a second side flow channel; the middle flow channel, the first side flow channel and the second side flow channel satisfy a preset flow distribution ratio; in this way, the overall flow channel has a large expansion angle, each flow channel maintains a small local expansion angle, the airflow can reach the deceleration requirement in the shortest axial distance, the turning degree of the airflow to the inner ring and the outer ring of the flame tube is relieved, the airflow separation phenomenon is reduced, the total pressure loss is reduced, and therefore the expander meets the size requirement, the total pressure loss requirement and the flow distribution ratio requirement.

Description

Technical Field

[0001] This invention relates to the technical field of aero-engines, and more particularly to a diffuser and an integrated diffuser-stabilized central staged combustion chamber. Background Technology

[0002] The diffuser is one of the key components of the combustion chamber. It is mainly used to be installed between the compressor outlet and the combustion chamber flame tube. The diffuser has a flow channel with a gradually increasing cross-sectional area along the air flow direction. When the high-speed airflow at the compressor outlet flows through the diffuser, it is decelerated and pressurized, restoring the dynamic pressure of the high-speed airflow to static pressure as much as possible. Then it flows into the flame tube and the inner and outer ring channels, so that the flame tube maintains efficient and stable combustion.

[0003] Reducing total pressure loss is one way to improve combustion chamber performance. When airflow passes through the combustion chamber, a series of physicochemical processes, including friction, diffusion, intake, mixing, and combustion, inevitably cause a decrease in the total pressure of the airflow. The total pressure loss of the combustion chamber includes cold losses without heat release and additional heat losses with heat release. Cold losses are the main part of the total pressure loss, including the pressure loss in the flame tube and the loss of airflow through the diffuser. Approximately one-third of the total pressure loss of the combustion chamber occurs in the diffuser. The pressure loss caused by diffusion does not contribute to the combustion process; it only reduces the efficiency of the combustion chamber. Generally, for every 1% increase in the total pressure loss coefficient, the unit fuel consumption rate will increase by 0.5%. Therefore, maintaining a low total pressure loss in the diffuser is of great significance.

[0004] However, for ultra-compact aero-engine combustors, the outlet airflow velocity of the high-pressure compressor is higher, and the radial dimension of the flame tube is large while the axial dimension of the overall combustor is small, leaving almost no space for sudden expansion. If a conventional diffuser is used in such a combustor, the length of the diffuser alone will occupy half the length of the combustor. Its size is too large and does not meet the design requirements. Moreover, if designed with this length, the diffuser length is too large, and the airflow will cause a large total pressure loss, which cannot meet the total pressure recovery coefficient index.

[0005] Due to the limited length of the diffuser, its sudden expansion zone is almost non-existent, while the relative height of the flame tube (flame tube radial dimension / diffuser inlet height) is very large. This means that the airflow will make a large turn after flowing out of the pre-diffuser, which will result in a huge total pressure loss.

[0006] In order to achieve the purpose of pressurization and deceleration within a very short diffuser, and to ensure that the total pressure recovery coefficient meets the design requirements, the expansion angle and area ratio of the pre-diffuser must be maintained at a large value. A large expansion angle and area ratio can easily cause the airflow to separate in the pre-diffuser, resulting in unnecessary total pressure loss.

[0007] Therefore, how to adapt the size and total pressure loss of the diffuser to the ultra-compact central staged combustion chamber is an important issue that urgently needs to be addressed. Summary of the Invention

[0008] This invention provides a diffuser and an integrated diffuser-stabilized central staged combustion chamber to solve the defects in the prior art where the size and total pressure loss of the diffuser are difficult to adapt to the ultra-compact central staged combustion chamber, and enables the diffuser to meet the size requirements, total pressure loss requirements and flow distribution ratio requirements.

[0009] This invention provides a diffuser, comprising:

[0010] The diffuser body has a diffuser inlet on one side and a diffuser outlet on the opposite side, and has a gradually expanding flow channel inside from the diffuser inlet to the diffuser outlet.

[0011] A pair of baffles are disposed within the flow channel and arranged along the extension direction of the flow channel. The pair of baffles are alternately disposed on both sides of the middle flow line of the flow channel, which is suitable for dividing the flow channel into a middle flow channel and a first side flow channel and a second side flow channel respectively located on both sides of the middle flow channel.

[0012] The intermediate flow channel, the first side flow channel, and the second side flow channel satisfy a preset flow distribution ratio.

[0013] According to a diffuser provided by the present invention, a pre-combustion stage diffuser is further disposed in the intermediate flow channel;

[0014] The pre-combustion stage diffuser has an air inlet on one side and an air outlet on the opposite side. It has an internal channel that gradually widens from the air inlet to the air outlet, and the channel is arranged along the extension direction of the intermediate flow channel. The air outlet is circular.

[0015] According to a diffuser provided by the present invention, the shape of the air inlet is adapted to the cross-sectional shape at the corresponding position of the intermediate flow channel.

[0016] According to a diffuser provided by the present invention, the flow channel coincides with the middle streamline of the intermediate flow channel.

[0017] According to a diffuser provided by the present invention, the intermediate flow channel coincides with the intermediate streamline of the channel.

[0018] According to a diffuser provided by the present invention, the diffuser body includes a first side plate and a second side plate disposed opposite to each other; the partition includes a first partition disposed near the first side plate and a second partition disposed near the second side plate;

[0019] The first side flow channel is formed between the inner wall of the first side plate and the outer wall of the first partition plate;

[0020] The intermediate flow channel is formed between the inner wall of the first partition and the inner wall of the second partition;

[0021] The second side channel is formed between the inner wall of the first side plate and the outer wall of the second partition.

[0022] The present invention also provides an integrated diffuser-stabilized central staged combustion chamber, including a combustion chamber casing and a diffuser as described in any of the above.

[0023] The diffuser outlet of the diffuser body is connected to the inlet of the combustion chamber casing.

[0024] According to the present invention, an integrated diffuser-stabilized central staged combustion chamber further includes a flame tube disposed in the combustion chamber casing, wherein the end of the flame tube facing the diffuser outlet is a flame tube head, and the flame tube includes a flame tube main combustion stage and a flame tube pre-combustion stage.

[0025] The combustion chamber casing includes an inner casing and an outer casing. The outer wall of the flame tube and the inner casing form an inner annular cavity, and the outer wall of the flame tube and the outer casing form an outer annular cavity.

[0026] The first side channel is adapted to guide airflow into the inner annular cavity, the second side channel is adapted to guide airflow into the outer annular cavity, and the intermediate channel is adapted to guide airflow into the pre-combustion stage of the flame tube.

[0027] According to the present invention, in a central staged combustion chamber with integrated expansion and stabilization, the inlet of the pre-combustion stage of the flame tube is located on the middle flow line of the pre-combustion stage diffuser in the intermediate flow channel.

[0028] According to the present invention, in an integrated central staged combustion chamber for expansion and stabilization, a pair of baffles extend to the edges of opposite sides of the flame tube head, such that the outlet of the first side flow channel extends to the inlet of the inner annular cavity, and the outlet of the second side flow channel extends to the inlet of the outer annular cavity.

[0029] This invention provides a diffuser and an integrated diffuser-stabilized central staged combustion chamber. By setting a baffle in the flow channel, the flow channel can be divided into a first side flow channel, a middle flow channel, and a second side flow channel. The high-speed airflow from the high-pressure compressor flows into the diffuser inlet and is divided into three airflows with a preset flow distribution ratio. The three airflows flow into the first side flow channel, the middle flow channel, and the second side flow channel, respectively. The airflow in the middle flow channel is introduced into the pre-combustion stage of the flame tube, and the airflow in the first and second side flow channels is introduced into the inner and outer rings of the combustion chamber, respectively. With this configuration, the flow channel as a whole has a large expansion angle, while each flow channel maintains a small local expansion angle. This allows the airflow to achieve the deceleration requirement within the shortest possible axial distance, while also reducing the degree of bend in the airflow towards the inner and outer rings of the flame tube, reducing airflow separation, and thus reducing total pressure loss. This allows the diffuser to meet the size requirements, total pressure loss requirements, and flow distribution ratio requirements, enabling it to match the combustion chamber and ensuring the performance of the combustion chamber. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0031] Figure 1 This is one of the structural schematic diagrams of the diffuser provided in the embodiments of the present invention;

[0032] Figure 2 This is a second schematic diagram of the diffuser provided in an embodiment of the present invention;

[0033] Figure 3 This is the third schematic diagram of the diffuser provided in the embodiment of the present invention;

[0034] Figure 4 This is one of the structural schematic diagrams of the pre-combustion stage diffuser provided in the embodiments of the present invention;

[0035] Figure 5 This is the second schematic diagram of the pre-combustion stage diffuser provided in the embodiment of the present invention;

[0036] Figure 6 This is a schematic diagram of the combustion chamber provided in an embodiment of the present invention.

[0037] Figure label:

[0038] 10. Diffuser body; 100. First side plate; 101. Second side plate; 11. Baffle; 110. First baffle; 111. Second baffle; 12. First side flow channel; 13. Intermediate flow channel; 14. Second side flow channel; 20. Pre-combustion stage diffuser; 200. Channel; 30. Combustion chamber casing; 300. Inner casing; 301. Outer casing; 302. Inner annular cavity; 303. Outer annular cavity; 40. Flame tube; 50. Flame tube pre-combustion stage. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0040] To facilitate understanding of the diffuser and integrated central staged combustion chamber provided by this invention, its application background is first explained. The diffuser is one of the key components of the combustion chamber. It has a flow channel with a gradually increasing cross-sectional area along the air flow direction. It is mainly used to restore the dynamic pressure of the high-speed airflow at the compressor outlet to static pressure as much as possible, and then flow into the flame tube and inner and outer ring channels to maintain efficient and stable combustion in the flame tube.

[0041] Reducing total pressure loss is one way to improve combustion chamber performance. About one-third of the total pressure loss of the combustion chamber occurs in the diffuser. The pressure loss caused by diffusion does not help the combustion process and only reduces the working efficiency of the combustion chamber. Under normal circumstances, every 1% increase in the total pressure loss coefficient will increase the unit fuel consumption rate by 0.5%. Therefore, it is of great significance to keep the diffuser with a small total pressure loss.

[0042] From a design perspective, the ideal goal of diffuser design should be to reduce the required air velocity and increase static pressure with minimal total pressure loss over the shortest possible distance, while also creating a uniform and stable flow at the outlet. Studies have shown that a large expansion angle and area ratio can easily lead to airflow separation in the pre-diffuser, resulting in unnecessary total pressure loss. Although a smaller abrupt expansion gap can suppress airflow separation to some extent, its combination with the relatively large flame tube height of the dual-variable combustion chamber will cause the airflow to have a large degree of turning in the extreme abrupt expansion zone, which will also lead to a large total pressure loss.

[0043] For ultra-compact aero-engine combustors, the outlet airflow velocity of the high-pressure compressor is higher, and the radial dimension of the flame tube is large while the axial dimension of the overall combustor is small, leaving almost no space for sudden expansion. If a conventional diffuser is used in such a combustor, the length of the diffuser alone will occupy half the length of the combustor. Its size is too large and does not meet the design requirements. Moreover, if designed with this length, the diffuser length is too large, and the airflow will cause a large total pressure loss, which cannot meet the total pressure recovery coefficient index.

[0044] Due to the limited length of the diffuser, its sudden expansion zone is almost non-existent, while the relative height of the flame tube (flame tube radial dimension / diffuser inlet height) is very large. This means that the airflow will make a large turn after flowing out of the pre-diffuser, which will result in a huge total pressure loss.

[0045] In order to achieve the purpose of pressurization and deceleration within a very short diffuser, and to ensure that the total pressure recovery coefficient meets the design requirements, the expansion angle and area ratio of the pre-diffuser must be maintained at a relatively large value. A large expansion angle and area ratio can easily cause the airflow to separate in the pre-diffuser, resulting in unnecessary total pressure loss.

[0046] Therefore, how to adapt the size and total pressure loss of the diffuser to the ultra-compact central staged combustion chamber is an important issue that urgently needs to be addressed.

[0047] Based on the above, the present invention provides a diffuser and an integrated diffuser-stabilized central staged combustion chamber, which can match the size requirements, total pressure loss requirements and flow distribution ratio requirements of the diffuser with those of the combustion chamber.

[0048] The following is combined with Figures 1-6 The present invention describes the diffuser and the integrated diffuser-stabilized central staged combustion chamber.

[0049] Reference Figure 1 A diffuser includes a diffuser body 10 and baffles 11. The diffuser body 10 has a diffuser inlet on one side and a diffuser outlet on the opposite side, and has a gradually widening flow channel from the diffuser inlet to the diffuser outlet inside. There is a pair of baffles 11 disposed in the flow channel. The two baffles 11 are arranged along the extension direction of the flow channel and are alternately arranged on both sides of the middle streamline of the flow channel, which is suitable for dividing the flow channel into a middle flow channel 13 and a first side flow channel 12 and a second side flow channel 14 located on both sides of the middle flow channel 13. The middle flow channel 13, the first side flow channel 12 and the second side flow channel 14 satisfy a preset flow distribution ratio.

[0050] In practical applications, by installing a baffle 11 within the flow channel, the flow channel can be divided into a first side flow channel 12, a middle flow channel 13, and a second side flow channel 14. High-speed airflow from the high-pressure compressor flows in through the diffuser inlet and is divided into three streams with a preset flow distribution ratio. These three streams flow into the first side flow channel 12, the middle flow channel 13, and the second side flow channel 14, respectively. The airflow from the middle flow channel 13 flows into the pre-combustion stage 50 of the flame tube, while the airflow from the first side flow channel 12 and the second side flow channel 14 flows into the inner and outer rings of the combustion chamber, respectively. This configuration results in a significantly improved overall flow channel performance. While maintaining a small local expansion angle in each flow channel, the airflow can achieve the deceleration requirement within the shortest possible axial distance. At the same time, with almost no sudden expansion zone in the diffuser section of the central staged combustion chamber, the degree of bend in the airflow towards the inner and outer rings of the flame tube is reduced. The diffuser and combustion chamber stabilizer are integrated into a matching design, which reduces airflow separation and thus reduces total pressure loss. This allows the diffuser to meet the size requirements, total pressure loss requirements, and flow distribution ratio requirements, enabling it to match the structure of the central staged combustion chamber and ensuring the performance of the combustion chamber.

[0051] It is understandable that, based on different application scenarios, the diffuser body 10 can have a variety of selectable shapes, and similarly, the flow channels within the diffuser body 10 can have a variety of selectable cross-sectional shapes.

[0052] In this embodiment, refer to Figure 2 and Figure 3 The diffuser body 10 includes a first side plate 100 and a second side plate 101, wherein the first side plate 100 and the second side plate 101 are spaced apart and arranged opposite to each other, and the opposite side of the first side plate 100 and the second side plate 101 is their inner wall. A flow channel is formed between the inner wall of the first side plate 100 and the inner wall of the second side plate 101, and the cross-section of the flow channel is approximately square. The inner walls of the first side plate 100 and the second side plate 101 are both set as streamlined curved surfaces, and the distance between the inner walls of the first side plate 100 and the second side plate 101 gradually increases from the diffuser inlet to the diffuser outlet to form a funnel shape, thereby forming a gradually expanding flow channel with a preset expansion angle.

[0053] Two baffles 11 are located on both sides of the middle streamline of the flow channel. One baffle 11 is located close to the inner wall of the first side plate 100 and is called the first baffle 110. The other baffle 11 is located close to the inner wall of the second side plate 101 and is called the second baffle 111. The side of the first baffle 110 and the second baffle 111 facing each other is the inner wall of the two baffles, and the side facing away from each other is the outer wall of the two baffles. The inner and outer walls of the first baffle 110 and the second baffle 111 are both set as streamlined curved surfaces. The first side flow channel 12 is formed between the inner wall of the first side plate 100 and the outer wall of the first baffle 110. The middle flow channel 13 is formed between the inner wall of the first baffle 110 and the inner wall of the second baffle 111. The second side flow channel 14 is formed between the inner wall of the second side plate 101 and the outer wall of the second baffle 111. By controlling the inclination angles of the inner wall of the first side plate 100, the inner and outer walls of the first partition 110, the inner and outer walls of the second partition 111, and the inner wall of the second side plate 101, the first side flow channel 12, the middle flow channel 13, and the second side flow channel 14 are made to have preset expansion angles. By controlling the flow area of ​​the first side flow channel 12, the middle flow channel 13, and the second side flow channel 14, the first side flow channel 12, the middle flow channel 13, and the second side flow channel 14 are made to meet preset flow distribution ratios, thereby allowing the airflow to be diverted in advance and flow into each flow channel at a preset flow rate, which is beneficial for each stream of airflow to flow smoothly into the pre-combustion stage 50 of the flame tube and the inner and outer rings.

[0054] Specifically, the first diaphragm 110 and the second diaphragm 111 extend from the diffuser inlet to the diffuser outlet.

[0055] Of course, the diffuser body 10 includes, but is not limited to, the shapes and structures listed above, and other structures or forms of diffuser bodies 10 are also applicable; based on the different shapes and structures of the diffuser body 10, the partition 11 and the diffuser body 10 are not limited to the matching methods listed above, and can be flexibly configured according to the actual application scenario.

[0056] Reference Figure 4 and Figure 5 The diffuser also includes a pre-combustion stage diffuser 20 disposed in the intermediate flow channel 13; the pre-combustion stage diffuser 20 has an air inlet on one side and an air outlet on the opposite side, and has a gradually expanding channel 200 inside from the air inlet to the air outlet, and the channel 200 is arranged along the extension direction of the intermediate flow channel 13, and the air outlet of the pre-combustion stage diffuser 20 is circular.

[0057] Since the cross-section of the intermediate flow channel 13 is approximately square and the inlet of the pre-combustion stage 50 of the flame tube is approximately circular, the addition of a pre-combustion stage diffuser 20 in the intermediate flow channel 13 can make the airflow in the intermediate flow channel 13 flow into the pre-combustion stage 50 of the flame tube more smoothly.

[0058] Specifically, the inner and outer walls of the pre-combustion stage diffuser 20 are both designed as streamlined curved surfaces, and the inner and outer walls of the pre-combustion stage diffuser 20 gradually move away from the center line of the channel 200 from the air inlet to the air outlet, forming a trumpet shape.

[0059] Specifically, the shape of the air inlet of the pre-combustion stage diffuser 20 is adapted to the cross-sectional shape of the corresponding position of the intermediate flow channel 13. Since the cross-sectional shape of the intermediate flow channel 13 is approximately square, the shape of the air inlet of the pre-combustion stage diffuser 20 is set to square. Furthermore, the channel 200 inside the pre-combustion stage diffuser 20 smoothly transitions from the air inlet to the air outlet.

[0060] Specifically, when the pre-combustion stage diffuser 20 is placed in the intermediate flow channel 13, the intermediate flow line of the pre-combustion stage diffuser 20 coincides with the intermediate flow line of the intermediate flow channel 13.

[0061] The integrated diffuser-stabilized central staged combustion chamber provided by the present invention is described below. The integrated diffuser-stabilized central staged combustion chamber described below can be referred to in correspondence with the diffuser described above.

[0062] Reference Figure 6 An integrated diffuser-stabilized central staged combustion chamber includes a combustion chamber casing 30 and the aforementioned diffuser; the diffuser outlet of the diffuser body 10 is connected to the inlet of the combustion chamber casing 30, and the diffuser inlet is the inlet of the combustion chamber.

[0063] Specifically, the combustion chamber also includes a flame tube 40 disposed within the combustion chamber casing 30, with the end of the flame tube 40 facing the diffuser outlet being the flame tube head; the flame tube 40 has a centrally staged structure, including a flame tube main combustion stage and a flame tube pre-combustion stage 50, with the flame tube pre-combustion stage 50 located at the flame tube head; the casing includes an inner casing 300 and an outer casing 301, with the outer wall of the flame tube 40 and the inner wall of the inner casing 300 forming an inner annular cavity 302, and the outer wall of the flame tube 40 and the inner wall of the outer casing 301 forming an outer annular cavity 303; the outlet of the first side flow channel 12 faces the inner annular cavity 302, suitable for guiding airflow into the inner annular cavity 302, the outlet of the second side flow channel 14 faces the outer annular cavity 303, suitable for guiding airflow into the outer annular cavity 303, and the outlet of the intermediate flow channel 13 faces the flame tube pre-combustion stage 50, suitable for guiding airflow into the flame tube pre-combustion stage 50.

[0064] It should be noted that the specific structure of the flame tube pre-combustion stage 50 can refer to the prior art, since its specific structure is not the main inventive point of this invention, and no changes have been made to the structure and principle of the flame tube pre-combustion stage 50 in this invention. Therefore, the specific structure of the flame tube pre-combustion stage 50 will not be described in detail in the embodiments of this invention.

[0065] Specifically, the inlet of the pre-combustion stage 50 is located on the middle flow line of the pre-combustion stage diffuser 20.

[0066] Specifically, the first baffle 110 extends to the edge of the flame tube head near the inner annular cavity 302, so that the first side flow channel 12 extends to the inlet of the inner annular cavity 302, which is beneficial for the first side flow channel 12 to introduce the preset flow rate of airflow into the inner annular cavity 302; the second baffle 111 extends to the edge of the flame tube head near the outer annular cavity 303, so that the second side flow channel 14 extends to the inlet of the outer annular cavity 303, which is beneficial for the second side flow channel 14 to introduce the preset flow rate of fluid into the outer annular cavity 303.

[0067] It is understood that the above description is only a part of the structure of the combustion chamber and not all of it. In order to achieve stable combustion, the combustion chamber may also include other components or structures. For details, please refer to the prior art. This invention does not make any improvements to other components or structures of the combustion chamber. Therefore, in the embodiments of this invention, other components or structures of the combustion chamber will not be described in detail.

[0068] The novelty of this invention lies in the fact that by setting a baffle 11 within the flow channel, the flow channel can be divided into a first side flow channel 12, a middle flow channel 13, and a second side flow channel 14. High-speed airflow from the high-pressure compressor flows in through the diffuser inlet and is divided into three streams with a preset flow distribution ratio. These three streams flow into the first side flow channel 12, the middle flow channel 13, and the second side flow channel 14, respectively. The airflow from the middle flow channel 13 is introduced into the pre-combustion stage 50 of the flame tube, while the airflow from the first side flow channel 12 and the second side flow channel 14 is introduced into the inner and outer rings of the combustion chamber, respectively. This arrangement results in a more efficient overall flow channel design. While maintaining a large expansion angle, each flow channel maintains a small local expansion angle, enabling the airflow to achieve deceleration requirements within the shortest possible axial distance. At the same time, with almost no sudden expansion zone in the diffuser section of the central staged combustion chamber, the degree of bend in the airflow towards the inner and outer rings of the flame tube is reduced. The diffuser and combustion chamber stabilizer are integrated into a matching design, reducing airflow separation and thus reducing total pressure loss. This ensures that the diffuser meets the size requirements, total pressure loss requirements, and flow distribution ratio requirements, allowing it to match the structure of the central staged combustion chamber and guaranteeing the performance of the combustion chamber.

[0069] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A diffuser, characterized in that, include: The diffuser body (10) has a diffuser inlet on one side and a diffuser outlet on the opposite side, and has a gradually expanding flow channel inside from the diffuser inlet to the diffuser outlet. A pair of partitions (11) are disposed in the flow channel and arranged along the extension direction of the flow channel. The pair of partitions (11) are arranged alternately on both sides of the middle flow line of the flow channel, which is suitable for dividing the flow channel into a middle flow channel (13) and a first side flow channel (12) and a second side flow channel (14) respectively located on both sides of the middle flow channel (13). The intermediate flow channel (13), the first side flow channel (12), and the second side flow channel (14) satisfy a preset flow distribution ratio; It also includes a pre-combustion stage diffuser (20) disposed in the intermediate flow channel (13); the pre-combustion stage diffuser (20) has an air inlet on one side and an air outlet on the opposite side, and has a channel (200) that gradually expands from the air inlet to the air outlet inside, and the channel (200) is arranged along the extension direction of the intermediate flow channel (13), the shape of the air inlet is adapted to the cross-sectional shape of the corresponding position of the intermediate flow channel (13), and the air outlet is circular; A pair of partitions (11) extend to the edges of opposite sides of the flame tube head, such that the outlet of the first side channel (12) extends to the inlet of the inner annular cavity (302), and the outlet of the second side channel (14) extends to the inlet of the outer annular cavity (303). The inner annular cavity (302) is formed by the outer wall of the flame tube (40) and the inner casing (300), and the outer annular cavity (303) is formed by the outer wall of the flame tube (40) and the outer casing (301).

2. The diffuser according to claim 1, characterized in that, The flow channel coincides with the middle streamline of the intermediate flow channel (13).

3. The diffuser according to claim 2, characterized in that, The intermediate flow channel (13) coincides with the intermediate flow line of the channel (200).

4. The diffuser according to claim 1, characterized in that, The diffuser body (10) includes a first side plate (100) and a second side plate (101) disposed opposite to each other; the partition (11) includes a first partition (110) disposed near the first side plate (100) and a second partition (111) disposed near the second side plate (101); The first side channel (12) is formed between the inner wall of the first side plate (100) and the outer wall of the first partition (110); The intermediate flow channel (13) is formed between the inner wall of the first partition (110) and the inner wall of the second partition (111); The second side channel (14) is formed between the inner wall of the first side plate (100) and the outer wall of the second partition (111).

5. A centrally staged combustion chamber with integrated expansion and stabilization, characterized in that, It includes a combustion chamber casing (30) and a diffuser as described in any one of claims 1-4; The diffuser outlet of the diffuser body (10) is connected to the inlet of the combustion chamber casing (30).

6. The integrated central staged combustion chamber with extended stability according to claim 5, characterized in that, The flame tube (40) is disposed inside the combustion chamber casing (30), and the end of the flame tube (40) facing the diffuser outlet is the flame tube head; the flame tube includes a flame tube main combustion stage and a flame tube pre-combustion stage (50); The combustion chamber casing (30) includes the inner casing (300) and the outer casing (301); The first side channel (12) is adapted to guide airflow into the inner annular cavity (302), the second side channel (14) is adapted to guide airflow into the outer annular cavity (303), and the intermediate channel (13) is adapted to guide airflow into the flame tube pre-combustion stage (50).

7. The integrated central staged combustion chamber with extended stability according to claim 6, characterized in that, The inlet of the pre-combustion stage (50) is located on the middle flow line of the pre-combustion stage diffuser (20) within the intermediate flow channel (13).

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