Light helium storage spray pipe with integrated efficiency of efficiency increasing, pushing changing, phase change heat prevention and infrared stealth

Abstract

According to the light helium storage spray pipe with the integrated efficiency of efficiency increasing, pushing changing, phase change heat prevention and infrared stealth, by means of the high phase change latent heat characteristic of liquid helium, the liquid helium is directly injected into the spray pipe to be mixed with high-temperature fuel gas; the temperature of fuel gas and thermal stress borne by a spray pipe material are remarkably reduced through phase change heat absorption, heat convection and gas film cooling, efficient thermal protection is achieved, the infrared radiation intensity of exhaust plume is effectively restrained, and the infrared stealth effect is achieved; the characteristic that helium is small in molecular weight is utilized, the expansion power capability of mixed gas and the propulsive efficiency and specific impulse of the engine are improved, meanwhile, through real-time regulation and control of helium injection flow, thrust adjustment to a certain degree can be achieved, and the maneuverability of the engine is enhanced. According to the designed composite interlayer structure, the thickness of the wall face of the spray pipe can be greatly reduced, the structural strength of the spray pipe is improved, and then the overall mass of an engine is reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of engine nozzles, and in particular relates to a lightweight helium storage nozzle with integrated performance of enhanced variable thrust, phase change thermal protection and infrared stealth. Background Art

[0002] Space launch vehicles and propulsion systems need to operate in extreme environments of high temperature and high pressure. Their power systems face the dual technical challenges of high-temperature ablation of nozzle throat materials and prominent infrared radiation signatures. As the core component of rocket engine energy conversion, the nozzle throat area is subjected to gas erosion at up to 3000°C. At the same time, the high-temperature gas flow discharged generates strong thermal radiation, with infrared radiation intensity reaching up to 10 6 The W / sr level far exceeds the detection sensitivity threshold of the fourth-generation infrared imaging seeker. The infrared radiation of solid rocket engines mainly comes from the thermal radiation of the high-temperature tail flame (gas plume) and the surface of the engine casing. Reducing the temperature of the gas is the core means to reduce infrared characteristics. The following methods are usually used: (1) improving the solid propellant formula and adding additives that reduce the combustion temperature (such as nitrogen-containing compounds, metal hydrides, etc.) to reduce the plume temperature; (2) designing air film cooling, water spray cooling structure in the nozzle or injecting cooling medium (such as liquid water, carbon dioxide) into the tail flame to accelerate the cooling of the gas; (3) using high thermal conductivity materials (such as copper alloys) or phase change materials (such as paraffin) on the shell or nozzle surface to delay the surface temperature rise. However, according to the thermodynamic theory of rocket engines, the reduction of gas temperature will directly lead to specific impulse loss, forming an inherent contradiction between infrared stealth and propulsion performance. Summary of the Invention

[0003] The purpose of this invention is to provide a lightweight helium-storage nozzle that combines enhanced variable thrust, phase-change thermal protection, and infrared stealth. Through an innovative nozzle sandwich structure and active cooling mechanism, a composite cooling technology based on liquid helium is proposed. Specifically addressing the infrared stealth requirements of solid rocket engines, this technology leverages liquid helium's ultra-low boiling point (4.2K), high phase-change latent heat (20.7kJ / kg), and low molecular weight to achieve lightweight nozzle thermal protection while also optimizing propulsion performance through fuel gas blending.

[0004] A lightweight helium storage nozzle with integrated performance of variable thrust, phase change thermal protection, and infrared stealth comprises a liquid helium tank tube located on the outside and a nozzle located on the inside. A hollow interlayer is left between the liquid helium tank tube and the nozzle, a liquid helium pipeline is provided in the hollow interlayer, and a micropore array is opened on the tail wall of the nozzle; one end of the liquid helium pipeline is connected to the liquid helium tank tube, and the other end extends from the head to the tail of the nozzle and is connected to the micropore array.

[0005] Furthermore, the tail of the nozzle is in communication with the combustion chamber of the engine;

[0006] Before the engine is ignited, liquid helium is injected into the liquid helium tank tube to its rated capacity. Pre-cooling begins with liquid helium being injected into the liquid helium pipeline at a controllable flow rate. Liquid helium flows along the liquid helium pipeline and penetrates the micropore array. Convection heat transfer occurs between the liquid helium and the inner wall of the nozzle, rapidly reducing the nozzle's inner wall temperature and forming an initial cryogenic protective layer.

[0007] When the engine is working, the mainstream of the gas generated by the reaction of the fuel and oxidizer in the combustion chamber enters the nozzle. The liquid helium undergoes a vaporization phase change under the action of the high-temperature gas. 80% to 90% of the helium is directly mixed with the gas. Through thermal convection heat transfer, a small part of the helium adheres to the inner wall of the nozzle and flows to form a layer of low-temperature helium film. At the same time, the liquid helium in the liquid helium pipeline conducts convection heat exchange with the inner wall of the nozzle. Under the synergistic effect of phase change heat absorption, thermal convection and gas film cooling, the liquid helium reduces the ablation effect of the high-temperature gas on the wall and throat of the nozzle, while suppressing the infrared radiation characteristics of the exhaust plume.

[0008] Furthermore, the nozzle includes a head, a throat and a tail. The head of the nozzle is a gradually expanding section with a radius gradually increasing from the inlet to the outlet, and the tail of the nozzle is a gradually converging section with a radius gradually decreasing from the inlet to the outlet.

[0009] Furthermore, the liquid helium is injected into the liquid helium pipeline at a controllable flow rate, and the helium injection ratio is adjusted according to the requirements of the engine thrust specific impulse and infrared radiation intensity. The specific calculation method is:

[0010] Use the helium mass fraction x He Characterize the helium injection ratio, m is the mass of the gas involved in the mixture, m He is the mass of helium involved in the mixing;

[0011] The calculation method for the total temperature of the mixed gas in the engine at a certain helium injection ratio is:

[0012]

[0013] Among them, T0 is the total temperature of gas; T 0-He is the total temperature of helium; T mix is the temperature of the mixed gas, C p is the constant pressure specific heat capacity of the gas; C p-He is the specific heat capacity of helium at constant pressure;

[0014] Nozzle outlet pressure P e and the combustion chamber pressure P c The ratio is solved by the isentropic flow equation:

[0015]

[0016] Among them, A eA is the cross-sectional area at the exit of the nozzle’s first diverging section; t M is the cross-sectional area of ​​the narrowest part of the nozzle throat; e is the Mach number at the nozzle's diverging section exit; k mix is the specific heat ratio of the mixed gas, C v is the constant volume specific heat capacity of the gas, C v-He is the specific heat capacity at constant volume of helium;

[0017] Mixed gas outlet velocity u e The calculation method is:

[0018]

[0019] Where R0 is the universal gas constant; is the average molecular mass of the mixed gas, which is the ratio of the total mass of the mixed gas to the number of moles of the mixed gas;

[0020] The total thrust F of the engine is calculated as:

[0021] F=m total ·u e +(P e -P a )A e

[0022] Among them, m total is the total mass flow rate of the mixed gas at the outlet of the nozzle's first diverging section;

[0023] Engine specific impulse I sp The calculation method is:

[0024]

[0025] Where g is the acceleration due to gravity;

[0026] When the gas passes through the nozzle, it undergoes adiabatic expansion, and the temperature changes with pressure according to the isentropic relationship. The temperature of the mixed gas at the nozzle outlet is T e The calculation method is:

[0027]

[0028] According to Planck's blackbody radiation law in wavelength form, the infrared radiation intensity is solved:

[0029]

[0030] Where λ is the wavelength, B λ is the radiation intensity corresponding to the wavelength; h is Planck's constant; c is the speed of light; k B is the Boltzmann constant.

[0031] Furthermore, a flow valve is provided on the liquid helium pipeline.

[0032] Furthermore, a supporting rib structure is provided in the hollow interlayer.

[0033] Furthermore, the support rib structure adopts high-strength lightweight alloy, and achieves high rigidity and low mass through topological optimization design, with a compressive strength of ≥500MPa, ensuring the stability of the hollow interlayer under an internal pressure of 15MPa. At the same time, the support rib structure also has a flow-guiding function, guiding the liquid helium to flow along a predetermined path.

[0034] Furthermore, the pore size range of the micropore array is 100μm to 500μm, the porosity is 5% to 15%, the micropores are formed by laser precision processing or additive manufacturing process, and the pore axis is inclined at 30° to 45° to the wall surface to prevent carbon deposits and particulate matter from reversely penetrating into the hollow interlayer.

[0035] Furthermore, the inner wall of the nozzle is made of a carbon-carbon composite material that is resistant to high-temperature ablation, using chemical vapor deposition densification and SiC anti-oxidation coating technology, and the outer wall is made of a high-silicon oxide material with good mechanical properties, which is reinforced by fiber weaving and densified by sol-gel.

[0036] Furthermore, the wall of the liquid helium tank is made of a 30crmnsia lining combined with a carbon fiber wall, so as to reduce the weight of the tank as much as possible while ensuring sufficient structural strength.

[0037] The beneficial effects of the present invention are:

[0038] This invention utilizes the high latent heat of liquid helium, injecting it directly into the nozzle to mix with the high-temperature combustion gas. This significantly reduces the combustion gas temperature and thermal stress on the nozzle material through phase transition heat absorption, convective heat transfer, and film cooling, achieving efficient thermal protection and effectively suppressing the infrared radiation intensity of the exhaust plume, thereby achieving infrared stealth. The low molecular weight of helium is exploited to improve the expansion work capacity of the mixed gas, as well as the engine's propulsion efficiency and specific impulse. Furthermore, real-time control of the helium injection flow rate allows for a certain degree of thrust regulation, enhancing the engine's maneuverability. The composite sandwich structure designed in this invention significantly reduces the thickness of the nozzle wall, improving the nozzle's structural strength and thus reducing the overall engine mass. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 It is an overall schematic diagram of the present invention.

[0040] Figure 2 Schematic diagram of the principle of liquid helium cooling nozzle structure.

[0041] Figure 3This is a flow chart of the calculation method for engine thrust specific impulse and infrared radiation intensity under different helium injection ratios.

[0042] Figure 1: 1-combustion chamber, 2-combustion chamber shell, 3-nozzle, 4-liquid helium tank pipe, 5-flow valve, 6-liquid helium pipeline, 7-inner wall of nozzle, 8-hollow interlayer (including support ribs), 9-outer wall of nozzle, 10-nozzle throat lining, 11-microporous structure array, 12-liquid helium, 13-supercritical helium, 14-interlayer flow channel, 15-main stream of fuel gas, 16-low-temperature helium membrane, 17-mixed gas. DETAILED DESCRIPTION

[0043] The present invention will be further described below with reference to the accompanying drawings.

[0044] The present invention provides a lightweight helium storage nozzle with the integrated performance of enhanced variable thrust, phase change thermal protection and infrared stealth. Figure 1 As shown, the nozzle 3 includes a liquid helium tank tube 4 located on the outside and a nozzle 3 located on the inside. A hollow interlayer 8 is left between the liquid helium tank tube 4 and the nozzle 3. A liquid helium pipeline 6 is provided in the hollow interlayer 8. A micropore array 11 is provided on the rear wall of the nozzle 3. One end of the liquid helium pipeline 6 is connected to the liquid helium tank tube 4, and the other end extends from the head to the rear of the nozzle 3 and is connected to the micropore array 11.

[0045] The nozzle 3 comprises a nose, a throat 10, and a tail. The nose is a diverging section with a gradually increasing radius from the inlet to the outlet, while the tail is a converging section with a gradually decreasing radius from the inlet to the outlet. A flow valve 5 is provided on the liquid helium pipeline 6, through which the flow of liquid helium supplied by the liquid helium tank pipe 4 is regulated.

[0046] The combustion chamber 1 is a cylindrical structure, serving as the primary location for propellant combustion and combustion gas. The nozzle 3, a convergent-divergent nozzle, is connected to the rear end of the combustion chamber 1, converting the internal energy of the combustion gas into kinetic energy. The outlet of the combustion chamber 1 and the inlet of the nozzle 3 are butted together via a high-strength alloy flange. Bolt preload combined with high-temperature graphite gaskets creates a seal, enabling multiple, rapid disassembly of the combustion chamber and nozzle. The liquid helium tank tube 4 is an annular tank. Its outer wall radius matches that of the combustion chamber housing 2 to minimize air resistance. Its inner wall closely aligns with the outer wall of the nozzle, secured by a flange connection.

[0047] The present invention utilizes a multi-layer composite architecture, integrating a hollow interlayer 8 into the traditional single-layer structure. This interlayer comprises a flow channel 14 and supporting ribs, extending from the nozzle's diverging section to the front end of the nozzle's converging section. A microporous structure array 11 is designed on the inner wall of the nozzle's converging section. Liquid helium flows through the interlayer flow channel 14 to the nozzle's converging section, and then enters the nozzle through the microporous structure.

[0048] The hollow interlayer 8 starts from 20% to 50% of the front of the nozzle convergent section and runs through the nozzle throat and divergent section, keeping the cross-sectional area of ​​the interlayer the same at all locations and the profile consistent with the nozzle.

[0049] The support rib structure is made of high-strength lightweight alloy, and achieves high rigidity and low mass through topological optimization design. The compression strength is ≥500MPa, ensuring the stability of the hollow interlayer 8 under an internal pressure of 15MPa. At the same time, the support rib structure also has a flow-guiding function, guiding the liquid helium to flow along a predetermined path.

[0050] The pore size of the micropore array 11 ranges from 100 μm to 500 μm, with a porosity of 5% to 15%. The micropores are formed by laser precision machining or additive manufacturing, with the pore axis and the wall at an angle of 30° to 45° to prevent carbon deposits and particulate matter from penetrating the hollow interlayer 8 in reverse.

[0051] The inner wall of nozzle 3 is constructed from a high-temperature, ablation-resistant carbon-carbon composite material densified using chemical vapor deposition and a SiC anti-oxidation coating process. The outer wall is constructed from a high-silicon-oxygen material with excellent mechanical properties, reinforced with fiber braiding and densified using a sol-gel process. The liquid helium tank's walls utilize a 30CrMnSIA lining combined with a carbon fiber cladding to minimize tank weight while ensuring sufficient structural strength.

[0052] Before the engine is ignited, liquid helium is injected into the liquid helium tank tube 4 to its rated capacity. Pre-cooling begins with the liquid helium being injected into the liquid helium pipeline 6 at a controllable flow rate. Liquid helium flows along the liquid helium pipeline 6 and penetrates the micropore array 11. The liquid helium undergoes convective heat exchange with the inner wall of the nozzle 3, rapidly reducing the inner wall temperature of the nozzle 3 and forming an initial low-temperature protective layer.

[0053] like Figure 2 As shown, during engine operation, the fuel and oxidizer react in the combustion chamber to form a mainstream gas that enters nozzle 3. Liquid helium undergoes a vaporization phase transition under the action of the high-temperature gas, with 80% to 90% of the helium directly mixing with the gas. Through convection, a small portion of the helium adheres to the inner wall of nozzle 3 and forms a low-temperature helium film. Simultaneously, the liquid helium in liquid helium pipe 6 engages in convection heat exchange with the inner wall of nozzle 3. Through the synergistic effects of phase transition heat absorption, convection, and film cooling, the liquid helium reduces the ablation effect of the high-temperature gas on the nozzle 3 wall and throat, while also suppressing the infrared radiation signature of the exhaust plume. After the mission is completed, nozzle 3 and liquid helium tank pipe 4 are quickly disassembled and liquid helium is replenished. High-pressure helium is then used to backflush the interlayer to remove carbon deposits and particulate matter within the interlayer and micropores. The nozzle inner wall material is then inspected for thermal fatigue and ablation.

[0054] Liquid helium is injected into the liquid helium pipe 6 at a controllable flow rate. The helium injection ratio is adjusted according to the requirements of the engine thrust specific impulse and infrared radiation intensity. The specific calculation method is as follows:

[0055] Use the helium mass fraction xHe Characterize the helium injection ratio, m is the mass of the gas involved in the mixture, m He is the mass of helium involved in the mixing;

[0056] The calculation method for the total temperature of the mixed gas in the engine at a certain helium injection ratio is:

[0057]

[0058] Among them, T0 is the total temperature of gas; T 0-He is the total temperature of helium; T mix is the temperature of the mixed gas, C p is the constant pressure specific heat capacity of the gas; C p-He is the specific heat capacity of helium at constant pressure;

[0059] Nozzle 3 outlet pressure P e and the combustion chamber pressure P c The ratio is solved by the isentropic flow equation:

[0060]

[0061] Among them, A e A is the cross-sectional area at the exit of the nozzle’s first diverging section; t M is the cross-sectional area of ​​the narrowest part of the nozzle throat 10; e is the Mach number at the nozzle's diverging section exit; k mix is the specific heat ratio of the mixed gas, C v is the constant volume specific heat capacity of the gas, C v-He is the specific heat capacity at constant volume of helium;

[0062] Mixed gas outlet velocity u e The calculation method is:

[0063]

[0064] Where R0 is the universal gas constant; M is the average molecular mass of the mixed gas, which is the ratio of the total mass of the mixed gas to the number of moles of the mixed gas;

[0065] The total thrust F of the engine is calculated as:

[0066] F=m total ·u e +(P e -P a )A e

[0067] Among them, m totalis the total mass flow rate of the mixed gas at the outlet of the nozzle's first diverging section;

[0068] Engine specific impulse I sp The calculation method is:

[0069]

[0070] Where g is the acceleration due to gravity;

[0071] When the gas passes through the nozzle, it undergoes adiabatic expansion, and the temperature changes with pressure according to the isentropic relationship. The temperature of the mixed gas at the nozzle outlet is T e The calculation method is:

[0072]

[0073] According to Planck's blackbody radiation law in wavelength form, the infrared radiation intensity is solved:

[0074]

[0075] Where λ is the wavelength, B λ is the radiation intensity corresponding to the wavelength; h is Planck's constant; c is the speed of light; k B is the Boltzmann constant.

[0076] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A lightweight helium storage nozzle with integrated performance of variable thrust, phase change thermal protection, and infrared stealth, characterized by: The invention comprises a liquid helium tank pipe (4) located on the outside and a nozzle (3) located on the inside, a hollow interlayer (8) being left between the liquid helium tank pipe (4) and the nozzle (3), a liquid helium pipeline (6) being provided in the hollow interlayer (8), and a microhole array (11) being provided on the rear wall surface of the nozzle (3); one end of the liquid helium pipeline (6) is connected to the liquid helium tank pipe (4), and the other end extends from the head to the rear of the nozzle (3) and is connected to the microhole array (11).

2. The lightweight helium storage nozzle with integrated performance of enhanced variable thrust, phase change thermal protection and infrared stealth according to claim 1, characterized in that: The tail of the nozzle (3) is in communication with the combustion chamber of the engine; Before the engine is ignited, liquid helium is injected into the liquid helium tank tube (4) to a rated capacity; pre-cooling is started, and the liquid helium is injected into the liquid helium pipeline (6) at a controllable flow rate, flows along the liquid helium pipeline (6) and penetrates into the microporous array (11), and the liquid helium and the inner wall surface of the nozzle (3) undergo convection heat exchange, rapidly reducing the inner wall surface temperature of the nozzle (3) and forming an initial low-temperature protective layer; When the engine is working, the main stream of gas generated by the reaction of fuel and oxidant in the combustion chamber enters the nozzle (3), and the liquid helium undergoes a vaporization phase change under the action of the high-temperature gas. 80% to 90% of the helium is directly mixed with the gas. Through heat convection heat exchange, a small part of the helium adheres to the inner wall surface of the nozzle (3) and flows to form a layer of low-temperature helium film. At the same time, the liquid helium in the liquid helium pipe (6) and the inner wall surface of the nozzle (3) are subjected to convection heat exchange. Under the synergistic effect of phase change heat absorption, heat convection and gas film cooling, the liquid helium reduces the ablation effect of the high-temperature gas on the wall surface and throat of the nozzle (3), and at the same time suppresses the infrared radiation characteristics of the exhaust plume.

3. The lightweight helium storage nozzle with integrated performance of enhanced variable thrust, phase change thermal protection and infrared stealth according to claim 2, characterized in that: The nozzle (3) comprises a head, a throat (10) and a tail, wherein the head of the nozzle (3) is a gradually expanding section with a radius gradually increasing from the inlet to the outlet, and the tail of the nozzle (3) is a gradually contracting section with a radius gradually decreasing from the inlet to the outlet.

4. The lightweight helium storage nozzle with integrated performance of enhanced variable thrust, phase change thermal protection and infrared stealth according to claim 3 is characterized by: The liquid helium is injected into the liquid helium pipeline (6) at a controllable flow rate, and the helium injection ratio is adjusted according to the requirements of the engine thrust specific impulse and infrared radiation intensity. The specific calculation method is: Use the helium mass fraction x He Characterize the helium injection ratio, m is the mass of the gas involved in the mixture, m He is the mass of helium involved in the mixing; The calculation method for the total temperature of the mixed gas in the engine at a certain helium injection ratio is: Among them, T0 is the total temperature of gas; T 0-He is the total temperature of helium; T mix is the temperature of the mixed gas, C p is the constant pressure specific heat capacity of the gas; C p-He is the specific heat capacity of helium at constant pressure; Nozzle (3) outlet pressure P e and the combustion chamber pressure P c The ratio is solved by the isentropic flow equation: Among them, A e A is the cross-sectional area at the exit of the nozzle’s first diverging section; t M is the cross-sectional area of ​​the narrowest part of the nozzle throat (10); e is the Mach number at the nozzle's diverging section exit; k mix is the specific heat ratio of the mixed gas, C v is the constant volume specific heat capacity of the gas, C v-He is the specific heat capacity at constant volume of helium; Mixed gas outlet velocity u e The calculation method is: Where R0 is the universal gas constant; is the average molecular mass of the mixed gas, which is the ratio of the total mass of the mixed gas to the number of moles of the mixed gas; The total thrust F of the engine is calculated as: F=m total ·u e +(P e -P a )A e Among them, m total is the total mass flow rate of the mixed gas at the outlet of the nozzle's first diverging section; Engine specific impulse I sp The calculation method is: Where g is the acceleration due to gravity; When the gas passes through the nozzle, it undergoes adiabatic expansion, and the temperature changes with pressure according to the isentropic relationship. The temperature of the mixed gas at the nozzle outlet is T e The calculation method is: According to Planck's blackbody radiation law in wavelength form, the infrared radiation intensity is solved: Where λ is the wavelength, B λ is the radiation intensity corresponding to the wavelength; h is Planck's constant; c is the speed of light; k B is the Boltzmann constant.

5. The lightweight helium storage nozzle with integrated performance of enhanced variable thrust, phase change thermal protection and infrared stealth according to claim 1 is characterized by: A flow valve (5) is provided on the liquid helium pipeline (6).

6. The lightweight helium storage nozzle with integrated performance of enhanced variable thrust, phase change thermal protection and infrared stealth according to claim 1 is characterized by: A supporting rib structure is provided in the hollow interlayer (8).

7. The lightweight helium storage nozzle with integrated performance of enhanced variable thrust, phase change thermal protection and infrared stealth according to claim 6, characterized in that: The support rib structure adopts high-strength lightweight alloy and realizes high rigidity and low mass through topological optimization design, with a compression strength of ≥500MPa, thereby ensuring the stability of the hollow interlayer (8) under an internal pressure of 15MPa. At the same time, the support rib structure also has a flow guiding function, guiding the liquid helium to flow along a predetermined path.

8. The lightweight helium storage nozzle with integrated performance of enhanced variable thrust, phase change thermal protection and infrared stealth according to claim 1 is characterized by: The micropore array (11) has a pore size range of 100 μm to 500 μm and a porosity of 5% to 15%. The micropores are formed by laser precision machining or additive manufacturing technology, and the pore axis is inclined at a 30° to 45° angle to the wall surface to prevent carbon deposits and particulate matter from reversely penetrating into the hollow interlayer (8).

9. The lightweight helium storage nozzle with integrated performance of enhanced variable thrust, phase change thermal protection and infrared stealth according to claim 1 is characterized by: The inner wall surface of the nozzle (3) is made of a carbon-carbon composite material resistant to high temperature ablation, and is densified using chemical vapor deposition and SiC anti-oxidation coating technology. The outer wall surface is made of a high-silicon-oxygen material with good mechanical properties, and is reinforced by fiber braiding and densified by sol-gel.

10. The lightweight helium storage nozzle with integrated performance of enhanced variable thrust, phase change thermal protection and infrared stealth according to claim 1, characterized in that: The wall of the liquid helium tank is made of a combination of a 30crmnsia lining and a carbon fiber wall, so as to reduce the weight of the tank as much as possible while ensuring sufficient structural strength.

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