Combustion stabilizing device and combustion stabilizing method for enhancing mixing of supersonic combustion chamber

Abstract

The invention discloses a mixing-enhanced combustion stabilizing device and method for a supersonic combustion chamber, and belongs to the technical field of combustion stabilizing of combustion chambers. A mixing-enhanced stable combustion device for a supersonic combustion chamber comprises a wedge-shaped supporting plate, the supporting plate is located in an expansion section and located on the axis of the expansion section, an oil spraying structure for spraying oil into the expansion section is arranged at the end, close to the air inlet end of the expansion section, of the supporting plate, turbulent flow fins are arranged on the side wall of the other end of the supporting plate, and a low-speed backflow area is formed at the tail end of the supporting plate. A wavy surface is arranged on the side wall of the support plate and is positioned between the oil injection structure and the turbulent flow fins; the supporting plate is connected with the expansion section through a mounting seat, and an igniter mounting hole is formed in the mounting seat and located in the downstream of the tail end of the supporting plate. By the adoption of the mixing-enhanced combustion stabilizing device and method for the supersonic combustion chamber, the problems that an existing device is poor in fuel and air mixing effect, and stable ignition and combustion of the combustion chamber are affected can be solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of combustion chamber stable combustion, and particularly relates to a stable combustion device and a stable combustion method for supersonic combustion chamber mixing enhancement. BACKGROUND

[0002] The super-aero ramjet engine is the best choice for realizing high-altitude supersonic flight at present. The hypersonic vehicle powered by the super-aero ramjet engine has a speed of more than 2 kilometers per second, has the ability of instant penetration and destruction, and has important value in terms of earth orbit transportation and improving the air defense capability in the near space. Therefore, the super-aero ramjet engine is the hotspot of the current aerospace research and competition of various countries. The combustion chamber is a key technical component of the super-aero ramjet engine and is also the main source of power in the engine. Whether the combustion chamber can work efficiently directly relates to whether the ramjet engine can realize high-performance operation, and ensuring efficient fuel mixing will directly affect the combustion efficiency of the combustion chamber. Especially when liquid hydrocarbon kerosene is used as fuel, the fuel must first undergo the stages of atomization and mixing before combustion, which brings great difficulties to the uniformity of fuel mixing and the stability of ignition.

[0003] The injection mixing method of supersonic combustion fuel mainly includes active method and passive method. In the active method, the mixing of fuel is enhanced by excitation of the main flow. The application of this method requires large changes to the engine, and various modifications and details are considered, which is high in cost. Common passive methods include step injection, cavity injection, hole injection, film injection, slope injection and strut injection, etc. However, the mixing effect of fuel and air is poor only by the way of injection excitation, which affects the stable and uniform combustion of the combustor. SUMMARY

[0004] The purpose of the present application is to provide a stable combustion device and a stable combustion method for supersonic combustion chamber mixing enhancement, which solves the problem of poor mixing effect of fuel and air in the existing device, affecting the stable ignition and combustion of the combustion chamber.

[0005] To achieve the above purpose, the present application provides a stable combustion device for supersonic combustion chamber mixing enhancement, which comprises a wedge-shaped strut plate, the strut plate is located in the expansion section and on the axis of the expansion section, an oil injection structure for injecting oil into the expansion section is arranged on one end of the strut plate close to the inlet end of the expansion section, a spoiler fin is arranged on the other end of the strut plate, a low-speed backflow zone is formed at the tail end of the strut plate, a corrugated surface is arranged on the side wall of the strut plate, and the corrugated surface is located between the oil injection structure and the spoiler fin; the strut plate is connected with the expansion section through a mounting seat, an igniter mounting hole is arranged on the mounting seat, and the igniter mounting hole is located downstream of the tail end of the strut plate.

[0006] Preferably, the fuel injection structure comprises a fuel channel arranged inside the support plate, and a plurality of fuel injection holes arranged uniformly on the side wall of the support plate and communicated with the fuel channel, fuel being injected into the expansion section through the fuel channel and the fuel injection holes.

[0007] Preferably, the spoiler fin comprises a first spoiler fin arranged on one side of the tail end of the support plate and a second spoiler fin arranged on the other side of the tail end of the support plate, and the first spoiler fin is arranged spaced apart from the second spoiler fin.

[0008] Preferably, the first spoiler fin and the second spoiler fin are of identical structure and are both of obtuse triangle structure, the thickness of the first spoiler fin and the second spoiler fin is 7-9 mm, the length of the connecting edge of the first spoiler fin and the second spoiler fin connecting with the support plate is 73-78 mm, the distance from the vertex of the tail edge of the tail end of the first spoiler fin and the second spoiler fin to the connecting edge is 8-12 mm, and the obtuse angle between the connecting edge and the tail edge is 150-155°.

[0009] Preferably, the wave surface is symmetrically distributed on both sides of the axis of the expansion section, and the wave surface comprises a plurality of wave units arranged in linear array around the wedge surface of the support plate and connected in series, each wave unit comprising a first straight line segment, a second straight line segment and a third straight line segment, the first straight line segment and the second straight line segment being connected through the third straight line segment, the first straight line segment and the third straight line segment being smoothly connected through a first circular arc, and the second straight line segment and the third straight line segment being smoothly connected through a second circular arc.

[0010] Preferably, the radius of the first circular arc is 1-2 mm, the radius of the second circular arc is 2-4 mm, the angle between the first straight line segment and the wedge surface of the support plate is 4-6°, the angle between the second straight line segment and the wedge surface of the support plate is 4-6°, and the angle between the third straight line segment and the wedge surface of the support plate is 30-40°.

[0011] Preferably, the angle between the wedge surfaces of the support plate is not greater than the angle between the side surfaces of the expansion section, and the expansion ratio of the expansion section is 1.5.

[0012] Preferably, the upstream of the expansion section is connected with the isolation section of the scramjet engine, the downstream of the expansion section is connected with the equal-area section of the combustion chamber, the top of the expansion section is provided with a plurality of fuel grooves, the fuel grooves are provided with a plurality of fuel injection holes, the fuel injection holes are located on both sides of the support plate, and fuel is injected into the expansion section through the fuel injection holes.

[0013] Preferably, the bottom of the expansion section is provided with a mounting hole for placing a mounting seat, and the expansion section is provided with a standby mounting hole for mounting a standby igniter, the standby mounting hole being located downstream of the igniter mounting hole.

[0014] The stable combustion method based on the above-mentioned stable combustion device for enhancing mixing of supersonic combustion chamber comprises the following steps:

[0015] S1, fuel is sprayed into the expansion section through the fuel passage and the fuel injection hole on the branch plate, the fuel is broken, atomized and evaporated under the action of supersonic airflow, the wave surface on both sides of the branch plate destroys the shear layer of the airflow to improve the air-fuel mixing effect, the air-fuel mixture is mixed and diffused under the vortex induced by the first spoiler fin and the second spoiler fin, and a low-speed backflow area is formed at the tail of the branch plate, is ignited by an igniter, and a self-sustaining value service flame is formed, without additional oxygen supplement;

[0016] S2, the fuel is sprayed into the combustion chamber through the fuel injection hole of the expansion section, the fuel is ignited by the diffused value service flame, a global flame is formed, and combustion is performed.

[0017] The advantages and positive effects of the supersonic combustion chamber mixing-enhanced stable combustion device and stable combustion method are as follows:

[0018] 1. The branch plate is arranged in the expansion section of the combustion chamber, the wave surface is arranged on the wedge surface of the branch plate, the wave surface is used for destroying the shear layer of the air-fuel mixture, so that the fuel and air are fully mixed, and the speed of the mixture is reduced, which is beneficial to subsequent stable ignition and stable combustion.

[0019] 2. The spoiler fin is arranged at the tail end of the branch plate, the first spoiler fin and the second spoiler fin arranged in a staggered manner enhance the mixing of the fuel and the air, and generate vortexes diffusing to the main flow, so that a low-speed backflow area is formed between the first spoiler fin and the second spoiler fin at the tail end of the branch plate, the ignition is facilitated, and additional oxygen supplement is not needed; and stable combustion of the combustion chamber is facilitated.

[0020] The technical solutions of the present application will be further described in detail below with reference to the drawings and examples. DRAWINGS

[0021] Figure 1 It is a three-dimensional structure schematic diagram of the embodiment of the present application;

[0022] Figure 2 It is a cross-sectional structure schematic diagram of the embodiment of the present application;

[0023] Figure 3 It is a three-dimensional structure schematic diagram of the branch plate of the embodiment of the present application;

[0024] Figure 4 It is a front view structure schematic diagram of the branch plate of the embodiment of the present application;

[0025] Figure 5 It is a top view structure schematic diagram of the branch plate of the embodiment of the present application;

[0026] Figure 6 It is a cross-sectional structure schematic diagram of the branch plate of the embodiment of the present application;

[0027] Figure 7 Fig. 2 is a side view of the support plate of the embodiment of the present application;

[0028] Figure 8 Fig. 3 is a schematic view of the wavy surface structure of the embodiment of the present application;

[0029] Figure 9 Fig. 4 is a schematic view of the spoiler fin structure of the embodiment of the present application;

[0030] Figure 10 Fig. 5 is a schematic view of the expansion section of the embodiment of the present application.

[0031] Reference signs

[0032] 1, support plate; 2, mounting seat; 3, oil injection hole; 4, first spoiler fin; 5, second spoiler fin; 6, wavy surface; 7, fuel passage; 8, igniter mounting hole; 9, first straight section; 10, second straight section; 11, third straight section; 12, connecting edge; 13, tail edge; 14, expansion section; 15, isolation section; 16, equal-area section; 17, fuel groove; 18, fuel injection hole; 19, spare mounting hole. DETAILED DESCRIPTION

[0033] In the description of the present application, it should be noted that the terms "upper", "lower", "inner", "outer", and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the present application is usually placed, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. In the description of the present application, it should also be noted that, unless otherwise explicitly specified and limited, the terms "provided", "mounted", "connected" should be understood broadly, for example, can be fixedly connected, can be detachably connected, or integrally connected; can be mechanically connected, or electrically connected; can be directly connected, or indirectly connected through an intermediate medium, or can be connected inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0034] In the present application, unless otherwise defined, all technical and scientific terms used herein have the same meaning as understood by those skilled in the art to which the present application belongs. If there is any inconsistency, the meaning described in the specification or derived from the content described in the specification shall prevail. In addition, the terms used herein are only for the purpose of describing the embodiments of the present application and are not intended to limit the present application.

[0035] The embodiments of the present application will be described in detail below with reference to the accompanying drawings. The embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0036] As Figure 1 , Figure 2 shown, a supersonic combustion chamber mixing-enhanced flame-holding device includes a wedge-shaped support plate 1 fixed on a mounting seat 2. The bottom of the expansion section 14 is provided with a mounting hole for placing the mounting seat 2, and the mounting seat 2 is fixedly connected with the expansion section 14 by screws and sealing pads. The support plate 1 is inserted into the expansion section 14 under the action of the mounting seat 2. The top end of the support plate 1 is in close contact with the inner wall of the top of the expansion section 14, so that the supersonic airflow in the expansion section 14 only passes through the two sides of the support plate 1. The included angle between the wedge surfaces of the support plate 1 is not greater than the included angle of the side surface of the expansion section 14, which is to ensure that the flow area of the combustion chamber expansion section 14 is not lower than the flow area of the isolation section 15 to suppress the tendency of the combustion chamber not to start. The expansion ratio of the expansion section 14 is 1.5, and the flow area in the combustion chamber reaches the maximum value at the end of the expansion section 14.

[0037] As Figures 3-7 shown, the support plate 1 is located in the expansion section 14 and on the axis of the expansion section 14, and the wedge surfaces of the support plate 1 are symmetrically distributed on both sides of the axis of the expansion section 14. An oil injection structure for injecting oil into the expansion section 14 is arranged on one end of the support plate 1 close to the inlet end of the expansion section 14. The oil injection structure includes a fuel channel 7 arranged inside the support plate 1, and the fuel channel 7 is located on the axis of the expansion section 14. A plurality of oil injection holes 3 in communication with the fuel channel 7 are uniformly arranged on the side wall of the support plate 1, and the oil injection holes 3 are symmetrically distributed on the wedge side wall of the support plate 1. Fuel is injected into the expansion section 14 through the fuel channel 7 and the oil injection holes 3. The fuel injected from the oil injection holes 3 on the support plate 1 is ignited by an igniter to form a pilot flame.

[0038] A turbulence fin is arranged on the side wall of the other end of the support plate 1, which improves the disturbance of fuel and air, thereby improving the mixing effect and generating vortex diffusion to the main flow. Under the action of the turbulence fin, a low-speed backflow area is formed at the tail end of the support plate 1, which is convenient for ignition by the igniter. The turbulence fin includes a first turbulence fin 4 arranged on one side of the tail end of the support plate 1 and a second turbulence fin 5 arranged on the other side of the tail end of the support plate 1, and the first turbulence fin 4 and the second turbulence fin 5 are arranged at intervals.

[0039] The first turbulence fin 4 and the second turbulence fin 5 are of the same structure and are both obtuse triangle structures. The thickness of the first turbulence fin 4 and the second turbulence fin 5 is 7mm-9mm, the length of the connecting edge 12 connecting the first turbulence fin 4 and the second turbulence fin 5 with the support plate 1 is 73mm-78mm, the distance from the top point of the tail edge 13 at the tail end of the first turbulence fin 4 and the second turbulence fin 5 to the connecting edge 12 is 8mm-12mm, and the obtuse angle between the connecting edge 12 and the tail edge 13 is 150°-155°.

[0040] In this embodiment, the thickness of the first spoiler fin 4 and the second spoiler fin 5 is 8 mm, the length of the connecting edge 12 of the first spoiler fin 4 and the second spoiler fin 5 connected to the branch plate 1 is 75.1 mm, the distance from the top point of the tail edge 13 of the tail end of the first spoiler fin 4 and the second spoiler fin 5 to the connecting edge 12 is 10 mm, and the obtuse angle between the connecting edge 12 and the tail edge 13 is 153.4°. The height of the branch plate 1 is 40 mm, the first spoiler fin 4 is provided with two, and the second spoiler fin 5 is provided with three.

[0041] The side wall of the branch plate 1 is provided with a wave surface 6 between the oil injection hole 3 and the spoiler fin. The wave surface 6 is symmetrically distributed on both sides of the axis of the expansion section 14. The wave surface 6 includes a plurality of wave units connected in series, and the wave units are linearly arranged along the wedge surface of the branch plate 1.

[0042] As shown in Figure 8 The wave unit includes a first straight line segment 9, a second straight line segment 10, and a third straight line segment 11, and the first straight line segment 9 and the second straight line segment 10 are connected by the third straight line segment 11. The first straight line segment 9 and the third straight line segment 11 are connected by a first circular arc, and the second straight line segment 10 and the third straight line segment 11 are connected by a second circular arc. The radius of the first circular arc is 1 mm-2 mm, and the radius of the second circular arc is 2 mm-4 mm. The angle between the first straight line segment 9 and the wedge surface of the branch plate 1 is 4°-6°, the angle between the second straight line segment 10 and the wedge surface of the branch plate 1 is 4°-6°, and the angle between the third straight line segment 11 and the wedge surface of the branch plate 1 is 30°-40°.

[0043] In this embodiment, five wave units are arranged on each side of the wedge surface of the branch plate 1. The radius of the first circular arc is 1.5 mm, and the radius of the second circular arc is 3 mm. The angle between the first straight line segment 9 and the wedge surface of the branch plate 1 is 5°, the angle between the second straight line segment 10 and the wedge surface of the branch plate 1 is 5°, and the angle between the third straight line segment 11 and the wedge surface of the branch plate 1 is 35°. The wave surface 6 is used to break the shear layer of the air-fuel mixture, so that the fuel and air are fully mixed.

[0044] The mounting seat 2 is provided with an igniter mounting hole 8, which is located in the middle downstream of the tail end of the branch plate 1, and is used to ignite the mixture of fuel and air in the low-speed backflow area between the first spoiler fin 4 and the second spoiler fin 5 to form a standing flame.

[0045] As shown in Figure 10As shown, the upstream of the expansion section 14 is connected with the isolation section 15 of the scramjet engine, and the downstream of the expansion section 14 is connected with the equal-area section 16 of the combustion chamber. The equal-area section 16 can effectively accommodate the fuel-air mixture. The top of the expansion section 14 is provided with a plurality of fuel grooves 17, and the fuel grooves 17 are provided with a plurality of fuel injection holes 18 located on both sides of the strut 1. The fuel is injected into the expansion section 14 through the fuel injection holes 18 on both sides of the strut 1, and the fuel forms a global flame under the action of the pilot flame, and the stable combustion is maintained. The number of the fuel grooves 17 and the fuel injection holes 18 can be set according to the actual needs to improve the stability of the combustion chamber combustion.

[0046] The expansion section 14 is provided with a standby mounting hole 19 for mounting a standby igniter, and the standby mounting hole 19 is located downstream of the igniter mounting hole 8.

[0047] Based on the above-mentioned stable combustion device and stable combustion method for the supersonic combustion chamber with enhanced mixing, the stable combustion method comprises the following steps:

[0048] S1, the fuel is injected into the expansion section 14 through the fuel channel 7 and the fuel injection hole 3 on the strut 1, the fuel is broken, atomized and evaporated under the action of the supersonic airflow, the wave surface 6 on both sides of the strut 1 breaks the airflow shear layer to improve the air-fuel mixing effect, the air-fuel mixture is mixed and diffused into the main flow of the combustion chamber under the vortex induced by the first spoiler fin 4 and the second spoiler fin 5, and forms a low-speed backflow area at the tail of the strut 1, is ignited by the igniter, and forms a self-sustaining pilot flame without additional oxygen supplement.

[0049] S2, the fuel is injected into the combustion chamber through the fuel injection hole 18 of the expansion section 14, and the fuel is ignited by the diffused pilot flame to form a global flame for combustion.

[0050] 1. Is there a synergistic effect between the wave surface and the spoiler fin in fuel mixing? Can a simulation example be provided to prove the effect of fuel mixing.

[0051] 2. Are there specific requirements (such as specific formulas for shape) that need to be met in the design of the size and shape of the wave surface and the spoiler fin to achieve better mixing effect.

[0052] Therefore, by adopting the stable combustion device and stable combustion method for the supersonic combustion chamber with enhanced mixing, the problem of poor fuel and air mixing effect of the existing device affecting the stable ignition and combustion of the combustion chamber can be solved.

[0053] It should be pointed out finally that the above examples are only used to illustrate the technical solutions of the present application but not to limit it, and although the present application has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the technical solutions of the present application can still be modified or replaced equivalently, and these modifications or equivalent replacements should not make the modified technical solutions deviate from the spirit and scope of the technical solutions of the present application.

Claims

1. A combustion stabilization device for supersonic combustion chamber mixing enhancement, characterized by: The invention comprises a wedge-shaped support plate, which is located in the expansion section and on the axis of the expansion section. An oil injection structure for injecting oil into the expansion section is provided on one end of the support plate close to the air inlet end of the expansion section, and a spoiler fin is provided on the side wall of the other end of the support plate. A low-speed reflux zone is formed at the tail end of the support plate, and a wave surface is provided on the side wall of the support plate, and the wave surface is located between the oil injection structure and the spoiler fin; the support plate is connected to the expansion section through a mounting seat, and an igniter mounting hole is provided on the mounting seat, and the igniter mounting hole is located downstream of the tail end of the support plate.

2. The combustion stabilization device for supersonic combustion chamber mixing enhancement according to claim 1, characterized in that: The fuel injection structure includes a fuel channel arranged inside the support plate, and a plurality of fuel injection holes connected to the fuel channel are evenly arranged on the side wall of the support plate. The fuel is injected into the expansion section through the fuel channel and the fuel injection holes.

3. The combustion stabilization device for supersonic combustion chamber mixing enhancement according to claim 1, characterized in that: The spoiler fins include a first spoiler fin arranged on one side of the rear end of the support plate and a second spoiler fin arranged on the other side of the rear end of the support plate. The first spoiler fin and the second spoiler fin are arranged at intervals.

4. The combustion stabilization device for supersonic combustion chamber mixing enhancement according to claim 3, characterized in that: The first spoiler fin and the second spoiler fin have the same structure, both of which are obtuse triangle structures. The thickness of the first spoiler fin and the second spoiler fin is 7mm-9mm, the length of the connecting edge of the first spoiler fin and the second spoiler fin and the support plate is 73mm-78mm, the distance from the trailing edge vertex of the tail end of the first spoiler fin and the second spoiler fin to the connecting edge is 8mm-12mm, and the obtuse angle between the connecting edge and the trailing edge is 150°-155°.

5. The combustion stabilization device for supersonic combustion chamber mixing enhancement according to claim 1, characterized in that: The wave surface is symmetrically distributed on both sides of the axis of the expansion section. The wave surface includes wave units connected end to end and distributed in a linear array along the wedge surface of the support plate. The wave unit includes a first straight line segment, a second straight line segment, and a third straight line segment. The first straight line segment and the second straight line segment are connected by the third straight line segment. The first straight line segment and the third straight line segment are connected by a first circular arc for smooth transition, and the second straight line segment and the third straight line segment are connected by a second circular arc for smooth transition.

6. The combustion stabilization device for supersonic combustion chamber mixing enhancement according to claim 5, characterized in that: The radius of the first arc is 1mm-2mm, the radius of the second arc is 2mm-4mm, the angle between the first straight line segment and the wedge surface of the support plate is 4°-6°, the angle between the second straight line segment and the wedge surface of the support plate is 4°-6°, and the angle between the third straight line segment and the wedge surface of the support plate is 30°-40°.

7. The combustion stabilization device for supersonic combustion chamber mixing enhancement according to claim 1, characterized in that: The included angle between the wedge-shaped surfaces of the support plates is no greater than the side angle of the expansion section, and the expansion ratio of the expansion section is 1.

5.

8. The combustion stabilization device for supersonic combustion chamber mixing enhancement according to claim 1, characterized in that: The upstream of the expansion section is connected to the isolation section of the scramjet engine, and the downstream of the expansion section is connected to the equal-area section of the combustion chamber. A plurality of fuel tanks are provided on the top of the expansion section, and a plurality of fuel spray holes are provided on the fuel tanks. The fuel spray holes are located on both sides of the support plate, and the fuel is sprayed into both sides of the support plate in the expansion section through the fuel spray holes.

9. The combustion stabilization device for supersonic combustion chamber mixing enhancement according to claim 1, characterized in that: The bottom of the expansion section is provided with a mounting hole for placing the mounting seat, and the expansion section is provided with a spare mounting hole for mounting a spare igniter, and the spare mounting hole is located downstream of the igniter mounting hole.

10. A combustion stabilization method based on the supersonic combustion chamber mixing enhancement combustion stabilization device according to any one of claims 1 to 9, characterized in that: The following steps are involved: S1. Fuel is injected into the expansion section through the fuel channels and injection holes on the support plate. Under the action of the supersonic airflow, the fuel is broken, atomized, and evaporated. The wavy surfaces on both sides of the support plate destroy the airflow shear layer, improving the air-fuel mixing effect. The air-fuel mixture is mixed and diffused into the main flow of the combustion chamber under the vortex induced by the first and second spoiler fins. A low-speed recirculation zone is formed at the tail of the support plate, and the fuel is ignited by the igniter, forming a self-sustaining duty flame without the need for additional oxygen. S2. The fuel is sprayed into the combustion chamber through the fuel nozzles in the expansion section. The fuel is ignited by the diffused flame to form a global flame for combustion.

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