Low pressure self-extinguishing restartable micro solid orbit and attitude control engine

Abstract

The present invention proposes a low-pressure self-extinguishing and restartable micro solid attitude and orbit control engine. The attitude control side and the orbit control side are connected by a threaded structure and are not interconnected. The opening of the attitude control gas cylinder is fixedly connected to the attitude control end cover. The attitude control nozzle and the solenoid valve are arranged in a straight line to form an attitude control solenoid valve-nozzle assembly. Six attitude control solenoid valve-nozzle assemblies are arranged in a "middle" shape. The inner wall of the orbit control combustion chamber is provided with an insulating layer, and the orbit control combustion chamber is provided with propellant charge. The orbit control end cover is an ellipsoidal end cover and is recessed inward in the middle. The orbit control nozzle and the floating lift valve form an assembly, and four assemblies are arranged orthogonally in a "cross" shape. The corresponding orbit control solenoid valve assemblies are arranged at an angle with the central axis of the orbit control nozzle in the same plane. The present invention provides a structural scheme for a solid attitude and orbit control engine with small size and light weight, and solves the problems of difficult multiple starts and short working time of the micro solid attitude and orbit control engine through the low-pressure self-extinguishing technology and the decoupling design of the attitude control and orbit control systems.

Description

Technical Field

[0001] This invention proposes a low-pressure self-extinguishing and restartable micro solid attitude and trajectory control engine, which can achieve the requirements of light weight, small size, multiple starts, and long-term operation of attitude and trajectory control engine through low-pressure self-extinguishing technology. It mainly provides power for the attitude and trajectory control of multi-target kinetic energy interceptors and belongs to the field of engine technology. Background Technology

[0002] Current attitude and trajectory control systems are limited by advancements in technologies such as housing materials, valve technology, and manufacturing processes, making it difficult to meet the new demands of such lightweight and small-sized engines.

[0003] In addition, existing solid propellants are difficult to controllably shut down and restart, resulting in solid rocket engines requiring the propellant to burn out completely before they can stop operating once ignited. In solid rocket attitude and orbit control systems, multi-pulse propellant loading schemes are often used to enable repeated restarts of the solid rocket engine, where only one pulse of propellant is burned out per ignition. However, this scheme generates pulse thrust, which places high demands on the control algorithm.

[0004] Due to limitations in mass and size, solid rocket motors have a limited propellant capacity. Furthermore, the difficulty in preparing low-burning-rate solid propellants limits the operational time of current solid rocket motor attitude control systems to approximately 10 hours. 0 ~10 1 The magnitude is on the order of s, which is insufficient to meet the needs of long-term work. Summary of the Invention

[0005] Based on the aforementioned technical background, this invention discloses a design scheme for a low-pressure self-extinguishing, restartable micro solid-propellant attitude and trajectory control engine. It provides a small-sized, lightweight solid-propellant attitude and trajectory control engine structure and solves the problems of difficult multiple starts and short operating time of micro solid-propellant attitude and trajectory control engines through low-pressure self-extinguishing technology and a decoupling design between the attitude control and trajectory control systems. This scheme employs a "trajectory control combustion chamber - attitude control gas cylinder" structure to decouple attitude control from trajectory control. The attitude control side has six nozzles using nitrogen-cooled gas propulsion, with nitrogen generated by the reaction of a sodium azide composite formula. The trajectory control side has four nozzles using gas propulsion, with gas generated by the combustion of a solid propellant that can be depressurized and extinguished. The attitude control nozzles use direct-acting solenoid valves for on / off control; the trajectory control nozzles, to reduce valve mass, use spring-assisted floating lifting valves for on / off control, working in conjunction with the solenoid valves. This invention also provides solenoid valve structure schemes for the attitude control and trajectory control nozzles respectively, to reduce the mass and size of the solenoid valves. The entire structural scheme can be used in the attitude and trajectory control power system of multi-target interceptors.

[0006] The specific technical solution is as follows:

[0007] Low-pressure self-extinguishing and restartable micro solid attitude and orbit control engine, including an attitude control side and an orbit control side, decouples attitude control and orbit control; the attitude control side and the orbit control side are connected by a threaded structure and are not connected to each other;

[0008] The attitude control side includes: a spherical attitude control gas cylinder, an attitude control end cap, and an attitude control solenoid valve-nozzle assembly;

[0009] The attitude control gas cylinder is fixedly connected to the attitude control end cap at the opening, and the attitude control end cap is in the shape of a pipeline; a pipe joint is reserved on the outer side of the attitude control end cap for facilitating the cold gas test of the attitude control side.

[0010] The attitude control nozzle and the solenoid valve are arranged in a straight line to form an attitude control solenoid valve-nozzle assembly. There are a total of six attitude control solenoid valve-nozzle assemblies, arranged in a "middle" shape. The attitude control solenoid valve-nozzle assembly is connected to the attitude control end cap by a threaded connection.

[0011] The orbit control side includes: an orbit control end cap, an orbit control combustion chamber, an insulating layer, an orbit control nozzle, a floating lift valve, and an orbit control solenoid valve assembly;

[0012] An insulating layer is provided on the inner wall of the orbit control combustion chamber, and a charge is provided in the orbit control combustion chamber;

[0013] The orbit control side igniter is installed from the orbit control end cap side;

[0014] The orbit control end cap is an ellipsoidal end cap and is recessed inward in the middle, forming an installation space for the orbit control nozzle, the floating lift valve, and the orbit control solenoid valve assembly.

[0015] The orbit control end cap is connected to the orbit control combustion chamber by a threaded connection. There are four "cross"-shaped orthogonally arranged cylindrical structures on the orbit control end cap. The cylindrical structures are provided with inner shafts for axial positioning and line sealing.

[0016] The orbit control nozzle and the floating lift valve form an assembly. Four assemblies are arranged in a "cross" shape orthogonally. The corresponding orbit control solenoid valve assemblies are arranged at an angle with the axis of the orbit control nozzle in the same plane.

[0017] The component structure formed by the orbit control nozzle and the floating lift valve is: the floating lift valve and the spring are installed in the ceramic sleeve, and the ceramic sleeve is installed in the cylindrical structure of the orbit control end cap; the orbit control nozzle with a shoulder is installed outside the floating lift valve, and is threadedly connected to the cylindrical structure of the orbit control end cap with an external thread by a nozzle end cap with an internal thread. While pressing the orbit control nozzle, line sealing is achieved through the protruding structure on the shoulder of the orbit control nozzle.

[0018] The orbit control solenoid valve assembly is connected to the orbit control end cap by a threaded connection. The gas passage on the orbit control end cap is thermally protected by an yttria-stabilized zirconia ceramic sleeve.

[0019] The main structures of the orbit control combustion chamber and the attitude control gas cylinder are made of TC titanium alloy; the charge is made of a low-temperature composite charge, and the insulating layer is made of ethylene propylene diene monomer rubber material.

[0020] The nozzle of the attitude control end cap and attitude control solenoid valve-nozzle assembly is made of MA21 grade magnesium-lithium alloy material.

[0021] The ceramic sleeve of the track control nozzle and floating lift valve assembly is made of zirconia ceramic material, while the track control nozzle and floating lift valve are made of silicon carbide ceramic.

[0022] This invention can meet the attitude and orbit control propulsion system requirements of multi-target interceptors, and solves the technical challenges of solid attitude and orbit control engines in terms of "light weight, small size, restartability, and long operating time". Its advantages are:

[0023] (1) Repeated ignition can be achieved using ordinary solid propellant with low pressure index. Compared with multi-pulse propellant design, this scheme can provide continuous thrust; compared with negative pressure index propellant and high pressure self-extinguishing propellant, the propellant of this scheme is easier to obtain and more technically feasible.

[0024] (2) Small size and light weight. The structural envelope of the attitude control power system can be within 150mm in diameter and 200mm in length, and the total mass of the system is less than 1.5kg.

[0025] (3) Can be on standby for a long time, with working hours up to 10 hours. 2 On the order of s.

[0026] (4) Decoupling of energy between attitude control gas cylinder and orbit control combustion chamber. The energy required for attitude control missions is usually much lower than that required for orbit change missions. Cold gas propulsion is used on the attitude control side, so that the gas cylinder is always at room temperature, eliminating the need for thermal protection, reducing the material strength requirements, and greatly reducing the mass of the engine casing.

[0027] (5) Decoupling of the track control nozzle and the attitude control nozzle. The track control nozzle is usually used much less frequently than the attitude control nozzle. After the propellant is deactivated, the attitude control nozzle can still work normally, improving the response speed of attitude control.

[0028] (6) The propellant only burns during the orbital change mission, and the thermal protection of the combustion chamber is easier than that of the traditional scheme.

[0029] (7) The lightweight design of the solenoid valve makes the weight of a single solenoid valve less than 30g. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the structure of the present invention;

[0031] Figure 2 This is a partial cross-sectional structural diagram of the present invention;

[0032] Figure 3 This is an overall sectional view of the present invention;

[0033] Among them, 1-attitude control gas cylinder, 2-attitude control end cap, 3-attitude control solenoid valve-nozzle assembly, 4-track control combustion chamber, 5-insulation layer, 6-charge, 7-track control end cap, 8-track control solenoid valve assembly, 9-floating lift valve, 10-track control nozzle.

[0034] Figure 4 This is a half-sectional view of the layout of the attitude control nozzle and direct-acting solenoid valve of the present invention.

[0035] Figure 5 is a half-sectional view of the layout of the track control nozzle and the secondary amplified gas valve of the present invention. Detailed Implementation

[0036] The present invention aims to provide a design scheme for a solid attitude control engine that is "lightweight, small in size, restartable, and has a long operating time".

[0037] To meet the above requirements, the present invention adopts a "track control combustion chamber 4 - attitude control gas cylinder 1" structure to decouple attitude control from track control;

[0038] Engine overall structure scheme as follows Figure 1 and Figure 2 As shown, the attitude control and orbit control systems are decoupled, with six nozzles on the attitude control side and four nozzles on the orbit control side. The main engine components are as follows: Figure 3 As shown.

[0039] The attitude control side includes: a spherical attitude control gas cylinder 1, an attitude control end cap 2, and an attitude control solenoid valve-nozzle assembly 3, etc.

[0040] The track control side includes: track control end cover 7, track control combustion chamber 4, insulation layer 5, track control nozzle 10, floating lift valve 9, and track control solenoid valve assembly 8, etc.

[0041] The attitude control and track control components are connected by a threaded structure and are not interconnected. The track control side igniter is installed from the track control end cover 7, with sufficient installation space reserved. The main structure of the track control combustion chamber 4 and attitude control gas cylinder 1 is made of TC4 titanium alloy, while other metal components with lower strength requirements are made of MA21 magnesium-lithium alloy. The solid propellant is a low-temperature composite propellant, and the insulation layer 5 is made of EPDM rubber.

[0042] For the attitude control side design: To meet strength requirements, the opening diameter of attitude control gas cylinder 1 is made as small as possible; to reduce redundant mass, the attitude control end cap 2 is designed almost in the shape of a pipe. The attitude control gas cylinder 1 and the attitude control end cap 2 are connected by welding, and a pipe joint is reserved on the outside of the attitude control end cap 2 to facilitate cold air testing on the attitude control side.

[0043] Since the thrust of the attitude control side jet nozzle is very small, a direct-acting solenoid valve is adopted in this scheme to achieve on-off control, that is, the attitude control nozzle and the solenoid valve are arranged linearly to form the attitude control solenoid valve-nozzle assembly 3. There are a total of six attitude control solenoid valve-nozzle assemblies 3, which are arranged in a "middle" shape. The attitude control solenoid valve-nozzle assembly 3 is connected to the attitude control end cover 2 by threads. The nozzle of the attitude control solenoid valve-nozzle assembly 3 and the attitude control end cover 2 is made of magnesium-lithium alloy material of MA21 grade.

[0044] For the design of the orbit control side: In order to reduce the mass as much as possible and make the axial layout compact, the orbit control end cover 7 is designed with an inward depression on the basis of an ellipsoidal end cover while ensuring the strength, leaving the installation space for the orbit control nozzle 10, the floating lift valve 9, and the orbit control solenoid valve assembly 8. Due to the special shape of the orbit control end cover 7, the 3D printing processing technology needs to be used during preparation, and the material used is TC4 titanium alloy. The orbit control end cover 7 is connected to the orbit control combustion chamber 4 by threads, and the inner shoulder on the orbit control end cover 7 is axially positioned and line-sealed.

[0045] Since the thrust of the orbit control side nozzle is large, while the electromagnetic driving force of the lightweight solenoid valve is limited, a gas valve in the form of two-stage amplification is adopted in this scheme to achieve on-off control, that is, the floating lift valve 9 and the solenoid valve are used in combination. The specific structure is: four orbit control nozzle-floating lift valve 9 assemblies, which are arranged orthogonally in a "cross" shape, and the corresponding orbit control solenoid valve assemblies 8 are arranged at a certain angle with the central axis of the orbit control nozzle 10 in the same plane.

[0046] Among them, the specific installation method of the orbit control nozzle-floating lift valve 9 assembly is: the floating lift valve 9 and the spring are placed in the ceramic sleeve, then the ceramic sleeve is placed in the cylindrical structure of the orbit control end cover 7, and then the orbit control nozzle 10 with a shoulder is placed in, and finally the nozzle end cover with an internal thread is thread-connected to the cylindrical structure of the orbit control end cover 7 with an external thread. While pressing the orbit control nozzle 10, line sealing is achieved through the convex structure on the shoulder of the orbit control nozzle 10. The ceramic sleeve is made of zirconia ceramic material and plays a thermal protection role. The orbit control nozzle 10 and the floating lift valve 9 are made of silicon carbide ceramic.

[0047] The orbit control solenoid valve assembly 8 is connected to the orbit control end cover 7 by threads, and the gas passage on the orbit control end cover 7 is also thermally protected by a zirconia ceramic sleeve.

[0048] Since the traditional strength design is too conservative and it is difficult to make the designed engine meet the lightweight requirement, structural finite element simulation calculation needs to be introduced in the design stage of this scheme. The simulation results show that for the structure with a safety factor of 1.5, when using the structure of TC4 titanium alloy, the wall thickness of 3D printing should be greater than 1.2 mm, and the wall thickness of machining should be greater than 0.7 mm; when using the structure of magnesium-lithium alloy, the wall thickness should be greater than 1.2 mm.

[0049] To meet quality requirements, lightweight design of solenoid valves is a key technology. Commercially available solenoid valves typically have the following characteristics: tight sealing, long-term operation, copper wiring, long stroke, and corrosion resistance. However, solid-state attitude control engines have the opposite requirements for solenoid valves: no need for tight sealing, extremely short operating time, aluminum wiring, short stroke, and no corrosion resistance requirements. Therefore, significant weight reduction can be achieved, meeting overall performance requirements.

[0050] Aluminum alloy can be used for the coil wire of the solenoid valve. The conductivity of aluminum alloy conductors is 61.2% that of copper, and the density of aluminum alloy is 2.7 g / cm³, while the density of copper is 8.9 g / cm³. Therefore, using aluminum alloy as the conductor reduces the coil weight. Considering that the coil does not need to operate for extended periods, aluminum alloy is chosen as the coil material to reduce weight. According to the national standard GB-T 3955-2009 Electrical Round Aluminum Wire, the minimum diameter of aluminum wire can be 0.3 mm.

[0051] Based on electromagnetic simulation results, the core component of the attitude control electromagnet weighs 22.5 g, and the core component of the track control electromagnet weighs 18.1 g. Finally, parametric modeling results show that the designed track control solenoid valve weighs approximately 28 g, and the designed attitude control solenoid valve weighs approximately 24 g.

[0052] Attitude control uses nitrogen-cooled gas propulsion, with nitrogen generated by the reaction of a sodium azide composite formula. The attitude control nozzle uses a direct-acting solenoid valve for on / off control, and its structural principle is as follows: Figure 4 As shown.

[0053] For attitude control, the workflow is as follows: When the direct-acting solenoid valve is energized, the valve core moves away from the nozzle under the action of electromagnetic force, opening the nozzle and generating thrust; after attitude control is completed, the solenoid valve is de-energized, and the valve core presses against the nozzle under the action of spring force, closing the nozzle.

[0054] The track control uses gas propulsion, which is generated by the combustion of solid propellant 6. It can be extinguished and ignited multiple times. The track control nozzle 10 is controlled by a spring-assisted floating lifting valve 9, which works in conjunction with a solenoid valve. The structural principle is shown in Figure 5.

[0055] If a track change is required, the working process of the track control nozzle 10 is as follows:

[0056] (1) Ignite the charge 6 with the igniter;

[0057] (2) The floating lifting valve 9 works in conjunction with the solenoid valve to open the nozzle, and the gas is discharged from the track control nozzle 10, generating thrust;

[0058] (3) After completing the predetermined track change task, all track control nozzles 10 are opened, the track control combustion chamber 4 is depressurized, and the propellant 6 is extinguished.

[0059] (4) Close all rail control nozzles 10. If another rail change is required, repeat steps (1) to (3). Use several solid igniters to meet the requirements of several rail changes.

[0060] The structural principles of the floating lift valve 9 and the solenoid valve are as follows: Figure 5 As shown, the movement of the amplified floating lift valve 9 is controlled by a solenoid valve, and the nozzle switch is controlled by the floating lift valve 9, which can achieve the opening and closing of the track-controlled nozzle 10 with a small electromagnetic force. The specific working process is as follows: (a) When the solenoid valve is de-energized and closed, the gas fills the tail chamber of the valve core. At this time, the pressure in the tail chamber is the stagnation pressure, which is greater than the high-velocity gas pressure at the valve head. The valve core is pushed by the pressure difference before and after and the spring assistance, so that the nozzle is in the closed state; (b) When the solenoid valve is energized and opened, the tail chamber of the valve core is connected to the external environment. At this time, the pressure in the tail chamber is the ambient pressure, which is less than the gas pressure at the valve head. The valve core is pushed by the pressure difference before and after, so that the nozzle is in the open state.

Claims

1. A low-pressure self-extinguishing and restartable micro solid-propellant attitude control motor, characterized in that, The "thrust chamber for orbit control - gas bottle for attitude control" structure is adopted to decouple the attitude control and orbit control. Cold nitrogen gas propulsion is used, and the nitrogen gas is generated by the reaction of a sodium azide composite formula. It includes an attitude control side and an orbit control side, decoupling the attitude control and orbit control; the attitude control side and the orbit control side are connected by a threaded structure and are not interconnected. The attitude control side includes: a spherical gas bottle for attitude control (1), an attitude control end cover (2), and an attitude control solenoid valve - nozzle assembly (3). The gas bottle for attitude control (1) is fixedly connected to the attitude control end cover (2) at its opening, and the attitude control end cover (2) is in the shape of a pipeline; pipe joints are reserved on the outer side of the attitude control end cover (2) for facilitating the cold gas test of the attitude control side. The attitude control nozzles and solenoid valves are arranged linearly to form the attitude control solenoid valve - nozzle assembly (3); there are a total of six attitude control solenoid valve - nozzle assemblies (3), arranged in a "middle" shape, and the attitude control solenoid valve - nozzle assembly (3) is connected to the attitude control end cover (2) by a threaded connection. The orbit control side includes: an orbit control end cover (7), an orbit control combustion chamber (4), an insulation layer (5), an orbit control nozzle (10), a floating lift valve (9), and an orbit control solenoid valve assembly (8). An insulation layer (5) is provided on the inner wall of the orbit control combustion chamber (4), and a charge (6) is provided inside the orbit control combustion chamber (4). The orbit control side igniter is installed from the side of the orbit control end cover (7). The orbit control end cover (7) is an ellipsoidal end cover and is recessed inward in the middle, forming an installation space for the orbit control nozzle (10), the floating lift valve (9), and the orbit control solenoid valve assembly (8). The orbit control end cover (7) is connected to the orbit control combustion chamber (4) by a threaded connection. There are four cylindrical structures arranged orthogonally in a "cross" shape on the orbit control end cover (7), and the cylindrical structures are provided with inner shafts for axial positioning and line sealing. The orbit control nozzle (10) and the floating lift valve (9) form an assembly, and four assemblies are arranged orthogonally in a "cross" shape. The corresponding orbit control solenoid valve assembly (8) is arranged at an angle with the central axis of the orbit control nozzle (10) in the same plane, and the orbit control solenoid valve assembly (8) is connected to the orbit control end cover (7) by a threaded connection. The component structure formed by the orbit control nozzle (10) and the floating lift valve (9) is: the floating lift valve (9) and the spring are installed in a ceramic sleeve, and the ceramic sleeve is installed in the cylindrical structure of the orbit control end cover (7); the orbit control nozzle (10) with a shoulder is installed outside the floating lift valve (9), and a nozzle end cover with an internal thread is thread - connected to the cylindrical structure of the orbit control end cover (7) with an external thread. While pressing the orbit control nozzle (10), line sealing is achieved through the raised structure on the shoulder of the orbit control nozzle (10).

2. The low-pressure self-extinguishing and restartable micro solid rocket motor according to claim 1, characterized in that, The main structures of the orbit control combustion chamber (4) and the gas bottle for attitude control (1) are made of TC titanium alloy; the charge (6) uses a low - temperature composite charge, and the insulation layer (5) uses ethylene propylene diene monomer rubber material. The nozzle of the attitude control end cover (2) and the attitude control solenoid valve - nozzle assembly (3) is made of magnesium - lithium alloy material of MA21 grade. The ceramic sleeve of the component formed by the orbit control nozzle (10) and the floating lift valve (9) uses zirconia ceramic material, and the orbit control nozzle (10) and the floating lift valve (9) use silicon carbide ceramic.

3. The low-pressure self-extinguishing and restartable micro solid rocket motor according to claim 1, characterized in that, The gas passage on the orbit control end cover (7) is thermally protected by a zirconia ceramic sleeve.

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