Electrical propulsion propellant on-orbit high-density storage and supply device and method

Abstract

This invention relates to an on-orbit high-density storage and supply device and method for electric propulsion working propellant, belonging to the field of spacecraft deep space exploration and on-orbit servicing technology, which can effectively save space and mass resources of spacecraft. The cooling circuit consists of a storage tank, a refrigerator, a pump, and an injection pipe connected sequentially; the pressurization circuit consists of a storage tank, a heating evaporator, and a third solenoid valve connected in a loop; and the gaseous working propellant circuit consists of a storage tank, a vaporizer, and a buffer chamber connected sequentially. This invention simplifies the complexity of the propulsion system and reduces potential failure risks, effectively supporting the application of high-power, high-specific-impulse, and long-life new electric propulsion technologies, providing important support for deep space exploration and on-orbit servicing missions.

Description

Technical Field

[0001] This invention relates to an on-orbit high-density storage and supply device and method for electric propulsion propellant, belonging to the field of spacecraft deep space exploration and on-orbit servicing technology. Background Technology

[0002] To meet the demands of deep space exploration and on-orbit servicing missions, spacecraft propulsion systems must possess the following characteristics: high propulsion efficiency and high specific impulse to increase payload mass; large velocity increments and high thrust to shorten mission cycles; and long lifespan to support repeated transfers between different orbits. Addressing these new mission requirements, high-power electric propulsion systems, such as those using nuclear power, with their high impulse, high thrust, and long lifespan, can effectively extend spacecraft lifespan, reduce launch costs, and meet the requirements of highly maneuverable missions. This comprehensively enhances the functionality and performance of propulsion systems and expands their application scenarios. Publication number CN104075104B, invention titled "Method for Hot-Pressurized Xenon Refueling in Satellite Electric Propulsion System"; Publication number CN104075105B, invention titled "A Hot-Pressurized Xenon Refueling System for Satellite Electric Propulsion System," discloses that the purity, pressure, temperature, and refueling volume of xenon meet the required requirements during the xenon refueling process. The key focus is on solving the problems of xenon purity and temperature control, ensuring the safety of the refueling test. It does not directly involve the high-density on-orbit storage and management of electric propulsion propellant; Publication number CN214663682U, invention titled "A Xenon Refueling System for Satellite Electric Propulsion System," wherein the xenon transfer device utilizes liquid... Nitrogen is used to cool and heat xenon gas, allowing it to be stored and transferred in different states. However, other cooling media are required for cooling. In aerospace, where space design requirements are stringent and severely constrained, this cooling method is not suitable for on-orbit use. The existing demand for high-thrust, high-total-impact propulsion systems means that more propellant needs to be carried. Space and mass resources are extremely valuable in spacecraft. Therefore, the existing methods for storing xenon, krypton, and argon propellants in gaseous or supercritical states in electric propulsion systems can no longer meet mission requirements due to low storage density and the need for large-volume pressure vessels. Thus, how to achieve high-density on-orbit storage and management of electric propulsion propellants is a problem that must be solved to further improve space propulsion technology.

[0003] Therefore, there is an urgent need to propose an on-orbit high-density storage and supply device and method for electric propulsion working propellant to solve the above-mentioned technical problems. Summary of the Invention

[0004] To address the complexities of propulsion systems, an on-orbit high-density storage and supply device and method for electric propulsion propellants are provided. A brief overview of the invention is given below to provide a basic understanding of certain aspects of the invention. It should be understood that this overview is not an exhaustive summary of the invention. It is not intended to identify key or essential parts of the invention, nor is it intended to limit the scope of the invention.

[0005] The technical solution of the present invention:

[0006] A high-density on-orbit storage and supply device for electric propulsion working fluid, comprising a refrigeration circuit: a storage tank, a refrigeration unit, a pump, and an injection pipe connected in sequence, with the injection pipe of the refrigeration circuit located inside the storage tank;

[0007] The pressurization circuit consists of a storage tank, a heating evaporator, and a third solenoid valve connected in a loop.

[0008] Gaseous working fluid path: storage tank, vaporizer, and buffer tank are connected in sequence.

[0009] Preferably, one opening of the four-way pipe is connected to the output end of the storage tank, and the other three openings of the four-way pipe are respectively connected to the input ends of the refrigeration unit, the heating evaporator, and the vaporizer.

[0010] Preferably, the injection pipe has several uniformly arranged working fluid outlet holes.

[0011] Preferably, the output end of the heating evaporator of the booster circuit is connected to the input end of the storage tank through a second conduit, and a third solenoid valve is installed on the second conduit.

[0012] Preferably, the gaseous working fluid path is equipped with a first solenoid valve, which is installed on a four-way pipe. The output end of the first solenoid valve is connected to the input end of the vaporizer, and a first safety valve is installed on the pipeline between the input end of the first solenoid valve and the four-way pipe.

[0013] A second solenoid valve and a second safety valve are installed on the pipeline between the buffer tank inlet and the vaporizer. The buffer tank is equipped with a second temperature sensor and a second pressure sensor.

[0014] Preferably, the number of buffer tanks is two or more.

[0015] Preferably, the first solenoid valve and the first safety valve in the gaseous working fluid path are both connected to the four-way pipe through the first flange, and the second safety valve and the buffer tank are both connected to the second solenoid valve through the third flange.

[0016] Preferably, the tank is wrapped with an insulation layer on the outside and is provided with a second flange for connection to the satellite structure.

[0017] Preferably, the storage tank is equipped with a first pressure sensor and a first temperature sensor.

[0018] A method for high-density on-orbit storage and supply of electric propulsion propellant, employing an on-orbit high-density storage and supply device for electric propulsion propellant, includes the following steps:

[0019] Working fluid storage: The tank contains the working fluid; when the temperature does not meet the set value or the pressure is too high, the refrigeration circuit is activated, and the liquid working fluid in the tank is cooled and sprayed into the tank; when the propellant is delivered to the outside of the tank, the pressurization circuit is activated, and the liquid working fluid in the tank is vaporized and delivered to the buffer tank.

[0020] Working fluid delivery: The working fluid is delivered to the buffer tank until the pressure of the buffer tank is detected to meet the set value.

[0021] The present invention has the following beneficial effects:

[0022] This invention, applied in the aerospace field, considers space and weight as key factors in its design. It addresses the problems of traditional electric propulsion systems storing xenon, krypton, and argon in gaseous or supercritical states in cylinders. This storage method results in excessive pressure, complex pressure vessel structures, and the need for high strength, while also offering lower density and storage capacity compared to liquid storage. The liquid propellant storage of this invention significantly increases propellant carrying capacity. It utilizes the medium within the tank for cyclic pressure and temperature regulation, saving space, drastically reducing tank volume, and improving mission feasibility. It meets the higher requirements for propellant carrying capacity and storage density, enabling high-density storage and efficient supply of xenon, krypton, and argon for electric propulsion, and has broad application prospects.

[0023] This invention simplifies the complexity of propulsion systems and reduces potential failure risks. It can be applied to multiple aspects such as spacecraft thermal control, microgravity management of liquid propellants, and the use of liquid propellant vaporization and evaporation, providing important support for missions such as deep space exploration and on-orbit servicing.

[0024] Based on the physical properties of electric propulsion propellants such as xenon, krypton, and argon, this invention designs a scheme for high-density storage of propellants through cryogenic storage in orbit, taking into account the change in propellant density with temperature and considering multiple factors such as space, weight, and environment. This effectively increases the amount of propellant carried in orbit and is suitable for in-orbit use. Attached Figure Description

[0025] Figure 1 It is an on-orbit high-density storage and supply device for electric propulsion working fluid;

[0026] Figure 2 This is a partial diagram of an on-orbit high-density storage and supply device for electric propulsion working fluid;

[0027] Figure 3 This is the PρT relationship diagram for xenon.

[0028] In the diagram, 1-storage tank, 2-injection pipe, 3-first conduit, 4-refrigeration unit, 5-first solenoid valve, 6-first safety valve, 7-vaporizer, 8-second solenoid valve, 9-second safety valve, 10-buffer tank, 11-second temperature sensor, 12-second pressure sensor, 13-third flange, 14-first flange, 15-second flange, 16-insulation layer, 17-satellite structure, 18-pump, 19-heating evaporator, 20-four-way pipe, 21-second conduit, 22-third solenoid valve, 23-working fluid outlet, 24-guide plate, 25-accumulator, 26-first pressure sensor, 27-first temperature sensor. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of this invention clearer, the invention is described below with reference to specific embodiments shown in the accompanying drawings. However, it should be understood that these descriptions are merely exemplary and not intended to limit the scope of the invention. Furthermore, descriptions of well-known structures and technologies are omitted in the following description to avoid unnecessarily obscuring the concept of the invention.

[0030] Specific implementation method one: Combining Figure 1-2 This embodiment describes an on-orbit high-density storage and supply device for electric propulsion working fluid, comprising:

[0031] Refrigeration circuit: Storage tank 1, refrigerator 4, pump 18, and injection pipe 2 are connected in sequence to form a refrigeration circuit; Storage tank 1 is a surface tension storage tank used to store the working fluid; pump 18 is a liquid pump; the working fluid in storage tank 1 is cooled by refrigerator 4 and then evenly sprayed into storage tank 1 through injection pipe 2; injection pipe 2 is used to reduce the temperature of the working fluid in storage tank 1.

[0032] The cooling circuit also includes a first conduit 3, through which the output end of the pump 18 located outside the tank 1 is connected to the input end of the injection pipe 2 located inside the tank 1; the present invention increases the portable working fluid in a limited space and reduces the impact on the spacecraft configuration design;

[0033] The injection pipe 2 is located at the axis of the storage tank 1. Several uniformly arranged medium outlet holes 23 are machined on the injection pipe 2 as the output end of the injection pipe 2. The mixture is uniform and the cooling efficiency is improved. This invention achieves zero evaporation of the working fluid, which greatly improves the service life and can meet the 15-year on-orbit working life. Based on the physical properties of electric propulsion working fluids such as xenon, krypton, and argon, this patent designs a scheme to achieve high-density storage of working fluid through low-temperature storage on orbit, based on the change of working fluid density with temperature, which effectively improves the amount of working fluid carried on orbit.

[0034] The pressurization circuit consists of storage tank 1, heating evaporator 19, and third solenoid valve 22 connected in a loop to form a pressurization circuit; the working fluid in storage tank 1 is heated and vaporized by heating evaporator 19 and then returns to storage tank 1 for pressure regulation;

[0035] The pressurization circuit also includes a second conduit 21, through which the output end of the heating evaporator 19 is connected to the input end of the storage tank 1; the liquid working fluid is heated and vaporized by the heating evaporator and filled into the storage tank to achieve self-regulation of the storage tank pressure; the heat insulation layer separates the second conduit 21 from the storage tank 1, effectively preventing heat exchange and ensuring the working fluid state in the storage tank;

[0036] Gaseous working fluid path: Storage tank 1, vaporizer 7, and buffer tank 10 are connected in sequence to form a gaseous working fluid path; vaporizer 7 is used to vaporize the working fluid; the working fluid in storage tank 1 enters vaporizer 7 for heating and vaporization, vaporizer 7 uses a heating evaporator, and enters buffer tank 10 to form a high-pressure working fluid.

[0037] It also includes a four-way pipe 20, one opening of which is connected to the accumulator 25 at the output end of the storage tank 1. Screens are provided at the liquid outlets on the top and side of the accumulator 25. The other three openings of the four-way pipe 20 are respectively connected to the input ends of the refrigeration unit 4, the heating evaporator 19, and the vaporizer 7.

[0038] The gaseous working fluid path also includes a first solenoid valve 5 and a first safety valve 6. The storage tank 1 is connected to the input end of the first solenoid valve 5 through the opening of the four-way pipe 20 vaporizer. The output end of the first solenoid valve 5 is connected to the input end of the vaporizer 7. The first safety valve 6 is installed on the pipeline between the input end of the first solenoid valve 5 and the opening of the four-way pipe 20 vaporizer.

[0039] The gaseous working fluid path also includes a second solenoid valve 8, a second safety valve 9, a second temperature sensor 11, and a second pressure sensor 12. The second solenoid valve 8 and the second safety valve 9 are both connected to the input end of the buffer tank 10, and the second temperature sensor 11 and the second pressure sensor 12 are both connected to the output end of the buffer tank 10. By controlling the opening and closing time of the valves and combining temperature and pressure control measures, this invention controls the working fluid flowing into the buffer gas container after vaporization within the required pressure range, thereby facilitating downstream pressure and flow management.

[0040] There are two buffer tanks 10, and the output end of the vaporizer 7 is connected to the input end of two parallel second solenoid valves 8; this facilitates control and ensures stable flow delivery.

[0041] The present invention has a simple structure, low cost, and is not easily damaged. It can realize high-density storage and efficient supply of working fluids such as xenon, krypton, and argon for electric propulsion, and is a cryogenic high-density storage tank and management system for electric propulsion working fluids with "zero evaporation" in orbit; effectively supporting the promotion and application of electric propulsion in deep space exploration, on-orbit servicing and other fields.

[0042] The gaseous working fluid path also includes a third flange 13 and a first flange 14. The first solenoid valve 5 and the first safety valve 6 are both connected to the corresponding openings of the four-way pipe 20 vaporizer through the first flange 14. The second safety valve 9 and the buffer tank 10 are both connected to the second solenoid valve 8 through the third flange 13. The output end of this invention is the outlet, and the input end is the inlet.

[0043] It also includes a second flange 15 and a heat insulation layer 16. The outer side of the storage tank 1 is wrapped with a heat insulation layer 16, which is made of multi-layer foam insulation. The storage tank 1 is detachably connected to the satellite structure 17 through the second flanges 15 arranged on the upper and lower sides. The flanges are made of heat-insulating material to achieve the heat insulation function. This invention provides heat insulation treatment for the storage tank to isolate the heat conduction between the inside and outside of the storage tank. This invention addresses the issue of heat conduction both internally and externally; it increases the portable working propellant within a limited space, reducing the impact on spacecraft configuration design; it achieves high-density on-orbit storage of xenon, krypton, and argon working propellants for electric propulsion throughout their entire lifecycle; it solves the problem of limited storage capacity caused by the use of supercritical or gaseous storage for electric propulsion working propellants; and it addresses the issue of low storage density, which is mainly addressed by increasing the volume of gas cylinders to improve the carrying capacity of the working propellant. This invention is applicable to the high-density storage and supply of xenon, krypton, and argon working propellants for electric propulsion, enabling independent control of key aerospace resources, providing strong support for the development and application of high-performance propulsion systems for spacecraft, providing strong guarantees for the development of high-performance propulsion systems for space probes, and providing important support for the implementation of major national missions such as deep space exploration and on-orbit servicing.

[0044] Specific Implementation Method Two: Combining Figure 1-3 This embodiment describes a method for high-density on-orbit storage and supply of electric propulsion working fluid, comprising:

[0045] Working fluid storage is achieved through the upstream structure of the vaporizer: Tank 1 contains the working fluid, which can be xenon, krypton, or argon. The pressure and temperature within tank 1 are detected by the first pressure sensor 26 and the first temperature sensor 27. If temperature stratification and / or pressure instability occur, i.e., the temperature and pressure do not meet the set values; when the temperature does not meet the set value or the pressure is too high (above the set range), the refrigeration circuit's refrigeration unit 4 and pump 18 are activated, while the other circuits are closed. The liquid working fluid in tank 1 is cooled and transported to the injection pipe 2, and then evenly sprayed into tank 1 through the working fluid outlet 23 of the injection pipe 2; when the pressure is too low (below the set range), the third solenoid valve 22 and the heating evaporator 19 of the pressurization circuit are activated, while the other circuits are closed. When closed, the liquid working fluid in tank 1 is vaporized and transported into tank 1 via heating evaporator 19. This invention is applied to the on-orbit high-density storage and management system for electric propulsion working fluids. Based on the physical properties of electric propulsion working fluids such as xenon, krypton, and argon, by controlling the temperature of the on-orbit working fluid storage cylinders, the supercritical working fluid is converted into a liquid, gas-liquid mixture, or even a solid state, thereby increasing the storage density of the working fluid, effectively increasing the carrying capacity of the electric propulsion working fluid, and also effectively reducing the system's working pressure, simplifying the complexity of the propulsion system, and reducing potential failure risks. It can be applied to multiple aspects such as spacecraft thermal control, microgravity management of liquid propellants, and vaporization and evaporation of liquid propellants, providing important support for missions such as deep space exploration and on-orbit servicing.

[0046] The working fluid is supplied via a pneumatic or solenoid valve connected to the electric thruster downstream of the vaporizer. The working fluid, which can be xenon, krypton, or argon, is supplied to the electric thruster. The pressure and temperature within the storage tank 1 are monitored by a first pressure sensor 26 and a first temperature sensor 27 to ensure they meet the requirements for working fluid storage. If not, adjustments are made to the storage process to bring the working fluid to the set values ​​before supplying it downstream of the evaporator. During the supply of gaseous working fluid downstream of the evaporator, the refrigeration circuit and the pressurization circuit are closed, the second solenoid valve 8 is activated, and then the first... A solenoid valve 5 detects the pressure of the buffer tank 10 through the second pressure sensor 12 until the set value is met, then closes the second solenoid valve 8 and the first solenoid valve 5. If the set value is not met, the second solenoid valve 8 and the first solenoid valve 5 are restarted. The second temperature sensor 11 detects the pressure of the buffer tank 10. If the pressure is too low, the heating device can be activated until the set value is met. When the pressure is less than the set value when the end valve is opened for supply, the end valve is closed to stop the gas supply, and the second solenoid valve 8 and the first solenoid valve 5 are restarted. This enables high-density on-orbit storage and management of the electric propulsion working fluid.

[0047] This invention proposes a method for high-density storage and supply of working propellants in electric propulsion systems. Based on the physical properties of electric propulsion working propellants such as xenon, krypton, and argon, and considering multiple factors including space, weight, and environment, a scheme is designed to achieve high-density storage of working propellants through on-orbit cryogenic storage. This effectively increases the on-orbit carrying capacity of working propellants and is a pioneering innovation in China. It is applicable to the on-orbit high-density storage and supply of xenon, krypton, and argon working propellants in spacecraft electric propulsion systems. By controlling the temperature of the on-orbit working propellant storage cylinders, the supercritical working propellant is converted into a liquid, gas-liquid mixture, or even a solid state, thereby increasing the storage density of the working propellant and effectively increasing the carrying capacity of electric propulsion working propellants. It can also effectively reduce the system's operating pressure, simplify the complexity of the propulsion system, and reduce potential failure risks, providing support for deep space exploration, on-orbit servicing, and other missions.

[0048] Example 1:

[0049] Combination Figures 1-3 As shown:

[0050] An on-orbit high-density storage and supply device for electric propulsion working propellant is employed, comprising:

[0051] Refrigeration circuit: Storage tank 1, refrigeration unit 4, pump 18, and injection pipe 2 are connected in sequence in a loop;

[0052] The injection pipe 2 of the refrigeration circuit is installed inside the storage tank 1. Several uniformly arranged working fluid outlet holes 23 are machined on the injection pipe 2 to achieve uniform refrigeration. Through the active and passive refrigeration system, zero evaporation of the working fluid is achieved, which meets the 15-year working life in orbit.

[0053] The pressurization circuit consists of a storage tank 1 and a heating evaporator 19 connected in a loop.

[0054] The output end of the heating evaporator 19 in the pressurization circuit is connected to the input end of the storage tank 1 through the second conduit 21. The second conduit 21 is equipped with a third solenoid valve 22. The pressure self-regulating system can heat and vaporize the liquid working fluid flowing out of the storage tank, and then the vaporized working fluid flows back into the storage tank to pressurize the storage tank.

[0055] Gaseous working fluid path: Storage tank 1, vaporizer 7, and buffer tank 10 are connected in sequence;

[0056] The input end of the first solenoid valve 5 in the gaseous working fluid path is connected to the storage tank 1 through the four-way pipe 20, the output end of the first solenoid valve 5 is connected to the input end of the vaporizer 7, and a first safety valve 6 is provided between the input end of the first solenoid valve 5 and the four-way pipe 20.

[0057] A second solenoid valve 8 and a second safety valve 9 are sequentially installed along the working fluid flow direction on the pipeline between the input end of buffer tank 10 and vaporizer 7. A second temperature sensor 11 and a second pressure sensor 12 are installed at the output end of buffer tank 10. Buffer tank 10 is...

[0058] There are two buffer tanks 10. The output end of the buffer tank 10 is equipped with a solenoid valve, and a heating device is installed on the outside of the buffer tank 10.

[0059] The first solenoid valve 5 and the first safety valve 6 in the gaseous working fluid path are both connected to the four-way pipe 20 through the first flange 14, and the second safety valve 9 and the buffer tank 10 are both connected to the second solenoid valve 8 through the third flange 13.

[0060] The outer side of the storage tank 1 is covered with a heat insulation layer 16, and the storage tank 1 is detachably connected to the satellite structure 17 through the second flanges 15 arranged on the upper and lower sides;

[0061] The storage tank 1 is equipped with a first pressure sensor 26 and a first temperature sensor 27. The output end and input end of the storage tank 1 are located on different sides, such as the output end and input end of the storage tank 1 being located at the upper and lower ends of the storage tank 1 respectively, or the output end of the storage tank 1 being located on the lower side of the storage tank 1, and the input end of the storage tank 1 being located on the side of the storage tank 1. The storage tank contains a propellant management device (PMD), which can realize the effective management of propellant under microgravity and ensure that the working fluid discharged from the storage tank is a liquid working fluid.

[0062] The opening section of the injection pipe 2 is located inside the storage tank 1. A circumferentially evenly arranged guide plate 24 is provided on the outside of the injection pipe 2. Several working fluid outlet holes 23 are machined on the injection pipe 2. The storage tank 1 stores the working fluid and contains a propellant management device (PMD) to achieve effective management of the propellant under microgravity and ensure that the working fluid discharged from the storage tank is liquid. The PMD consists of a cylindrical structure (central cylinder) and guide plates. The central cylinder plays a structural support role, and the central cylinder is evenly distributed with injection holes. Under the action of the refrigeration unit and the pump, the cooled working fluid is injected to various parts of the storage tank.

[0063] The device further includes:

[0064] Tank 1 and heating evaporator 19 are sequentially connected to form a pressurization loop. The working fluid in tank 1 is heated and vaporized by heating evaporator 19 and then returns to tank 1 for pressure regulation. Taking advantage of the low boiling point and easy vaporization of commonly used electric propulsion working fluids such as xenon (boiling point -108.1℃), krypton (boiling point -153.35℃), and argon (boiling point -185.3℃), a pressure self-regulating system is designed to regulate the working pressure of the tank and meet the working fluid supply requirements. That is, by utilizing the low boiling point of electric propulsion working fluids such as xenon, krypton, and argon, combined with a vaporizer, the outflowing liquid working fluid is vaporized and then flows back into the tank, realizing the self-regulation of the tank pressure and further simplifying the system complexity.

[0065] Storage tank 1, refrigerator 4, pump 18, and injection pipe 2 are sequentially connected to form a refrigeration circuit. Storage tank 1 is a surface tension storage tank used to store the working fluid. Pump 18 is a liquid pump. The working fluid in storage tank 1 is cooled by refrigerator 4 and then evenly sprayed into storage tank 1 through injection pipe 2. Injection pipe 2 is used to reduce the temperature of the working fluid in storage tank 1.

[0066] Based on the physical properties of electric propulsion propellants such as xenon, krypton, and argon, this invention designs a scheme for high-density propellant storage through cryogenic storage in orbit, based on the change in propellant density with temperature. This effectively increases the amount of propellant carried in orbit. Simultaneously, the propellant within the storage tank 1 is used to enter the pressurization and cooling circuits, achieving pressure and temperature control through propellant self-circulation. The propellant state is adjustable, not only increasing the amount of propellant that can be carried within a limited space but also significantly reducing the space occupied by additional storage tanks and other equipment, minimizing the impact on spacecraft configuration design. Furthermore, it achieves controllable adjustment of the propellant storage and transportation process. The pressure self-regulation technology designed based on the propellant properties greatly simplifies traditional high-pressure gas pressurization systems, significantly saves space and weight resources in spacecraft, and improves mission feasibility.

[0067] The inlet of the storage tank 1, serving as a pressurization inlet for the working gas, is located on the upper or side side, and the lower side of the storage tank 1 has an opening for installing the injection pipe 2; the structure of this invention is simple, low in cost, and not easily damaged;

[0068] The injection pipe 2 is located at the center. The injection pipe 2 is a cylindrical shape with an inner cavity. The inner cavity of the injection pipe 2 is connected to the inner cavity of the storage tank 1 through several circumferential openings 23. The lower end of the injection pipe 2 is connected to the pump 18 outside the storage tank 1 through the first conduit 3. The upper end of the injection pipe 2 is sealed. The hydraulic pressure is concentrated at the openings 23. The working fluid is sprayed over a long distance, which further improves the cooling range and achieves uniform and efficient cooling.

[0069] The injection pipe 2 is machined with working fluid outlet holes 23 and is provided with circumferentially uniformly arranged guide plates 24. The side wall of the injection pipe 2 between adjacent guide plates 24 has a number of working fluid outlet holes 23 along the axial direction.

[0070] The injection pipe 2 is connected to the first port of the four-way pipe 20. The second port of the four-way pipe 20 is connected to the refrigerator 4 to supply working fluid to the refrigeration circuit. The third port of the four-way pipe 20 is connected to the heating evaporator 19 to supply working fluid to the pressurization circuit. The fourth port of the four-way pipe 20 is used to supply working fluid into the gaseous working fluid path. The injection pipe 2 is connected to the pump 18, thereby connecting the pump 18 to the annular cavity for injecting low-temperature medium for uniform cooling. The structure is compact and easy to install and maintain. Based on the physical properties of the gaseous working fluid...

[0071] All substances may exhibit multiple states such as solid, liquid, gas-liquid mixture, gas and supercritical state under different combinations of pressure P and temperature T, and the corresponding density is a definite value;

[0072] Taking xenon as an example, its phase transition (density) is related to pressure P and temperature T as follows: Figure 3 As shown in the figure, when the temperature is above 16.6℃, xenon is in a gaseous state. If the pressure is above 5.84MPa at the same time, xenon is in a supercritical state. In the supercritical state, xenon has a density similar to that of a liquid, but its transport properties are similar to those of a gas.

[0073] The properties of working fluids such as xenon, krypton, and argon are summarized in Table 1. Similar to the physical properties of xenon, liquid or solid working fluids only appear when the storage temperature is below the critical temperature. Therefore, in order to achieve high-density storage of working fluids, the storage temperature must first be lowered to below the supercritical temperature of the working fluid.

[0074] Table 1. Characteristics of working fluids: xenon, krypton, and argon

[0075]

[0076] Based on this, a suitable cryogenic storage temperature can be selected according to the physical properties of different working fluids such as xenon, krypton, and argon, based on factors such as the amount of electric propulsion working fluid carried by the spacecraft in orbit, the structural envelope requirements of the spacecraft itself, and the on-orbit cooling capacity, so as to achieve high-density storage of the working fluid.

[0077] The corresponding relationships between the saturated vapor pressure, liquid phase density, and gas phase density of xenon, krypton, and argon at different temperatures are shown in Table 2. As the temperature decreases, the saturated vapor pressure of the working fluid decreases, while the liquid phase density increases, which means that more electric propulsion working fluid can be stored and carried.

[0078] Table 2. Density of working fluid at different temperatures

[0079]

[0080] Cryogenic working fluid on-orbit management and supply system hardware

[0081] Achieving high-density on-orbit storage of xenon, krypton, and argon working propellants for electric propulsion throughout the entire life cycle through spacecraft thermal design involves multiple aspects such as spacecraft thermal control, microgravity management of liquid propellants, and the vaporization and evaporation of liquid propellants.

[0082] The cryogenic propellant on-orbit management and supply system mainly consists of a surface tension tank, a thermal control system (refrigerator 4, injection pipe 2), valves, a buffer gas tank (buffer tank 10), a heating evaporator (vaporizer 7), and temperature and pressure sensors. Tank 1 requires insulation to prevent heat conduction between the inside and outside of tank 1. The flow rate of liquid propellant into the buffer gas cylinder is controlled by adjusting the opening and closing times of the valves, and the liquid propellant is heated and vaporized by the heating evaporator. Ultimately, the system provides gaseous propellant to the downstream storage and supply system.

[0083] Workflow

[0084] Taking the storage and supply of liquid xenon as an example, the process for storing and supplying liquid xenon is as follows:

[0085] Step 1: The propellant working fluid is stored in liquid form in tank 1. The temperature of tank 1 is actively controlled to be -25℃ to -20℃, and the pressure is about 2 to 3 MPa.

[0086] During storage, the storage tank 1 is cooled to lower the storage temperature of the working fluid below the critical temperature, transforming the working fluid into a liquid, gas-liquid mixture, or solid state. This increases the storage density of the working fluid, effectively increasing the carrying capacity of the electric propulsion working fluid. It also effectively reduces the system's operating pressure, simplifies the complexity of the propulsion system, and reduces potential failure risks, providing support for missions such as deep space exploration and on-orbit servicing. This invention solves the problem that current electric propulsion working fluids are stored in a supercritical or gaseous state with low storage density, mainly by increasing the volume of gas cylinders to increase the carrying capacity. This invention creatively provides a method for high-density storage and supply of xenon, krypton, and argon working fluids for electric propulsion. Currently, there are no similar methods or systems for electric propulsion gas working fluids, and this device does not propose such a method.

[0087] Step 2: Open the first solenoid valve 5. Liquid xenon pushes the propellant working medium into the downstream pipeline through the action of surface tension and pressure difference and is vaporized by the vaporizer 7. A small amount of xenon gas enters the cryogenic buffer tank 10 at the moment the first solenoid valve 5 is briefly opened.

[0088] Step 3: After a certain amount of xenon gas flows into the buffer tank 10, it is heated to above 16.6℃ to completely vaporize it, forming high-pressure xenon gas (about 3~5 MPa) which enters the downstream pressure control module;

[0089] The branches of the two sets of buffer tanks 10 are connected in parallel to alternate the flow of vaporized xenon into the branches, so as to make the downstream flow as stable as possible.

[0090] Step 4: Supply is made to buffer tank 10. When the pressure in any buffer tank 10 is less than a certain value, proceed to step 2.

[0091] This invention controls the opening and closing time of the valve, and combines temperature and pressure control measures to control the working fluid flowing into the buffer gas container after vaporization within the required pressure range, thereby facilitating downstream pressure and flow management.

[0092] With the application of electric propulsion technology in spacecraft deep space exploration and on-orbit servicing, higher requirements have been placed on the amount of propellant carried and the storage density. The method of this patent invention can achieve high-density storage and efficient supply of propellants such as xenon, krypton, and argon for electric propulsion, and has broad application prospects in the above-mentioned fields.

[0093] It should be noted that in the above embodiments, as long as the technical solutions are not contradictory, they can be permuted and combined. Those skilled in the art can exhaust all possibilities based on the mathematical knowledge of permutation and combination. Therefore, the present invention will not describe the technical solutions after permutation and combination one by one, but it should be understood that the technical solutions after permutation and combination have been disclosed by the present invention.

[0094] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for high-density on-orbit storage and supply of electric propulsion working fluid, characterized in that: An on-orbit high-density storage and supply device for electric propulsion working propellant is employed, comprising: Refrigeration circuit: storage tank (1), refrigeration unit (4), pump (18), and injection pipe (2) are connected in sequence in a loop. The injection pipe (2) of the refrigeration circuit is set inside the storage tank (1). The pressurization circuit consists of a storage tank (1), a heating evaporator (19), and a third solenoid valve (22) connected in a loop. Gaseous working fluid path: storage tank (1), vaporizer (7), and buffer tank (10) are connected in sequence; The injection pipe (2) is machined with several uniformly arranged working fluid outlet holes (23), and the injection pipe (2) is provided with circumferentially uniformly arranged guide plates (24). The side wall of the injection pipe (2) between adjacent guide plates (24) has several working fluid outlet holes (23) along the axial direction. The method includes the following steps: Working fluid storage: The storage tank (1) contains the working fluid; when the temperature does not meet the set value or the pressure is too high, the refrigeration circuit is activated, and the liquid working fluid in the storage tank (1) is cooled and transported into the storage tank (1); when the propellant is transported out of the storage tank, the pressurization circuit is activated, and the liquid working fluid in the storage tank (1) is vaporized and transported into the buffer tank (10); Working medium delivery: The working medium is delivered to the buffer tank (10) until the pressure of the buffer tank is detected to meet the set value.

2. The method for high-density on-orbit storage and supply of electric propulsion working fluid according to claim 1, characterized in that: One opening of the four-way pipe (20) is connected to the output end of the storage tank (1), and the other three openings of the four-way pipe (20) are connected to the input ends of the refrigeration unit (4), the heating evaporator (19), and the vaporizer (7), respectively.

3. A method for high-density on-orbit storage and supply of electric propulsion working fluid according to claim 1 or 2, characterized in that: The output end of the heating evaporator (19) of the booster circuit is connected to the input end of the storage tank (1) through the second conduit (21), and a third solenoid valve (22) is provided on the second conduit (21).

4. A method for high-density on-orbit storage and supply of electric propulsion working fluid according to claim 2, characterized in that: The gaseous working fluid path is equipped with a first solenoid valve (5), which is installed on the four-way pipe (20). The output end of the first solenoid valve (5) is connected to the input end of the vaporizer (7). A first safety valve (6) is installed on the pipeline between the input end of the first solenoid valve (5) and the four-way pipe (20). A second solenoid valve (8) and a second safety valve (9) are installed on the pipeline between the input end of the buffer tank (10) and the vaporizer (7). A second temperature sensor (11) and a second pressure sensor (12) are installed on the buffer tank (10).

5. A method for high-density on-orbit storage and supply of electric propulsion working fluid according to claim 4, characterized in that: The number of buffer tanks (10) is two or more.

6. A method for high-density on-orbit storage and supply of electric propulsion working fluid according to claim 5, characterized in that: The first solenoid valve (5) and the first safety valve (6) of the gaseous working fluid circuit are connected to the four-way pipe (20) through the first flange (14), and the second safety valve (9) and the buffer tank (10) are connected to the second solenoid valve (8) through the third flange (13).

7. A method for high-density on-orbit storage and supply of electric propulsion working fluid according to claim 1, characterized in that: The tank (1) is wrapped with a heat insulation layer (16) on the outside and is provided with a second flange (15) for connection with the satellite structure (17).

8. A method for high-density on-orbit storage and supply of electric propulsion working fluid according to claim 1, characterized in that: The storage tank (1) is equipped with a first pressure sensor (26) and a first temperature sensor (27).

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