An asymmetric afterburner inner step ignition structure

Abstract

The present application belongs to the field of afterburner design, and is an asymmetric afterburner internal step ignition structure, comprising a cone, a support plate and an ignition nozzle; an annular step ignition zone is provided in the middle of the cone, and the step ignition zone comprises a first step zone, a transition zone and a second step zone. During the ignition process of the afterburner, the fuel passes through the fuel nozzle in the first step zone through the casing and the support plate into the interior of the step, and is ignited by the ignition nozzle located at the center of gravity of the first step zone. The oil-gas mixture is first ignited and burned in the first step zone. Since the step angle of the first step zone is 90°, it can produce an obvious sudden expansion effect on the airflow, thereby constructing a stable recirculation zone, and at the same time has excellent flame propagation characteristics. The flame quickly propagates to the transition zone and the second step zone. The setting of the transition zone can make the vortex formed in the first step zone during the flame transfer more stable and will not fall off, thereby realizing fast and reliable ignition of the afterburner.

Description

Technical Field

[0001] The present application belongs to the field of afterburner combustion chamber design, and in particular relates to an asymmetric afterburner inner step ignition structure. Background Art

[0002] In the afterburner, which is integrated with the turbine rear strut, the inner step formed by the inner cone is a key component for afterburner ignition and flame transmission. The inner step's primary function is to create a recirculation zone. After fuel is supplied to the combustion chamber and ignited, the fuel-air mixture is ignited by the high-energy ignition nozzle and burns stably within the inner step, ensuring reliable afterburner ignition.

[0003] As aircraft demand increasingly high radar stealth from their engines, so too does the need for radar stealth in the afterburner. The cone is one of the visible components of the afterburner from behind, and the inner steps placed on it must take radar stealth into account.

[0004] In the current solution, the inner step formed by the cone shape serves as the ignition zone. By supplying oil into the inner step and igniting through a high-energy ignition nozzle, ignition and combustion of the afterburner are achieved.

[0005] In the current integrated afterburner combustion chamber scheme, the inner step angle is 125 degrees. When the airflow flows through the inner step, this inner step structure has a good flow guidance effect, but the recirculation zone formed is small, the oil and gas matching effect is poor, and the combustion conditions are poor, resulting in the afterburner combustion chamber unable to achieve reliable ignition and difficulty in afterburner connection. Summary of the Invention

[0006] The purpose of this application is to provide an asymmetric afterburner inner step ignition structure to solve the problem in the prior art that the inner step angle on the cone is 125°, resulting in a smaller recirculation area.

[0007] The technical solution of the present application is: an asymmetric afterburner inner step ignition structure, comprising a cone, a support plate and an ignition nozzle, wherein an annular step ignition area is provided in the middle of the cone, and the step ignition area comprises a first step area, a transition area and a second step area, and the transition area is provided between the first step area and the second step area. There are two groups of transition areas and they are symmetrically arranged on both sides of the first step area, the step angle of the first step area is 90°, the step angle of the second step area is 125°, and the step angle of the transition area is between 90° and 125°. There are multiple groups of support plates and they are evenly arranged along the circumference of the cone, and the end of each group of support plates is provided with a fuel nozzle located at the inner step position, and the ignition nozzle is provided at the center position of the first step area.

[0008] Preferably, the first step area is located directly below the afterburner, and the second step area is located directly above the first step area.

[0009] Preferably, the first step area corresponds to three groups of support plates, and each group of transition areas corresponds to one group of support plates.

[0010] Preferably, the transition zone has a triangular structure.

[0011] The present application discloses an asymmetric afterburner inner step ignition structure, comprising a cone, a support plate and an ignition nozzle; a ring-shaped step ignition zone is provided in the middle of the cone, and the step ignition zone comprises a first step zone, a transition zone and a second step zone. During the ignition process of the afterburner, the fuel passes through the fuel nozzle in the first step zone through the casing and the support plate into the interior of the step, and is ignited by the ignition nozzle located at the center of gravity of the first step zone. The oil-gas mixture is first ignited and burned in the first step zone. Since the step angle of the first step zone is 90°, it can produce an obvious sudden expansion effect on the airflow, thereby constructing a stable recirculation zone, and at the same time has excellent flame propagation characteristics. The flame quickly propagates to the transition zone and the second step zone. The setting of the transition zone can make the vortex formed in the first step zone during the flame transfer more stable and will not fall off, thereby realizing fast and reliable ignition of the afterburner. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] In order to more clearly illustrate the technical solutions provided by this application, the following is a brief introduction to the accompanying drawings. Obviously, the accompanying drawings described below are only some embodiments of this application.

[0013] Figure 1 This is a schematic diagram of the overall structure of this application;

[0014] Figure 2 for Figure 1 Schematic diagram of the AA cross-section structure;

[0015] Figure 3 This is the airflow streamline diagram of the gas at different flow rates in the first step area of ​​this application;

[0016] Figure 4 This is the airflow streamline diagram of the gas at different flow rates in the second step area of ​​this application;

[0017] Figure 5 This is a schematic diagram of the structure of the cooperation between this application and the binary nozzle;

[0018] Figure 6 Axonometric view of the stepped ignition structure highlighting the transition zone for this application.

[0019] 1. Cone; 2. First step area; 3. Transition area; 4. Second step area; 5. Support plate; 6. Receiver; 7. Ignition nozzle; 8. Fuel nozzle; 9. Dual nozzle. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solutions and advantages of the implementation of this application clearer, the technical solutions in the embodiments of this application will be described in more detail below in conjunction with the drawings in the embodiments of this application.

[0021] An asymmetric afterburner inner step ignition structure, such as Figure 1-2 As shown, it includes a cone 1, a support plate 5 and an ignition nozzle 7. An annular step ignition zone is provided in the middle of the cone 1. The step ignition zone includes a first step zone 2, a transition zone 3 and a second step zone 4. The transition zone 3 is provided between the first step zone 2 and the second step zone 4. There are two groups of transition zones 3 and they are symmetrically arranged on both sides of the first step zone 2. The step angle of the first step zone 2 is 90°, the step angle of the second step zone 4 is 125°, and the step angle of the transition zone 3 is between 90° and 125°. There are multiple groups of support plates 5 and they are evenly arranged along the circumference of the cone 1. The end of each group of support plates 5 is provided with a fuel nozzle 8 located at the inner step position. The ignition nozzle 7 is located at the center of the first step zone 2.

[0022] During the ignition process of the afterburner, the fuel passes through the fuel nozzle 8 in the first step area 2, through the casing 6 and the support plate 5, and enters the interior of the step. It is ignited by the ignition nozzle 7 located at the center of gravity of the first step area 2. The oil-gas mixture is first ignited and burned in the first step area 2. Since the step angle of the first step area 2 is 90 degrees, it can produce a significant sudden expansion effect on the airflow, thereby constructing a stable recirculation area. Figure 3 As shown, it also has excellent flame propagation characteristics. The flame quickly propagates to the transition zone 3 and the second step zone 4. The setting of the transition zone 3 can make the vortex formed in the first step zone 2 more stable during the flame transmission process and will not fall off, so that the second step zone 4 can also form a stable vortex. Figure 4 As shown, rapid and reliable ignition of the afterburner is achieved.

[0023] Since the step angle of the first step area 2 is 90°, its radar stealth performance is poor. In order to solve this problem, preferably, the first step area 2 is located directly below the afterburner, and the second step area 4 is located directly above the first step area 2. Figure 5 As shown, when observing from the rearward direction of the engine, due to the obstruction of the dual nozzle 9, the radar reflection signal of the first step area 2 can be found only when the observation angle is within the range of θ. Since θ is relatively small and the angle θ is upward, it can completely avoid detection by ground radar. Only aircraft that are higher than the aircraft and within the angle range of θ can be detected, thereby avoiding detection by most radars. At the same time, even if the observation angle is within the range of θ, the radar stealth performance is weak only below the step, and the rest of the positions have efficient radar stealth performance.

[0024] Preferably, there are 18 groups of support plates 5, and the first step area 2 corresponds to three groups of support plates 5, and each group of transition areas 3 corresponds to one group of support plates 5, so that the second step area 4 still occupies most of the step ignition area. Since the second step area 4 has a larger step angle, its continuous flame performance is better. Therefore, after the ignition of the first step area 2 is completed, the excellent continuous flame performance of the second step area 4 can make the flame spread to the second step area 4, and then quickly spread to all areas of the second step area 4, thereby realizing rapid ignition of the entire step ignition area.

[0025] Combine Figure 6 Preferably, the transition zone 3 has a triangular structure and occupies a small area, ensuring that the oil-gas mixture can quickly flow into the second step zone 4 through the first step zone 2; of course, other shapes can also be set, such as square, rectangular, etc., and adjusted according to actual usage requirements.

[0026] During the flame propagation in the step ignition zone, the faster the internal gas flows, the faster the flame propagates. At this time, if the step angle changes rapidly, it is easy to cause the vortex to fall off when the flame propagates in the first step zone 2, resulting in the inability to form a recirculation zone in the second step zone 4.

[0027] For different aircraft engines, the area of ​​the transition zone 3 occupied by the concave cavity can be variable. For aircraft engines with a higher internal gas flow rate, a larger transition zone 3 is set to occupy the concave cavity area; for aircraft engines with a lower internal gas flow rate, a smaller transition zone 3 is set to occupy the concave cavity area, thereby ensuring that the vortex will not fall off during the flame propagation process.

[0028] The step angle in the second step area 4 is variable and can be adjusted according to different step combustion characteristics and radar stealth characteristics requirements, such as being modified to 120° or 130°.

[0029] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

Claims

1. An asymmetric afterburner inner step ignition structure, characterized by: The invention comprises a cone (1), a support plate (5) and an ignition nozzle (7). The cone (1) is provided with an annular step ignition zone in the middle, and the step ignition zone comprises a first step zone (2), a transition zone (3) and a second step zone (4). The transition zone (3) is provided between the first step zone (2) and the second step zone (4). There are two groups of transition zones (3) and they are symmetrically arranged on both sides of the first step zone (2). The step angle of the first step zone (2) is 90°, the step angle of the second step zone (4) is 125°, and the step angle of the transition zone (3) is between 90° and 125°. There are multiple groups of support plates (5) and they are evenly arranged along the circumference of the cone (1). The end of each group of support plates (5) is provided with a fuel nozzle (8) located at the inner step position. The ignition nozzle (7) is provided at the center of the first step zone (2).

2. The asymmetric afterburner inner step ignition structure according to claim 1, characterized in that: The first step area (2) is located directly below the afterburner, and the second step area (4) is located directly above the first step area (2).

3. The asymmetric afterburner inner step ignition structure according to claim 1, characterized in that: The first step area (2) is provided corresponding to three groups of support plates (5), and each group of transition areas (3) is provided corresponding to one group of support plates (5).

4. The asymmetric afterburner inner step ignition structure according to claim 1, characterized in that: The transition zone (3) has a triangular structure.

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