An inclined combustion chamber

Abstract

The present invention belongs to the field of aero-engine technology, and discloses an inclined combustion chamber, comprising a diffuser, an outer casing, an inner casing, a head support ring, a flame tube outer ring, and a flame tube inner ring; an annular cavity is provided between the outer casing and the inner casing, the diffuser is arranged at the air inlet of the annular cavity, the air outlet of the diffuser is connected to the air inlet of the annular cavity, the flame tube outer ring and the flame tube inner ring are both located in the annular cavity, the flame tube outer ring and the flame tube inner ring form a flame tube flow channel, the flame tube outer ring and the outer casing form an outer ring flow channel, and the flame tube inner ring and the inner casing form an inner ring flow channel; the centerline of the diffuser outlet, the centerline of the flame tube flow channel, the centerline of the outer ring flow channel, and the centerline of the inner ring flow channel are parallel to each other and have an angle with the axial centerline of the rotating shaft. The inclined combustion tube of the present invention fully utilizes the radial drop of the inlet and outlet, the axial length of the combustion chamber is short, and the airflow flows smoothly.

Description

Technical Field

[0001] The invention belongs to the technical field of aviation engines, and in particular relates to an inclined combustion chamber. Background Art

[0002] The combustion chamber is one of the core components of an aircraft engine / gas turbine. Its function is to burn fuel, convert the chemical energy in the fuel into thermal energy, increase the total enthalpy of the air entering the combustion chamber, and drive the gas turbine to perform work. Its design directly affects the efficiency and emissions of the aircraft engine / gas turbine.

[0003] For aircraft engines / gas turbines using centrifugal compressors, the radial height difference between the inlet and outlet of the combustion chamber is usually large, and a recirculation combustion chamber is often used, such as Figure 1 As shown, the recirculation combustion chamber primarily consists of a diffuser, casing, swirler, flame tube, large and small elbows, and other components. The specific operating process is as follows: High-pressure air compressed by the compressor enters the combustion chamber through the diffuser, where it splits into outer and inner annular channels. The air then enters the flame tube through openings in the inner and outer rings, head, large and small elbows, and other components of the flame tube. Fuel enters the flame tube through the fuel nozzle, where it mixes with the high-pressure air and flows through the flame tube. During combustion chamber startup, an electric spark generated by an ignition nozzle located near the flame tube wall ignites the fuel-air mixture. During normal combustion chamber operation, the high-temperature combustion gas generated in the combustion chamber enters the turbine axially, driving it to produce work. Cooling holes are provided in the inner and outer rings of the flame tube and the large and small elbows to insulate the high-temperature combustion gas and prevent ablation. The airflow within the combustion chamber undergoes two 180-degree directional adjustments from entry to exit.

[0004] Combustion chambers with large radial height differences between inlet and outlet usually adopt a recirculation configuration. However, recirculation combustion chambers have the following problems:

[0005] 1. The airflow needs to turn 180 degrees twice, the flow is not smooth, and the useless total pressure loss is large;

[0006] 2. The static pressure of the inner and outer annular flow channels is unbalanced, making the design of the air intake opening difficult;

[0007] 3. The cooling area of ​​the flame tube is large, and the cooling design is difficult, which is not suitable for aircraft engines / gas turbines with high thermodynamic cycle parameters;

[0008] 4. The gas residence time is long and the NOx emission is high; 5. The combustion chamber structure is complex, difficult to process and heavy. Summary of the Invention

[0009] In order to solve the above problems, the present invention provides an inclined combustion chamber, which adopts the following technical solutions:

[0010] An inclined combustion chamber comprises a diffuser, an outer casing, an inner casing, a head support ring, a flame tube outer ring and a flame tube inner ring;

[0011] There is an annular cavity between the outer casing and the inner casing, the diffuser is arranged at the air inlet of the annular cavity, the air outlet of the diffuser is communicated with the air inlet of the annular cavity, the outer ring of the flame tube and the inner ring of the flame tube are both located in the annular cavity, the outer ring of the flame tube and the inner ring of the flame tube form a flame tube flow channel, the outer ring of the flame tube and the outer casing form an outer ring flow channel, and the inner ring of the flame tube and the inner casing form an inner ring flow channel;

[0012] The center line of the air outlet of the diffuser, the center line of the flame tube flow channel, the center line of the outer ring flow channel and the center line of the inner ring flow channel are parallel to each other and form an angle with the axial center line of the rotating shaft.

[0013] Furthermore, total pressure air inlet holes and static pressure air inlet holes are circumferentially arranged on the outer ring of the flame tube and the inner ring of the flame tube, and the total pressure air inlet holes and the static pressure air inlet holes on the outer ring of the flame tube are perpendicular to each other, and the total pressure air inlet holes and the static pressure air inlet holes on the inner ring of the flame tube are perpendicular to each other.

[0014] Furthermore, a head support ring is provided between the flame tube outer ring and the flame tube inner ring at one end close to the diffuser, and both sides of the head support ring are fixedly connected to the flame tube outer ring and the flame tube inner ring respectively.

[0015] Furthermore, the center line of the total pressure air inlet holes of the inner ring of the flame tube, the center line of the total pressure air inlet holes of the outer ring of the flame tube and the center line of the flame tube flow channel are parallel to each other.

[0016] Furthermore, the cross-sectional area of ​​the outer ring flow channel is equal to the cross-sectional area of ​​the inner ring flow channel.

[0017] Furthermore, a plurality of air film cooling structures are axially arranged on the outer ring of the flame tube and the inner ring of the flame tube, and the air film cooling structure includes a cooling ring and a cantilever tongue;

[0018] In which, the cantilever tongue is arranged on the inner wall of the cooling ring, and an air film channel is formed between the cantilever tongue and the inner wall of the cooling ring, an air inlet portion is provided at the connection between the cantilever tongue and the cooling ring, the air inlet portion is axially provided with the total pressure air inlet hole, the total pressure air inlet hole is connected with the air film channel, and the cooling ring is radially provided with the static pressure air inlet hole in the middle position of the air film channel.

[0019] Furthermore, it also includes a vortex finder, which is arranged on the head support ring, and the center line of the vortex finder is concentric with the center line of the flame tube flow channel.

[0020] Furthermore, an outer ring main combustion hole and an outer ring mixing hole are provided on the outer ring of the flame tube, and the outer ring mixing hole is located downstream of the outer ring main combustion hole. An inner ring main combustion hole and an inner ring mixing hole are provided on the inner ring of the flame tube, and the inner ring mixing hole is located downstream of the inner ring main combustion hole.

[0021] Furthermore, the line connecting the bottom midpoint of the outer ring main combustion hole and the bottom midpoint of the inner ring main combustion hole is perpendicular to the center line of the flame tube flow channel, and the line connecting the bottom midpoint of the outer ring mixing hole and the bottom midpoint of the inner ring mixing hole is perpendicular to the center line of the flame tube flow channel.

[0022] Furthermore, the outer ring main combustion holes and the outer ring mixing holes are both located between two adjacent air film cooling structures on the outer ring of the flame tube, and the inner ring main combustion holes and the inner ring mixing holes are both located between two adjacent air film cooling structures on the inner ring of the flame tube.

[0023] Beneficial effects of the present invention:

[0024] 1. The center line of the air outlet of the diffuser of the combustion chamber of the present invention, the center line of the flame tube flow channel, the center line of the outer ring flow channel, the center line of the inner ring flow channel and the axial center line of the rotating shaft form an angle, forming an inclined combustion tube, making full use of the radial drop between the inlet and outlet, the axial length of the combustion chamber is short, and the airflow flows smoothly.

[0025] 2. The center lines of the air outlet of the diffuser of the combustion chamber of the present invention, the center lines of the flame tube flow channel, the center lines of the outer ring flow channel and the center lines of the inner ring flow channel are parallel to each other, which ensures the smooth flow of air in the combustion chamber and reduces useless total pressure loss.

[0026] 3. The outer annular flow channel and the inner annular flow channel of the combustion chamber of the present invention are designed with equal cross-sectional areas, and their center lines are parallel, which ensures that the static pressure distribution of the inner and outer annular flow channels is the same, ensures that their flow coefficients are the same, and reduces the difficulty of designing the inner and outer ring air intake openings of the flame tube.

[0027] 4. In the present invention, the connecting line of the inner and outer ring main combustion holes and the connecting line of the inner and outer ring mixing holes are perpendicular to the center line of the flame tube flow channel. The inner and outer ring main combustion holes form symmetrical jets, which can effectively cut off the high-temperature combustion gas; under the quenching effect of the mixing hole jet not far downstream from the main combustion hole, the high-temperature combustion gas quickly enters the lean combustion state, further reducing NOx emissions.

[0028] 5. The direction of the total pressure air inlet of the present invention is the same as the direction of the center line of the flame tube flow channel, which fully utilizes the dynamic pressure head of the airflow to ensure the wall adhesion of the airflow. At the same time, the reverse momentum formed by the impact of the static pressure intake airflow and the cantilever tongue is utilized to further enhance the wall adhesion of the air film and the uniformity of the circumferential cooling air, thereby improving the service life of the flame tube.

[0029] 6. The combustion chamber of the present invention has a simple structure, low processing difficulty and light weight.

[0030] Other features and advantages of the present invention will be described in the following description, and in part will become apparent from the description, or will be understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures pointed out in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following is a brief introduction to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0032] Figure 1 A schematic structural diagram of a recirculation combustion chamber according to the prior art is shown;

[0033] Figure 2 It shows a schematic structural diagram of an inclined combustion chamber according to an embodiment of the present invention;

[0034] Figure 3 Shown Figure 2 Enlarged view of point A in the middle;

[0035] Figure 4 A schematic diagram of the flow passage and jet of an inclined combustion chamber according to an embodiment of the present invention is shown.

[0036] In the figure: 1. Diffuser; 2. Outer casing; 3. Inner casing; 4. Head support ring; 5. Flame tube outer ring; 6. Flame tube inner ring; 7. Annular cavity; 8. Flame tube flow channel; 9. Outer ring flow channel; 10. Inner ring flow channel; 11. Total pressure air inlet; 12. Static pressure air inlet; 13. Center line of diffuser outlet; 14. Center line of flame tube flow channel; 15. Center line of outer ring flow channel; 16. Center line of inner ring flow channel; 17. Rotating shaft; 18. Film cooling structure; 19. Cooling ring; 20. Cantilever tongue; 21. Film channel; 22. Air inlet; 23. Swirl finder; 24. Outer ring main combustion hole; 25. Inner ring main combustion hole; 26. Outer ring mixing hole; 27. Inner ring mixing hole. DETAILED DESCRIPTION

[0037] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0038] It should be noted that the terms "first", "second" etc. in this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the application described herein. In this application, the directions or positional relationships indicated by the terms "upper", "lower", "left", "right", "front", "back", "top", "bottom", "inside", "outside", "center", "vertical", "horizontal", "lateral", "longitudinal" etc. are based on the directions or positional relationships shown in the accompanying drawings.

[0039] The present invention provides an inclined combustion chamber, which can significantly shorten the axial length of the combustion chamber and has the following advantages: 1. Smooth airflow; 2. Static pressure balance between the inner and outer annular flow channels, and low difficulty in designing the air intake opening; 3. Small cooling area of ​​the flame tube, good total and static pressure air intake cooling effects, long flame tube life, and can be used in high thermodynamic cycle parameter aircraft engines / gas turbines; 4. Short gas residence time, low NOx emissions; 5. Simple combustion chamber structure, low processing difficulty, and light weight.

[0040] like Figure 2 As shown, an inclined combustion chamber for an aircraft engine or a gas turbine includes a diffuser 1, an outer casing 2, an inner casing 3, a head support ring 4, a flame tube outer ring 5 and a flame tube inner ring 6.

[0041] Among them, the outer casing 2 is arranged on the outside of the inner casing 3, and there is an annular cavity 7 between the outer casing 2 and the inner casing 3. The diffuser 1 is arranged at the air inlet of the annular cavity 7, and the air outlet of the diffuser 1 is connected to the air inlet of the annular cavity 7.

[0042] The outer ring 5 and the inner ring 6 of the flame tube are both located in the annular cavity 7. A head support ring 4 is provided between the outer ring 5 and the inner ring 6 of the flame tube at one end close to the diffuser 1. The two sides of the head support ring 4 are fixedly connected to the outer ring 5 and the inner ring 6 of the flame tube respectively.

[0043] The flame tube outer ring 5 and the flame tube inner ring 6 form an annular flame tube flow channel 8, the flame tube outer ring 5 and the outer casing 2 form an outer ring flow channel 9, and the flame tube inner ring 6 and the inner casing 3 form an inner ring flow channel 10.

[0044] Total pressure air inlet holes 11 and static pressure air inlet holes 12 are circumferentially arranged on the outer ring 5 of the flame tube and the inner ring 6 of the flame tube, and the total pressure air inlet holes 11 and the static pressure air inlet holes 12 on the outer ring 5 of the flame tube are perpendicular to each other, and the total pressure air inlet holes 11 and the static pressure air inlet holes 12 on the inner ring 6 of the flame tube are perpendicular to each other.

[0045] like Figure 2 and Figure 4 As shown, the diffuser outlet centerline 13, the flame tube flow channel centerline 14, the outer ring flow channel centerline 15 and the inner ring flow channel centerline 16 are parallel to each other and have an angle with the axial centerline of the rotating shaft 17, forming an inclined combustion tube.

[0046] In this embodiment, the diffuser outlet centerline 13, the flame tube flow channel centerline 14, the outer ring flow channel centerline 15, and the inner ring flow channel centerline 16 are designed to be parallel, which ensures the smooth flow of air in the combustion chamber and reduces useless total pressure loss.

[0047] In this embodiment, the diffuser outlet centerline 13, the flame tube flow channel centerline 14, the outer ring flow channel centerline 15 and the inner ring flow channel centerline 16 form an angle with the axial centerline of the rotating shaft 17, which fully utilizes the radial drop between the inlet and outlet of the combustion chamber, shortens the axial length of the combustion chamber, and ensures smooth airflow.

[0048] For example, the cross-sectional area of ​​the outer ring flow channel 9 is equal to the cross-sectional area of ​​the inner ring flow channel 10. The outer ring flow channel 9 and the inner ring flow channel 10 are designed with equal cross-sectional areas, and their center lines are parallel, which ensures that the static pressure distribution of the inner ring flow channel 10 and the outer ring flow channel 9 are the same, ensures that their flow coefficients are the same, and reduces the difficulty of designing the air intake openings of the flame tube inner ring 6 and the flame tube outer ring 5.

[0049] like Figure 2 As shown, for example, multiple air film cooling structures 18 are provided on the outer ring 5 and the inner ring 6 of the flame tube along the axial direction, such as Figure 3 As shown, the film cooling structure 18 includes a cooling ring 19 and cantilever tongues 20 .

[0050] Among them, the cantilever tongue 20 is arranged on the inner wall of the cooling ring 19, and an air film channel 21 is formed between the cantilever tongue 20 and the inner wall of the cooling ring 19, and an air inlet part 22 is provided at the connection between the cantilever tongue 20 and the cooling ring 19. A total pressure air inlet hole 11 is axially arranged on the air inlet part 22, and the total pressure air inlet hole 11 is connected to the air film channel 21. The cooling ring 19 is radially provided with a static pressure air inlet hole 12 in the middle position of the air film channel 21.

[0051] In this embodiment, the center lines of the total pressure air inlet holes 11 of the inner ring 6 of the flame tube and the center lines of the total pressure air inlet holes 11 of the outer ring 5 of the flame tube are parallel to each other and the direction of the total pressure air inlet holes 11 is the same as the direction of the center line 14 of the flame tube flow channel. The dynamic pressure head of the airflow is fully utilized to ensure the wall adhesion of the airflow. At the same time, the reverse momentum formed by the impact of the static pressure intake airflow and the cantilever tongue 20 is utilized to further enhance the wall adhesion of the air film and the uniformity of the circumferential cooling air, thereby improving the service life of the flame tube.

[0052] For example, the inclined combustion chamber further includes a swirler 23 , which is disposed on the head support ring 4 , and the center line of the swirler 23 is concentric with the center line 14 of the flame tube flow channel.

[0053] like Figure 2 As shown, for example, an outer ring main combustion hole 24 and an outer ring mixing hole 26 are provided on the outer ring 5 of the flame tube, and the outer ring mixing hole 26 is located downstream of the outer ring main combustion hole 24. An inner ring main combustion hole 25 and an inner ring mixing hole 27 are provided on the inner ring 6 of the flame tube, and the inner ring mixing hole 27 is located downstream of the inner ring main combustion hole 25.

[0054] Among them, the main combustion holes and mixing holes are designed with short-range symmetrical jets. The line connecting the bottom midpoint of the outer ring main combustion hole 24 and the bottom midpoint of the inner ring main combustion hole 25 is perpendicular to the center line 14 of the flame tube flow channel. The line connecting the bottom midpoint of the outer ring mixing hole 26 and the bottom midpoint of the inner ring mixing hole 27 is perpendicular to the center line 14 of the flame tube flow channel. The inner ring main combustion holes 25 and the outer ring main combustion holes 24 form symmetrical jets, which can well cut off the high-temperature combustion gas. Under the quenching effect of the mixing hole jet not far downstream from the main combustion hole, the high-temperature combustion gas quickly enters the lean combustion state, further reducing NOx emissions.

[0055] like Figure 2 As shown, for example, the outer ring main combustion holes 24 and the outer ring mixing holes 26 are both located between two adjacent air film cooling structures 18 on the outer ring 5 of the flame tube, and the inner ring main combustion holes 25 and the inner ring mixing holes 27 are both located between two adjacent air film cooling structures 18 on the inner ring 6 of the flame tube.

[0056] The working principle of the combustion chamber of the present invention is as follows: the high-pressure air compressed by the compressor enters the annular cavity 7 between the outer casing 2 and the inner casing 3 through the outlet of the diffuser 1, and the air is divided into the outer ring flow channel 9 and the inner ring flow channel 10, and then enters the flame tube flow channel 8 through the flame tube inner ring 6, the flame tube outer ring 5 and the vortex finder 23 on the head support ring 4; the fuel enters the flame tube flow channel 8 through the fuel nozzle, mixes with the high-pressure air in the flame tube flow channel 8 and flows along with it; when the combustion chamber is ignited and started, the electric spark generated by the ignition nozzle ignites the oil-gas mixture to form high-temperature and high-pressure combustion gas; the air entering from the outer ring main combustion hole 24, the outer ring mixing hole 26, the inner ring main combustion hole 25 and the inner ring mixing hole 27 quickly extinguishes the mixed high-temperature and high-pressure combustion gas, and then the high-temperature combustion gas with the required temperature distribution enters the turbine to drive it to do work.

[0057] Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein; and these modifications or replacements 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. An inclined combustion chamber, characterized in that: It comprises a diffuser (1), an outer casing (2), an inner casing (3), a head support ring (4), a flame tube outer ring (5) and a flame tube inner ring (6); wherein an annular cavity (7) is provided between the outer casing (2) and the inner casing (3); the diffuser (1) is arranged at the air inlet of the annular cavity (7); the air outlet of the diffuser (1) is communicated with the air inlet of the annular cavity (7); the flame tube outer ring (5) and the flame tube inner ring (6) are both located in the annular cavity (7); the flame tube outer ring (5) and the flame tube inner ring (6) form a flame tube flow channel (8); the flame tube outer ring (5) and the outer casing (2) form an outer ring flow channel (9); and the flame tube inner ring (6) and the inner casing (3) form an inner ring flow channel (10); The center line (13) of the air outlet of the diffuser, the center line (14) of the flame tube flow channel, the center line (15) of the outer ring flow channel, and the center line (16) of the inner ring flow channel are parallel to each other and have an angle with the axial center line of the rotation axis (17); The flame tube outer ring (5) and the flame tube inner ring (6) are both provided with total pressure air inlet holes (11) and static pressure air inlet holes (12) along the circumferential direction, and the total pressure air inlet holes (11) and the static pressure air inlet holes (12) on the flame tube outer ring (5) are perpendicular to each other, and the total pressure air inlet holes (11) and the static pressure air inlet holes (12) on the flame tube inner ring (6) are perpendicular to each other; A plurality of air film cooling structures (18) are axially arranged on the outer ring (5) of the flame tube and the inner ring (6) of the flame tube, and the air film cooling structure (18) includes a cooling ring (19) and a cantilever tongue (20); wherein the cantilever tongue (20) is arranged on the inner wall of the cooling ring (19), and an air film channel (21) is formed between the cantilever tongue (20) and the inner wall of the cooling ring (19); an air inlet portion (22) is arranged at the connection between the cantilever tongue (20) and the cooling ring (19); the air inlet portion (22) is axially arranged with the total pressure air inlet hole (11), the total pressure air inlet hole (11) is communicated with the air film channel (21), and the cooling ring (19) is radially arranged with the static pressure air inlet hole (12) at the middle position of the air film channel (21); The outer ring (5) of the flame tube is further provided with an outer ring main combustion hole (24) and an outer ring mixing hole (26), and the outer ring mixing hole (26) is located downstream of the outer ring main combustion hole (24); the inner ring (6) of the flame tube is provided with an inner ring main combustion hole (25) and an inner ring mixing hole (27), and the inner ring mixing hole (27) is located downstream of the inner ring main combustion hole (25); The line connecting the bottom midpoint of the outer ring main combustion hole (24) and the bottom midpoint of the inner ring main combustion hole (25) is perpendicular to the center line (14) of the flame tube flow channel, and the line connecting the bottom midpoint of the outer ring mixing hole (26) and the bottom midpoint of the inner ring mixing hole (27) is perpendicular to the center line (14) of the flame tube flow channel.

2. The inclined combustion chamber according to claim 1, characterized in that: A head support ring (4) is provided between the flame tube outer ring (5) and the flame tube inner ring (6) at one end close to the diffuser (1), and both sides of the head support ring (4) are fixedly connected to the flame tube outer ring (5) and the flame tube inner ring (6) respectively.

3. The inclined combustion chamber according to claim 1, characterized in that: The center line of the total pressure air inlet hole (11) of the flame tube inner ring (6), the center line of the total pressure air inlet hole (11) of the flame tube outer ring (5) and the center line (14) of the flame tube flow channel are parallel to each other.

4. The inclined combustion chamber according to any one of claims 1 to 3, characterized in that: The cross-sectional area of ​​the outer annular flow channel (9) is equal to the cross-sectional area of ​​the inner annular flow channel (10).

5. The inclined combustion chamber according to claim 2, characterized in that: It also includes a vortex finder (23), which is arranged on the head support ring (4), and the center line of the vortex finder (23) is concentric with the center line (14) of the flame tube flow channel.

6. The inclined combustion chamber according to claim 1, characterized in that: The outer ring main combustion hole (24) and the outer ring mixing hole (26) are both located between two adjacent air film cooling structures (18) on the outer ring (5) of the flame tube, and the inner ring main combustion hole (25) and the inner ring mixing hole (27) are both located between two adjacent air film cooling structures (18) on the inner ring (6) of the flame tube.

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