A centrally initiated oblique detonation engine

Abstract

The present application relates to the technical field of aero-engine, and discloses a center initiation type oblique detonation engine, which comprises a fuel injection support plate and an initiation support plate, the fuel injection support plate is fixed in a combustion chamber, a plurality of first reverse jet holes are formed on the end face of the fuel injection support plate opposite to an air inlet, a plurality of fuel injection holes are formed on the end face of the fuel injection support plate opposite to the air inlet, a first gas conveying flow channel and a fuel conveying flow channel are respectively formed in the fuel injection support plate, the initiation support plate is fixed in the combustion chamber and is arranged in parallel with the fuel injection support plate, a plurality of second reverse jet holes are formed on the end face of the initiation support plate opposite to the fuel injection holes, the initiation support plate is arranged instead of the original wedge surface, the initiation support plate and the fuel injection support plate are both subjected to thermal protection by reverse jet, the arc shock induced by the reverse jet plays a role in strengthening initiation, and the oblique detonation wave is in the center initiation, so that the boundary layer separation of the lower wall surface is avoided.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of aero-engine, in particular to a center initiation type oblique detonation engine. BACKGROUND

[0002] The structure of the conventional oblique detonation engine is shown in the figure, a fuel injection branch plate A is arranged in the combustion chamber, and an initiation wedge surface B is arranged on the lower wall surface of the combustion chamber behind the fuel injection branch plate A. Figure 1 When initiation is performed, high-speed gas flow enters the combustion chamber, fuel is sprayed from the tail of the fuel injection branch plate A, the mixture formed after the fuel mixes with the air flow impacts the initiation wedge surface B close to the lower wall surface, an oblique shock wave is formed, the temperature and pressure behind the oblique shock wave increase, and when the ignition point of the mixture is reached, the deflagration wave is triggered, and then is converted into an oblique detonation wave.

[0003] Since the above initiation process is initiated by the initiation wedge surface B, this initiation method is also called initiation close to the lower wall surface. However, this method has the following problems: boundary layer separation is easy to occur near the initiation wedge surface, which affects the stable operation of the engine, and the initiation wedge surface is not cooled, which is easy to be ablated under the high-temperature erosion of the detonation wave, in addition, the fuel injection branch plate is not cooled, which is easy to be ablated. SUMMARY

[0004] The purpose of the present application is to provide a center initiation type oblique detonation engine to solve the problems of the oblique detonation engine using the initiation close to the lower wall surface of the existing initiation method.

[0005] The technical solution of the present application is:

[0006] The application discloses a center-initiated oblique detonation engine, which comprises a fuel injection support plate and an initiation support plate, wherein the fuel injection support plate is arranged in a combustion chamber, a plurality of first reverse jet holes are arranged on the end surface of the fuel injection support plate facing the air inlet, the first reverse jet holes are arranged along the width direction of the fuel injection support plate, a plurality of fuel injection holes are arranged on the end surface of the fuel injection support plate facing away from the air inlet, the fuel injection holes are arranged along the width direction of the fuel injection support plate, a first gas conveying channel and a fuel conveying channel are arranged in the fuel injection support plate, the first reverse jet holes are connected with external high-pressure gas flow conveying devices through the first gas conveying channel, and the fuel injection holes are connected with external fuel conveying devices through the fuel conveying channel; the initiation support plate is arranged in the combustion chamber, the initiation support plate is arranged on the side of the fuel injection support plate provided with the fuel injection holes, the initiation support plate is arranged in parallel with the fuel injection support plate, a plurality of second reverse jet holes are arranged on the end surface of the initiation support plate facing the fuel injection holes, the second reverse jet holes are arranged along the width direction of the initiation support plate, and the initiation support plate is provided with a second gas conveying channel, and the second reverse jet holes are connected with the external high-pressure gas flow conveying devices through the second gas conveying channel.

[0007] Preferably, as a further improvement of the application, the first gas conveying channel is arranged on one side wall of the fuel injection support plate and arranged along the width direction of the fuel injection support plate, the fuel conveying channel is arranged on the other side wall of the fuel injection support plate and arranged in parallel with the first gas conveying channel, and the second gas conveying channel is arranged on one side wall of the initiation support plate and arranged in parallel with the first gas conveying channel.

[0008] Preferably, as a further improvement of the application, the fuel injection holes and the second reverse jet holes are arranged on the same horizontal plane.

[0009] Preferably, as a further improvement of the application, the fuel injection holes and the second reverse jet holes are arranged in pairs.

[0010] Preferably, as a further improvement of the application, the ratio of the total pressure of the gas flow jetted out of the 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 jetted out of the second reverse jet holes to the total pressure of the supersonic incoming flow is 1: (0.2-0.8).

[0011] Preferably, as a further improvement of the application, the ratio of the total pressure of the gas flow jetted out of the 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 jetted out of the second reverse jet holes to the total pressure of the supersonic incoming flow is 1:0.3.

[0012] Preferably, as a further improvement of the application, the fuel injection support plate is in the shape of an isosceles triangle with rounded tip or a wedge with rounded tip, the shape of the ignition support plate is the same as that of the fuel injection support plate, a plurality of the first reverse jet holes are arranged at the tip of the fuel injection support plate, a plurality of the fuel injection holes are arranged on the wall surface of the fuel injection support plate opposite to the tip, a plurality of the second reverse jet holes are arranged at the tip of the ignition support plate, and the tips of the fuel injection support plate and the ignition support plate are both arranged to face one side of the combustion chamber connecting inlet.

[0013] Preferably, as a further improvement of the application, the ignition support plate is arranged at a position of 4 / 11 to 6 / 11 of the height of the combustion chamber.

[0014] Compared with the prior art, the application has the following beneficial effects:

[0015] 1. The ignition support plate is used to replace the original wedge surface, the horizontal position of the ignition support plate is at the horizontal position of the original wedge surface, and the ignition support plate is suspended in parallel with the fuel injection support plate in the combustion chamber, so that the ignition support plate is located at a position of 4 / 11 to 6 / 11 of the height of the combustion chamber. During ignition, the fuel injected through the plurality of fuel injection holes of the fuel injection support plate mixes with the supersonic airflow to form an ignitable mixed airflow downstream. In this process, the second reverse jet holes of the ignition support plate inject reverse jet flow, the reverse jet flow pushes the supersonic airflow away from the surface of the support plate and forms an arc shock wave at the same time, the arc shock wave compresses the incoming flow to ignite the ignitable mixed airflow to form an oblique detonation wave, the oblique detonation wave passes through the ignition support plate to realize central ignition, and the oblique detonation wave does not cause separation of the boundary layer of the lower wall surface, thereby reducing the influence on the stable operation of the engine.

[0016] 2. The fuel injection support plate injects reverse jet flow through the plurality of first reverse jet holes, so that a gas layer is formed on the surface of the fuel injection support plate to isolate the high-temperature incoming flow and prevent the high-temperature airflow formed by the stagnation of the incoming flow from ablation of the fuel injection support plate, thereby achieving thermal protection of the fuel injection support plate.

[0017] 3. The ignition support plate injects reverse jet flow through the plurality of second reverse jet holes, which can achieve thermal protection, and the arc shock wave induced by the reverse jet flow can strengthen ignition. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 FIG. 1 is a structural schematic diagram of an oblique detonation engine in the prior art.

[0019] Figure 2 FIG. 2 is a three-dimensional structural schematic diagram of a central ignition type oblique detonation engine according to the application.

[0020] Figure 3It is another perspective view of the three-dimensional structure of the center initiation type oblique detonation engine.

[0021] Figure 4 It is a front view of the structure of the center initiation type oblique detonation engine.

[0022] Figure 5 It is a perspective view of the fuel injection support plate in the center initiation type oblique detonation engine.

[0023] Figure 6 It is a schematic view of the first gas delivery channel and the fuel delivery channel arranged inside the fuel injection support plate in the center initiation type oblique detonation engine.

[0024] Figure 7 It is a perspective view of the ignition support plate in the center initiation type oblique detonation engine.

[0025] Figure 8 It is a schematic view of the second gas delivery channel arranged inside the ignition support plate in the center initiation type oblique detonation engine.

[0026] Figure 9 It is a temperature cloud atlas comparison of the fuel injection support plate without reverse jet and with reverse jet in the center initiation type oblique detonation engine.

[0027] Figure 10 It is a schematic view of the reverse jet flow field structure in the center initiation type oblique detonation engine. DETAILED DESCRIPTION

[0028] The specific embodiments of the present application will be described in detail below. Figures 2-10 In the description of the application, it should be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, 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.

[0029] The terms "first" and "second" are only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features referred to. Therefore, the features defined with "first" and "second" can explicitly or implicitly include one or more of the features; in the description of the application, unless otherwise specified, the meaning of "a plurality of" is two or more.

[0030] EMBODIMENT

[0031] As Figures 2-8 shown in the figure, the embodiment of the application provides a center initiation type oblique detonation engine, which comprises a fuel injection support plate 2 and an initiation support plate 3, the fuel injection support plate 2 is fixedly arranged in a combustion chamber 1, a plurality of first reverse jet holes 21 are arranged on an end face of the fuel injection support plate 2 facing an air inlet, the plurality of first reverse jet holes 21 are arranged along a width direction of the fuel injection support plate 2, a plurality of fuel injection holes 22 are arranged on an end face of the fuel injection support plate 2 facing away from the air inlet, the plurality of fuel injection holes 22 are arranged along the width direction of the fuel injection support plate 2, a first gas delivery flow channel 23 and a fuel delivery flow channel 24 are respectively arranged in the fuel injection support plate 2, the plurality of first reverse jet holes 21 are connected with an external high-pressure gas flow delivery device through the first gas delivery flow channel 23, and the plurality of fuel injection holes 22 are connected with an external fuel delivery device through the fuel delivery flow channel 24; the initiation support plate 3 is suspendedly arranged in the combustion chamber 1, two side walls of the initiation support plate 3 are fixed to two inner walls of the combustion chamber 1, the initiation support plate 3 is located on a side of the fuel injection support plate 2 where the fuel injection holes 22 are arranged, and the initiation support plate 3 is arranged in parallel with the fuel injection support plate 2, a plurality of second reverse jet holes 31 are arranged on an end face of the initiation support plate 3 facing the fuel injection holes 22, the plurality of second reverse jet holes 31 are arranged along a width direction of the initiation support plate 3, and a second gas delivery flow channel 32 is arranged in the initiation support plate 3, the plurality of second reverse jet holes 31 are connected with the external high-pressure gas flow delivery device through the second gas delivery flow channel 32.

[0032] In the embodiment, the plurality of first reverse jet holes 21 are additionally arranged on the original fuel injection support plate 2, so that the fuel injection support plate 2 has a reverse jet function, the original initiation wedge surface is replaced by the initiation support plate 3, the initiation support plate 3 is arranged in a horizontal position in the combustion chamber 1, and the horizontal position of the initiation support plate 3 is the same as that of the original initiation wedge surface arranged in the combustion chamber 1, the initiation support plate 3 is suspendedly arranged in parallel with the fuel injection support plate 2 in the combustion chamber 1, the plurality of second reverse jet holes 31 are arranged on the initiation support plate 3, so that the initiation support plate 3 has a reverse jet function, and the center initiation type oblique detonation engine is obtained. Figure 4As shown, the supersonic incoming flow moves into the combustion chamber 1 from the air inlet 1a from left to right, the counter-jet is opposite to the direction of the supersonic incoming flow, so it is called counter-jet, the pressure ratio of the counter-jet to the supersonic incoming flow can be adjusted according to the actual flight situation, the high-pressure gas flow is injected into and sprayed out of the plurality of first counter-jet holes 21 and the plurality of second counter-jet holes 31 through the external high-pressure gas flow delivery device, the fuel is injected into and sprayed out of the plurality of fuel injection holes 22 through the external fuel delivery device, the high-pressure gas flow is horizontally injected into the direction of the supersonic incoming flow through the first counter-jet hole 21, the supersonic incoming flow is pushed away from the surface of the fuel injection panel 2 to form an arc shock wave, and a gas layer is formed on the surface of the fuel injection panel 2 to isolate the high-temperature incoming flow, preventing the high-temperature gas flow formed by the stagnation of the incoming flow from ablation of the fuel injection panel, thereby playing a role of thermal protection for the fuel injection panel, ensuring the stable operation of the fuel injection panel, the high-pressure gas flow sprayed out of the second counter-jet hole 31 works in the same principle as above, and can realize thermal protection for the detonation panel 3, the fuel sprayed out of the plurality of fuel injection holes 22 mixes with the supersonic flow to form an explosive mixed gas flow downstream, in this process, the second counter-jet hole 31 sprays a counter-jet, the counter-jet pushes the supersonic incoming flow away from the surface of the panel and forms an arc shock wave at the same time, the arc shock wave compresses the incoming flow to detonate the explosive mixed gas flow to form an oblique detonation wave, and then the combustion products flow out to produce thrust in the tail nozzle, since the oblique detonation wave is formed under the action of the detonation panel 3, compared with the traditional detonation mode of using a detonation wedge on the lower wall of the combustion chamber, the present application is equivalent to detonating in the center of the combustion chamber, so it will not cause the separation of the boundary layer on the lower wall, thereby reducing the influence on the stable operation of the engine.

[0033] In another embodiment of the present application, as shown in Figure 5 and Figure 6 The first gas delivery channel 23 is arranged on one side wall of the fuel injection panel 2 and extends along the width direction of the fuel injection panel 2, the first gas delivery channel 23 is connected with the aircraft gas tank through the first injection pipe 231 after passing through the combustion chamber 1, the fuel delivery channel 24 is arranged on the other side wall of the fuel injection panel 2 and is parallel to the first gas delivery channel 23, the fuel delivery channel 24 is connected with the aircraft gas tank through the second injection pipe 241 after passing through the combustion chamber 1, and the second gas delivery channel 32 is fixed on one side wall of the detonation panel 3 and is parallel to the first gas delivery channel 23, the second gas delivery channel 32 is connected with the aircraft gas tank through the third injection pipe 321 after passing through the combustion chamber 1.

[0034] The above arrangement makes the reverse flow path and the fuel injection path isolated by different pipelines, and the reverse flow (high pressure air flow) can be selected from air, nitrogen and inert gas. The fuel is combustible gas such as hydrogen, ethylene and methane. The reverse flow is distributed to each injection hole from the aircraft gas tank through a main pipeline. Similarly, the fuel injection is distributed to each injection hole from the aircraft gas tank through a main pipeline.

[0035] Further, in order to improve the stability of the formation of the bow shock wave, the plurality of fuel injection holes 22 and the plurality of second reverse flow holes 31 are arranged on the same horizontal plane.

[0036] Further, in order to better form the bow shock wave, the plurality of fuel injection holes 22 and the plurality of second reverse flow holes 31 are arranged one by one.

[0037] In another embodiment of the present application, the ratio of the total pressure of the gas flow injected from the plurality of first reverse flow 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 injected from the plurality of second reverse flow holes 31 to the total pressure of the supersonic incoming flow is 1: (0.2-0.8).

[0038] In a specific implementation, the ratio of the total pressure of the gas flow injected from the plurality of first reverse flow 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 injected from the plurality of second reverse flow holes 31 to the total pressure of the supersonic incoming flow is 1:0.3.

[0039] In another embodiment of the present application, the fuel injection support plate 2 is an isosceles triangular structure with a rounded tip or a wedge-shaped structure with a rounded tip, the shape of the ignition support plate 3 is the same as that of the fuel injection support plate 2, the plurality of first reverse flow holes 21 are arranged at the tip of the fuel injection support plate 2, the plurality of fuel injection holes 22 are arranged on the wall surface of the fuel injection support plate 2 opposite to the tip, the plurality of second reverse flow holes 31 are arranged at the tip of the ignition support plate 3, and the tips of the fuel injection support plate 2 and the ignition support plate 3 are arranged on the side of the combustion chamber 1 connected to the air inlet.

[0040] In another embodiment of the present application, the ignition support plate 3 and the fuel injection support plate 2 are suspended and fixed in parallel in the combustion chamber 1 and are located at 4 / 11-6 / 11 of the height of the combustion chamber 1. In a specific implementation, the ignition support plate 3 is arranged at 1 / 2 of the height of the combustion chamber 1, so that the oblique detonation wave is located at the center of the combustion chamber 1.

[0041] The working principle of the present application is as follows:

[0042] The combustion chamber 1 is connected with an air inlet channel, and the compressed supersonic flow passes through the air inlet channel. Meanwhile, a plurality of first reverse jet holes 21 arranged on the fuel injection support plate 2 inject high-pressure gas flow horizontally to the flow direction, the total pressure of the high-pressure gas flow is 0.2-0.8 times of the total pressure of the supersonic flow, and the high-pressure gas flow injected by the first reverse jet hole 21 pushes the supersonic flow away from the surface of the support plate 1 to form an arc-shaped shock wave (as shown in Figure 4 The total temperature of the high-pressure gas flow injected by the reverse jet hole is close to 300K, the static temperature is lower than 300K, the Mach number at the jet hole is 1, and the reverse jet gas composition can be selected from nitrogen and air. The low static temperature flow can effectively isolate the high-temperature flow from the surface of the fuel injection support plate 2, and plays a heat protection role on the fuel injection support plate 2.

[0043] Meanwhile, the fuel injection support plate 2 injects fuel through the fuel injection hole 22, the fuel mixes with the supersonic flow to form an explosive mixed gas flow to the downstream. A plurality of second reverse jet holes 31 arranged in front of the ignition support plate 3 inject high-pressure gas flow horizontally to the flow direction, the total pressure of the high-pressure gas flow is 0.2-0.8 times of the total pressure of the supersonic flow, the total temperature of the high-pressure gas flow injected by the reverse jet hole is close to 300K, the static temperature is lower than 300K, the Mach number at the jet hole is 1, and the reverse jet gas composition can be selected from nitrogen and air. The reverse jet pushes the supersonic flow away from the surface of the ignition support plate 3 to form an arc-shaped shock wave, the arc-shaped shock wave compresses the flow to ignite the explosive mixed gas to form an oblique detonation wave, and then the combustion products flow out of the outlet to generate thrust in the tail nozzle.

[0044] The feasibility of the present application is verified by experimental data, the Mach number of the flow is 4.2, the static pressure is 61000Pa, the static temperature is 857K, the total pressure of the reverse jet is 0.3 times of the total pressure of the supersonic flow, the ignition support plate 3 and the fuel injection support plate 2 are arranged at 1 / 2 of the height of the combustion chamber 1, the diameters of the first reverse jet hole and the second reverse jet hole are 1mm, and the experimental results are shown in Figure 9 , Figure 9 (a) is a flow field temperature cloud diagram without reverse jet, from the diagram, it can be seen that the highest temperature of the high-temperature layer at the front end of the support plate is higher than 3000K, which is far greater than the material bearing limit. As shown in Figure 9 (b), when the reverse jet hole is increased to perform reverse jet, the low-temperature layer formed by the reverse jet separates the high-temperature layer from the support plate, and the low-temperature layer can effectively protect the support plate. Meanwhile, Figure 10 (b) is a typical structure diagram of the reverse jet, which is composed of a bottle-shaped shock wave formed by the arc-shaped shock wave and the reverse jet.

[0045] The above disclosure is only a few preferred specific embodiments of the present application, but the embodiments of the present application are not limited thereto, and any changes that can be thought of by those skilled in the art should fall within the protection scope of the present application.

Claims

1. A centrally initiated oblique detonation engine, characterized by, The application relates to a fuel injection and ignition device for a combustion chamber (1), which comprises: a fuel injection support plate (2) fixedly arranged in the combustion chamber (1), a plurality of first reverse flow holes (21) being formed on the end face of the fuel injection support plate (2) facing the air inlet channel, the first reverse flow holes (21) being arranged along the width direction of the fuel injection support plate (2), a plurality of fuel injection holes (22) being formed on the end face of the fuel injection support plate (2) facing away from the air inlet channel, the fuel injection holes (22) being arranged along the width direction of the fuel injection support plate (2), a first gas conveying flow channel (23) and a fuel conveying flow channel (24) being formed in the fuel injection support plate (2), the first reverse flow holes (21) being connected with external high-pressure gas flow conveying devices through the first gas conveying flow channel (23), and the fuel injection holes (22) being connected with external fuel conveying devices through the fuel conveying flow channel (24); an ignition support plate (3) fixedly arranged in the combustion chamber (1), the ignition support plate (3) being arranged on the side of the fuel injection support plate (2) provided with the fuel injection holes (22) and being parallel to the fuel injection support plate (2), a plurality of second reverse flow holes (31) being formed on the end face of the ignition support plate (3) facing the fuel injection holes (22), the second reverse flow holes (31) being arranged along the width direction of the ignition support plate (3), and a second gas conveying flow channel (32) being formed in the ignition support plate (3), the second reverse flow holes (31) being connected with external high-pressure gas flow conveying devices through the second gas conveying flow channel (32).

2. The centrally initiated oblique detonation engine of claim 1, wherein, The first gas conveying flow channel (23) is formed 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 conveying flow channel (24) is formed on the other side wall of the fuel injection support plate (2) and is parallel to the first gas conveying flow channel (23), and the second gas conveying flow channel (32) is fixed on one side wall of the ignition support plate (3) and is parallel to the first gas conveying flow channel (23).

3. The centrally initiated oblique detonation engine of claim 2, wherein, The fuel injection holes (22) and the second reverse flow holes (31) are arranged on the same horizontal plane.

4. The centrally initiated oblique detonation engine of claim 3, wherein, The fuel injection holes (22) and the second reverse flow holes (31) are arranged in pairs.

5. The centrally initiated oblique detonation engine of claim 1, wherein, The ratio of the total pressure of the gas flow jetted out of the first reverse flow 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 jetted out of the second reverse flow holes (31) to the total pressure of the supersonic incoming flow is 1: (0.2-0.8).

6. The centrally initiated oblique detonation engine of claim 5, wherein, The ratio of the total pressure of the gas flow jetted out of the first reverse flow 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 jetted out of the second reverse flow holes (31) to the total pressure of the supersonic incoming flow is 1:0.

3.

7. The centrally initiated oblique detonation engine of claim 1, wherein, The fuel injection branch plate (2) is an isosceles triangle structure with rounded tip or a wedge structure with rounded tip, the shape of the ignition branch plate (3) is the same as that of the fuel injection branch plate (2), a plurality of first reverse jet holes (21) are arranged at the tip of the fuel injection branch plate (2), a plurality of fuel injection holes (22) are arranged on the wall surface of the fuel injection branch plate (2) opposite to the tip, a plurality of second reverse jet holes (31) are arranged at the tip of the ignition branch plate (3), and the tips of the fuel injection branch plate (2) and the ignition branch plate (3) are both arranged opposite to one side of the connecting inlet channel of the combustion chamber (1).

8. The centrally initiated oblique detonation engine of claim 1, wherein, The ignition branch plate (3) is arranged at 4 / 11-6 / 11 of the height of the combustion chamber (1).

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