A blending hopper and combustion chamber

Abstract

The application discloses an aero-engine technical field and relates to a mixing hopper and a combustion chamber. The diameter of the mixing hopper barrel part is smaller than the diameter of the mixing hole, so that a cooling gap is formed between the mixing hopper and the mixing hole. Cooling holes are arranged on the mixing hopper and are connected with the inner cavity of the mixing hopper and the cooling gap, respectively. Cooling gas is introduced into the cooling gap through the cooling holes, and the flow direction of the cooling gas is guided through the cooling gap. Under the guidance of the cooling gap, a cooling gas film is formed on the surface of the part of the mixing hopper located in the flame tube, the part of the mixing hopper located in the flame tube is cooled, the ablation of the part of the mixing hopper located in the flame tube caused by high-temperature gas is prevented, and the service life of the flame tube is prolonged. The cooling effect of the mixing hopper is improved without increasing the structural complexity and the size of the mixing hopper. The processing is simpler, and the mixing hopper is more suitable for the design of compact high-temperature-rise combustion chambers.

Description

Technical Field

[0001] This invention relates to the field of aero-engine technology, specifically to a mixing bucket and combustion chamber. Background Technology

[0002] With the advancement of aero-engine technology, the development trend of aero-engine combustors is towards high-temperature rise and compact design. Existing high-temperature rise combustors have inlet temperatures exceeding 800K and temperature rises exceeding 1100K, significantly increasing the heat load on the flame tube and making flame tube cooling difficult. At the same time, compact combustors have small flame tube dimensions and volumes, resulting in short gas residence times and making it difficult to obtain a high-quality outlet temperature field. Using a mixing bucket can effectively improve the mixing depth, enhance the mixing efficiency of cold gas with high-temperature gas, and improve the combustor outlet temperature field. However, as the combustion chamber temperature rise continues to increase, the inner wall temperature of the flame tube also rises, and the mixing bucket, which extends deep into the gas side, is prone to ablation. Therefore, the application of mixing buckets in high-temperature rise combustors requires breakthroughs in the existing mixing bucket structure and the implementation of measures to reduce the mixing bucket wall temperature and prevent mixing bucket ablation.

[0003] Patent CN 111780165 proposes a mixing bucket design with a tangential angle, employing an inclined bucket with a short side on the windward side and a long side on the leeward side. This bucket structure can reduce the scouring of high-temperature combustion gases, but it lacks an active cooling structure and can only passively reduce the impact of high-temperature combustion gases, making it unsuitable for high-temperature combustion chambers. Patent CN 114791109 proposes a ceramic matrix composite flame tube with an air intake bucket. This patent mainly uses a floating structure to install the air intake bucket, forming a circumferential gap between the wall of the air intake bucket and the wall of the flame tube for cooling. This method has a complex installation structure, low reliability, low cooling efficiency, and requires a large amount of cooling air.

[0004] Based on this, the present invention designs a mixing hopper and a combustion chamber to solve the above problems. Summary of the Invention

[0005] To achieve the above objectives, the present invention provides the following technical solution: a mixing bucket for installation on the wall of a flame tube, characterized in that: the mixing bucket includes a cylinder and a bucket cap fixed to one end of the cylinder for connection with the flame tube wall; the cylinder and the bucket cap together form a mixing cavity for mixing high-temperature combustion gas and cooling gas flow; the flame tube wall has a mixing hole for the cylinder to extend into the flame tube cavity; the outer diameter of the cylinder is smaller than the diameter of the mixing hole, so that when the mixing bucket is installed on the flame tube wall, an annular cooling gap is formed between the outer wall of the cylinder and the wall of the mixing hole; the bucket cap has a plurality of cooling holes circumferentially connected to the mixing cavity and the cooling gap respectively; the cooling holes are used to introduce cooling gas flow into the cooling gap to impact the wall of the mixing hole and form a cooling gas film under the guidance of the cooling gap to cool the cylinder.

[0006] As a further embodiment of the present invention, the side of the bucket cap used to connect with the flame tube is provided with a limiting platform, the outer diameter of the limiting platform being matched with the inner diameter of the mixing hole, so as to limit the position of the mixing bucket by the side of the limiting platform abutting against the inner wall of the mixing hole.

[0007] As a further embodiment of the present invention, the side of the bucket cap that is connected to the flame tube is provided with an annular groove, the inner diameter of the annular groove being matched with the inner diameter of the mixing hole, so as to limit the position of the mixing bucket by the step surface of the annular groove abutting against the inner wall surface of the mixing hole.

[0008] As a further aspect of the present invention, the distance between the impact point of the cooling airflow introduced by the cooling hole on the inner wall of the mixing hole and the inner side of the flame tube wall is H, where H is 0.5mm-1mm.

[0009] As a further aspect of the present invention, the radial length of the cooling gap is B, where B is 0.3mm-0.7mm.

[0010] As a further embodiment of the present invention, the length of the cylinder 21 extending into the flame tube relative to the flame tube wall is D, where D is 1.5mm-3.0mm.

[0011] As a further embodiment of the present invention, the angle between the side of the bucket cap 22 away from the flame tube wall and the axis of the cooling hole is α, where α is 50°-75°.

[0012] As a further embodiment of the present invention, the distance between the side of the bucket cap 22 away from the flame tube wall and the flame tube wall is A, where A is 1mm-2mm.

[0013] As a further aspect of the present invention, the inner wall of the bucket cap is chamfered on the side away from the flame tube wall.

[0014] A combustion chamber comprising the aforementioned mixing bucket.

[0015] The present invention has the following beneficial effects:

[0016] This mixing hopper controls the diameter of the cylinder so that when the cylinder is installed in the mixing hole, a cooling gap is formed between its outer wall and the inner wall of the mixing hole. Cooling holes are opened on the mixing hopper to connect the mixing chamber and the cooling gap. Cooling airflow is introduced into the cooling gap through the cooling holes and formed by the cooling gap. The cooling air film is formed and exits along the outlet direction of the cooling gap to cool the part of the cylinder located in the flame tube, preventing the cylinder surface from being burned by high-temperature gas. The cylinder is cooled without increasing the complexity and weight of the overall structure. At the same time, the cooling airflow is guided by the annular cooling gap to form a cooling air film that fully covers the mixing hopper, resulting in better cooling effect.

[0017] In addition to the objectives, features, and advantages described above, the present invention has other objectives, features, and advantages. The invention will now be described in further detail with reference to the figures. Attached Figure Description

[0018] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0019] Figure 1 This is a schematic diagram of the overall structure of the present invention.

[0020] Figure 2 This is a schematic diagram of the structure of the limiting platform 24 of the present invention.

[0021] Figure 3 This is a schematic diagram of the structure of the annular groove 25 of the present invention.

[0022] Figure 4 This is a schematic cross-sectional view of the mixing hopper of the present invention.

[0023] Legend:

[0024] 1. Flame tube; 11. Mixing hole; 21. Tube body; 22. Bucket cap; 23. Cooling hole; 24. Limiting platform; 25. Annular groove; 3. Cooling gap. Detailed Implementation

[0025] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings. However, the present invention can be implemented in many different ways as defined and covered below.

[0026] Please see Figure 1-4 This invention provides a technical solution: a mixing hopper, used to be arranged on the wall of a flame tube 1. The diameter of a portion of the mixing hopper body 21 is smaller than the diameter of the mixing hole 11, so that a cooling gap 3 is formed between the mixing hopper and the mixing hole 11. At the same time, cooling holes 23 are opened on the mixing hopper, which respectively connect the inner cavity of the mixing hopper and the cooling gap 3. Cooling airflow is introduced into the cooling gap 3 through the cooling holes 23, and the direction of the cooling airflow is guided by the cooling gap 3. Under the guidance of the cooling gap 3, the cooling airflow forms a cooling gas film on the surface of the part of the mixing hopper located inside the flame tube 1, which cools the part of the mixing hopper located inside the flame tube 1, prevents the high-temperature gas from causing ablation of the part of the mixing hopper located inside the flame tube 1, increases the service life of the flame tube 1, improves the cooling effect of the mixing hopper without increasing the structural complexity and size of the mixing hopper, and is simpler to manufacture and more suitable for the design of compact high-temperature combustion chambers.

[0027] Specifically, the mixing hopper includes a cylinder 21 and a bucket cap 22 fixed to one end of the cylinder 21 for connection with the wall of the flame tube 1. The cylinder 21 and the bucket cap 22 enclose a mixing cavity for mixing high-temperature combustion gas and cooling gas flow. A mixing hole 11 is provided on the wall of the flame tube 1 for the cylinder 21 to extend into the inner cavity of the flame tube 1. The outer diameter of the cylinder 21 is smaller than the diameter of the mixing hole 11, so that when the mixing hopper is installed on the wall of the flame tube 1, an annular cooling gap 3 is formed between the outer wall of the cylinder 21 and the wall of the mixing hole 11. The diameter of the bucket cap 22 is larger than the diameter of the mixing hole 11, so that the bucket cap 22 can be connected to the wall of the flame tube 1. The welding is done on the surface, and the welding area is annular, which increases the connection stability between the mixing hopper and the flame tube 1. At the same time, the hopper cap 22 can also close the side of the cooling gap 3 near the hopper cap 22 to control the air intake flow. The hopper cap 22 has several cooling holes 23 circumferentially open, which are respectively connected to the mixing chamber and the cooling gap 3. The cooling holes 23 are used to introduce cooling airflow into the cooling gap 3 to impact the wall of the mixing hole 11 and form a cooling air film under the guidance of the cooling gap 3 to cool the cylinder 21. The diameter of the cylinder 21 is smaller than the diameter of the mixing hole 11. The cylinder 21 is installed in the mixing hole 11 through the hopper cap 22. When the mixture is inside, a cooling gap 3 is formed between the cylinder 21 and the mixing hole 11. The bucket cap 22 has cooling holes 23 connecting the cooling gap 3 and the mixing chamber. During operation, the cooling air pressure outside the flame tube 1 is greater than the pressure of the high-temperature combustion gas inside the flame tube 1. When a pressure difference is formed, the cooling airflow outside the flame tube 1 enters the flame tube 1 from the mixing chamber and mixes with the high-temperature combustion gas inside the flame tube 1. Simultaneously, the cooling airflow also enters the cooling gap 3 through the cooling holes 23 and impacts the inner wall of the mixing hole 11. Then, guided by the cooling gap 3, a cooling film is formed along the cylinder 21. The gas enters the flame tube 1 in the axial direction and cools the outer wall of the tube 21 through the cooling gas film, preventing the part of the tube 21 located inside the flame tube 1 from being burned by the high-temperature gas, thus increasing the service life of the mixing bucket. Without increasing the structural complexity of the mixing bucket, it achieves efficient cooling of the mixing bucket. Under the same cooling effect, it is smaller in size and simpler in structure, making it suitable for the design of compact combustion chambers. The cooling hole 23 is opened at the bucket cap 22, so that the air inlet end of the cooling hole 23 is closer to the high-pressure area, thereby increasing the pressure difference between the two ends of the cooling hole 23, increasing the air inlet flow, and increasing the cooling effect.

[0028] Preferably, the cylinder 21 and the mixing hole 11 are coaxially arranged, so that the radial width of the cooling gap 3 is equal at any point, making the cooling gas film more uniform.

[0029] like Figure 2 As shown, the bucket cap 22 is provided with a limiting platform 24 on one side for connecting with the flame tube 1. The outer diameter of the limiting platform 24 matches the inner diameter of the mixing hole 11. The limiting platform 24 is used to restrict the position of the mixing bucket by abutting against the inner wall of the mixing hole 11 through the side of the limiting platform 24.

[0030] In this embodiment, since a cooling gap 3 is formed between the cylinder 21 and the mixing hole 11, the cylinder 21 and the mixing hole 11 cannot be tightly attached. A limiting platform 24 is provided on the side of the bucket cap 22 that is connected to the wall of the flame tube 1. The limiting platform 24 is annular and its outer diameter matches the inner diameter of the mixing hole 11. In this way, the limiting platform 24 can just enter the mixing hole 11 and be tightly attached to the wall of the mixing hole 11, thereby limiting the position of the mixing bucket, maintaining the stability of the mixing bucket, and preventing the mixing bucket from shifting during subsequent use.

[0031] like Figure 3 As shown, the side of the bucket cap 22 that is used to connect with the flame tube 1 has an annular groove 25. The inner diameter of the annular groove 25 matches the inner diameter of the mixing hole 11. The stepped surface of the annular groove 25 abuts against the inner wall surface of the mixing hole 11 to limit the position of the mixing bucket.

[0032] In this embodiment, an annular groove 25 is opened on the side of the bucket cap 22 that connects to the wall of the flame tube 1. The inner diameter of the annular groove 25 matches the inner diameter of the mixing hole 11. When the bucket cap 22 is connected to the flame tube 1, the stepped surface of the annular groove 25 is just in close contact with the wall of the mixing hole 11, so as to limit the position of the mixing bucket, maintain the stability of the mixing bucket after it is installed in the flame tube 1, and prevent the mixing bucket from shifting during subsequent use.

[0033] like Figure 4 As shown, the distance between the impact point of the cooling airflow introduced by the cooling hole 23 on the inner wall of the mixing hole 11 and the inner side of the flame tube 1 wall is H, where H is 0.5mm-1mm. When H is between 0.5mm and 1mm, the cooling gap 3 has the best guiding effect on the cooling airflow. If H is too small, the guiding distance of the cooling air groove on the cooling airflow becomes shorter, the guiding effect becomes worse, and a stable cooling air film cannot be formed. If H is too large, the aperture and angle of the cooling hole 23 in the mixing bucket are limited, which will cause the air inlet position of the cooling hole 23 to be biased towards the inner side of the flame tube 1. The air pressure in the mixing chamber gradually decreases towards the flame tube 1. That is to say, the more the air inlet position of the cooling hole 23 is biased towards the inner side of the flame tube 1, the smaller the pressure difference on both sides of the cooling hole 23 will be, which will reduce the airflow of the cooling hole 23 and worsen the cooling effect.

[0034] like Figure 4 As shown, the radial length of the cooling gap 3 is B, which is 0.3mm-0.7mm. When the radial length of the cooling gap 3 is 0.3mm-0.7mm, the cooling gap 3 has the best guiding effect on the cooling airflow and can form a stable cooling air film. When B is less than 0.3mm, the airflow of the cooling gap 3 will be low, and the cooling air film will be easily dispersed by the high-temperature combustion gas. When B is greater than 0.7mm, it cannot effectively guide the cooling airflow, and the guiding length of the cooling airflow becomes shorter, resulting in a low strength of the formed cooling air film.

[0035] like Figure 4 As shown, the length of the cylinder 21 extending into the flame tube 1 relative to the wall of the flame tube 1 is D, where D is 1.5mm-3.0mm. When D is 1.5mm-3.0mm, the mixing effect is good, and the pressure on the cooling gas film is relatively small. When D is less than 1.5mm, the total mixing length is small, and the mixing effect is poor. When D is greater than 3.0mm, the wall of the cylinder 21 is easily ablated, and the pressure on the cooling gas film increases.

[0036] like Figure 4 As shown, the angle between the side of the cap 22 away from the wall of the flame tube 1 and the axis of the cooling hole 23 is α, where α is 50°-75°. When α is 50°-75°, the cooling gap 3 has the best guiding effect on the cooling airflow, the pressure difference on both sides of the cooling hole 23 is appropriate, and the flow coefficient inside the cooling hole 23 is appropriate. When α is less than 50°, the flow coefficient of the cooling hole 23 is low, resulting in low cooling efficiency. When α is greater than 75°, the guiding effect of the cooling gap 3 on the cooling airflow becomes worse, and a stable cooling air film cannot be formed.

[0037] like Figure 4 As shown, the distance between the side of the bucket cap 22 away from the wall of the flame tube 1 and the wall of the flame tube 1 is A. A is 1mm-2mm. When A is 1mm-2mm, the mixing effect of the mixing bucket on the flame tube 1 is the best. If A is less than 1mm, it will lead to insufficient mixing airflow and the mixing jet will be too shallow. If A is greater than 2mm, it will no longer enhance the mixing airflow and will increase the weight and affect the installation.

[0038] like Figure 4 As shown, the inner wall of the bucket cap 22 is chamfered on the side away from the wall of the flame tube 1 to improve the flow coefficient. Specifically, the chamfer R1 is 0.5mm-1.0mm.

[0039] Specifically, the bucket cap 22 is welded and fixed to the wall of the flame tube 1.

[0040] A combustion chamber includes the aforementioned mixing bucket, which increases the mixing effect within the combustion chamber and extends the service life of the mixing bucket within the combustion chamber.

[0041] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. 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 mixing bucket for use on the wall of a flame tube (1), characterized in that: The mixing hopper includes a cylinder (21) and a bucket cap (22) fixed at one end of the cylinder (21) for connecting with the wall of the flame tube (1). The cylinder (21) and the bucket cap (22) enclose a mixing cavity for mixing high-temperature gas and cooling gas flow. The flame tube (1) has a mixing hole (11) on its wall for the tube body (21) to extend into the inner cavity of the flame tube (1). The outer diameter of the cylinder (21) is smaller than the diameter of the mixing hole (11), so that when the mixing bucket is installed on the wall of the flame tube (1), an annular cooling gap (3) is formed between the outer wall of the cylinder (21) and the wall of the mixing hole (11). The bucket cap (22) is provided with several cooling holes (23) in the circumferential direction, which are respectively connected to the mixing chamber and the cooling gap (3). The cooling holes (23) are used to introduce the cooling airflow into the cooling gap (3) to impact the wall of the mixing hole (11) and form a cooling air film under the guidance of the cooling gap (3) to cool the cylinder (21). The distance between the impact point of the cooling airflow introduced by the cooling hole (23) on the inner wall of the mixing hole (11) and the inner side of the flame tube (1) is H, where H is 0.5mm-1mm. The radial length of the cooling gap (3) is B, where B is 0.3mm-0.7mm; The length of the cylinder (21) extending into the flame tube (1) relative to the wall of the flame tube (1) is D, where D is 1.5mm-3.0mm; The angle between the side of the bucket cap (22) away from the wall of the flame tube (1) and the axis of the cooling hole (23) is α, where α is 50°-75°; The distance between the side of the bucket cap (22) away from the wall of the flame tube (1) and the wall of the flame tube (1) is A, where A is 1mm-2mm.

2. A mixing bucket according to claim 1, characterized in that: The bucket cap (22) is provided with a limiting platform (24) on one side for connecting with the flame tube (1). The outer diameter of the limiting platform (24) matches the inner diameter of the mixing hole (11) so as to limit the position of the mixing bucket by abutting the side of the limiting platform (24) against the inner wall of the mixing hole (11).

3. A mixing bucket according to claim 1, characterized in that: The bucket cap (22) has an annular groove (25) on the side for connecting with the flame tube (1). The inner diameter of the annular groove (25) matches the inner diameter of the mixing hole (11) so that the stepped surface of the annular groove (25) abuts against the inner wall surface of the mixing hole (11) to limit the position of the mixing bucket.

4. A mixing bucket according to any one of claims 1-3, characterized in that: The inner wall of the bucket cap (22) is chamfered on the side away from the wall of the flame tube (1).

5. A combustion chamber, characterized in that, Includes the mixing bucket as described in any one of claims 1-4.

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