Center detonation type oblique detonation engine

Abstract

The invention relates to the technical field of aero-engines, and discloses a center detonation type oblique detonation engine which comprises a fuel injection supporting plate and a detonation supporting plate, the fuel injection supporting plate is erected and fixed in a combustion chamber, and a plurality of first reverse jet holes are formed in the end face, directly facing an air inlet channel, of the fuel injection supporting plate; a plurality of fuel injection holes are formed in the end face, back to the gas inlet channel, of the fuel injection supporting plate, and a first gas conveying flow channel and a fuel conveying flow channel are formed in the fuel injection supporting plate; the detonating supporting plate is erected and fixed in the combustion chamber and is parallel to the fuel injection supporting plate, and a plurality of second reverse jet holes are formed in the end face, directly facing the fuel injection holes, of the detonating supporting plate; the detonation supporting plate is arranged to replace an original wedge face, the detonation supporting plate and the fuel injection supporting plate both adopt reverse jet flow for thermal protection, arch shock waves formed through induction of the reverse jet flow play a role in intensifying detonation, meanwhile, oblique detonation waves are located in the center for detonation, and separation of a boundary layer of the lower wall face cannot be caused.

Description

Technical Field

[0001] This invention relates to the field of aero-engine technology, specifically a center-initiated oblique detonation engine. Background Technology

[0002] The structure of a traditional slant knock engine is as follows: Figure 1 As shown, a fuel injection support plate A is provided in the combustion chamber, and an initiation wedge surface B is provided on the lower wall surface of the combustion chamber located behind the fuel injection support plate A. During initiation, a high-speed gas flow enters the combustion chamber, and fuel is ejected from the tail of the fuel injection support plate A. After the fuel mixes with the incoming air, the resulting mixture impacts the initiation wedge surface B near the lower wall surface, forming an oblique shock wave. The temperature and pressure rise after the oblique shock wave, and when the ignition point of the mixture is reached, a deflagration wave is triggered, which then transforms into an oblique detonation shock wave.

[0003] Since the above-mentioned detonation process is initiated through the detonation wedge B, this detonation method is also called detonation near the lower wall surface. However, this method has the following problems: boundary layer separation is prone to form near the detonation wedge, affecting the stable operation of the engine; and the detonation wedge is not cooled, making it easy to ablate under the high temperature erosion of the detonation wave. In addition, the fuel injection support plate is not cooled and is also prone to ablation. Summary of the Invention

[0004] The purpose of this invention is to provide a center-initiated oblique detonation engine to solve the problems of existing oblique detonation engines that use initiation near the lower wall.

[0005] The technical solution of this invention is: A center-initiated oblique detonation engine includes a fuel injection support plate and an initiation support plate. The fuel injection support plate is mounted and fixed in the combustion chamber. Multiple first reverse jet holes are formed on the end face of the fuel injection support plate facing the air intake, and these first reverse jet holes are arranged along the width direction of the fuel injection support plate. Multiple fuel injection holes are formed on the end face of the fuel injection support plate facing away from the air intake, and these multiple fuel injection holes are arranged along the width direction of the fuel injection support plate. A first gas delivery channel and a fuel delivery channel are respectively formed inside the fuel injection support plate. The multiple first reverse jet holes are connected to the external combustion chamber through the first gas delivery channel. A high-pressure gas flow delivery device is connected, and multiple fuel injection holes are connected to an external fuel delivery device through a fuel delivery channel. An initiation support plate is mounted and fixed in the combustion chamber. The initiation support plate is located on the side of the fuel injection support plate with fuel injection holes, and the initiation support plate is arranged parallel to the fuel injection support plate. Multiple second reverse jet holes are opened on the end face of the initiation support plate facing the fuel injection holes. The multiple second reverse jet holes are arranged along the width direction of the initiation support plate. A second gas delivery channel is provided inside the initiation support plate, and the multiple second reverse jet holes are connected to an external high-pressure gas flow delivery device through the second gas delivery channel.

[0006] Preferably, as a further improvement of the present invention, the first gas delivery channel is formed on one side wall of the fuel injection support plate and is arranged along the width direction of the fuel injection support plate; the fuel delivery channel is formed on the other side wall of the fuel injection support plate and is arranged parallel to the first gas delivery channel; and the second gas delivery channel is fixed on one side wall of the detonation support plate and is arranged parallel to the first gas delivery channel.

[0007] Preferably, as a further improvement of the present invention, the plurality of fuel injection holes and the plurality of second reverse jet holes are located on the same horizontal plane.

[0008] Preferably, as a further improvement of the present invention, the plurality of fuel injection holes are arranged opposite to the plurality of second reverse jet holes.

[0009] Preferably, as a further improvement of the present invention, the ratio of the total pressure of the gas flow ejected from the plurality of first reverse jet holes to the total pressure of the supersonic incoming flow is 1:(0.2~0.8), and the ratio of the total pressure of the gas flow ejected from the plurality of second reverse jet holes to the total pressure of the supersonic incoming flow is 1:(0.2~0.8).

[0010] Preferably, as a further improvement of the present invention, the ratio of the total pressure of the gas flow ejected from the plurality of first reverse jet holes to the total pressure of the supersonic incoming flow is 1:0.3, and the ratio of the total pressure of the gas flow ejected from the plurality of second reverse jet holes to the total pressure of the supersonic incoming flow is 1:0.3.

[0011] Preferably, as a further improvement of the present invention, the fuel injection support plate is an isosceles triangle structure with a rounded tip or a wedge structure with a rounded tip. The shape of the detonation support plate is the same as that of the fuel injection support plate. A plurality of first reverse jet holes are disposed at the tip of the fuel injection support plate, a plurality of fuel injection holes are disposed on the wall surface of the fuel injection support plate opposite to the tip, and a plurality of second reverse jet holes are disposed at the tip of the detonation support plate. The tips of the fuel injection support plate and the tips of the detonation support plate are both disposed on the side of the combustion chamber connected to the air intake.

[0012] Preferably, as a further improvement of the present invention, the detonation support plate is disposed at 4 / 11 to 6 / 11 of the height of the combustion chamber.

[0013] Compared with the prior art, the beneficial effects of the present invention are: 1. An initiating support plate is used instead of the original wedge surface. The horizontal position of the initiating support plate is located at the same level as the original wedge surface. The initiating support plate and the fuel injection support plate are suspended parallel to each other in the combustion chamber, with the initiating support plate located at 4 / 11 to 6 / 11 of the combustion chamber height. During initiation, the fuel injected through multiple fuel injection holes on the fuel injection support plate mixes with the supersonic airflow to form an explosive mixture that flows downstream. During this process, the second reverse jet hole of the initiating support plate injects a reverse jet, which pushes the supersonic incoming flow away from the support plate surface and forms a bow-shaped shock wave. The bow-shaped shock wave compresses the incoming flow and initiates the explosive mixture to form a slanted detonation shock wave. The slanted detonation shock wave is achieved through the initiating support plate and is centered on the initiating plate, which will not cause boundary layer separation on the lower wall and reduce the impact on the stable operation of the engine.

[0014] 2. The fuel injection support plate injects reverse flow through multiple first reverse flow holes, which forms a gas layer on the surface of the fuel injection support plate to isolate the high-temperature flow and prevent the high-temperature airflow formed by the stagnation of the flow from burning the fuel injection support plate, thereby playing a role in thermal protection of the fuel injection support plate.

[0015] 3. The detonation support plate adopts multiple second reverse jet holes. The reverse jet can provide thermal protection, and the bow-shaped shock wave induced by the reverse jet can enhance the detonation. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of a conventional oblique detonation engine.

[0017] Figure 2 This is a three-dimensional structural diagram of a center-initiated oblique detonation engine according to the present invention.

[0018] Figure 3 This is a three-dimensional structural schematic diagram of a center-initiated oblique detonation engine according to the present invention from another perspective.

[0019] Figure 4 This is a front view schematic diagram of a center-initiated oblique detonation engine according to the present invention.

[0020] Figure 5 This is a three-dimensional structural diagram of the fuel injection support plate in a center-initiated oblique detonation engine according to the present invention.

[0021] Figure 6 This is a schematic diagram of the first gas delivery channel and the fuel delivery channel arranged inside the fuel injection support plate in a center-initiated oblique detonation engine according to the present invention.

[0022] Figure 7 This is a three-dimensional structural diagram of the detonation support plate in a center-initiated oblique detonation engine according to the present invention.

[0023] Figure 8 This is a schematic diagram of the second gas delivery channel inside the detonation support plate of a center-initiated oblique detonation engine according to the present invention.

[0024] Figure 9 This invention provides a comparison of temperature contour maps of the fuel injection support plate in a center-initiated oblique detonation engine with and without reverse jet flow.

[0025] Figure 10 This is a schematic diagram of the reverse jet flow field structure in a center-initiated oblique detonation engine according to the present invention. Detailed Implementation

[0026] The following is combined with Figures 2-10 The specific embodiments of the present invention will be described in detail below. In the description of the invention, it should be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0027] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature; in the description of the invention, unless otherwise stated, "a plurality of" means two or more.

[0028] Example like Figures 2-8As shown, this embodiment of the invention provides a center-initiated oblique detonation engine, including a fuel injection support plate 2 and an initiation support plate 3. The fuel injection support plate 2 is mounted and fixed inside the combustion chamber 1. Multiple first reverse jet holes 21 are formed on the end face of the fuel injection support plate 2 facing the air intake, and these holes are arranged along the width direction of the fuel injection support plate 2. Multiple fuel injection holes 22 are formed on the end face of the fuel injection support plate 2 facing away from the air intake, and these holes are also arranged along the width direction of the fuel injection support plate 2. A first gas delivery channel 23 and a fuel delivery channel 24 are respectively formed inside the fuel injection support plate 2. The multiple first reverse jet holes 21 are connected to the external high-pressure gas flow through the first gas delivery channel 23. The fuel injection device is connected, and multiple fuel injection holes 22 are connected to an external fuel delivery device through a fuel delivery channel 24. The detonation support plate 3 is suspended in the combustion chamber 1, and the two side walls of the detonation support plate 3 are fixed to the two inner side walls of the combustion chamber 1. The detonation support plate 3 is located on the side of the fuel injection support plate 2 with fuel injection holes 22, and the detonation support plate 3 is arranged parallel to the fuel injection support plate 2. Multiple second reverse jet holes 31 are opened on the end face of the detonation support plate 3 facing the fuel injection holes 22. The multiple second reverse jet holes 31 are arranged along the width direction of the detonation support plate 3. The detonation support plate 3 has a second gas delivery channel 32 inside, and the multiple second reverse jet holes 31 are connected to an external high-pressure gas delivery device through the second gas delivery channel 32.

[0029] In this embodiment, multiple first reverse jet holes 21 are added to the original fuel injection support plate 2, enabling the fuel injection support plate 2 to have a reverse jet function. The original detonation wedge surface is replaced by a detonation support plate 3. The horizontal position of the detonation support plate 3 in the combustion chamber 1 is the same as the horizontal position of the original detonation wedge surface in the combustion chamber 1. At the same time, the detonation support plate 3 and the fuel injection support plate 2 are suspended and fixed in the combustion chamber 1 in parallel. By providing multiple second reverse jet holes 31 on the detonation support plate 3, the detonation support plate 3 also has a reverse jet function. (Refer to...) Figure 4As shown, the supersonic incoming flow enters the combustion chamber 1 from left to right through the air intake. The reverse jet direction is opposite to the supersonic incoming flow, hence the name reverse jet. The pressure ratio between the reverse jet and the supersonic incoming flow can be adjusted according to actual flight conditions. High-pressure airflow is simultaneously injected and ejected into multiple first reverse jet holes 21 and multiple second reverse jet holes 31 through an external high-pressure airflow delivery device. Fuel is injected and ejected into multiple fuel injection holes 22 through an external fuel delivery device. The first reverse jet holes 21 horizontally inject high-pressure airflow in the direction of the supersonic incoming flow, pushing the supersonic incoming flow away from the surface of the fuel injection support plate 2 to form a bow-shaped shock wave. A gas layer is formed on the surface of the fuel injection support plate 2 to isolate the high-temperature incoming flow and prevent the high-temperature airflow formed by the stagnation of the incoming flow from burning the fuel injection support plate, thereby providing thermal protection for the fuel injection support plate. The function of the second reverse jet hole 31 is to ensure the stable operation of the fuel injection support plate. The high-pressure airflow ejected from the second reverse jet hole 31 works on the same principle as above, which can achieve thermal protection for the detonation support plate 3. The fuel ejected from the multiple fuel injection holes 22 mixes with the supersonic airflow to form an explosive mixed airflow downstream. During this process, the second reverse jet hole 31 ejects a reverse jet, which pushes the supersonic incoming flow away from the support plate surface and forms a bow-shaped shock wave. The bow-shaped shock wave compresses the incoming flow and detonates the explosive mixed airflow to form a slanted detonation shock wave. Subsequently, the combustion products flow out and flow towards the tail nozzle to generate thrust. Since the slanted detonation shock wave is formed under the action of the detonation support plate 3, compared with the traditional method of detonation on the lower wall of the combustion chamber, this invention is equivalent to detonation at the center of the combustion chamber. Therefore, it will not cause the lower wall boundary layer separation, thereby reducing the impact on the stable operation of the engine.

[0030] In other embodiments of the present invention, such as Figure 5 and Figure 6 As shown, the first gas delivery channel 23 is opened on one side wall of the fuel injection support plate 2 and is arranged along the width direction of the fuel injection support plate 2. The first gas delivery channel 23 passes through the combustion chamber 1 through the first injection pipe 231 and is connected to the aircraft gas tank. The fuel delivery channel 24 is opened on the other side wall of the fuel injection support plate 2 and is arranged parallel to the first gas delivery channel 23. The fuel delivery channel 24 passes through the combustion chamber 1 through the second injection pipe 241 and is connected to the aircraft gas tank. The second gas delivery channel 32 is fixed on one side wall of the detonation support plate 3 and is arranged parallel to the first gas delivery channel 23. The second gas delivery channel 32 passes through the combustion chamber 1 through the third injection pipe 321 and is connected to the aircraft gas tank.

[0031] The above configuration isolates the reverse jet flow path from the fuel injection flow path, using separate pipelines. The reverse jet (high-pressure airflow) can be air, nitrogen, or an inert gas. The fuel is an explosive gas such as hydrogen, ethylene, or methane. The reverse jet is distributed to each nozzle from the aircraft's gas storage tank via a main pipeline. Similarly, the fuel injection is distributed to each nozzle from the aircraft's gas storage tank via a main pipeline.

[0032] Furthermore, in order to improve the stability of the formed bow shock wave, multiple fuel injection holes 22 and multiple second reverse jet holes 31 are located on the same horizontal plane.

[0033] Furthermore, in order to better form a bow-shaped shock wave, multiple fuel injection holes 22 and multiple second reverse jet holes 31 are arranged facing each other.

[0034] In another embodiment of the present invention, the ratio of the total pressure of the gas flow ejected from the plurality of first reverse jet holes 21 to the total pressure of the supersonic incoming flow is 1:(0.2~0.8), and the ratio of the total pressure of the gas flow ejected from the plurality of second reverse jet holes 31 to the total pressure of the supersonic incoming flow is 1:(0.2~0.8).

[0035] In practice, the ratio of the total pressure of the airflow ejected from the multiple first reverse jet holes 21 to the total pressure of the supersonic incoming flow is 1:0.3, and the ratio of the total pressure of the airflow ejected from the multiple second reverse jet holes 31 to the total pressure of the supersonic incoming flow is 1:0.3.

[0036] In another embodiment of the present invention, the fuel injection support plate 2 is an isosceles triangle structure with a rounded tip or a wedge structure with a rounded tip. The shape of the detonation support plate 3 is the same as that of the fuel injection support plate 2. A plurality of first reverse jet holes 21 are provided at the tip of the fuel injection support plate 2. A plurality of fuel injection holes 22 are provided on the wall surface of the fuel injection support plate 2 facing away from the tip. A plurality of second reverse jet holes 31 are provided at the tip of the detonation support plate 3. The tips of the fuel injection support plate 2 and the tips of the detonation support plate 3 are both positioned facing the side of the combustion chamber 1 connected to the air intake.

[0037] In another embodiment of the present invention, the detonation support plate 3 is suspended and fixed in the combustion chamber 1 in parallel with the fuel injection support plate 2, and is located at 4 / 11 to 6 / 11 of the height of the combustion chamber 1. In a specific implementation, the detonation support plate 3 is set at 1 / 2 of the height of the combustion chamber 1, so that the oblique detonation shock wave is located exactly at the center of the combustion chamber 1 for detonation.

[0038] The working principle of this invention is as follows: Combustion chamber 1 is connected to the intake manifold, receiving the supersonic incoming flow compressed through the intake manifold. Simultaneously, multiple first reverse jet nozzles 21 on the fuel injection support plate 2 horizontally inject high-pressure airflow in the direction of the incoming flow. The total pressure of the high-pressure airflow is 0.2 to 0.8 times the total pressure of the supersonic incoming flow. The high-pressure airflow injected by the first reverse jet nozzles 21 pushes the supersonic incoming flow away from the surface of the support plate 1, forming a bow-shaped shock wave (e.g., ...). Figure 4 (As shown). The total temperature of the high-pressure gas flow ejected from the reverse jet orifice is close to 300K, while its static temperature is below 300K. The Mach number at the nozzle is 1. The composition of the reverse jet gas can be either nitrogen or air. This low static temperature gas flow can effectively isolate the high-temperature incoming flow from the surface of the fuel injection support plate 2, providing thermal protection for the fuel injection support plate 2.

[0039] Simultaneously, fuel injection support plate 2 injects fuel through fuel injection holes 22. The fuel mixes with the supersonic gas flow, forming an explosive mixture that flows downstream. Multiple second reverse jet holes 31 in front of the detonation support plate 3 horizontally inject high-pressure gas flow in the direction of the incoming flow. The total pressure of the high-pressure gas flow is 0.2 to 0.8 times that of the supersonic incoming flow. The total temperature of the high-pressure gas flow ejected from the reverse jet holes is close to 300 K, while its static temperature is below 300 K. The Mach number at the nozzle is 1. The composition of the reverse jet gas can be either nitrogen or air. The reverse jet pushes the supersonic incoming flow away from the surface of the detonation support plate 3 and simultaneously forms a bow-shaped shock wave. The bow-shaped shock wave compresses the incoming flow, igniting the explosive mixture and forming a slanted detonation shock wave. Subsequently, the combustion products flow out from the outlet and into the tail nozzle, generating thrust.

[0040] The feasibility of this invention is verified by experimental data. The incoming Mach number was set to 4.2, the static pressure to 61000 Pa, the static temperature to 857 K, and the total pressure of the reverse jet to be 0.3 times the total pressure of the supersonic incoming flow. The detonation support plate 3 and the fuel injection support plate 2 were positioned at half the height of the combustion chamber 1. The diameters of the first and second reverse jet holes were 1 mm. The experimental results are as follows: Figure 9 As shown, Figure 9 (a) is a flow field temperature contour map without reverse jet. The map shows that the highest temperature of the high-temperature layer at the front end of the support plate exceeds 3000K, far exceeding the material's withstand limit. For example... Figure 9 As shown in (b), when a reverse jet orifice is added for reverse jetting, the low-temperature layer formed by the reverse jetting separates the high-temperature layer from the support plate, and this low-temperature layer can effectively protect the support plate. Meanwhile, Figure 10 This is a typical structural diagram of a reverse jet, consisting of a bow-shaped shock wave and a bottle-shaped shock wave formed by the reverse jet.

[0041] The above-disclosed embodiments are merely preferred embodiments of the present invention. However, the embodiments of the present invention are not limited thereto, and any variations that can be conceived by those skilled in the art should fall within the protection scope of the present invention.

Claims

1. A center-initiated oblique detonation engine, characterized in that, include: A fuel injection support plate (2) is mounted and fixed inside the combustion chamber (1). The end face of the fuel injection support plate (2) facing the air intake is provided with a plurality of first reverse jet holes (21). The plurality of first reverse jet holes (21) are arranged along the width direction of the fuel injection support plate (2). The end face of the fuel injection support plate (2) facing away from the air intake is provided with a plurality of fuel injection holes (22). The plurality of fuel injection holes (22) are arranged along the width direction of the fuel injection support plate (2). The interior of the fuel injection support plate (2) is provided with a first gas conveying channel (23) and a fuel conveying channel (24). The plurality of first reverse jet holes (21) are connected to an external high-pressure gas flow conveying device through the first gas conveying channel (23). The plurality of fuel injection holes (22) are connected to an external fuel conveying device through the fuel conveying channel (24). The detonation support plate (3) is mounted and fixed inside the combustion chamber (1). The detonation support plate (3) is located on the side of the fuel injection support plate (2) with fuel injection holes (22) and is arranged parallel to the fuel injection support plate (2). Multiple second reverse jet holes (31) are opened on the end face of the detonation support plate (3) facing the fuel injection holes (22). The multiple second reverse jet holes (31) are arranged along the width direction of the detonation support plate (3). The detonation support plate (3) is provided with a second gas conveying channel (32). The multiple second reverse jet holes (31) are connected to the external high-pressure gas conveying device through the second gas conveying channel (32).

2. The center-initiated oblique detonation engine according to claim 1, characterized in that, The first gas delivery channel (23) is opened on one side wall of the fuel injection support plate (2) and is arranged along the width direction of the fuel injection support plate (2). The fuel delivery channel (24) is opened on the other side wall of the fuel injection support plate (2) and is arranged parallel to the first gas delivery channel (23). The second gas delivery channel (32) is fixed on one side wall of the detonation support plate (3) and is arranged parallel to the first gas delivery channel (23).

3. The center-initiated oblique detonation engine according to claim 2, characterized in that, The plurality of fuel injection holes (22) and the plurality of second reverse jet holes (31) are located on the same horizontal plane.

4. The center-initiated oblique detonation engine according to claim 3, characterized in that, The plurality of fuel injection holes (22) are arranged opposite to the plurality of second reverse jet holes (31).

5. The center-initiated oblique detonation engine according to claim 1, characterized in that, The ratio of the total pressure of the gas flow ejected from the plurality of first reverse jet holes (21) to the total pressure of the supersonic incoming flow is 1:(0.2~0.8), and the ratio of the total pressure of the gas flow ejected from the plurality of second reverse jet holes (31) to the total pressure of the supersonic incoming flow is 1:(0.2~0.8).

6. The center-initiated oblique detonation engine according to claim 5, characterized in that, The ratio of the total pressure of the gas flow ejected from the plurality of first reverse jet holes (21) to the total pressure of the supersonic incoming flow is 1:0.3, and the ratio of the total pressure of the gas flow ejected from the plurality of second reverse jet holes (31) to the total pressure of the supersonic incoming flow is 1:0.

3.

7. The center-initiated oblique detonation engine according to claim 1, characterized in that, The fuel injection support plate (2) is an isosceles triangle structure with a rounded tip or a wedge structure with a rounded tip. The shape of the detonation support plate (3) is the same as that of the fuel injection support plate (2). A plurality of first reverse jet holes (21) are provided at the tip of the fuel injection support plate (2). A plurality of fuel injection holes (22) are provided on the wall surface of the fuel injection support plate (2) facing away from the tip. A plurality of second reverse jet holes (31) are provided at the tip of the detonation support plate (3). The tips of the fuel injection support plate (2) and the detonation support plate (3) are both located on the side of the combustion chamber (1) connected to the air intake.

8. The center-initiated oblique detonation engine according to claim 1, characterized in that, The detonation support plate (3) is located at 4 / 11 to 6 / 11 of the height of the combustion chamber (1).

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