High mach number ramjet with afterburner

Abstract

The application relates to the field of aerospace technology, in particular to a high-Mach number ramjet engine with an afterburner. The high-Mach number ramjet engine with the afterburner comprises an aircraft body, an engine lower wall surface and an air inlet; the aircraft body is internally provided with a fuel tank; an isolation section, a first combustion chamber and a nozzle section are arranged between the aircraft body and the engine lower wall surface; the side, away from the first combustion chamber, of the isolation section is provided with the air inlet; the high-Mach number ramjet engine with the afterburner further comprises a powder fuel injection assembly and a second combustion chamber; the powder fuel injection assembly is arranged on the aircraft body, and the second combustion chamber is formed between the first combustion chamber and the nozzle section; the powder fuel injection assembly can inject metal fuel into the second combustion chamber; the metal fuel can be subjected to secondary combustion with combustion products in the second combustion chamber; and the energy generated by the secondary combustion is used to improve the thrust of the aircraft.

Description

Technical Field

[0001] This application relates to the field of aerospace technology, and in particular to a high Mach number ramjet engine with an afterburner. Background Technology

[0002] Space-powered vehicles, characterized by hypersonic flight and round-trip air travel, have extremely high requirements for fuel energy density and combustion performance. Currently, the main power source for aerospace propulsion systems is hydrocarbon fuel, and the combustion performance of hydrocarbon fuel directly determines the performance of the vehicle, such as range, speed, and payload.

[0003] The theoretical maximum flight speed of existing high-Mach-number ramjet engines with afterburners and hydrocarbon fuels is Mach 8. Beyond this point, the heat of combustion is roughly equivalent to the incoming kinetic energy, resulting in insufficient fuel heat release and thus failing to generate effective net thrust. Therefore, for high-Mach-number ramjet engines with afterburners and hydrocarbon fuels operating at even higher Mach numbers, insufficient thrust will be a problem.

[0004] Regarding the aforementioned thrust deficiency, there are currently two typical solutions. The first solution is to reduce the internal flow resistance of the aircraft through methods such as boundary layer combustion and film drag reduction, thereby reducing drag and increasing net thrust. The second solution is to further increase thrust by increasing the combustion temperature. The second solution mainly focuses on researching hydrocarbon fuels containing high-energy metal particles, specifically: adding nano-sized metal particles, such as magnesium, aluminum, and boron, to hydrocarbon fuels. This allows the thermal energy of the metal particles to be released simultaneously during combustion, and the metal particles do not dissociate in the high-temperature inflow; however, the calorific value generated by this method still cannot meet the requirements, and this solution also prevents the aircraft from using hydrocarbon fuel for regenerative cooling due to the high viscosity of the fuel after adding metal particles.

[0005] Therefore, there is an urgent need for a high Mach number ramjet engine with an afterburner to solve, to some extent, the technical problems existing in the current technology. Summary of the Invention

[0006] The purpose of this application is to provide a high Mach number ramjet engine with an afterburner, so as to solve to some extent the technical problem in the prior art that the engine cannot generate effective net thrust due to insufficient heat release from fuel combustion during high Mach number flight.

[0007] This application provides a high Mach number ramjet engine with an afterburner, including an aircraft body, an engine lower wall, and an air intake; the aircraft body contains a fuel tank; an isolation section, a first combustion chamber, and a nozzle section are arranged sequentially along a first direction between the aircraft body and the engine lower wall; the isolation section has an air intake on the side away from the first combustion chamber; the air intake is used to compress a high enthalpy inflow, the compressed high enthalpy inflow passes through the isolation section and burns with hydrocarbon fuel released from the fuel tank in the first combustion chamber, and the combustion products generated by the high enthalpy inflow and the fuel combustion are ejected from the nozzle section;

[0008] The high Mach number ramjet engine with an afterburner also includes a powder fuel injection assembly and a second combustion chamber;

[0009] The powder fuel injection assembly is disposed on the main body of the aircraft, and the second combustion chamber is formed between the first combustion chamber and the nozzle section;

[0010] The powder fuel injection assembly can inject metallic fuel into the second combustion chamber, where the metallic fuel can undergo secondary combustion with the combustion products. The energy generated by the secondary combustion is used to increase the thrust of the aircraft.

[0011] In the above technical solution, the powder fuel injection assembly further includes an injector, an electrical conduit, a power supply, and a metal fuel storage component.

[0012] One end of the attached electric tube is connected to the metal fuel storage component and the other end is connected to the injector; the metal fuel storage component can inject metal fuel into the injector through the attached electric tube.

[0013] The power source is electrically connected to the attached tube so that the metallic fuel passing through the attached tube is positively charged.

[0014] The injector contains a solenoid carrying a constant current, which generates a magnetic field along its axis to cause the positively charged metallic fuel to move circumferentially within the injector.

[0015] In the above technical solution, the bottom of the injector has a tapered structure.

[0016] In the above technical solution, the metal fuel storage component further includes a housing and a piston;

[0017] The piston is disposed on the housing and divides the housing into a first area and a second area. The first area is used to store high-pressure gas source and the second area is used to store metal fuel.

[0018] The high-pressure gas source can drive the piston, so that the piston pushes the metal fuel into the injector.

[0019] In the above technical solution, a heat exchange pipeline is further included. The heat exchange pipeline extends along the side wall of the aircraft body and is connected to the fuel tank. It can exchange heat with the fuel exported from the fuel tank. At least a portion of the heat-exchanged fuel can be introduced into the powder fuel injection assembly through the second pipeline, and at least another portion can be introduced into the first combustion chamber through the hydrocarbon fuel injector.

[0020] In the above technical solution, the opening end of the first concave cavity faces the first combustion chamber;

[0021] The fuel tank is connected to the first cavity via a hydrocarbon fuel injector, and the hydrocarbon fuel injector and the first cavity are at a first preset angle. The side wall of the first cavity away from the air intake is at a second preset angle to the bottom wall of the aircraft.

[0022] The fuel in the fuel tank is injected into the first cavity at the first preset angle; the first cavity enables the high-speed, high-enthalpy incoming flow to form a low-speed recirculation zone at that location, so that the hydrocarbon fuel and the high-enthalpy incoming flow can burn stably.

[0023] In the above technical solution, the first preset angle is further set between 20° and 50°; the second preset angle is set between 20° and 50°.

[0024] The ratio of the length of the opening end of the first cavity to the depth of the first cavity is set between 7 and 10.

[0025] In the above technical solution, a second cavity is further formed on the side wall of the aircraft body facing the second combustion chamber, and the opening end of the second cavity faces the second combustion chamber;

[0026] The injector is connected to the second cavity via a powder fuel injector, and the powder fuel injector and the second cavity are at a third preset angle. The side wall of the second cavity away from the air intake is at a fourth preset angle to the bottom wall of the aircraft.

[0027] The metal fuel in the injector is injected into the second cavity at the third preset angle; when the combustion products generated after combustion in the first combustion chamber enter the second combustion chamber, they can form a backflow in the second cavity so that the metal fuel and the combustion products can burn stably.

[0028] In the above technical solution, the third preset angle is further set between 30° and 90°; the fourth preset angle is set between 30° and 90°.

[0029] The ratio of the length of the opening end of the second cavity to the depth of the second cavity is less than or equal to 7.

[0030] In the above technical solution, the compression surface of the air intake is further compressed using four oblique shock waves, and the compression surface has four deflection angles.

[0031] Compared with the prior art, the beneficial effects of this application are as follows:

[0032] This application provides a high Mach number ramjet engine with an afterburner, comprising an aircraft body, an engine lower wall, and an air intake; the aircraft body contains a fuel tank; an isolation section, a first combustion chamber, and a nozzle section are arranged sequentially along a first direction between the aircraft body and the engine lower wall; the isolation section has an air intake on the side away from the first combustion chamber; the air intake is used to compress a high enthalpy inflow, the compressed high enthalpy inflow passes through the isolation section and burns with fuel released from the fuel tank in the first combustion chamber, and the combustion products generated by the high enthalpy inflow and the fuel combustion are ejected from the nozzle section;

[0033] The high Mach number ramjet engine with an afterburner also includes a powder fuel injection assembly and a second combustion chamber;

[0034] The powder fuel injection assembly is disposed on the main body of the aircraft, and the second combustion chamber is formed between the isolation section and the first combustion chamber;

[0035] The powder fuel injection assembly can inject metallic fuel into the second combustion chamber, where the metallic fuel can undergo secondary combustion with the combustion products. The energy generated by the secondary combustion is used to increase the thrust of the aircraft.

[0036] Specifically, this application ingeniously utilizes the combustion products (mainly nitrogen, carbon dioxide, and water) of hydrocarbon fuel and high-enthalpy air flowing into the first combustion chamber, allowing them to undergo secondary combustion with magnesium fuel, thereby increasing the upper limit of the actual fuel-to-gas ratio. Specifically, the combustion of magnesium metal and combustion products releases heat to further increase the maximum operating temperature of the aircraft, thereby achieving a higher flight Mach number. This overcomes the problem in the prior art where insufficient heat release from fuel combustion during high Mach number flight prevents the generation of effective net thrust. Attached Figure Description

[0037] To more clearly illustrate the technical solutions in the specific embodiments of this application or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0038] Figure 1 This is a schematic diagram of the structure of a high Mach number ramjet engine with an afterburner provided in Embodiment 1 of this application;

[0039] Figure 2 A schematic diagram of the injector in a high Mach number ramjet engine with an afterburner provided in Embodiment 1 of this application;

[0040] Figure 3 A schematic diagram of the intake duct in a high Mach number ramjet engine with an afterburner provided in Embodiment 1 of this application;

[0041] Figure 4 This is a schematic diagram of the structure of a high Mach number ramjet engine with an afterburner provided in Embodiment 2 of this application.

[0042] Figure label:

[0043] 1-Air intake; 2-Isolation section; 3-First combustion chamber; 4-Second combustion chamber; 5-Nozzle section; 6-Aircraft body; 7-Heat exchange pipeline; 8-Fuel tank; 9-Powder fuel injection assembly; 10-Box; 11-Piston; 12-Second region; 13-First cavity; 14-Second cavity; 15-Second pipeline; 16-Injector; 17-Electrified conduit; 18-Power supply; 19-Solenoid; 20-Converging structure; 21-Powder fuel injector; 22-First compression surface; 23-Second compression surface; 24-Third compression surface; 25-Fourth compression surface; 26-Engine lower wall; 27-First direction; 29-Metallic fuel storage component; 30-Hydrocarbon fuel injector. Detailed Implementation

[0044] The technical solutions of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of this application, but not all embodiments.

[0045] The components of the embodiments of this application described and shown in the accompanying drawings can be arranged and designed in a variety of different configurations. Therefore, the following detailed description of the embodiments of this application provided in the drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application.

[0046] Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0047] In the description of this application, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0048] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0049] Example 1

[0050] Combination Figure 1As shown, this application provides a high Mach number ramjet engine with an afterburner, including an aircraft body 6, an engine lower wall 26, and an air intake 1; specifically, the aircraft body 6 has a fuel tank 8, which stores hydrocarbon fuel; specifically, an isolation section 2, a first combustion chamber 3, and a nozzle section 5 are arranged sequentially along a first direction 27 (here, the first direction 27 refers to the length direction of the aircraft body 6) between the aircraft body 6 and the engine lower wall 26; the isolation section 2 has an air intake 1 on the side away from the first combustion chamber 3; wherein, the air intake 1 is used to compress the high enthalpy air flow, so that the high enthalpy air flow entering the first combustion chamber 3 has a higher temperature and pressure, and reduces the flow velocity of the high enthalpy air flow; wherein, the isolation section 2 isolates the air intake 1 from the first combustion chamber 3 through shock wave action; The hydrocarbon fuel stored and released from the fuel tank is mixed with high-enthalpy air and combusted in the first combustion chamber 3 to release heat. The combustion products generated after combustion can be ejected through the nozzle section 5, generating a certain thrust. Specifically, in order to further improve the thrust, the high Mach number ramjet engine with afterburner also includes a powder fuel injection assembly 9 and a second combustion chamber 4. Further, the powder fuel injection assembly 9 is disposed in the main body 6 of the aircraft, and the second combustion chamber 4 is formed between the nozzle section 5 and the first combustion chamber 3. The powder fuel injection assembly 9 can inject metallic fuel into the second combustion chamber 4. The metallic fuels include, for example, magnesium, aluminum, lithium, beryllium, etc. In this embodiment, magnesium is used as an example. The magnesium fuel can undergo secondary combustion with the combustion products in the second combustion chamber 4, and the energy generated by the secondary combustion can further improve the thrust of the aircraft.

[0051] In summary, this application ingeniously utilizes the combustion products (mainly nitrogen, carbon dioxide, and water, which are inert working fluids for the engine) of hydrocarbon fuel and high-enthalpy air flowing in the first combustion chamber 3 to achieve secondary combustion with magnesium fuel, thereby increasing the upper limit of the actual fuel-to-air ratio. Specifically, the combustion of magnesium metal and combustion products releases heat to further increase the maximum operating temperature of the aircraft, thereby achieving a higher flight Mach number. This overcomes the problem in the prior art where insufficient heat release from fuel combustion during high Mach number flight prevents the generation of effective net thrust.

[0052] In this embodiment, combined with Figure 2 As shown, the powder fuel injection assembly 9 includes an injector 16, an electrical conduit 17, a power supply 18, and a metal fuel storage component 29. Specifically, the metal fuel storage component 29 includes a housing 10 and a piston 11. The piston 11 is disposed in the housing 10 and divides the housing 10 into a first region and a second region 12. The first region is used to store a high-pressure gas source, and the second region 12 is used to store metal fuel. In actual use, the high-pressure gas source can push the piston 11 so that the piston 11 pushes the metal fuel into the injector 16.

[0053] Preferably, the injector 16 is a cylindrical injector 16.

[0054] Specifically, one end of the energized tube 17 is connected to the housing 10 and the other end is connected to the injector 16; magnesium fuel is finally injected into the injector 16 through the energized tube 17; the power supply 18 is electrically connected to the energized tube 17; the injector 16 has a solenoid 19 that carries a constant current. Specifically, the bottom of the injector 16 has a tapered structure 20.

[0055] Specifically, it also includes a heat exchange pipeline 7, which extends along the side wall of the aircraft body 6 and is connected to the fuel tank 8. It can exchange heat with the fuel discharged from the fuel tank. At least a portion of the heat-exchanged fuel can be introduced into the powder fuel injection assembly 9 through the second pipeline 15, and at least another portion can be introduced into the first combustion chamber 3 through the hydrocarbon fuel injector 30.

[0056] In actual operation: hydrocarbon fuel is output from fuel tank 8 to heat exchange pipeline 7. At room temperature, the hydrocarbon fuel absorbs a large amount of heat as it flows through the inner surface of the aircraft fuselage, causing its temperature and pressure to rise rapidly and quickly reach a supercritical state, forming high-temperature, high-pressure pyrolysis gas. The main components of the pyrolyzed fuel are small-molecule gases such as methane, ethylene, and propane. These gases continue to pass through heat exchange, with the majority being injected into the first combustion chamber 3. The pyrolyzed hydrocarbon fuel is fully combusted in the first combustion chamber 3, raising the temperature to 2500K before entering the second combustion chamber 4. The combustion gas entering the second combustion chamber 4 mainly consists of nitrogen, carbon dioxide, and water vapor. At this point, the high-pressure gas source controls the piston 11 to push the magnesium fuel in the housing 10 to the injector 16 for dispersion. Before entering the injector 16, the magnesium fuel (magnesium powder) acquires a positive charge in the electrified tube 17, achieved through a power supply 18 connected to the metal electrified tube 17. Positively charged magnesium powder enters the injector 16 radially with a certain initial velocity. A solenoid 19 carrying a constant current runs along the inner wall of the cylindrical injector 16, generating a magnetic field along its axis. This causes the magnesium powder with radial initial velocity to move circumferentially along the inner wall of the injector 16. A small portion of the high-pressure cracked gas in the heat exchange tube is injected axially into the injector 16 through the second pipeline 15, further dispersing the magnesium powder and carrying it into the second combustion chamber 4. To improve injection stability and speed, an inverted conical constriction slope is designed at the bottom of the metal powder injector 16. The gas accelerates and contracts towards the center as it flows through this slope, and is then injected into the second combustion chamber 4 through the powder fuel injector 21. In the second combustion chamber 4, the magnesium powder is fully mixed with the combustion products and undergoes combustion and heat release. Before entering the tail section, the gas temperature reaches approximately 2800K. The supersonic, high-temperature exhaust gas expands and does work through the high-speed tail nozzle, thus propelling the aircraft to fly at higher Mach numbers.

[0057] It is worth noting that, in order to achieve gas-solid two-phase flow congestion within the powder fuel injector 21, the upstream pressure is at least twice the pressure of the second combustion chamber 4. To reduce the maximum cross-sectional size of the aircraft while improving its performance, the nozzle exit pressure is designed to be 1.5 times the ambient pressure.

[0058] In summary, this application utilizes the regenerative cooling function of hydrocarbon fuels to enable high Mach number ramjet engines with afterburners powered by hydrocarbon fuels to be applied to even higher Mach numbers.

[0059] In this embodiment, the compression surface of the air intake is compressed using four oblique shock waves.

[0060] Specifically, the aircraft is designed to cruise at Mach 8. Therefore, the high-enthalpy incoming flow is first compressed through the intake duct 1. Preferably, the intake duct 1 uses four oblique shock waves for compression to decelerate and pressurize the high-speed incoming flow. At the outlet of the intake duct 1, the gas velocity is reduced from Mach 8.0 to Mach 3.0. Then, after passing through the isolation section 2, it enters the first combustion chamber 3.

[0061] Preferably, combined with Figure 3 As shown, the wedge angle α of the first compression surface 22 is 6.8°, the wedge angle β of the second compression surface 23 is 8.4°, the wedge angle γ of the third compression surface 24 is 10.5°, and the wedge angle of the fourth compression surface 25 is... After the high-speed incoming flow passes through intake 1, the static pressure ratio (static pressure at intake 1 outlet / static pressure of incoming flow) is 118, and the static temperature ratio (static temperature at intake 1 outlet / ambient temperature of incoming flow) is 4.7.

[0062] It is worth noting that the ratio of the outlet area of ​​the first combustion chamber 3 to the outlet area of ​​the isolation section 2 is 2.46, the ratio of the outlet area of ​​the second combustion chamber 4 to the inlet area is 1.37, and the ratio of the outlet area of ​​the high-speed tail injection section to the inlet area of ​​the intake pipe is 3.48.

[0063] Example 2

[0064] In this embodiment, combined with Figure 4 As shown, a first cavity 13 is formed on the side wall of the aircraft body 6 facing the first combustion chamber 3, and the opening end of the first cavity 13 faces the first combustion chamber 3; the fuel tank 8 is connected to the first cavity 13 through a hydrocarbon fuel injector 30, and the hydrocarbon fuel injector 30 and the first cavity 13 are at a first preset angle, and the side wall of the first cavity 13 away from the air intake 1 is at a second preset angle to the bottom wall of the aircraft; the fuel in the fuel tank 8 is injected into the first cavity 13 at the first preset angle; the first cavity enables the high-speed, high-enthalpy incoming flow to form a low-speed recirculation zone at this position, so that the hydrocarbon fuel and the high-enthalpy incoming flow can burn stably.

[0065] Furthermore, the first preset angle is set between 20° and 50°; the second preset angle is set between 20° and 50°, preferably, both the first preset angle and the second preset angle are 45°; the ratio of the length L1 of the opening end of the first cavity 13 to the depth L2 of the first cavity 13 is set between 3 and 5.

[0066] Preferably, the first preset angle is 45°; the second preset angle is 22°; and the ratio of the length of the opening end of the first cavity 13 to the depth of the first cavity 13 is 4.

[0067] In this embodiment, a second cavity 14 is formed on the side wall of the aircraft body 6 facing the second combustion chamber 4, and the opening end of the second cavity 14 faces the second combustion chamber 4; the injector 16 is connected to the second cavity 14 through the powder fuel injector 21, and the powder fuel injector 21 and the second cavity 14 are at a third preset angle, and the side wall of the second cavity 14 away from the air intake 1 is at a fourth preset angle with the bottom wall of the aircraft; the metal fuel in the injector 16 is injected into the second cavity 14 at the third preset angle; when the combustion products generated after combustion in the first combustion chamber 3 enter the second combustion chamber 4, they can form a backflow in the second cavity 14, so that the metal fuel and combustion products can burn at low temperature and high speed.

[0068] Furthermore, the third preset angle is set between 30° and 90°; the fourth preset angle is set between 30° and 90°; the ratio of the length L3 of the opening end of the second cavity 14 to the depth L4 of the second cavity 14 is less than or equal to 7.

[0069] Preferably, the third preset angle is 45°; the fourth preset angle is 25°; and the ratio of the length of the opening end of the second cavity 14 to the depth of the second cavity 14 is 5.

[0070] In summary, since the high-enthalpy incoming flow still maintains a velocity of 3.0 Ma after being decelerated through the intake pipe, a stable low-speed, high-temperature combustion zone is maintained in the first combustion chamber 3 by utilizing the recirculation zone (backflow) generated when the high-enthalpy incoming flow passes through the first cavity 13. Furthermore, the backflow zone of the second cavity 14 allows the magnesium powder to fully combust with the combustion products generated after combustion in the first combustion chamber.

[0071] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A high Mach number ramjet engine with an afterburner, comprising an aircraft body, an engine lower wall, and an air intake; the aircraft body contains a fuel tank; an isolation section, a first combustion chamber, and a nozzle section are arranged sequentially along a first direction between the aircraft body and the engine lower wall; the isolation section has an air intake on the side away from the first combustion chamber; the air intake is used to compress a high enthalpy inflow, the compressed high enthalpy inflow passes through the isolation section and combusts with hydrocarbon fuel released from the fuel tank in the first combustion chamber, and the combustion products generated by the high enthalpy inflow and the fuel combustion are ejected from the nozzle section; characterized in that The high Mach number ramjet engine with an afterburner also includes a powder fuel injection assembly and a second combustion chamber; The powder fuel injection assembly is disposed on the main body of the aircraft, and the second combustion chamber is formed between the first combustion chamber and the nozzle section; The powder fuel injection assembly can inject metallic fuel into the second combustion chamber, where the metallic fuel can undergo secondary combustion with the combustion products. The energy generated by the secondary combustion is used to increase the thrust of the aircraft. The compression surface of the inlet passage adopts 4 inclined shock waves for compression to form a first compression surface, a second compression surface, a third compression surface and a fourth compression surface; the wedge angle α of the first compression surface (22) is 6.8°, the wedge angle β of the second compression surface (23) is 8.4°, the wedge angle γ of the third compression surface (24) is 10.5°, and the wedge angle of the fourth compression surface (25) is 17.1°. 17.1°. The ratio of the outlet area of ​​the first combustion chamber to the outlet area of ​​the isolation section is 2.46, the ratio of the outlet area of ​​the second combustion chamber to the inlet area is 1.37, and the ratio of the outlet area of ​​the nozzle section to the inlet area of ​​the intake duct is 3.

48. The powder fuel injection assembly includes an injector, an electrical conduit, a power source, and a metal fuel storage component; One end of the attached electric tube is connected to the metal fuel storage component and the other end is connected to the injector; the metal fuel storage component can inject metal fuel into the injector through the attached electric tube. The power source is electrically connected to the attached tube so that the metallic fuel passing through the attached tube is positively charged. The injector contains a solenoid carrying a constant current, which generates a magnetic field along its axis to cause the positively charged metallic fuel to move circumferentially within the injector. The bottom of the injector has a tapering structure; The metal fuel storage component includes a housing and a piston; The piston is disposed on the housing and divides the housing into a first area and a second area. The first area is used to store high-pressure gas source and the second area is used to store metal fuel. The high-pressure gas source can drive the piston, causing the piston to push the metallic fuel into the injector; It also includes a heat exchange pipeline that extends along the side wall of the aircraft body and is connected to the fuel tank. The heat exchange pipeline is capable of exchanging heat with the fuel discharged from the fuel tank. At least a portion of the heat-exchanged fuel can be introduced into the powder fuel injection assembly through a second pipeline, and at least another portion can be introduced into the first combustion chamber through a hydrocarbon fuel injector. The aircraft body has a second cavity formed on the side wall facing the second combustion chamber, and the opening end of the second cavity faces the second combustion chamber; The injector is connected to the second cavity via a powder fuel injector, and the powder fuel injector and the second cavity are at a third preset angle. The side wall of the second cavity away from the air intake is at a fourth preset angle to the bottom wall of the aircraft. The metal fuel in the injector is injected into the second cavity at the third preset angle; when the combustion products generated after combustion in the first combustion chamber enter the second combustion chamber, they can form a backflow in the second cavity so that the metal fuel and the combustion products can burn stably.

2. The high Mach number ramjet engine with an afterburner according to claim 1, characterized in that, The aircraft body has a first cavity formed on the side wall facing the first combustion chamber, and the opening end of the first cavity faces the first combustion chamber; The fuel tank is connected to the first cavity via a hydrocarbon fuel injector, and the hydrocarbon fuel injector and the first cavity are at a first preset angle. The side wall of the first cavity away from the air intake is at a second preset angle to the bottom wall of the aircraft. The fuel in the fuel tank is injected into the first cavity at the first preset angle; at the location of the first cavity, the high-speed, high-enthalpy inflow can form a low-speed recirculation zone, so that the hydrocarbon fuel and the high-enthalpy inflow can burn stably.

3. The high Mach number ramjet engine with an afterburner according to claim 2, characterized in that, The first preset angle is set between 20° and 50°; the second preset angle is set between 20° and 50°. The ratio of the length of the opening end of the first cavity to the depth of the first cavity is set between 7 and 10.

4. The high Mach number ramjet engine with an afterburner according to claim 1, characterized in that, The third preset angle is set between 30° and 90°; the fourth preset angle is set between 30° and 90°. The ratio of the length of the opening end of the second cavity to the depth of the second cavity is less than or equal to 7.

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