Space engine nozzle and space vehicle

Abstract

The present invention provides a space engine nozzle and a space vehicle, comprising a niobium alloy substrate, an anti-oxidation silicide coating and an infrared stealth coating; the engine nozzle comprises a thin-walled rotating body of a Rafale nozzle shape composed of a niobium alloy substrate; the anti-oxidation silicide coating is sprayed on the inner and outer surfaces of the niobium alloy substrate; the infrared stealth coating preparation area is located on the outer wall of the expansion end of the engine nozzle, and the infrared stealth coating comprises a matching layer, a bonding layer and a low emissivity layer; the matching layer is prepared on the anti-oxidation silicide coating on the outer surface of the niobium alloy substrate, the bonding layer is prepared on the matching layer, and the low emissivity layer is prepared on the bonding layer. The area of ​​the engine nozzle where the infrared stealth coating is not attached adopts a structural shielding method to achieve infrared stealth. The present invention helps to reduce the infrared emissivity of the outer surface of the nozzle by preparing an infrared stealth coating, thereby helping to significantly improve the infrared stealth capability of the space engine nozzle.

Description

Technical Field

[0001] The present invention relates to the technical field of spacecraft propulsion systems, and in particular to a space engine nozzle and a space vehicle. Background Art

[0002] Space engines provide power for spacecraft to change their orbit and adjust their attitude, and are widely used in weapons, satellites, spacecraft, etc. The nozzle is the core component of the space engine, which converts the heat energy of the high-temperature gas in the combustion chamber into kinetic energy, allowing the engine to generate thrust.

[0003] With the rapid development of infrared detection technology, infrared detection has become one of the important means of battlefield situation awareness for advanced weapons, which has gradually attracted the attention of various military powers, and related technologies have also been rapidly developed. The nozzle of space weapons has the highest temperature and the most obvious signs of infrared exposure, which increases the threat of being attacked by infrared guided weapons. In order to improve the survivability and penetration capability of the new generation of space weapons, it is urgent to develop advanced and effective infrared stealth technology.

[0004] Infrared radiation is mainly transmitted through the atmosphere, and most of the infrared rays will be absorbed and lost by the atmosphere. Only certain bands of infrared radiation can be transmitted over long distances in the atmosphere, usually called "atmospheric windows". The specific bands corresponding to these three windows are 0.76-2.6μm (near infrared), 3-5μm (mid infrared) and 8-14μm (far infrared). Infrared low-emissivity coating technology is to coat infrared low-emissivity materials on high-temperature parts to reduce the emissivity of specific wavelengths so that the shielded object has an infrared radiation intensity that matches the background. It is a simple, convenient and effective technical approach to improve stealth performance, and is mainly used in the field of military aircraft.

[0005] Patent document CN210714882U discloses a rocket engine nozzle, including a convergent section insulation layer, an expansion section insulation layer, a connecting section insulation layer arranged between the convergent section insulation layer and the expansion section insulation layer, and a shell arranged outside the convergent section insulation layer, the connecting section insulation layer and the expansion section insulation layer.

[0006] The inventor believes that the common nozzle structure is a niobium alloy substrate with an anti-oxidation silicide coating sprayed on the inner and outer surfaces. When the space engine is working, the gas temperature in the nozzle exceeds 3000°C, and the maximum temperature of the outer surface of the nozzle can reach 1400°C or even higher, which does not have infrared stealth function. Therefore, it is necessary to design a space engine nozzle with infrared stealth function, reduce the infrared emissivity of the outer surface of the nozzle, and improve the stealth capability of the space engine nozzle. Summary of the invention

[0007] In view of the defects in the prior art, an object of the present invention is to provide a space engine nozzle and a space vehicle.

[0008] A space engine nozzle provided according to the present invention comprises a niobium alloy substrate, an anti-oxidation silicide coating and an infrared stealth coating; the engine nozzle comprises a thin-walled rotating body of a Rafale nozzle shape formed by the niobium alloy substrate, and the engine nozzle comprises a contraction end, an intermediate throat and an expansion end arranged in sequence; the anti-oxidation silicide coating is sprayed on the inner surface and the outer surface of the niobium alloy substrate; the infrared stealth coating preparation area is located on the outer wall of the expansion end of the engine nozzle, and the infrared stealth coating comprises a matching layer, a bonding layer and a low emissivity layer; the matching layer is prepared on the anti-oxidation silicide coating on the outer surface of the niobium alloy substrate, the bonding layer is prepared on the matching layer, and the low emissivity layer is prepared on the bonding layer.

[0009] Preferably, the expansion end of the engine nozzle adopts a variable wall thickness design, and the thickness decreases uniformly from the end close to the middle throat to the end away from the middle throat.

[0010] Preferably, the preparation area of ​​the infrared stealth coating is the area within the range from the nozzle area ratio of 15:1 to the nozzle outlet.

[0011] Preferably, the temperature of the nozzle outer wall corresponding to the preparation area of ​​the infrared stealth coating is lower than 1200°C.

[0012] Preferably, the low emissivity layer includes a metal Pt film layer.

[0013] Preferably, the infrared stealth coating has a thickness of 2 to 10 μm.

[0014] Preferably, the total length of the engine nozzle is 10-1000 mm, the inner diameter of the contraction end is Φ10-200 mm, the inner diameter of the throat is Φ2-80 mm, and the inner diameter of the expansion end outlet is Φ15-600 mm.

[0015] Preferably, the anti-oxidation silicide coating has a thickness of 80 to 150 μm.

[0016] Preferably, the infrared stealth coating is prepared on the expansion end of the engine nozzle by a vacuum sputtering process.

[0017] A space vehicle provided according to the present invention adopts the space engine nozzle according to claim 1, and the area of ​​the engine nozzle to which the infrared stealth coating is not attached is shielded by a structure.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] 1. The present invention prepares an infrared stealth coating composed of a matching layer, an adhesive layer and a low emissivity layer on the outer surface of the anti-oxidation silicide coating of the engine nozzle, which helps to reduce the infrared emissivity of the outer surface of the nozzle, so that the shielded object has an infrared radiation intensity that matches the background, thereby helping to significantly improve the infrared stealth capability of the space engine nozzle.

[0020] 2. The present invention helps to maintain a constant maximum temperature of the nozzle by planning the preparation area of ​​the infrared stealth coating, thereby helping not to affect the life and reliability of the nozzle itself.

[0021] 3. The present invention uses a vacuum sputtering process to prepare the infrared stealth coating, which is relatively thin and has a negligible effect on the weight increase of the nozzle structure, thereby helping to achieve infrared stealth without affecting the performance of the spacecraft. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Other features, objects and advantages of the present invention will become more apparent from the detailed description of non-limiting embodiments made with reference to the following drawings:

[0023] Figure 1 This is a schematic diagram of the cross-sectional structure of the engine nozzle wall.

[0024] As shown in the figure:

[0025] Niobium alloy substrate 1 Anti-oxidation silicide coating 2 Infrared stealth coating 3 DETAILED DESCRIPTION

[0026] The present invention is described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those of ordinary skill in the art, several changes and improvements can also be made without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

[0027] Example

[0028] like Figure 1 As shown, a space engine nozzle provided according to the present invention includes a niobium alloy substrate 1, an anti-oxidation silicide coating 2 and an infrared stealth coating 3; the engine nozzle includes a thin-walled rotating body in the shape of a Rafale nozzle formed by the niobium alloy substrate 1, and the left contraction end of the nozzle contracts from large to small toward the middle throat, and the middle throat expands from small to large toward the right expansion end.

[0029] The anti-oxidation silicide coating 2 is sprayed on the inner and outer surfaces of the niobium alloy substrate 1; the preparation area of ​​the infrared stealth coating 3 is located on the outer wall of the expansion end of the engine nozzle, and the infrared stealth coating 3 includes a matching layer, a bonding layer and a low emissivity layer; the matching layer is prepared on the anti-oxidation silicide coating 2 on the outer surface of the niobium alloy substrate 1, the bonding layer is prepared on the matching layer, and the low emissivity layer is prepared on the bonding layer. The infrared stealth coating 3 formed by the matching layer, the bonding layer and the low emissivity layer can achieve an infrared stealth effect on the preparation area.

[0030] The total length of the engine nozzle is 10 to 1000 mm, the inner diameter of the left contraction end is Φ10 to 200 mm, the inner diameter of the middle throat is Φ2 to 80 mm, and the inner diameter of the right expansion end outlet is Φ15 to 600 mm.

[0031] The expansion end of the engine nozzle adopts a variable wall thickness design, and the thickness decreases evenly from the end close to the middle throat to the end of the middle throat.

[0032] The oxidation-resistant silicide coating 2 is sprayed on the inner surface and the outer surface of the niobium alloy substrate 1, and the thickness of the oxidation-resistant silicide coating 2 is 80-150 μm.

[0033] The infrared stealth coating 3 is prepared on the expansion end of the engine nozzle by vacuum sputtering process. The preparation area of ​​the infrared stealth coating 3 is the area within the nozzle area ratio of 15:1 to the nozzle outlet, and the corresponding nozzle outer wall temperature is lower than 1200℃. On the one hand, it ensures that the working temperature of the infrared stealth coating is lower than the allowable temperature, and on the other hand, it does not affect the nozzle throat temperature, which is about 1400℃, and does not affect the life and reliability of the nozzle itself.

[0034] The infrared stealth coating 3 is a multi-layer structure, which is divided into a matching layer, a bonding layer and a low emissivity layer. The matching layer is prepared on the oxidation-resistant silicide coating 2 on the outer surface of the niobium alloy substrate 1, and is used to block the high-temperature mutual diffusion between the low emissivity layer and the oxidation-resistant silicide coating elements; the bonding layer is prepared on the matching layer, and is used to reduce the adhesion of the emissivity layer on the substrate; the low emissivity layer is prepared on the bonding layer, and the low emissivity layer is a metal Pt film layer, which has the characteristics of high temperature resistance, low emissivity and strong oxidation resistance.

[0035] The thickness of the infrared stealth coating 3 is 2 to 10 μm, which is relatively thin, and the effect on the weight gain of the nozzle structure can be ignored. In addition, the infrared stealth coating 3 can effectively reduce the infrared emissivity of the outer surface of the nozzle, thereby significantly improving the stealth capability of the space engine nozzle. Furthermore, this application has strong scalability and is suitable for space engine nozzles with niobium alloy substrates 1. At the same time, it has certain reference significance for the infrared stealth design of nozzles of other materials in the field of space engines.

[0036] According to a space vehicle provided by the present invention, the area of ​​the engine nozzle not attached with the infrared stealth coating 3 is infrared-stealthy by means of structural shielding.

[0037] Preferred Example

[0038] According to a space engine nozzle provided by the present invention, the niobium alloy substrate 1 is a thin-walled rotating body of the Rafale nozzle shape, with a total length of 600 mm, an inner diameter of Φ100 mm at the left contraction end, an inner diameter of Φ40 mm at the middle throat, an inner diameter of Φ360 mm at the right expansion end outlet, a thickness of 5 mm at the left contraction end, and a variable wall thickness design at the right expansion end, with the thickness uniformly transitioning from 5 mm to 0.5 mm at the outlet.

[0039] The oxidation-resistant silicide coating 2 is sprayed on the inner and outer surfaces of the niobium alloy substrate 1, and the thickness of the oxidation-resistant silicide coating 2 is 120 μm.

[0040] Considering that the nozzle throat temperature is about 1400℃, without affecting the life and reliability of the nozzle itself, combined with the thermal calculation of the gas in the nozzle, the preparation area of ​​the infrared stealth coating 3 is determined. The preparation area is from the nozzle area ratio of 20:1 to the nozzle outlet. The total thickness of the infrared stealth coating 3 is 6μm and the total weight is 8g. The infrared stealth area is about 25000mm 2 , which can make about 70% of the outer surface of the nozzle have infrared stealth function.

[0041] How it works

[0042] The infrared stealth coating 3 is a multi-layer structure, which is divided into a matching layer, a bonding layer and a low emissivity layer. The matching layer is used to block the high-temperature mutual diffusion between the low emissivity layer and the anti-oxidation silicide coating elements. The bonding layer is used to reduce the adhesion of the emissivity layer on the substrate. The low emissivity layer is a metal Pt film, which has the characteristics of high temperature resistance, low emissivity and strong oxidation resistance. The infrared stealth coating 3 helps to effectively reduce the infrared emissivity of the outer surface of the nozzle, thereby helping to significantly improve the stealth capability of the space engine nozzle.

[0043] In the description of the present application, it should be understood that the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0044] The above describes the specific embodiments of the present invention. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art can make various changes or modifications within the scope of the claims, which does not affect the essence of the present invention. In the absence of conflict, the embodiments of the present application and the features in the embodiments can be combined with each other arbitrarily.

Claims

1. A space engine nozzle, characterized in that: include: A niobium alloy substrate (1), an oxidation-resistant silicide coating (2), and an infrared stealth coating (3); The engine nozzle comprises a thin-walled rotating body of a Rafale nozzle shape formed by the niobium alloy substrate (1), and the engine nozzle comprises a contraction end, an intermediate throat and a divergence end arranged in sequence; The oxidation-resistant silicide coating (2) is sprayed on the inner surface and the outer surface of the niobium alloy substrate (1); The infrared stealth coating (3) preparation area is located on the outer wall of the expansion end of the engine nozzle, and the infrared stealth coating (3) comprises a matching layer, a bonding layer and a low emissivity layer; The matching layer is prepared on the oxidation-resistant silicide coating (2) on the outer surface of the niobium alloy substrate (1), the bonding layer is prepared on the matching layer, and the low-emissivity layer is prepared on the bonding layer; The preparation area of ​​the infrared stealth coating (3) is the area within the range of the nozzle area ratio of 15:1 to the nozzle outlet; The preparation area of ​​the infrared stealth coating (3) is the area within the range of the nozzle area ratio of 15:1 to the nozzle outlet; The infrared stealth coating (3) has a thickness of 2 to 10 μm.

2. The space engine nozzle according to claim 1, characterized in that: The expansion end of the engine nozzle adopts a variable wall thickness design, and the thickness decreases evenly from the end close to the middle throat to the end far away from the middle throat.

3. The space engine nozzle according to claim 1, characterized in that: The low emissivity layer includes a metal Pt film layer.

4. The space engine nozzle according to claim 1, characterized in that: The engine nozzle has a total length of 10 to 1000 mm, an inner diameter of Φ10 to 200 mm at the contraction end, an inner diameter of Φ2 to 80 mm at the throat, and an inner diameter of Φ15 to 600 mm at the expansion end outlet.

5. The space engine nozzle according to claim 1, characterized in that: The thickness of the anti-oxidation silicide coating (2) is 80 to 150 μm.

6. The space engine nozzle according to claim 1, characterized in that: The infrared stealth coating (3) is prepared on the expansion end of the engine nozzle by using a vacuum sputtering process.

7. A space vehicle, using the space engine nozzle according to claim 1, wherein the area of ​​the engine nozzle not attached with the infrared stealth coating (3) is shielded by a structure.

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