A radial flame transfer integrated afterburner with a small outer annulus exit area

Abstract

This application belongs to the field of aero-engine design and manufacturing, and particularly relates to a radial flame transmission integrated afterburner with a small outer bypass exit area, including: a confluence ring, an inner cone, an outer diffuser wall, and a radial stabilizer; the outer wall of the confluence ring and the outer diffuser wall form an outer bypass channel, and a shock-absorbing and heat-insulating screen is provided at the exit of the outer bypass channel; the inner wall of the confluence ring and the inner cone form an inner bypass channel; the confluence ring gradually expands along the airflow direction; a plurality of circumferentially distributed radial stabilizers are installed at the tail end of the confluence ring, the root of the radial stabilizer is connected to the inner wall of the confluence ring, and the tip of the radial stabilizer points to the center line of the confluence ring; the radial stabilizer has a cavity, and a reheat spray bar is installed in the cavity, and the nozzle of the reheat spray bar is installed on the side wall of the radial stabilizer. The entire flame stabilization system of this application is completely arranged in the inner bypass airflow, which can make full use of the favorable condition of the high temperature of the inner bypass airflow and ensure the afterburning combustion efficiency and performance.

Description

Technical Field

[0001] This application belongs to the field of aero-engine design and manufacturing, and particularly relates to a radial flame transmission integrated afterburner with a small outer bypass exit area. Background Art

[0002] In order to achieve high performance, turbofan engines have put forward higher requirements for indicators such as the total pressure recovery coefficient, total excess air coefficient, and diffuser section length of the afterburner. Therefore, an integrated design of mixing and diffusing and combustion organization is adopted in the afterburner design. The afterburner with an integrated design of mixing and diffusing and combustion organization of a certain type of engine is as Figure 1 shown.

[0003] According to the requirements of the overall engine matching and the cooling of the afterburner and nozzle, etc., it is necessary to greatly reduce the outer bypass area on the basis of the integrated scheme of mixing and diffusing and combustion organization, which will bring the problem of overheating and ablation of the anti-vibration and heat insulation screen after the outer zone nozzle supplies fuel. After canceling the fuel supply of the outer zone nozzle to avoid overheating and ablation of the heat insulation screen, it will cause the problem that the afterburning performance does not meet the standard.

[0004] Therefore, it is necessary to propose a new form of afterburner, which can not only meet the requirements of a small outer bypass area, but also achieve the required afterburning performance, and at the same time ensure the structural reliability.

[0005] The traditional afterburner with an integrated design of mixing and diffusing and combustion organization uses an outer ring stabilizer for ignition duty. The outside of this ring stabilizer is the outer bypass area related to the overall engine performance matching. Since there is a high-temperature flame behind the ring stabilizer that plays the duty role, it cannot be too close to the anti-vibration and heat insulation screen, and there is a limit on the minimum distance between the two. This limit results in the outer bypass area being much larger than the overall engine demand, causing the outer-inner bypass pressure ratio to be low and the cold air pressure to be insufficient, which is not conducive to the cooling of the anti-vibration and heat insulation screen and nozzle behind the afterburner. Previously, attempts were made to continuously break through the limit of the minimum distance between the stabilizer and the heat insulation screen to achieve the purpose of reducing the outer bypass area, but the problem of overheating and ablation of the anti-vibration and heat insulation screen brought about the inability to supply fuel to the outer bypass, resulting in the afterburning performance not meeting the standard. That is to say, the existing technical solutions of the afterburner have an irreconcilable contradiction between the overall matching and performance requirements and the cooling reliability of the afterburner, and can neither meet the requirements of a small outer bypass area, nor achieve the required afterburning performance, and at the same time cannot meet the actual needs of the engine to ensure the structural reliability. Summary of the Invention

[0006] In order to solve the above problems, this application provides a radial flame transmission integrated afterburner with a small outer bypass exit area, including:

[0007] A confluence ring, an inner cone, an outer diffuser wall, a radial stabilizer;

[0008] The outer wall of the confluence ring and the outer wall of the diffuser form an outer flow passage, and a shock-proof and heat-insulating screen is provided at the outlet of the outer flow passage; the inner wall of the confluence ring and the inner cone form an inner flow passage; the confluence ring gradually expands along the air flow direction;

[0009] A plurality of circumferentially distributed radial stabilizers are installed at the tail end of the confluence ring. The root of the radial stabilizer is connected to the inner wall of the confluence ring, and the tip of the radial stabilizer points to the center line of the confluence ring;

[0010] The radial stabilizer has a cavity, and a reheat spray bar is installed in the cavity. The nozzle of the reheat spray bar is installed on the side wall of the radial stabilizer.

[0011] Preferably, the root of the radial stabilizer has a first through hole connecting the outer flow passage and the cavity, and the trailing edge of the radial stabilizer has a plurality of second through holes connecting the cavity and the end of the inner flow passage.

[0012] Preferably, an annular flame transfer groove is connected between adjacent two radial stabilizers. The annular flame transfer groove has a notch facing backward; the notch connects the cavities of adjacent two radial stabilizers.

[0013] Preferably, the plurality of second through holes are evenly distributed along the trailing edge of the radial stabilizer.

[0014] Preferably, the root of the reheat spray bar is connected to a reheat main pipe, and the reheat main pipe is placed on the outer wall surface of the confluence ring.

[0015] Preferably, an outer zone nozzle is installed on the outer wall of the diffuser. The outer zone nozzle passes through the outer flow passage and extends into the cavity of the radial stabilizer.

[0016] Preferably, the cross section of the notch of the annular flame transfer groove includes a V shape or a U shape.

[0017] Preferably, the end of the outer flow passage is a slit passage with the smallest cross-sectional area formed between the end of the confluence ring and the outer wall of the diffuser; the front end of the shock-proof and heat-insulating screen is placed in the slit passage.

[0018] Preferably, the width of the radial stabilizer gradually decreases from the root to the tip.

[0019] Preferably, the radial stabilizers are divided into long stabilizers and short stabilizers according to their lengths, and the long stabilizers and the short stabilizers are circumferentially staggered.

[0020] The advantages of this application include:

[0021] 1: The flow path area formed by the confluence ring that expands significantly outward and the outer wall of the diffuser gradually decreases for the outer flow, which can reduce the air flow loss;

[0022] 2: The slit channel on the outer side of the trailing edge of the confluence ring can guide the outer bypass airflow to form a curtain, which can effectively prevent the high-temperature airflow behind the stabilizer from approaching the vibration-proof and heat-insulating screen, causing ablation of the vibration-proof and heat-insulating screen.

[0023] 3: The radial stabilizer of the present application avoids the situation of high-temperature ablation of the vibration-proof and heat-insulating screen. Therefore, it can adjust the height of the slit channel on the outer side of the trailing edge of the confluence ring to achieve the aerodynamic matching area required by the overall engine.

[0024] 4: Multiple radially arranged stabilizers and annular flame transfer grooves are arranged as required. They are arranged on the cross-section of the trailing edge of the confluence ring to form a "ring + radial" combined flame stabilization system for afterburning ignition, duty, flame transfer, and flame stabilization.

[0025] 5: The entire flame stabilization system is completely arranged in the core airflow, which can make full use of the favorable condition of the high temperature of the core airflow and ensure the afterburning combustion efficiency and performance.

[0026] 6: The flame stabilization system maintains a sufficient safety distance from the vibration-proof and heat-insulating screen, which can effectively reduce the heat load of the vibration-proof and heat-insulating screen. At the same time, it will provide favorable cold air conditions for the rear components and ensure the structural reliability. Brief Description of the Drawings

[0027] Figure 1 is a schematic diagram of the structure of a traditional afterburner;

[0028] Figure 2 is a schematic diagram of the structure of the afterburner of a preferred embodiment of the present application;

[0029] Figure 3 is a schematic diagram of the structure of the confluence ring of a preferred embodiment of the present application;

[0030] Figure 4 is a schematic diagram of the airflow distribution in the afterburner of a preferred embodiment of the present application. Detailed Description of the Embodiment

[0031] To make the purpose, technical solutions, and advantages of the implementation of the present application clearer, the technical solutions in the embodiments of the present application will be described in more detail below with reference to the drawings in the embodiments of the present application. In the drawings, the same or similar reference numerals denote the same or similar elements or elements with the same or similar functions throughout. The described embodiments are some, but not all, of the embodiments of the present application. The embodiments described below with reference to the drawings are exemplary and are intended to explain the present application and should not be construed as limiting the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present application. The embodiments of the present application will be described in detail below with reference to the drawings.

[0032] To solve the above problems, the present application provides a radial flame transmission integrated afterburner with a small outer annulus exit area, as Figure 2 shown, which includes:

[0033] A confluence ring 2, an inner cone 3, an outer diffuser wall 1, and a radial stabilizer 4;

[0034] Confluence ring 2: It has an expanding spatial curved surface shape, as Figure 3 shown; the confluence ring is the boundary between the outer and inner annulus airflows. The outer wall surface of the confluence ring is the inner boundary of the outer annulus channel. Its outwardly expanding surface cooperates with the outer diffuser wall to form an outer annulus channel with a gradually decreasing flow path, which can reduce the airflow loss; a small slit channel is formed between the trailing edge of the confluence ring and the vibration-proof heat-insulating screen, and part of the airflow passes through it, which can isolate the high-temperature gas for the vibration-proof heat-insulating screen. At the mixing section at the trailing edge of the confluence ring, the inner and outer annulus airflows start to mix, and the confluence ring and the vibration-proof heat-insulating screen together achieve the aerodynamic area required by the overall engine. The inner side of the confluence ring wall surface is the outer boundary of the inner annulus channel. Its inner wall surface expands outward along the streamline and together with the inner cone 3 forms a diffuser flow path, which is responsible for diffusing and decelerating the high-speed airflow at the inner annulus inlet.

[0035] Inner cone 3: It is fixed to the turbine rear casing component and serves as the inner surface of the diffuser flow path for the inner annulus channel airflow.

[0036] Radial stabilizer 4: Multiple radial stabilizers are arranged according to the requirement of the aerodynamic blockage ratio, and they are evenly distributed at the trailing edge of the confluence ring, that is, at the mixing section of the inner and outer annulus airflows, in the circumferential direction; the radial stabilizer 4 has a cavity, and a fuel injection rod 6 is installed in the cavity. The nozzle of the fuel injection rod 6 is installed on the side wall of the radial stabilizer 4 for injecting fuel into the airflow; the root of the radial stabilizer 4 has a first through hole connecting the outer annulus channel and the cavity, and the trailing edge of the radial stabilizer 4 has multiple second through holes connecting the cavity and the end of the inner annulus channel, and the multiple second through holes are evenly distributed along the trailing edge of the radial stabilizer 4; cold air from the outer annulus is introduced into the inner cavity of the radial stabilizer to cool the fuel injection rod, the flame transmission groove, and itself. The radial stabilizer 4 and the flame transmission groove 5 together form a "ring + radial" combined flame stabilization system to organize combustion in the recirculation zone of the radial stabilizer 4 and the flame transmission groove 5. The radial stabilizer mainly plays the roles of ignition, standby, and flame stabilization; the width of the radial stabilizer 4 gradually decreases from the root to the tip, and the radial stabilizer 4 is divided into long stabilizers and short stabilizers according to its length, and the long stabilizers and short stabilizers are staggered in the circumferential direction.

[0037] Flame transfer slot 5: The flame transfer slot 5 is installed between two adjacent radial stabilizers 4. The annular flame transfer slot 5 has a rearward-facing slot; the slot communicates with the cavities of two adjacent radial stabilizers 4. The rear end of the flame transfer slot 5 and the trailing edge of the radial stabilizer 4 are in the same cross-section. The slot cross-section of the annular flame transfer slot 5 includes a V-shaped or U-shaped one, which together with the radial stabilizer 4 forms a "ring + radial" combined flame stabilization system, organizing combustion in the recirculation zones of the radial stabilizer 4 and the flame transfer slot 5. The flame transfer slot mainly plays the roles of flame transfer, flame linking, and flame stabilization. The flame transfer slot is completely arranged in the core flow and maintains a sufficient safety distance from the vibration-proof and heat-insulating screen.

[0038] Vibration-proof and heat-insulating screen 8: The end of the outer annulus passage is a narrow slit passage with the smallest cross-sectional area formed between the end of the confluence ring 2 and the outer wall 1 of the diffuser; the front end of the vibration-proof and heat-insulating screen 8 is placed in the narrow slit passage. The vibration-proof and heat-insulating screen 8 is a large porous part, arranged inside the outer wall of the diffuser, mainly for cooling and heat insulation of the outer wall casing, and at the same time has the function of suppressing oscillatory combustion.

[0039] Among them, an outer region nozzle 9 is installed on the outer wall 1 of the diffuser, and the outer region nozzle 9 extends through the outer annulus passage into the cavity of the radial stabilizer 4.

[0040] The afterburner with an integrated radial flame transfer design has a significantly different aerodynamic form from the traditional afterburner, and the airflow distribution in the afterburner also changes significantly. As Figure 4 shown, specifically:

[0041] The outer annulus airflow will be mainly divided into three major parts, namely airflow ①, airflow ②, and airflow ③, which enter the cooling passage between the vibration-proof and heat-insulating screen 8 and the outer wall 1 of the diffuser, the narrow slit passage formed between the vibration-proof and heat-insulating screen 8 and the confluence ring 2, and the inside of the radial stabilizer respectively. Airflow ②, airflow ③, and part of airflow ① will mix with the core airflow ④ behind the stabilizer and participate in combustion.

[0042] A plurality of circumferentially distributed radial stabilizers 4 are installed at the trailing end of the confluence ring 2. The root of the radial stabilizer is connected to the inner wall of the confluence ring 2, and the tip of the radial stabilizer points to the center line of the confluence ring 2;

[0043] The radial stabilizer 4 has a cavity, and a fuel injection lance 6 is installed in the cavity. The nozzle of the fuel injection lance 6 is installed on the side wall of the radial stabilizer 4.

[0044] In summary, in view of the current situation that the existing mixed-compression and combustion-organizing afterburner cannot simultaneously meet the requirements of the overall engine for the bypass area, afterburning performance, and reliability, the present application proposes a radial flame-transfer integrated afterburner scheme that can significantly reduce the bypass area. First, a compression flow path formed by an outward-expanding confluence ring and an inner cone is used to compress and decelerate the high-speed airflow at the core inlet. When the airflow velocity decreases to a range suitable for combustion organization, a certain number of radially arranged stabilizers evenly distributed in the circumferential direction are arranged as needed in the flow path, and an oil injection rod is arranged in cooperation with them. Annular flame-transfer grooves are arranged at appropriate radial positions between the stabilizers. Two airflows from the outer and inner cores will be mixed, fuel-injected, combusted, and finally compressed simultaneously at the mixing section.

[0045] For this radial flame-transfer integrated afterburner scheme, the trailing edge of the outward-expanding confluence ring is used to achieve the bypass area required by the overall engine. The radially arranged stabilizers are used as the duty structure for combustion ignition organization, and the flame-transfer grooves between the radially arranged stabilizers completely arranged in the core airflow are used to achieve circumferential flame transfer, which can avoid the problem of the high-temperature zone brought by the annular stabilizer being too close to the heat insulation screen. This afterburner scheme can reduce the bypass area by 50% and increase the outer-to-inner core pressure ratio by 4% while ensuring the performance indicators of the afterburner. On the basis of meeting the overall performance matching requirements, it can also improve the cooling conditions of the high-temperature parts of the afterburner vibration-proof heat insulation screen and nozzle components.

[0046] The above is only the specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed in the present application should be covered by the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claimed rights.

Claims

1. A radial flame transmission integrated afterburner with a small outer annulus exit area, characterized in that, Comprising: A confluence ring (2), an inner cone (3), an outer diffuser wall (1), and a radial stabilizer (4); The outer wall of the confluence ring (2) and the outer diffuser wall (1) form an outer duct passage, and an anti-vibration and heat insulation screen is provided at the outlet of the outer duct passage; the inner wall of the confluence ring (2) and the inner cone (3) form an inner duct passage; the confluence ring (2) gradually expands along the air flow direction; A plurality of circumferentially distributed radial stabilizers (4) are installed at the tail end of the confluence ring (2), the root of the radial stabilizer is connected to the inner wall of the confluence ring (2), and the tip of the radial stabilizer points to the center line of the confluence ring (2); The radial stabilizer (4) has a cavity, and a reheat lance (6) is installed in the cavity, and the nozzle of the reheat lance (6) is installed on the side wall of the radial stabilizer (4); The root of the radial stabilizer (4) has a first through hole connecting the outer duct passage and the cavity, and the trailing edge of the radial stabilizer (4) has a plurality of second through holes connecting the cavity and the end of the inner duct passage; an annular flame transfer groove (5) is connected between two adjacent radial stabilizers (4), and the annular flame transfer groove (5) has a slot facing backward; the slot connects the cavities of two adjacent radial stabilizers (4).

2. The radially integrated afterburner with a small outer duct exit area as claimed in claim 1, wherein A plurality of the second through holes are uniformly distributed along the trailing edge of the radial stabilizer (4).

3. The radial flame transfer integrated afterburner with a small outer annulus exit area as claimed in claim 1, wherein The root of the reheat lance (6) is connected to a reheat main pipe (7), and the reheat main pipe (7) is placed on the outer wall surface of the confluence ring (2).

4. The radially flame-transporting integrated afterburner with a small outer annulus exit area according to claim 1, characterized in that, An outer zone nozzle (9) is installed on the outer diffuser wall (1), and the outer zone nozzle (9) passes through the outer duct passage and extends into the cavity of the radial stabilizer (4).

5. The radial flame transfer integrated afterburner with a small outer duct outlet area as claimed in claim 1, characterized in that: The cross section of the slot of the annular flame transfer groove (5) includes a V shape or a U shape.

6. The radially flame-transporting integrated afterburner with a small outer annulus exit area as claimed in claim 1, wherein The end of the outer duct passage is a slit passage with the smallest cross-sectional area formed between the end of the confluence ring (2) and the outer diffuser wall (1); the front end of the anti-vibration and heat insulation screen (8) is placed in the slit passage.

7. The radial flame transfer integrated afterburner with a small outer duct outlet area as claimed in claim 1, characterized in that: The width of the radial stabilizer (4) gradually decreases from the root to the tip.

8. The radially flame-transporting integrated afterburner with a small outer annulus exit area according to claim 1, wherein The radial stabilizers (4) are divided into long stabilizers and short stabilizers according to their lengths, and the long stabilizers and the short stabilizers are distributed alternately in the circumferential direction.

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