A flame tube and combustion chamber with anti-intake distortion

Abstract

This invention discloses an anti-intake distortion flame tube and combustion chamber in the field of aero-engine technology. The anti-intake distortion flame tube includes an annular tube body and a mixing unit mounted on the tube body. The mixing unit includes a first-stage vortex generator fixedly mounted at the head of the tube body and a fuel nozzle coaxially mounted through the first-stage vortex generator for delivering fuel into the tube body. A fairing is mounted on the tube body to cover the first-stage vortex generator. The intake uniformity of the first-stage vortex generator is controlled by the air inlet opened in the fairing. The size of the fairing matches the first-stage vortex generator to cover a single first-stage vortex generator. By using a fairing that matches the size of the first-stage vortex generator to cover a single first-stage vortex generator, multiple fairings are independent of each other. Compared with improving the intake uniformity of the vortex generator by increasing the density of the vortex generator blades or enlarging the air inlet, the fairing can achieve greater rectification benefits with less weight.

Description

Technical Field

[0001] This invention relates to the field of aero-engine technology, specifically to an anti-intake distortion flame tube and combustion chamber. Background Technology

[0002] With the advancement of aero-engine technology, the power-to-weight ratio / thrust-to-weight ratio of engines is becoming increasingly higher. Currently, the power-to-weight ratio of advanced foreign turboshaft engines has exceeded 12, and future requirements will be even higher. This necessitates smaller, more compact combustion chamber structures, lower weight, and higher fuel-to-air ratios. To meet these requirements, the distance between the engine diffuser outlet and the vortex generator at the head of the combustion chamber needs to be shortened, and more fuel needs to be burned within a certain space. Objectively, this will cause a decrease in the uniformity of the air at the vortex generator inlet. However, high fuel-to-air ratio combustion chambers actually place even higher demands on the uniformity of the air at the vortex generator inlet.

[0003] There are currently two main technical directions for improving the intake uniformity of the vortex generator at the head of the high-temperature combustion chamber:

[0004] I. This is achieved by improving the profile and blade density of the guide vanes in the vortex inlet channel;

[0005] Second, a head fairing is installed outside the vortex generator at the head of the flame tube to almost completely enclose the entire vortex generator (usually two-stage, a few three-stage vortex generators), leaving only one air intake passage.

[0006] For example, Chinese invention patent CN 116358004B discloses a structure for a ring-shaped combustion chamber flame tube of a medium-thrust aero-engine. The structure is characterized by comprising an outer fairing, a head assembly, an outer cylinder, and an inner cylinder; the inner cylinder is disposed inside the outer cylinder, and the two are coaxially arranged; the rear end of the outer fairing is connected to the walls of the outer and inner cylinders respectively; the outer and inner rings of the rear end of the inner fairing in the head assembly are respectively connected to the pressure grooves at the front ends of the outer and inner cylinders; the head assembly includes two ignition heads and multiple non-ignition heads; the two ignition heads are disposed in the upper half-ring, and the two ignition heads are asymmetrically distributed; a single-stage axial-flow vortex generator is disposed in the ignition head; a double-stage axial-flow vortex generator is disposed in the non-ignition head; heat shields are disposed in both the ignition head and the non-ignition head, and the rear end of each heat shield is welded to the front end of the inner fairing.

[0007] For example, Chinese invention patent application CN 117346182 A discloses a combined cooling structure for the head of a flame tube and a vortex generator. This structure includes: a cooling gas film formed by cooling gas adhering tightly to the inner wall of a heat shield and then flowing to the inner wall of an inner rectifier to form another cooling gas film; and a combined cooling structure where the inner and outer walls of the sleeve formed by the expansion section also form a gas film. The cooling gas discharged from the head cooling oblique holes adheres tightly to the inner wall of the heat shield and then flows to the inner wall of the inner rectifier to form a cooling gas film. The cooling gas discharged from the cooling holes in the contraction section, the cooling holes in the expansion section, and the multiple oblique holes in the wall can adhere tightly to the inner and outer walls of the expansion section extending into the flame tube head to form a cooling gas film. Combined with the expansion section's structure where the thickness gradually decreases from the contraction section towards the heat shield, this ensures the safety of the gas film formed by the inner and outer walls of the sleeve formed by the expansion section within the combustion chamber space at the flame tube head. This solves the problem that the cooling gas discharged by the impact-type divergence cannot adhere tightly to the inner wall of the rectifier in the combustion chamber of the flame tube head and the inner and outer walls of the vortex generator extension section to form a protective gas film.

[0008] The aforementioned invention patents and invention patent applications all employ the second method of setting a head fairing to improve intake uniformity. Using a fairing to cover the entire flame tube will increase the size of the entire flame tube head and significantly increase the weight of the flame tube, which is not conducive to compact flame tube and weight reduction design, and has a limited effect on improving the engine's power-to-weight ratio / thrust-to-weight ratio. On the other hand, the solution of improving the intake uniformity of the vortex by improving the profile and blade density of the guide vanes in the vortex intake channel will result in a larger radial dimension of the vortex, which is not conducive to compact flame tube design.

[0009] Based on this, the present invention designs an anti-intake distortion flame tube and combustion chamber to solve the above problems. Summary of the Invention

[0010] To achieve the above objectives, the present invention provides the following technical solution: an anti-intake distortion flame tube, comprising an annular tube body and a mixing unit mounted on the tube body. The head of the tube body has multiple openings at equal intervals along the circumferential direction for the mixed gas to enter the inner cavity of the tube body. Each opening of the tube body is equipped with a mixing unit for forming the mixed gas. The mixing unit includes a first-stage vortex generator fixedly mounted on the head of the tube body and a fuel nozzle coaxially mounted through and coaxially with the first-stage vortex generator for delivering fuel into the tube body. The first-stage vortex generator is used to form a high-speed rotating jet of air entering the tube body from the outside, which mixes with the fuel sprayed from the fuel nozzle to form the mixed gas. A shroud is mounted on the tube body to cover the first-stage vortex generator. The air intake port of the shroud controls the uniformity of the intake of the first-stage vortex generator. The size of the shroud matches the first-stage vortex generator to cover a single first-stage vortex generator.

[0011] As a further embodiment of the present invention, the air inlet includes a head air inlet formed on the top of the fairing, the head air inlet being circular, and the extended axis of the first-stage vortex generator passing through the center of the head air inlet.

[0012] As a further embodiment of the present invention, the air inlet further includes a plurality of side air inlets equally spaced along the circumferential direction on the side of the fairing. The side air inlets are inclined to the wall of the fairing and the inclination direction is the same as that of the blades of the first-stage vortex generator, so as to make the air entering the fairing from the side air inlets form a vortex in the fairing with the same direction as the rotating jet in the first-stage vortex generator.

[0013] As a further aspect of the present invention, the maximum distance between the side air inlet and the bottom surface of the fairing does not exceed the distance between the top surface of the first-stage vortex inlet area and the bottom surface of the fairing.

[0014] As a further embodiment of the present invention, the angle between the side air inlet and the wall surface at the location on the fairing surface is no greater than 30°.

[0015] As a further embodiment of the present invention, the fairing consists of a top, a transition section and a bottom from top to bottom. The diameter of the top is smaller than that of the bottom, and the transition section is arc-shaped to smoothly transition between the top and the bottom to accommodate airflow.

[0016] As a further embodiment of the present invention, a secondary vortex is fixedly installed between the primary vortex and the cylinder. The primary vortex and the fairing are both fixedly installed on the side of the secondary vortex away from the cylinder. The secondary vortex is used to form a high-speed rotating jet and secondary mixing with fuel at a position closer to the inner cavity of the cylinder than the primary vortex.

[0017] As a further embodiment of the present invention, a Venturi tube is fixedly installed between the outlet of the first-stage vortex generator and the outlet of the second-stage vortex generator, thereby increasing the distance between the high-speed rotating jets generated by the first-stage and second-stage vortex generators without increasing the distance between the first-stage and second-stage vortex generators.

[0018] As a further aspect of the present invention, the blades of the secondary vortex generator rotate in the opposite direction to those of the primary vortex generator.

[0019] As a further aspect of the present invention, a combustion chamber includes an anti-intake distortion flame tube, a casing for mounting the tube body, and a diffuser installed inside the casing cavity, wherein the tube body head is mounted inside the casing cavity facing the diffuser.

[0020] The present invention has the following beneficial effects:

[0021] This invention improves the uniformity of air intake in the first-stage vortex generator by covering its surface with a shroud matching the size of the first-stage vortex generator. The shroud has a head air intake and a side air intake, which enhance the uniformity of air intake in the first-stage vortex generator. Since the size of the shroud matches the size of the first-stage vortex generator, installing the shroud does not increase the diameter of the cylinder and the increase in cylinder weight is minimal. This achieves greater rectification benefits with less weight, meeting the design requirements of high air-fuel ratio and compact combustion chamber, and solving the design problems of combustion chamber performance and combustion stability in high power-to-weight ratio / thrust-to-weight ratio engines.

[0022] 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

[0023] 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:

[0024] Figure 1 This is a schematic cross-sectional view of the present invention.

[0025] Figure 2 This is a schematic diagram of the structure of the hybrid unit in this invention.

[0026] Figure 3 This is a schematic diagram of the fairing structure in this invention.

[0027] Figure 4 This is a cross-sectional schematic diagram of the fairing in this invention.

[0028] Legend:

[0029] 1. Shell; 2. Opening; 31. First-stage vortex generator; 32. Fuel nozzle; 33. Second-stage fairing; 4. Fairing; 41. Head air inlet; 42. Side air inlet; 44. Transition section; 5. Venturi tube; 6. Casing; 7. Diffuser; 8. Ignition nozzle. Detailed Implementation

[0030] 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.

[0031] Please see Figure 1-4This invention provides a technical solution: an anti-intake distortion flame tube, comprising an annular tube body 1 and a mixing unit mounted on the tube body 1. The mixing unit includes a first-stage vortex generator 31 fixedly mounted at the head of the tube body 1 and a fuel nozzle 32 coaxially mounted through the first-stage vortex generator 31 for delivering fuel into the tube body 1. A shroud 4 is mounted on the tube body 1 to cover the first-stage vortex generator 31. The intake uniformity of the first-stage vortex generator 31 is controlled by the air inlet opened in the shroud 4. The size of the shroud 4 matches the size of the first-stage vortex generator 31 to cover a single first-stage vortex generator 31. The fairing 4 covers a single first-stage vortex generator 31. The multiple fairings 4 are independent of each other. Compared with improving the intake uniformity of the vortex generator by increasing the density of the vortex generator blades or enlarging the intake duct, the fairing 4 can achieve greater rectification benefits with less weight. Compared with the integrated fairing 4, the independent fairing 4 is lighter and smaller in size. The fairings 4 are not interconnected. While improving the circumferential intake uniformity of a single first-stage vortex generator 31, it can also reduce the mutual interference of intake between mixing units and improve the uniformity of the mixture generated between different mixing units, which is conducive to improving the uniformity of the combustion chamber outlet temperature field.

[0032] Specifically, the head of the cylinder 1 has multiple openings 2 at equal intervals along its circumference for the mixed air to enter the inner cavity of the cylinder 1. Each opening 2 of the cylinder 1 is equipped with a mixing unit for forming the mixed air. The first-stage vortex generator 31 is used to make the air entering the cylinder 1 from the outside form a high-speed rotating jet, which mixes with the fuel sprayed from the fuel nozzle 32 to form a mixed air. During operation, the high-pressure air from the outside will enter the cylinder 1 from the opening 2 after passing through the first-stage vortex generator 31 and forming a high-speed rotating jet. At the same time, the fuel nozzle 32 will spray atomized fuel into the cylinder 1. The high-speed rotating jet and the atomized fuel mix and move into the cylinder 1, ultimately forming a mixed air that burns inside the cylinder 1. By covering the surface of the first-stage vortex generator 31 with a shroud 4, high-pressure air can only enter the shroud 4 through the air inlet of the shroud 4 before entering the first-stage vortex generator 31. Compared with the direct open air intake of the first-stage vortex generator 31, the installation of the shroud 4 can effectively improve the intake uniformity of the first-stage vortex generator 31. At the same time, the size of the shroud 4 matches the first-stage vortex generator 31. After installing the shroud 4 on the first-stage vortex generator 31, the radial dimension of the flame tube will not be increased, and the mass of the flame tube will be increased by a small margin. This meets the design requirements of high fuel-air ratio and compact combustion chamber, while improving the intake uniformity of the first-stage vortex generator 31, and solving the design problems of combustion chamber performance and combustion stability of high power-to-weight ratio / thrust-to-weight ratio engines.

[0033] like Figure 1-4As shown, the air inlet includes a head air inlet 41 opened on the top of the fairing 4. The head air inlet 41 is circular, and the extension line of the axis of the first-stage vortex generator 31 passes through the center of the head air inlet 41.

[0034] In this embodiment, air is supplied to the shroud 4 through the head air inlet 41 opened at the top of the shroud 4. The axis of the first-stage vortex generator 31 passes through the center of the head air inlet 41. At the same time, the fuel nozzle 32 is coaxially arranged with the first-stage vortex generator 31, and the axis of the fuel nozzle 32 also passes through the center of the head air inlet 41, ensuring the uniformity of air intake at the head air inlet 41 and increasing the uniformity of air intake at the first-stage vortex generator 31.

[0035] like Figure 1-4 As shown, the air inlet also includes several side air inlets 42 that are equally spaced along the circumferential direction on the side of the fairing 4. The side air inlets 42 are inclined to the wall of the fairing 4, and the inclination direction is the same as that of the blades of the first-stage vortex generator 31. This is used to make the air entering the fairing 4 from the side air inlets 42 form a vortex in the fairing 4 with the same direction as the rotating jet in the first-stage vortex generator 31.

[0036] In this embodiment, the intake airflow is divided into two parts by the side air inlet 42 and the head air inlet 41, which can make the airflow entering the first-stage vortex 31 more uniform. At the same time, the airflow entering the shroud 4 from the side air inlet 42 will form a swirling flow inside the shroud 4. The direction of the swirling flow is the same as the direction of the rotating jet inside the first-stage vortex 31, so that the airflow inside the shroud 4 forms a uniform rotating flow in a unified direction, which can be more uniform when entering the first-stage vortex 31, further increasing the intake uniformity. The diversion of the flow by the side air inlet 42 and the formation of the swirling flow can both increase the intake uniformity of the first-stage vortex 31.

[0037] like Figure 3-4 As shown, the maximum distance between the side air inlet 42 and the bottom surface of the fairing 4 does not exceed the distance between the top surface of the air inlet area of ​​the first-stage vortex generator 31 and the bottom surface of the fairing 4.

[0038] In this embodiment, it is ensured that the airflow entering the shroud 4 from the side air inlet 42, after forming a vortex, can directly enter the first-stage vortex generator 31 together with the airflow entering the shroud 4 from the head air inlet 41, avoiding unnecessary movement in other directions and ensuring uniform air intake.

[0039] like Figure 4 As shown, the angle between the side air inlet 42 and the wall surface at the location on the surface of the fairing 4 is no greater than 30°.

[0040] In this embodiment, the smaller the angle between the side air inlet 42 and the wall of the shroud 4, the better the airflow adheres to the wall, and the easier it is to form a uniform vortex, which is more effective in improving the uniformity of air intake of the first-stage vortex generator 31.

[0041] like Figure 3-4 As shown, the fairing 4 consists of a top, a transition section 44, and a bottom from top to bottom. The diameter of the top is smaller than that of the bottom. The transition section 44 is arc-shaped to smoothly transition between the top and the bottom to accommodate airflow.

[0042] In this embodiment, the diameter of the head air inlet 41 needs to be smaller than the diameter of the first-stage vortex generator 31, but the shroud 4 needs to have space for gas flow. Therefore, the top dimension of the shroud 4 is smaller than the bottom dimension. While ensuring the size of the head air inlet 41, it is ensured that the inner cavity of the shroud 4 has enough space for air flow. When the air flows in the shroud 4, it will pass through the transition section 44. By setting the transition section 44 to be arc-shaped to adapt to the air flow, the disturbance of the air by the transition section 44 when the air flows from the top to the bottom of the shroud 4 is reduced.

[0043] like Figure 1-2 As shown, a secondary vortex 33 is fixedly installed between the primary vortex 31 and the cylinder 1. The primary vortex 31 and the fairing 4 are both fixedly installed on the side of the secondary vortex 33 away from the cylinder 1. The secondary vortex 33 is used to form a high-speed rotating jet and secondary mixing with fuel at a position closer to the inner cavity of the cylinder 1 than the primary vortex 31.

[0044] In this embodiment, a secondary vortex 33 is installed between the primary vortex 31 and the cylinder 1. The secondary vortex 33 is fixedly installed on the surface of the cylinder 1, while the primary vortex 31 is fixedly installed on the side of the secondary vortex 33 away from the cylinder 1. The fuel nozzle 32 passes through both the primary vortex 31 and the secondary vortex 33. The atomized fuel sprayed by the fuel nozzle 32 will first mix with the high-speed rotating jet generated by the primary vortex 31, and then mix with the high-speed rotating jet generated by the secondary vortex 33, thereby increasing the atomization effect of the fuel.

[0045] like Figure 1-2 As shown, a Venturi tube 5 is fixedly installed between the outlet of the first-stage vortex generator 31 and the outlet of the second-stage vortex generator 33, thereby increasing the distance between the high-speed rotating jets generated by the first-stage vortex generator 31 and the second-stage vortex generator 33 without increasing the distance between the first-stage vortex generator 31 and the second-stage vortex generator 33.

[0046] In this embodiment, the outlet end of the secondary vortex generator 33 is partially blocked by the venturi tube 5, so that the high-speed rotating jet generated by the primary vortex generator 31 can be fully mixed with the atomized fuel sprayed by the fuel nozzle 32 in the venturi tube 5 to form a mixture. The mixture is then mixed with the atomized fuel in the venturi tube 5 and then with the high-speed rotating jet generated by the secondary vortex generator 33, which improves the atomization effect of the fuel and the uniformity of the mixture. At the same time, the rectifier 4 is covered on the surface of the primary vortex generator 31, which makes the air intake of the primary vortex generator 31 more uniform, thereby increasing the uniformity of the fuel-air distribution in the venturi tube 5.

[0047] The blades of the secondary vortex generator 33 rotate in the opposite direction to those of the primary vortex generator 31. The high-speed rotating jet generated by the secondary vortex generator 33 impacts the air-fuel mixture, further increasing the fuel atomization effect.

[0048] A combustion chamber includes an anti-intake distortion flame tube, a housing 6 for mounting the cylinder body 1, and a diffuser 7 installed inside the housing 6. The head of the cylinder body 1 is mounted inside the housing 6 with the diffuser 7 facing it. The cylinder body 1 is connected to the tail end of the housing 6. The diffuser 7 delivers high-pressure air to the mixing unit. The high-pressure air passes through a primary vortex generator 31 and a secondary vortex generator 33 to form a rotating jet, which then mixes with atomized fuel sprayed from a fuel nozzle 32 to form a mixture. An ignition nozzle 8 is also installed inside the housing 6. The ignition end of the ignition nozzle 8 extends through the cylinder body 1 into the cylinder body 1 to ignite the mixture formed by the mixing unit.

[0049] 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 flame tube with anti-intake distortion, comprising an annular tube (1) and a mixing unit mounted on the tube (1), wherein the head of the tube (1) is provided with a plurality of openings (2) at equal intervals along the circumferential direction of the tube (1) for the mixed gas to enter the inner cavity of the tube (1), and a mixing unit for forming the mixed gas is installed at each opening (2) of the tube (1), characterized in that: The mixing unit includes a first-stage vortex generator (31) fixedly installed at the head of the cylinder (1) and a fuel nozzle (32) coaxially installed through the first-stage vortex generator (31) for delivering fuel into the cylinder (1). The first-stage vortex generator (31) is used to make the air entering the cylinder (1) from the outside pass through the first-stage vortex generator (31) to form a high-speed rotating jet, which mixes with the fuel sprayed out by the fuel nozzle (32) to form a mixed gas. A shroud (4) is installed on the cylinder (1) to cover the first-stage vortex generator (31). The air intake uniformity of the first-stage vortex generator (31) is controlled by the air intake port opened by the shroud (4). The size of the shroud (4) is matched with that of the first-stage vortex generator (31) to cover a single first-stage vortex generator (31). The air inlet includes a head air inlet (41) opened on the top of the fairing (4). The head air inlet (41) is circular, and the extension line of the axis of the first-stage vortex generator (31) passes through the center of the head air inlet (41). The air inlet also includes a number of side air inlets (42) evenly spaced along the circumferential direction on the side of the shroud (4). The side air inlets (42) are inclined to the wall of the shroud (4) and the inclination direction is the same as that of the blades of the first-stage vortex generator (31). This is used to make the air entering the shroud (4) from the side air inlets (42) form a vortex in the shroud (4) with the same direction as the rotating jet in the first-stage vortex generator (31).

2. The anti-intake distortion flame tube according to claim 1, characterized in that: The maximum distance between the side air inlet (42) and the bottom surface of the fairing (4) shall not exceed the distance between the top surface of the air intake area of ​​the first-stage vortex generator (31) and the bottom surface of the fairing (4).

3. The anti-intake distortion flame tube according to claim 1, characterized in that: The angle between the side air inlet (42) and the wall surface at the location of the opening on the surface of the fairing (4) is no greater than 30°.

4. The anti-intake distortion flame tube according to claim 1, characterized in that: The fairing (4) consists of a top, a transition section (44) and a bottom from top to bottom. The diameter of the top is smaller than that of the bottom. The transition section (44) is arc-shaped to smoothly transition between the top and the bottom to adapt to airflow.

5. The anti-intake distortion flame tube according to claim 1, characterized in that: A secondary vortex generator (33) is fixedly installed between the primary vortex generator (31) and the cylinder (1). The primary vortex generator (31) and the fairing (4) are both fixedly installed on the side of the secondary vortex generator (33) away from the cylinder (1). The secondary vortex generator (33) is used to form a high-speed rotating jet and secondary mixing with fuel at a position closer to the inner cavity of the cylinder (1) than the primary vortex generator (31).

6. The anti-intake distortion flame tube according to claim 5, characterized in that: A venturi tube (5) is fixedly installed between the outlet of the first-stage vortex (31) and the outlet of the second-stage vortex (33) to increase the distance between the high-speed rotating jets generated by the first-stage vortex (31) and the second-stage vortex (33) without increasing the distance between the first-stage vortex (31) and the second-stage vortex (33).

7. The anti-intake distortion flame tube according to claim 5, characterized in that: The blades of the secondary vortex generator (33) rotate in the opposite direction to those of the primary vortex generator (31).

8. A combustion chamber comprising an anti-intake distortion flame tube as described in any one of claims 1-7, characterized in that, Also includes: A casing (6) for mounting the cylinder (1) and a diffuser (7) installed inside the casing (6), wherein the head of the cylinder (1) is mounted inside the casing (6) with the diffuser (7) facing the head of the cylinder (1).

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