A microwave-based jet engine afterburner

Abstract

This application discloses a microwave-based jet engine afterburner, belonging to the field of thermomechanical technology. It includes a microwave heating mechanism, whose microwave generator comprises a cathode electron source, a heating component, a ring-shaped metal anode, an electromagnet, and a DC power supply component. The cathode electron source is located at the center of the ring-shaped metal anode. The heating component causes the cathode electron source to emit free electrons. The DC power supply component supplies power to the cathode electron source and the ring-shaped metal anode to form a DC electric field and supplies power to the electromagnet to generate a magnetic field orthogonal to the DC electric field. The strip-shaped groove within the ring-shaped metal anode serves as a microwave resonant cavity. The movement of free electrons excites microwaves, which are used to heat the exhaust gas from the engine's main combustion chamber. The microwave generator is coaxially positioned within the gas flow channel. This device replaces traditional afterburning with microwave heating, offering faster heating speed, a more compact structure, and improved thermal efficiency of the afterburner, solving the problems of easy flameout and low combustion efficiency in traditional afterburner combustion chambers.

Description

Technical Field

[0001] This application relates to the field of thermal machinery, and more particularly to a microwave-based jet engine afterburner. Background Technology

[0002] Jet engines generate thrust by heating high-pressure air through fuel combustion and then accelerating it outwards. Essentially, this process converts the internal energy of the high-pressure air into kinetic energy, and ensuring the high-pressure air receives sufficient heat is crucial for generating adequate thrust. To meet the demand for greater thrust in a short time, jet engines also incorporate an afterburner between the turbine and the exhaust nozzle. The afterburner further enhances the internal energy and exhaust velocity of the combustion gases by supplementing the high-enthalpy inlet flow, thereby increasing thrust. However, due to the high inlet velocity and low oxygen content, the afterburner operates under extremely harsh combustion conditions, facing challenges such as flameout and low combustion efficiency. Summary of the Invention

[0003] In view of this, this application provides a microwave-based jet engine afterburner, which solves the problems in the prior art and improves the thermal efficiency and structural compactness of the afterburner.

[0004] The microwave-based jet engine afterburner provided in this application adopts the following technical solution:

[0005] A microwave-based jet engine afterburner includes a microwave heating mechanism, which includes a microwave generator, comprising a cathode electron source, a heating component, a ring-shaped metal anode, an electromagnet, and a DC power supply component.

[0006] The cathode electron source is located at the axial center inside the annular metal anode. The heating component is used to heat the cathode electron source to make it emit free electrons. The DC power supply component is used to supply power to the cathode electron source and the annular metal anode to form a DC potential difference between them, thereby forming a DC electric field between them. The DC electric field provides kinetic energy to the free electrons, driving them to move towards the annular metal anode. Electromagnets are provided at both ends of the annular metal anode. The DC power supply component is also used to supply power to the electromagnets to generate a magnetic field orthogonal to the DC electric field.

[0007] The microwave generator is located inside the gas flow channel of the jet engine, and the annular metal anode is coaxially arranged with the jet engine. The inner wall of the annular metal anode is provided with several strip grooves. The length of the strip grooves extends along the axial direction of the annular metal anode. The strip grooves serve as microwave resonant cavities. Free electrons move around the strip grooves, causing the internal charge to change periodically to excite microwaves. The excited microwaves are used to heat the gas exhaust from the main combustion chamber of the jet engine.

[0008] Optionally, the microwave generator is used to be mounted on the turbine shaft of a jet engine, and the microwave generator is located between the two ends of the turbine shaft, with the annular metal anode being coaxially arranged with the turbine shaft.

[0009] Optionally, the annular metal anode and the turbine shaft are fixedly connected so that the annular metal anode rotates with the turbine shaft.

[0010] Optionally, the total power supplied to the microwave heating mechanism to form the DC electric and magnetic fields is... The total power supplied to the microwave heating mechanism to form a DC electric field and a magnetic field. Calculated using the following formula:

[0011] ;

[0012] in, For turbine efficiency, The electrothermal conversion efficiency of the microwave heating mechanism. For gas mass flow rate, For isobaric specific heat, This refers to the turbine inlet temperature. The turbine pressure ratio, This refers to the specific heat ratio of the fuel gas.

[0013] Optionally, the microwave heating mechanism further includes an annular microwave reflector wall surrounding the annular metal anode and located on the inner wall of the outer ring of the gas flow channel of the jet engine.

[0014] Optionally, the microwave generator is used to be installed on the side of the turbine shaft of the jet engine facing the exhaust end of the jet engine and / or at the axial position of the jet engine tail nozzle.

[0015] Optionally, the heat transfer power of the annular metal anode is greater than the power loss of the microwave heating mechanism;

[0016] The formula for calculating the upper limit of heat transfer power of annular metal anodes is:

[0017] ;

[0018] ;

[0019] in, The heat transfer power of the annular metal anode is [value missing]. The heat transfer coefficient, The heat transfer area is the outer surface of the annular metal anode. The temperature of the outer wall of the annular metal anode. The temperature of the incoming gas flow around the outer periphery of the annular metal anode is [temperature value missing]. For Nusselt numbers, D The outer diameter of the annular metal anode, The thermal conductivity of the gas;

[0020] The formula for calculating the power loss of a microwave heating mechanism is as follows:

[0021] ;

[0022] in, The power loss of the microwave heating mechanism. The total power supply for generating the DC electric and magnetic fields of the microwave heating mechanism. The electrothermal conversion efficiency of the microwave heating mechanism.

[0023] Optionally, the cathode electron source has a hollow structure, and the heating component is an air intake channel and / or a heating resistance wire located inside the cathode electron source;

[0024] The air intake passage is provided with an air intake connector and an exhaust connector at both ends, and the air intake connector is used to introduce combustion gases from the main combustion chamber of the jet engine.

[0025] In summary, this application includes the following beneficial technical effects:

[0026] This application applies microwaves to a high-enthalpy incoming flow, where water molecules are subjected to a high-frequency electromagnetic field, causing them to vibrate at high frequencies. Through intermolecular interactions, they transfer energy to other air molecules, ultimately achieving overall heating and acceleration of the high-enthalpy incoming flow. The microwave heating mechanism of this application forms an afterburner with advantages of simple structure and lightweight design. Its electrical energy consumption is supplied by a generator driven by the engine or a high-power battery, making it particularly suitable for future hybrid electric engines with higher power generation capabilities. Compared to traditional afterburners that heat the high-enthalpy incoming flow through fuel combustion, microwaves propagate at the speed of light, resulting in rapid heating and significantly reducing the length of the afterburner, potentially reducing the weight of the jet engine. Furthermore, it eliminates the need to consider fuel supply and flame stabilization issues, reducing flow resistance losses associated with traditional afterburner fuel nozzles and flame stabilizers.

[0027] This application adjusts the total power supply to the microwave heating mechanism to generate the DC electric and magnetic fields, making the total power supply equal to the total power supply through the microwave heating mechanism to generate the DC electric and magnetic fields. The calculated value of the formula can realize isothermal interstage heating, thereby transforming the adiabatic expansion process of the turbine in the Brayton cycle of a jet engine into an isothermal expansion process, converting all the heat energy output by microwave heating into shaft work to drive the turbine, making the overall thermodynamic cycle process closer to the Carnot cycle, thereby improving thermal efficiency. Attached Figure Description

[0028] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 This is a schematic diagram of the microwave generator of this application;

[0030] Figure 2 This is a schematic diagram of the internal structure of the microwave generator of this application;

[0031] Figure 3 This is a schematic diagram of a microwave generator installed between the two ends of a turbine shaft.

[0032] Figure 4 A schematic diagram of a microwave generator installed on the side of the turbine shaft facing the exhaust end of the jet engine;

[0033] Figure 5 This is a schematic diagram of a microwave generator installed between a high-pressure turbine shaft and a low-pressure turbine shaft.

[0034] Figure 6 This is a schematic diagram of a microwave generator installed in the tail nozzle.

[0035] Explanation of reference numerals in the attached drawings: 1. Microwave generator; 11. Cathode electron source; 12. Annular metal anode; 13. Electromagnet; 14. DC power supply assembly; 15. Support; 16. Air intake channel; 17. Air intake connector; 18. Exhaust connector; 2. Microwave reflector wall; 3. Turbine shaft; 31. High-pressure turbine shaft; 32. Low-pressure turbine shaft; 33. Tail nozzle. Detailed Implementation

[0036] The embodiments of this application will now be described in detail with reference to the accompanying drawings.

[0037] The following specific examples illustrate the implementation of this application. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. This application can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this application. It should be noted that, in the absence of conflict, the following embodiments and features in the embodiments can be combined with each other. 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.

[0038] It should be noted that various aspects of embodiments within the scope of the appended claims are described below. It will be apparent that the aspects described herein can be embodied in a wide variety of forms, and any particular structure and / or function described herein is merely illustrative. Based on this application, those skilled in the art will understand that one aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number of aspects set forth herein can be used to implement the device and / or practice the method. Additionally, this device and / or method can be implemented using structures and / or functionalities other than one or more of the aspects set forth herein.

[0039] It should also be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of this application. The illustrations only show the components related to this application and are not drawn according to the number, shape and size of the components in actual implementation. In actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0040] Furthermore, specific details are provided in the following description to facilitate a thorough understanding of the examples. However, those skilled in the art will understand that the described aspects can be practiced without these specific details.

[0041] This application provides a microwave-based jet engine afterburner.

[0042] like Figure 1 and Figure 2 As shown, a microwave-based jet engine afterburner includes a microwave heating mechanism and a connecting structure. The microwave heating mechanism includes a microwave generator 1, which includes a cathode electron source 11, a heating component, an annular metal anode 12, an electromagnet 13, and a DC power supply component 14.

[0043] The cathode electron source 11 is located at the axial center inside the annular metal anode 12. The heating assembly is used to heat the cathode electron source 11 so that it emits free electrons. The DC power supply assembly 14 is used to supply power to the cathode electron source 11 and the annular metal anode 12, creating a DC potential difference between them, thereby forming a DC electric field between them. This DC electric field provides kinetic energy to the free electrons, driving them to move towards the annular metal anode 12. Electromagnets 13 are provided at both ends of the annular metal anode 12. The current supply component 14 is also used to supply power to the electromagnet 13 to generate a magnetic field orthogonal to the DC electric field. The microwave generator 1 is located inside the gas flow channel of the jet engine, and the annular metal anode 12 is coaxially arranged with the jet engine. The inner wall of the annular metal anode 12 has several strip-shaped grooves, the length of which extends along the axial direction of the annular metal anode 12. These grooves serve as microwave resonant cavities, where free electrons move around the grooves, causing periodic changes in internal charge to excite microwaves. The excited microwaves are used to heat the exhaust gas from the main combustion chamber of the jet engine. A connection structure is used to install the microwave generator 1 inside the gas flow channel of the jet engine.

[0044] The cathode electron source 11 is made of pure tungsten, thorium tungsten, or lanthanum hexaboride; the annular metal anode 12 is made of pure molybdenum.

[0045] The high-enthalpy incoming stream generated by combustion in the main combustion chamber of a jet engine contains abundant water vapor. Water molecules, being typical polar molecules, can be heated by microwave irradiation. This application applies microwaves to the high-enthalpy incoming stream, where water molecules are subjected to a high-frequency electromagnetic field, causing high-frequency vibrations. Through intermolecular interactions, they transfer energy to other air molecules, ultimately achieving overall heating and acceleration of the high-enthalpy incoming stream. Regarding microwave emission, the cathode electron source 11 emits free electrons under the combined action of heating and a high-voltage electric field. These electrons move in a spiral or cycloidal motion within a conductive resonant cavity with orthogonal high-voltage DC electric and magnetic fields, using the kinetic energy gained in the high-voltage DC electric field to drive a high-frequency change in the charge distribution of the resonant cavity, generating a high-frequency electromagnetic field with the same frequency as the microwaves. This generates strong microwave radiation outside the resonant cavity. The microwave heating mechanism of this application forms a power-enhancing device with advantages of simple structure and lightweight design. Its electrical energy consumption is supplied by a generator driven by the engine or a high-power battery, making it particularly suitable for future hybrid electric engines with higher power generation capabilities. Compared to traditional afterburners that heat high-enthalpy streams through fuel combustion, microwaves travel at the speed of light, resulting in rapid heating. This can significantly shorten the length of the afterburner, potentially reducing the weight of jet engines. Furthermore, it eliminates the need to consider fuel supply and flame stabilization, reducing flow resistance losses associated with traditional afterburner fuel nozzles and flame stabilizers.

[0046] like Figure 3 As shown, the microwave heating mechanism also includes an annular microwave reflector wall 2, which surrounds the annular metal anode 12 and is located on the inner wall of the outer ring of the gas flow channel of the jet engine. The microwave reflector wall 2 is used to reflect the microwaves emitted by the microwave generator 1, avoiding microwave energy waste caused by microwave heating of the gas flow channel wall and protecting the gas flow channel wall from overheating. The microwave reflector wall 2 is embedded in the inner wall of the outer ring of the gas flow channel, and the inner ring surface of the microwave reflector wall 2 is coplanar with the inner wall surface of the outer ring of the gas flow channel. In a specific embodiment, the microwave reflector wall 2 can be made of copper, aluminum, or stainless steel. The inner ring reflective surface of the microwave reflector wall 2 is polished to a smooth finish, and a silver / nickel coating can also be considered to further improve its reflectivity.

[0047] In one embodiment, the DC power supply component 14 includes a power supply circuit and a control circuit. The power supply circuit is used to convert the alternating current of the generator into direct current to power the cathode electron source 11, the annular metal anode 12 and the electromagnet 13. The control circuit can be responsible for adjusting the potential difference between the cathode electron source 11 and the annular metal anode 12 and the magnetic field strength of the electromagnet 13 to adjust the heating power of the microwave heating mechanism.

[0048] The cathode electron source 11 described in this application has a hollow structure, and the heating component is an air intake channel 16 and / or a heating resistance wire located inside the cathode electron source 11. The air intake channel 16 has an intake connector 17 and an exhaust connector 18 at both ends, and the intake connector 17 is used to introduce combustion gases from the main combustion chamber of a jet engine. In this embodiment, the heating component is an air intake channel 16 and a heating resistance wire located inside the cathode electron source 11; in other embodiments, the heating component can be either a heating resistance wire or an air intake channel 16. When the heating component includes a heating resistance wire, the heating power of the microwave heating mechanism can be adjusted by regulating the power supply to the heating resistance wire.

[0049] This application takes into account the energy loss during the conversion of electrical energy into microwaves in the microwave heating mechanism. This energy will heat the annular metal anode 12. To prevent the annular metal anode 12 from overheating, it is necessary to ensure that the heat transfer power of the annular metal anode 12 is greater than the energy loss power of the microwave heating mechanism. Specifically:

[0050] The formula for calculating the upper limit of heat transfer power of the annular metal anode 12 is as follows:

[0051] ;

[0052] ;

[0053] in, The heat transfer power of the annular metal anode 12 is... The heat transfer coefficient, The heat transfer area of ​​the outer wall surface of the annular metal anode 12 is [missing information]. The temperature of the outer wall surface of the annular metal anode 12. The temperature of the incoming gas flow around the outer periphery of the annular metal anode 12 is [temperature value missing]. For Nusselt numbers, D The outer diameter of the annular metal anode is 12. The thermal conductivity of the gas;

[0054] Power loss of microwave heating mechanism

[0055] ;

[0056] in, The power loss of the microwave heating mechanism. The total power supply for generating the DC electric and magnetic fields of the microwave heating mechanism. The electrothermal conversion efficiency of the microwave heating mechanism is the total power supply energy used to generate the DC electric and magnetic fields of the microwave heating mechanism.

[0057] If the heat exchange power of the annular metal anode 12 is not greater than the power loss of the microwave heating mechanism, it is possible to reduce the total power supply of the microwave heating mechanism to form the DC electric field and magnetic field, or to set heat exchange ribs on the outer wall of the annular metal anode 12 to increase the heat exchange area of ​​the outer wall of the annular metal anode 12.

[0058] like Figures 3 to 6 As shown, in this application, the microwave generator 1 can be installed at any or more of the following locations: between the two ends of the turbine shaft 3 of the jet engine, on the side of the turbine shaft 3 facing the exhaust end of the jet engine, or at the axial position of the jet engine tail nozzle 33. In one embodiment, as... Figure 3 As shown, microwave generators 1 are only installed between the two ends of turbine shaft 3. Since the turbine shaft 3 has a higher pressure gas flow than the downstream region, the gas flow has a stronger work-capacity. When using a microwave heating mechanism, installing microwave generators 1 between the two ends of turbine shaft 3 is more efficient in improving afterburner cycle efficiency. For jet engines with a high-pressure turbine shaft 31 and a low-pressure turbine shaft 32, microwave generators 1 are located on the high-pressure turbine shaft 31. In other embodiments, if multiple microwave generators 1 are provided, a corresponding microwave reflector wall 2 is provided on the outer periphery of each microwave generator 1.

[0059] In this application, the specific installation method of the microwave generator 1 between the two ends of the turbine shaft 3 is as follows: the turbine shaft 3 is divided into two sections, and the two electromagnets 13 of the microwave generator 1 are respectively fixedly connected to the two ends of the turbine shaft 3 that are close to each other. The entire microwave generator 1 is fixed in the middle of the turbine shaft 3, so that the annular metal anode 12 rotates with the turbine shaft 3, which is beneficial to the heat dissipation of the annular metal anode 12. In this embodiment, the specific connection structure for installing the microwave generator 1 is as follows: the cathode electron source 11 and the DC power supply component 14 are both fixed on the electromagnet 13 on the first end side of the annular metal anode 12, and the first end of the annular metal anode 12 faces the side of the turbine shaft 3 close to the main combustion chamber; the wiring terminals of the heating resistance wire of the heating component, the air inlet connector 17, the exhaust connector 18, and the DC power supply component 14 are all located on the side of the electromagnet 13 facing away from the annular metal anode 12 and are fixed on the electromagnet 13 by the bracket 15, and the bracket 15 and the corresponding A section of the turbine shaft 3 is fixedly connected to the end face of the turbine shaft 3. The terminals of the heating resistance wire and the DC power supply assembly 14 are electrically connected to an external power source through a conductive slip ring. The intake connector 17 is connected to an air intake pipe located inside the turbine shaft 3. The other end of the air intake pipe extends along the hollow channel inside the turbine shaft 3 to the main combustion chamber and is connected to the intake structure stationary relative to the main combustion chamber through a guide slip ring, thereby introducing combustion gas into the main combustion chamber. The exhaust connector 18 is connected to an exhaust pipe in the radial direction of the turbine shaft 3. The other end of the exhaust pipe extends out of the circumference of the turbine shaft 3 for exhaust. In addition, for jet engines with a high-pressure turbine shaft 31 and a low-pressure turbine shaft 32, microwave generators 1 can be installed on both the high-pressure turbine shaft 31 and the low-pressure turbine shaft 32.

[0060] like Figure 4 and Figure 6 As shown, the connection structure of the microwave generator 1, located on the side of the turbine shaft 3 facing the exhaust end of the jet engine and at the axial position of the jet engine nozzle 33, can be either directly fixed to the central shaft at the corresponding position and rotate with the central shaft, or fixed to the inner wall of the stator casing of the jet engine through a support structure. Figure 5 As shown, for a jet engine having a high-pressure turbine shaft 31 and a low-pressure turbine shaft 32, the microwave generator 1 located on the side of the high-pressure turbine shaft 31 facing the exhaust end of the jet engine is substantially located between the high-pressure turbine shaft 31 and the low-pressure turbine shaft 32.

[0061] In one embodiment, the specific design parameters for the microwave generator 1 installed between the two ends of the turbine shaft 3 are as follows:

[0062] The total power supply for the DC electric and magnetic fields generated by the microwave heating mechanism is: The total power supplied to the microwave heating mechanism to form a DC electric field and a magnetic field. Calculated using the following formula:

[0063] ;

[0064] in, For turbine efficiency, The electrothermal conversion efficiency of the microwave heating mechanism. For gas mass flow rate, For isobaric specific heat, This refers to the turbine inlet temperature. The turbine pressure ratio, This refers to the specific heat ratio of the fuel gas.

[0065] By adjusting the total power supply to the microwave heating mechanism to generate the DC electric and magnetic fields, the total power supply to the microwave heating mechanism to generate the DC electric and magnetic fields is made equal to the total power supply to the microwave heating mechanism to generate the DC electric and magnetic fields. The calculated value of the formula can realize isothermal interstage heating, thereby transforming the adiabatic expansion process of the turbine in the Brayton cycle of a jet engine into an isothermal expansion process, converting all the heat energy output by microwave heating into shaft work to drive the turbine, making the overall thermodynamic cycle process closer to the Carnot cycle, thereby improving thermal efficiency.

[0066] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A microwave-based jet engine afterburner, characterized in that, The microwave heating mechanism includes a microwave generator (1), which includes a cathode electron source (11), a heating component, an annular metal anode (12), an electromagnet (13), and a DC power supply component (14). The cathode electron source (11) is located at the axial position inside the annular metal anode (12). The heating component is used to heat the cathode electron source (11) so that the cathode electron source (11) emits free electrons. The DC power supply component (14) is used to supply power to the cathode electron source (11) and the annular metal anode (12) so that a DC potential difference is formed between the cathode electron source (11) and the annular metal anode (12) to form a DC electric field between the cathode electron source (11) and the annular metal anode (12). The DC electric field provides kinetic energy to the free electrons and drives the free electrons to move toward the annular metal anode (12). Electromagnets (13) are provided at both ends of the annular metal anode (12). The DC power supply component (14) is also used to supply power to the electromagnets (13) to generate a magnetic field orthogonal to the DC electric field. The microwave generator (1) is located in the gas flow channel of the jet engine, and the annular metal anode (12) is coaxially arranged with the jet engine. The inner wall of the annular metal anode (12) is provided with several strip grooves. The length of the strip grooves extends along the axial direction of the annular metal anode (12). The strip grooves serve as microwave resonant cavities. Free electrons move around the strip grooves, causing the internal charge to change periodically to excite microwaves. The excited microwaves are used to heat the gas exhaust from the main combustion chamber of the jet engine. The microwave generator (1) is used to be installed on the turbine shaft (3) of the jet engine, and the microwave generator (1) is located between the two ends of the turbine shaft (3). The annular metal anode (12) is coaxially arranged with the turbine shaft (3). The total power supply for the DC electric and magnetic fields generated by the microwave heating mechanism is: The total power supplied to the microwave heating mechanism to form a DC electric field and a magnetic field. Calculated using the following formula: ； in, For turbine efficiency, The electrothermal conversion efficiency of the microwave heating mechanism. For gas mass flow rate, For isobaric specific heat, This refers to the turbine inlet temperature. The turbine pressure ratio, This refers to the specific heat ratio of the fuel gas.

2. The microwave-based jet engine afterburner according to claim 1, characterized in that, The annular metal anode (12) and the turbine shaft (3) are fixedly connected so that the annular metal anode (12) rotates with the turbine shaft (3).

3. The microwave-based jet engine afterburner according to claim 1, characterized in that, The microwave heating mechanism further includes an annular microwave reflector wall (2), which surrounds the annular metal anode (12) and is located on the inner wall of the outer ring of the gas flow channel of the jet engine.

4. The microwave-based jet engine afterburner according to claim 1, characterized in that, The microwave generator (1) is used to be installed on the side of the turbine shaft (3) of the jet engine facing the exhaust end of the jet engine and / or at the axial position of the jet engine tail nozzle (33).

5. The microwave-based jet engine afterburner according to any one of claims 1-4, characterized in that, The heat transfer power of the annular metal anode (12) is greater than the power loss of the microwave heating mechanism; The formula for calculating the upper limit of heat transfer power of the annular metal anode (12) is as follows: ； ； in, The heat transfer power of the annular metal anode (12) is... The heat transfer coefficient, The heat transfer area of ​​the outer wall surface of the annular metal anode (12) is... The temperature of the outer wall of the annular metal anode (12) is... The temperature of the incoming gas flow around the outer periphery of the annular metal anode (12) is... For Nusselt numbers, D The outer diameter of the annular metal anode (12) is... The thermal conductivity of the gas; The formula for calculating the power loss of a microwave heating mechanism is as follows: ； in, The power loss of the microwave heating mechanism. The total power supply for generating the DC electric and magnetic fields of the microwave heating mechanism. The electrothermal conversion efficiency of the microwave heating mechanism.

6. The microwave-based jet engine afterburner according to any one of claims 1-4, characterized in that, The cathode electron source (11) has a hollow structure, and the heating component is an air intake channel (16) and / or a heating resistance wire located inside the cathode electron source (11). The two ends of the air intake passage (16) are respectively provided with an air intake connector (17) and an exhaust connector (18). The air intake connector (17) is used to introduce the combustion gas from the main combustion chamber of the jet engine.

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