Air-breathing radio frequency ion electric propulsion system with mixed working medium power and multi-mode working method thereof

Abstract

The invention relates to a propulsion system, in particular to an air-breathing radio frequency ion electric propulsion system with mixed working medium power and a multi-mode working method thereof, and aims to solve the problems that an existing air-breathing electric propulsion system only takes atmosphere as a single working medium, the atmosphere trapping efficiency is low, and the performance of a spacecraft is affected. The device comprises a propelling and gas trapping unit, a radio frequency neutralizer, a power and control unit and a xenon storage and supply unit, the propelling and gas trapping unit comprises a radio frequency ion thruster and an atmosphere trapping gas inlet channel; the power and control unit comprises a direct current module, a control module and a radio frequency module; the xenon storage and supply unit comprises a xenon bottle and a valve and sensor assembly; the control module and the valve are electrically connected with the sensor assembly. The radio frequency ion thruster is electrically connected with the radio frequency neutralizer through the radio frequency module. The first output end of the xenon storage and supply unit is connected with the gas path input end of the radio frequency neutralizer, and the second output end of the xenon storage and supply unit is connected with the gas path input end of the radio frequency ion thruster.

Description

Technical Field

[0001] The present invention relates to a propulsion system, and in particular to an air-breathing radio frequency ion electric propulsion system powered by a mixed working fluid and a multi-mode working method thereof. Background Art

[0002] Compared with conventional low-orbit satellites, spacecraft flying in ultra-low orbit (100-300km) can obtain clearer remote sensing information, shorten communication delays, and are widely used in remote sensing, communication, navigation and other fields, which can significantly improve the satellite's service capabilities and application benefits.

[0003] However, the atmosphere density in ultra-low orbit is high, the resistance of satellite operation is large, and the long-term operation of satellites in orbit consumes a lot of resources. The air-breathing electric propulsion system can capture the atmosphere in the surrounding environment as propellant, so that the satellite can theoretically achieve long-term residence and maneuvering in ultra-low orbit without carrying working fluid. It can solve the problem that existing technology cannot enable aircraft to stay and maneuver in the ultra-low orbit of the earth for a long time. It is a cutting-edge space power technology with great development prospects.

[0004] See also Figure 1 As an important component of the spacecraft, the existing air-breathing electric propulsion system mainly consists of a satellite core 6, an atmosphere capture inlet 012 and a thruster 011 arranged on both sides of the satellite core 6, and several solar panels 8 connected to the satellite core 6. Its working principle is: when the air-breathing electric propulsion system is running in the low-Earth orbit in space, it will generate a relative speed with the surrounding atmosphere to form an incoming atmosphere 71. The atmosphere capture inlet 012 of the air-breathing electric propulsion system is used to capture the relatively moving incoming atmosphere 71, and the incoming atmosphere 71 is transported to the thruster, and then ionized and accelerated to form thrust, and the incoming atmosphere 71 is finally converted into a plume 72.

[0005] In theory, an air-breathing electric propulsion system can continuously obtain atmosphere from the environment as a working fluid to perform ultra-long-term ultra-low orbit operation missions. However, the complex atmospheric environment in ultra-low orbits has caused great difficulties for the in-orbit application of air-breathing electric propulsion systems:

[0006] (1) The performance of atmospheric working fluid is poor. The atmospheric composition is mainly N 2 and O 2 The performance of the electric propulsion system is far lower than that of the rare gases commonly used in electric propulsion systems, such as Xe and Kr. Nitrogen and oxygen have small atomic masses and high ionization energies, and oxygen is active and corrosive. The working capacity of the electric propulsion system using nitrogen and oxygen as propellants is not enough to cope with many complex and extreme working conditions in ultra-low orbits;

[0007] (2) The density gradient of the working fluid in the ultra-low orbit atmosphere is large. From 150km to 250km orbit altitude, the atmospheric density decreases by dozens of times. Even at the same orbit altitude, the atmospheric density can fluctuate by more than one order of magnitude due to factors such as solar activity. Too high or too low atmospheric density is not conducive to the normal operation of the air-breathing electric propulsion system. When the atmospheric density is too high, the atmospheric resistance on the satellite increases. When the atmospheric density is too low, the atmospheric capture inlet 012 cannot capture enough working fluid.

[0008] The above factors put forward core requirements for the air-breathing electric propulsion system, that is, a sufficient amount of working fluid must be supplied to the thruster 011 at all times. It is almost impossible to passively capture the atmosphere from the environment by relying solely on the atmosphere capture inlet 012. The reasons are: first, the efficiency of the inlet in capturing the incoming atmosphere is limited; second, the gas captured by the inlet cannot be further pressurized and stored, and the flow of the working fluid supplied to the thruster 011 cannot be throttled, adjusted and controlled.

[0009] Someone has proposed a solution to add a turbomolecular pump to the air-breathing electric propulsion system. On the one hand, it can improve the efficiency of the air intake to capture the incoming atmosphere. On the other hand, it can pressurize the captured atmosphere and store it in a gas cylinder. The stored high-pressure gas can be throttled, regulated, and controlled by the valve system to be delivered to the thruster. However, the weight and power consumption of the turbomolecular pump are expensive, and it makes the system more complicated, so this solution has not yet been implemented in engineering. Summary of the invention

[0010] The purpose of the present invention is to solve the problem that the existing air-breathing electric propulsion system only uses the atmosphere as a single working fluid, has a low atmosphere capture efficiency, and thus affects the performance of the spacecraft, and to provide an air-breathing radio frequency ion electric propulsion system powered by a mixed working fluid and a multi-mode working method thereof, wherein the mixed working fluid is a mixed gas of atmosphere and xenon.

[0011] To achieve the above purpose, the technical solution provided by the present invention is:

[0012] A hybrid working fluid powered air-breathing radio frequency ion electric propulsion system, which is special in that:

[0013] It includes a propulsion and gas capture unit, a radio frequency neutralizer, a power and control unit, and a xenon gas storage and supply unit;

[0014] The propulsion and gas capture unit includes a radio frequency ion thruster and an atmosphere capture inlet connected to the input end of the radio frequency ion thruster;

[0015] The power and control unit includes a DC module, a control module and a radio frequency module electrically connected to an external spacecraft control system via a communication and power supply bus;

[0016] The xenon gas storage and supply unit comprises a xenon gas cylinder for storing high-pressure xenon gas and a valve and sensor assembly for supplying xenon gas, which are interconnected through a gas path;

[0017] The control module and the valve are electrically connected to the sensor assembly, and the RF ion thruster is electrically connected to the RF neutralizer through the RF module; the first output end of the xenon gas storage and supply unit is connected to the gas path input end of the RF neutralizer, and the second output end of the xenon gas storage and supply unit is connected to the gas path input end of the RF ion thruster; the DC module is electrically connected to the RF neutralizer and the RF ion thruster;

[0018] The control module is used to control the flow rate of xenon gas in the xenon gas storage and supply unit, the radio frequency neutralizer is used to neutralize the positively charged ion plume ejected by the radio frequency ion thruster, and the direct current module is used to provide electrical energy to the radio frequency neutralizer and the radio frequency ion thruster.

[0019] Further, the radio frequency ion thruster comprises a cylindrical thruster casing, a first air inlet nozzle and a radio frequency connector arranged on the side wall of the thruster casing, a plurality of annular first radio frequency antennas embedded in the thruster casing, a second collimating grid arranged at one end close to the atmosphere capture air inlet duct, and a grid arranged at the other end, wherein the space enclosed by the grid, the second collimating grid and the inner wall of the thruster casing constitutes a discharge chamber of the radio frequency ion thruster;

[0020] The gate is electrically connected to the DC module, and the plurality of first annular radio frequency antennas are all electrically connected to the radio frequency module.

[0021] Further, the atmosphere capture inlet comprises a cylindrical inlet casing and a first collimating grid arranged at one end of the inlet casing away from the radio frequency ion thruster, and the inlet casing is connected to the thruster casing;

[0022] The inner walls of the air inlet housing and the thruster housing are provided with an integrated liner.

[0023] Further, the radio frequency neutralizer comprises a neutralizer housing, a discharge chamber and a second radio frequency antenna arranged in the neutralizer housing, a second air inlet nozzle connected to the neutralizer housing and the discharge chamber, an ion collector arranged in the discharge chamber, an ignition probe connected to the inside of the discharge chamber, a radio frequency power supply connected to the second radio frequency antenna, and a direct current power supply whose cathode is connected to the ion collector;

[0024] The second RF antenna is electrically connected to the RF module, and the positive electrode of the DC power supply is electrically connected to the DC module.

[0025] Furthermore, the valve and sensor assembly includes a first pressure sensor, a first self-locking valve, a first proportional valve, and a second pressure sensor connected in sequence to the output end of the xenon gas bottle through an air path, and the output end air path of the second pressure sensor is divided into two paths, one path includes a second self-locking valve, a second proportional valve, and a first flow sensor connected in sequence; the other path includes a third self-locking valve, a third proportional valve, and a second flow sensor connected in sequence; the output end of the first flow sensor is connected to the first air inlet nozzle in the propulsion and gas capture unit, and the output end of the second flow sensor is connected to the second air inlet nozzle in the radio frequency neutralizer; the input end of the xenon gas bottle is provided with a discharge valve;

[0026] The adding and discharging valve is used to add or discharge xenon gas in the xenon gas cylinder, the first self-locking valve, the second self-locking valve and the third self-locking valve are all used to control the on-off of the gas path, and the first proportional valve, the second proportional valve and the third proportional valve are all used to adjust the size of the gas flow;

[0027] The first pressure sensor, the first self-locking valve, the first proportional valve, the second pressure sensor, the second self-locking valve, the second proportional valve, the first flow sensor, the third self-locking valve, the third proportional valve, and the second flow sensor are all electrically connected to the control module.

[0028] Furthermore, the cross-sectional shapes of the first collimating grid and the second collimating grid are strip-shaped, fan-shaped, square-shaped, long-grid-shaped or hexagonal-grid-shaped.

[0029] Furthermore, the material of the lining is ceramic, and the inner wall of the lining in the inlet duct shell close to the radio frequency ion thruster is in the shape of an elliptical parabola, which is used to achieve mirror reflection after the airflow collides with the wall.

[0030] At the same time, the present invention also provides a multi-mode working method of the above-mentioned mixed working fluid powered air-breathing radio frequency ion electric propulsion system, which is special in that it includes the following steps:

[0031] Step 1: The spacecraft determines the current working condition through sensors, and transmits the working condition data information to the power and control unit through the communication and power supply bus. The DC module in the power and control unit adjusts the gate voltage U, the RF module adjusts the RF power P, and the control module adjusts the xenon working medium flow M of the xenon storage and supply unit to adapt to different working conditions.

[0032] Step 2: If the current working condition is the standard working condition, execute step 3a;

[0033] If the current working condition is a high resistance working condition, execute step 3b;

[0034] If the current working condition is a low resistance working condition, execute step 3c;

[0035] If the current working condition is an extremely large resistance condition, execute step 3d;

[0036] If the current working condition is a particularly rarefied atmosphere condition, execute step 3e;

[0037] Definition of standard voltage U 0 、Standard flow rate M 0 、Standard power P 0 、Maximum flow rate M max ;

[0038] Step 3a: The DC module adjusts the gate voltage U to U 0 ±5%U 0 , the RF module adjusts the RF power P to P 0 ±5%P 0 , the control module adjusts the xenon working fluid flow M to M 0 ±5%M 0 , define the working mode at this time as the standard working mode;

[0039] Step 3b: The DC module adjusts the gate voltage U to 0.9U 0 ±5%U 0 , the RF module adjusts the RF power P to P 0 ±5%P 0 , the control module adjusts the xenon working fluid flow M to M 0 ~1.4M 0 , define the working mode at this time as high thrust working mode;

[0040] Step 3c: The DC module adjusts the gate voltage U to 1.2U 0 ±5%U 0 , the RF module adjusts the RF power P to P 0 ±5%P 0 , the control module adjusts the xenon working fluid flow M to 0~1.2M 0 , define the working mode at this time as high specific impulse working mode;

[0041] Step 3d: The DC module adjusts the gate voltage U to 0.9U 0 ±5%U 0 , The RF module adjusts the RF power P to 1.2P 0 ±5%P 0 , the control module adjusts the xenon working fluid flow M to 1.4M 0 ~M max , define the working mode at this time as a high flow and high thrust working mode;

[0042] Step 3e: The DC module adjusts the gate voltage U to 1.2U 0 ±5%U 0 , the RF module adjusts the RF power P to P0 ±5%P 0 , the control module adjusts the xenon working fluid flow M to 1.2M 0 ~M max , define the working mode at this time as high flow and high specific impulse working mode.

[0043] Furthermore, step 2 further includes: if the current operating condition is other operating conditions, executing step 3f;

[0044] Step 3f: The DC module adjusts the gate voltage U to U 1 , the RF module adjusts the RF power P to P 1 , the control module adjusts the xenon working fluid flow M to M 1 , define the working mode at this time as the custom working mode, where U 1 , P 1 and M 1 All values ​​are custom values.

[0045] Compared with the prior art, the present invention has the following beneficial effects:

[0046] 1. The hybrid working fluid-powered air-breathing radio frequency ion electric propulsion system provided by the present invention can not only utilize the atmosphere in the ultra-low orbit environment, but also carry xenon working fluid itself. The xenon gas storage and supply system can provide a controllable and reliable supply of xenon working fluid for the thruster to make up for the deficiency of atmospheric working fluid; the system can adapt to more types of working conditions, and has higher reliability in dealing with complex and extreme working conditions in ultra-low orbit; compared with the electric propulsion system with a single rare gas working fluid, the hybrid working fluid-powered air-breathing electric propulsion system not only utilizes the xenon gas it carries, but also utilizes the atmosphere captured from the space environment, and the total impulse and total range are greatly increased, which can meet the power requirements of satellites for ultra-long-term operation in ultra-low orbit;

[0047] 2. The mixed-working-fluid-powered air-breathing RF ion electric propulsion system provided by the present invention has an integrated design of RF ion thruster and atmosphere capture inlet to form a propulsion and gas capture unit, which is beneficial to saving space and gas capture efficiency;

[0048] 3. The hybrid-powered air-breathing RF ion electric propulsion system provided by the present invention has relatively independent ionization mechanism and acceleration mechanism of the RF ion thruster, which are adjustable separately. The ionization and acceleration parameters can be adjusted in real time for the complex and changeable ultra-low orbit environment, and multiple working modes can be executed. The ionization and acceleration mechanisms of the Hall thruster are highly coupled, and the ionization parameters of the DC ion thruster are basically not adjustable. The RF ion thruster has a high specific impulse and a long working life, which can meet the use requirements of long-term operation in ultra-low orbit. The RF ion thruster also has the advantages of simple structure, reliable operation, and high technical maturity;

[0049] 4. In the mixed working fluid powered air-breathing RF ion electric propulsion system provided by the present invention, the xenon gas storage and supply unit can deliver xenon gas to the RF ion thruster and the RF neutralizer in two ways at different flow rates under the control of the control module. The xenon gas flow rate is dynamically adjusted according to the working condition of the spacecraft. The xenon gas delivered to the RF ion thruster is mixed with the atmosphere to provide a mixed working fluid for the electric propulsion system. The xenon gas delivered to the RF neutralizer is to neutralize the positively charged ion plume ejected by the RF ion thruster to prevent charge accumulation. Such an arrangement can enable the spacecraft equipped with the mixed working fluid powered air-breathing RF ion electric propulsion system to adapt to various working conditions and achieve the optimal thrust of the spacecraft.

[0050] 5. The hybrid working fluid powered air-breathing radio frequency ion electric propulsion system provided by the present invention has a ceramic lining that allows the thruster housing and the inner wall of the air inlet housing to withstand physical wear and chemical corrosion, and the surface can remain smooth. When the atmospheric airflow collides with the smooth wall, mirror reflection occurs, which helps to improve the efficiency of the air inlet in capturing the atmosphere and also improves the service life of the air inlet. The lining adopts an elliptical parabola design, and the airflow is reflected to its focal position by the mirror after hitting the wall, which helps to further improve the efficiency of the air inlet in capturing the incoming atmosphere. The parabola can play an effective role only if mirror reflection occurs after the airflow collides with the wall.

[0051] 6. The multi-mode working method of the hybrid-powered air-breathing RF ion electric propulsion system provided by the present invention includes five preset working modes (standard working mode, high thrust working mode, high specific impulse working mode, high flow and high thrust working mode, high flow and high specific impulse working mode) and several custom modes. The selection and switching of different modes are automatically controlled by the DC module, control module and RF module in the power and control unit, which increases the stability and life of the spacecraft. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 It is a schematic diagram of the principle of the existing air-breathing electric propulsion system;

[0053] Figure 1 Marking instructions:

[0054] 012-atmospheric capture inlet, 011-thruster, 6-satellite core, 71-atmospheric flow, 72-plume; 8-solar panel;

[0055] Figure 2 It is a schematic diagram of the principle of an embodiment of the mixed working fluid powered air-breathing radio frequency ion electric propulsion system of the present invention;

[0056] Figure 3 It is a structural schematic diagram of a xenon gas storage and supply unit in an embodiment of an air-breathing radio frequency ion electric propulsion system with mixed working fluid power of the present invention;

[0057] Figure 4 It is a structural schematic diagram of a radio frequency neutralizer in an embodiment of an air-breathing radio frequency ion electric propulsion system with mixed working fluid power of the present invention;

[0058] Figure 5 It is a structural schematic diagram of the propulsion and gas capture unit in an embodiment of the mixed working fluid powered air-breathing radio frequency ion electric propulsion system of the present invention;

[0059] Figure 6 It is a structural schematic diagram of a radio frequency ion thruster in an embodiment of an air-breathing radio frequency ion electric propulsion system with mixed working fluid power of the present invention;

[0060] Figure 7 Schematic diagram of the cross-sectional shape of the first collimator grid and the second collimator grid in an embodiment of the hybrid working fluid powered air-breathing radio frequency ion electric propulsion system of the present invention, (a) to (e) represent different cross-sectional shapes;

[0061] Figure 2 to Figure 7 Marking instructions:

[0062] 1-propulsion and gas capture unit, 11-RF ion thruster, 1101-discharge chamber, 111-second collimation grid, 112-grid, 113-first air inlet, 114-RF connector, 115-thruster housing, 116-first RF antenna, 12-atmospheric capture air inlet, 121-air inlet housing, 122-lining, 123-first collimation grid; 2-RF neutralizer, 21-neutralizer housing, 22-second air inlet, 23-ignition probe, 24-discharge chamber, 25-ion collector, 26-second RF antenna, 27-RF power supply, 28-DC power supply; 3-power and control unit, 31-DC module, 32-control module, 33-RF module; 4-communication and power supply bus; 5-xenon gas storage and supply unit, 51-xenon gas bottle, 52-valve and sensor assembly; 71-atmospheric inflow;

[0063] P1-first pressure sensor, LV1-first self-locking valve, PV1-first proportional valve, P2-second pressure sensor, LV2-second self-locking valve, PV2-second proportional valve, LV3-third self-locking valve, PV3-third proportional valve, FL1-first flow sensor, FL2-second flow sensor, JP-addition and exhaust valve. DETAILED DESCRIPTION

[0064] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0065] A hybrid working fluid powered air-breathing radio frequency ion electric propulsion system, the schematic diagram of which is shown in Figure 2The mixed working fluid includes atmosphere and xenon. The reason for choosing xenon is that xenon has a large atomic mass and low ionization energy, and its performance is better than atmosphere. It is the most commonly used electric propulsion working fluid.

[0066] The system includes a propulsion and gas capture unit 1, a radio frequency neutralizer 2, a power and control unit 3 and a xenon gas storage and supply unit 5; the propulsion and gas capture unit 1 includes a radio frequency ion thruster 11, and an atmospheric capture inlet 12 connected to the input end of the radio frequency ion thruster 11; the power and control unit 3 includes a DC module 31, a control module 32 and a radio frequency module 33 electrically connected to an external spacecraft control system through a communication and power supply bus 4; the xenon gas storage and supply unit 5 includes a xenon gas bottle 51 for storing high-pressure xenon gas and a valve and sensor assembly 52 for supplying xenon gas, which are interconnected through a gas path; the control module 32 and the valve and sensor assembly 52 are connected to each other ... The component 52 is electrically connected, and the RF ion thruster 11 is electrically connected to the RF neutralizer 2 through the RF module 33; the first output end of the xenon gas storage and supply unit 5 is connected to the gas path input end of the RF neutralizer 2, and the second output end of the xenon gas storage and supply unit 5 is connected to the gas path input end of the RF ion thruster 11; the DC module 31 is electrically connected to the RF neutralizer 2 and the RF ion thruster 11; the control module 32 is used to control the flow rate of xenon gas in the xenon gas storage and supply unit 5, the RF neutralizer 2 is used to neutralize the positively charged ion plume ejected by the RF ion thruster 11, and the DC module 31 is used to provide electrical energy to the RF neutralizer 2 and the RF ion thruster 11.

[0067] The following is a detailed description of each component or unit:

[0068] See also Figure 5 and Figure 6The RF ion thruster 11 comprises a cylindrical thruster housing 115, a first air inlet nozzle 113 and a RF connector 114 arranged on the side wall of the thruster housing 115, a plurality of annular first RF antennas 116 embedded in the thruster housing 115, a second collimating grid 111 arranged at one end close to the atmosphere capture inlet 12, and a grid 112 arranged at the other end, wherein the space enclosed by the grid 112, the second collimating grid 111 and the inner wall of the thruster housing 115 constitutes a discharge chamber 1101 of the RF ion thruster 11; the grid 112 is electrically connected to the DC module 31, and the plurality of annular first RF antennas 116 are all electrically connected to the RF module 33. The RF ion thruster 11 uses electrical energy to ionize the mixed working fluid gas and then accelerate it, thereby forming thrust. In actual scenarios, the working environment of the air-breathing electric propulsion system is relatively complex, especially the concentration distribution gradient of the atmospheric working fluid is large and the composition is unstable. When the Hall thruster and DC ion thruster ionize the working fluid, they rely on the electromagnetic field generated by the external electromagnetic coil to constrain the electrons, which has high requirements for the concentration and composition of the gas working fluid, and the performance of ionizing the atmospheric working fluid is poor. The RF ion thruster 11 uses RF energy to directly ionize the working fluid. RF ionization is one of the most effective ionization technologies, which has low requirements for the concentration and composition of the gas working fluid and can effectively ionize the atmospheric working fluid.

[0069] The ionization mechanism and acceleration mechanism of the RF ion thruster 11 are relatively independent and adjustable. They can adjust the ionization and acceleration parameters in real time for the complex and changeable ultra-low orbit environment, and can execute multiple working modes. The ionization and acceleration mechanisms of the Hall thruster are highly coupled, and the ionization parameters of the DC ion thruster are basically not adjustable. The RF ion thruster 11 has a high specific impulse and a long working life, which can meet the needs of long-term operation in ultra-low orbit. The RF ion thruster 11 also has the advantages of simple structure, reliable operation, and high technical maturity.

[0070] The atmosphere capture inlet 12 comprises a cylindrical inlet casing 121 and a first collimating grid 123 arranged at one end of the inlet casing 121 away from the RF ion thruster 11 . The inlet casing 121 is connected to the thruster casing 115 .

[0071] An integral liner 122 is provided on the inner wall of the air inlet housing 121 and the thruster housing 115. The material of the liner 122 is ceramic, and the inner wall of the liner 122 near the RF ion thruster 11 in the air inlet housing 121 is in the shape of an elliptical parabola.

[0072] See also Figure 4The RF neutralizer 2 includes a neutralizer shell 21, a discharge chamber 24 and a second RF antenna 26 arranged in the neutralizer shell 21, a second air inlet nozzle 22 connected to the neutralizer shell 21 and the discharge chamber 24, an ion collector 25 arranged in the discharge chamber 24, an ignition probe 23 connected to the inside of the discharge chamber 24, an RF power supply 27 connected to the second RF antenna 26, and a DC power supply 28 whose negative electrode is connected to the ion collector 25; the second RF antenna 26 is electrically connected to the RF module 33, and the positive electrode of the DC power supply 28 is electrically connected to the DC module 31.

[0073] The working principle of the RF neutralizer 2 is: xenon gas enters the discharge chamber 24 through the second air inlet nozzle 22, and is ionized into plasma after being subjected to RF energy. The electrons in the plasma are accelerated and drawn out under the action of the electric field between the anode and the ion collector, and are used to neutralize the positively charged ion plume ejected by the RF ion thruster 11 to prevent charge accumulation; the ignition probe 23 is used to apply an instantaneous ignition voltage during ignition, and discharges violently and instantaneously at the tip to activate the ionization sequence of the gas working fluid.

[0074] See also Figure 3 The valve and sensor assembly 52 includes a first pressure sensor P1, a first self-locking valve LV1, a first proportional valve PV1, and a second pressure sensor P2, which are sequentially connected to the output end of the xenon gas bottle 51 through an air path. The output end air path of the second pressure sensor P2 is divided into two paths, one path includes a second self-locking valve LV2, a second proportional valve PV2 and a first flow sensor FL1 connected in sequence; the other path includes a third self-locking valve LV3, a third proportional valve PV3 and a second flow sensor FL2 connected in sequence; the output end of the first flow sensor FL1 is connected to the first air inlet nozzle 113 in the propulsion and gas capture unit 1, and the output end of the second flow sensor FL2 is connected to the second air inlet nozzle 22 in the radio frequency neutralizer 2; the input end of the xenon gas bottle 51 is provided with a charging and discharging valve JP.

[0075] The adding and discharging valve JP is used to add or discharge xenon gas in the xenon cylinder 51, the first self-locking valve LV1, the second self-locking valve LV2 and the third self-locking valve LV3 are all used to control the on-off of the gas circuit, and the first proportional valve PV1, the second proportional valve PV2 and the third proportional valve PV3 are all used to adjust the gas flow rate.

[0076] The first pressure sensor P1, the first self-locking valve LV1, the first proportional valve PV1, the second pressure sensor P2, the second self-locking valve LV2, the second proportional valve PV2, the first flow sensor FL1, the third self-locking valve LV3, the third proportional valve PV3, and the second flow sensor FL2 are all electrically connected to the control module 32.

[0077] See also Figure 7The cross-sectional shapes of the first collimating grid 123 and the second collimating grid 111 are strip-shaped (a), fan-shaped (b), square-shaped (c), long-shaped (d) or hexagonal-shaped (e). The second collimating grid 111 is provided to prevent gas backflow. Different shapes can be adapted to different working conditions. The first collimating grid 123 is conducive to improving the gas capture efficiency, is conducive to the airflow entering the atmospheric capture inlet duct 12 along the axial direction, and also has the function of decelerating the airflow, so that more gas working medium is stored in the atmospheric capture inlet duct 12.

[0078] In order to cope with the complex and extreme ultra-low orbit environment, this embodiment also provides a multi-mode working method for the above-mentioned hybrid working fluid-powered air-breathing RF ion electric propulsion system. The multi-mode working method is achieved by controlling three parameters: grid voltage U, xenon working fluid flow M, and RF power P, and includes the following steps:

[0079] Step 1: The spacecraft determines the current working condition through the sensor, and transmits the working condition data information to the power and control unit 3 through the communication bus 4, and adjusts the gate voltage U through the DC module 31 in the power and control unit 3, adjusts the RF power P through the RF module 33, and adjusts the xenon working medium flow M of the xenon storage and supply unit 5 through the control module 32 to adapt to different working conditions;

[0080] Step 2: If the current working condition is the standard working condition, execute step 3a;

[0081] If the current working condition is a high resistance working condition, execute step 3b;

[0082] If the current working condition is a low resistance working condition, execute step 3c;

[0083] If the current working condition is an extremely large resistance condition, execute step 3d;

[0084] If the current working condition is a particularly rarefied atmosphere condition, execute step 3e;

[0085] If the current working condition is other working conditions, execute step 3f;

[0086] Definition of standard voltage U 0 、Standard flow rate M 0 、Standard power P 0 、Maximum flow rate M max ;

[0087] Step 3a: Under standard working conditions, the DC module 31 adjusts the gate voltage U to U 0 ±5%U 0 , the RF module 33 adjusts the RF power P to P 0 ±5%P 0 , the control module 32 adjusts the xenon working medium flow rate M to M 0±5%M 0 , define the working mode at this time as the standard working mode;

[0088] Step 3b: Under high resistance conditions, the DC module 31 adjusts the gate voltage U to 0.9U 0 ±5%U 0 , the RF module 33 adjusts the RF power P to P 0 ±5%P 0 , the control module 32 adjusts the xenon working medium flow rate M to M 0 ~1.4M 0 , define the working mode at this time as high thrust working mode;

[0089] Step 3c: Under low resistance conditions, the DC module 31 adjusts the gate voltage U to 1.2U 0 ±5%U 0 , the RF module 33 adjusts the RF power P to P 0 ±5%P 0 , the control module 32 adjusts the xenon working medium flow rate M to 0-1.2M 0 , define the working mode at this time as high specific impulse working mode;

[0090] Step 3d: Under the condition of super large resistance, the DC module 31 adjusts the gate voltage U to 0.9U 0 ±5%U 0 , the RF module 33 adjusts the RF power P to 1.2P 0 ±5%P 0 , the control module 32 adjusts the xenon working medium flow rate M to 1.4M 0 ~M max , define the working mode at this time as a high flow and high thrust working mode;

[0091] Step 3e: When the atmosphere is extremely rarefied, the DC module 31 adjusts the gate voltage U to 1.2U. 0 ±5%U 0 , the RF module 33 adjusts the RF power P to P 0 ±5%P 0 , the control module 32 adjusts the xenon working medium flow rate M to 1.2M 0 ~M max , define the working mode at this time as high flow and high specific impulse working mode;

[0092] Step 3f: Under other working conditions, the DC module 31 adjusts the gate voltage U to U 1 , the RF module 33 adjusts the RF power P to P 1 , the control module 32 adjusts the xenon working medium flow rate M to M 1 , define the working mode at this time as the custom working mode, where U1 , P 1 and M 1 All values ​​are custom values.

[0093] Table 1 summarizes the different operating modes:

[0094] Table 1 Multi-mode operating parameters of the hybrid working fluid powered air-breathing RF ion electric propulsion system

[0095]

[0096]

[0097] Specific instructions:

[0098] The standard working mode is applicable to standard working conditions. Standard working conditions are the standard working conditions specified in the flight mission book. Standard working conditions generally refer to the working conditions where the satellite is operating at the orbital altitude (or orbital altitude range) where it usually works and the solar activity is stable. In the standard working mode, the gate voltage is set to the standard voltage U 0 , can be adjusted to ±5%U according to actual working conditions 0 Adjustment; the xenon working fluid flow rate is set to the standard flow rate M 0 , can be adjusted to ±5%M according to actual working conditions 0 Adjust; RF power is set to standard power P 0 , can be adjusted to ±5%P according to actual working conditions 0 Make adjustments.

[0099] The high thrust working mode is suitable for high drag conditions. High drag conditions refer to when the satellite orbit is lowered or the solar activity fluctuates, the atmospheric density increases, and the satellite drag increases. Under high drag conditions, the electric propulsion system reduces the grid voltage, increases the xenon working fluid flow, and increases the thrust to offset the drag.

[0100] The high specific impulse working mode is suitable for low resistance working conditions. Low resistance working conditions refer to when the satellite orbit rises or the solar activity fluctuates, the atmospheric density decreases and the satellite resistance becomes smaller. Under high specific impulse working conditions, the electric propulsion system increases the grid voltage and adjusts the xenon working fluid flow rate in real time according to the atmospheric environment data sent back by the satellite to increase the specific impulse under the premise of normal operation of the system. In the high specific impulse working mode, the xenon working fluid flow rate M can be reduced to 0 at the lowest.

[0101] The high flow and high thrust working mode is suitable for ultra-large resistance conditions. Ultra-large resistance conditions refer to when the satellite orbit is reduced to below a certain altitude or when solar activity fluctuates violently, the atmospheric density increases significantly and the satellite resistance is extremely large. Due to the extremely large resistance, the air-breathing electric propulsion system has a greater demand for the working fluid flow rate. The thrust provided by the atmospheric working fluid is limited, and the xenon working fluid flow rate must be increased, which can be increased to the upper limit of the thruster performance constraint. The corresponding RF power is increased, the grid voltage is reduced, and the thrust is greatly increased to offset the resistance.

[0102] The high flow rate and high specific impulse working mode is suitable for extremely thin atmosphere conditions. Extremely thin atmosphere conditions refer to when the satellite orbit rises above a certain altitude or when solar activity fluctuates violently, the atmospheric density decreases significantly and the satellite resistance is extremely small. Due to the extremely thin atmosphere, the amount of atmospheric fluid that can be effectively captured by the air-breathing electric propulsion system is greatly reduced, and the xenon fluid flow rate must be increased accordingly, which can be increased to the upper limit of the thruster performance constraint. The corresponding gate voltage is increased to maintain the normal operation of the system under extremely thin atmosphere conditions.

[0103] The system can operate in a custom working mode, and the system's gate voltage U, xenon working fluid flow M and RF power P can be customized according to actual working conditions.

[0104] It should be noted that the parameters in Table 1 are only for illustrating the basic idea of ​​the multi-mode working method. The specific value of each parameter can be optimized and adjusted according to actual conditions, and these optimization adjustments should be covered within the protection scope of the present invention.

Claims

1. A hybrid working fluid powered air-breathing radio frequency ion electric propulsion system, characterized in that: It comprises a propulsion and gas capture unit (1), a radio frequency neutralizer (2), a power and control unit (3) and a xenon gas storage and supply unit (5); The propulsion and gas capture unit (1) comprises a radio frequency ion thruster (11) and an atmosphere capture inlet (12) connected to an input end of the radio frequency ion thruster (11); The power and control unit (3) comprises a DC module (31), a control module (32) and a radio frequency module (33) which are electrically connected to an external spacecraft control system via a communication and power supply bus (4); The xenon gas storage and supply unit (5) comprises a xenon gas cylinder (51) for storing high-pressure xenon gas and a valve and sensor assembly (52) for supplying xenon gas, which are interconnected via a gas path; The control module (32) and the valve are electrically connected to the sensor assembly (52); the radio frequency ion thruster (11) is electrically connected to the radio frequency neutralizer (2) via the radio frequency module (33); the first output end of the xenon gas storage and supply unit (5) is connected to the gas path input end of the radio frequency neutralizer (2); the second output end of the xenon gas storage and supply unit (5) is connected to the gas path input end of the radio frequency ion thruster (11); the direct current module (31) is electrically connected to the radio frequency neutralizer (2) and the radio frequency ion thruster (11); The control module (32) is used to control the flow rate of xenon gas in the xenon gas storage and supply unit (5); the radio frequency neutralizer (2) is used to neutralize the positively charged ion plume ejected by the radio frequency ion thruster (11); and the direct current module (31) is used to provide electrical energy to the radio frequency neutralizer (2) and the radio frequency ion thruster (11).

2. The hybrid working fluid powered air-breathing radio frequency ion electric propulsion system according to claim 1, characterized in that: The radio frequency ion thruster (11) comprises a cylindrical thruster casing (115), a first air inlet nozzle (113) and a radio frequency connector (114) arranged on the side wall of the thruster casing (115), a plurality of annular first radio frequency antennas (116) embedded in the thruster casing (115), a second collimating grid (111) arranged at one end close to the atmosphere capture inlet duct (12), and a grid (112) arranged at the other end, wherein a space enclosed by the grid (112), the second collimating grid (111) and the inner wall of the thruster casing (115) constitutes a discharge chamber (1101) of the radio frequency ion thruster (11); The gate (112) is electrically connected to the DC module (31), and the plurality of annular first radio frequency antennas (116) are all electrically connected to the radio frequency module (33).

3. The hybrid working fluid powered air-breathing radio frequency ion electric propulsion system according to claim 2, characterized in that: The atmosphere capture inlet (12) comprises a cylindrical inlet casing (121) and a first collimating grid (123) arranged at an end of the inlet casing (121) away from the radio frequency ion thruster (11), and the inlet casing (121) is connected to the thruster casing (115); The inner walls of the air inlet housing (121) and the thruster housing (115) are provided with an integrated lining (122).

4. The hybrid working fluid powered air-breathing radio frequency ion electric propulsion system according to claim 3, characterized in that: The radio frequency neutralizer (2) comprises a neutralizer housing (21), a discharge chamber (24) and a second radio frequency antenna (26) arranged in the neutralizer housing (21), a second air inlet nozzle (22) connected to the neutralizer housing (21) and the discharge chamber (24), an ion collector (25) arranged in the discharge chamber (24), an ignition probe (23) connected to the inside of the discharge chamber (24), a radio frequency power source (27) connected to the second radio frequency antenna (26), and a direct current power source (28) having a negative electrode connected to the ion collector (25); The second radio frequency antenna (26) is electrically connected to the radio frequency module (33), and the positive electrode of the direct current power supply (28) is electrically connected to the direct current module (31).

5. The mixed-working-fluid-powered air-breathing radio frequency ion electric propulsion system according to claim 4, characterized in that: The valve and sensor assembly (52) comprises a first pressure sensor (P1), a first self-locking valve (LV1), a first proportional valve (PV1), and a second pressure sensor (P2) which are sequentially connected to the output end of the xenon gas bottle (51) through an air path. The output end air path of the second pressure sensor (P2) is divided into two paths, one path comprises a second self-locking valve (LV2), a second proportional valve (PV2), and a first flow sensor (FL1) which are sequentially connected; and the other path comprises a third self-locking valve (LV3), a third proportional valve (PV3), and a second flow sensor (FL2) which are sequentially connected. The output end of the first flow sensor (FL1) is connected to the first air inlet nozzle (113) in the propulsion and gas capture unit (1), and the output end of the second flow sensor (FL2) is connected to the second air inlet nozzle (22) in the radio frequency neutralizer (2). The input end of the xenon gas bottle (51) is provided with a charging and discharging valve (JP). The adding and discharging valve (JP) is used to add or discharge xenon gas in the xenon gas bottle (51); the first self-locking valve (LV1), the second self-locking valve (LV2) and the third self-locking valve (LV3) are all used to control the on-off of the gas path; the first proportional valve (PV1), the second proportional valve (PV2) and the third proportional valve (PV3) are all used to adjust the size of the gas flow; The first pressure sensor (P1), the first self-locking valve (LV1), the first proportional valve (PV1), the second pressure sensor (P2), the second self-locking valve (LV2), the second proportional valve (PV2), the first flow sensor (FL1), the third self-locking valve (LV3), the third proportional valve (PV3), and the second flow sensor (FL2) are all electrically connected to the control module (32).

6. The hybrid working fluid powered air-breathing radio frequency ion electric propulsion system according to claim 5, characterized in that: The cross-sectional shapes of the first collimating grid (123) and the second collimating grid (111) are stripe-shaped, fan-shaped, square-shaped, long-grid-shaped or hexagonal-grid-shaped.

7. The hybrid working fluid powered air-breathing radio frequency ion electric propulsion system according to claim 6, characterized in that: The material of the lining (122) is ceramic, and the shape of the inner wall of the lining (122) near the radio frequency ion thruster (11) in the air inlet housing (121) is an elliptical parabola, which is used to achieve mirror reflection after the airflow collides with the wall.

8. A multi-mode operation method of the mixed working fluid powered air-breathing radio frequency ion electric propulsion system according to any one of claims 1 to 7, characterized in that: The following steps are involved: Step 1: The spacecraft determines the current working condition through a sensor, and transmits the working condition data information to the power and control unit (3) through a communication and power supply bus (4); the DC module (31) in the power and control unit (3) adjusts the gate voltage U, the radio frequency module (33) adjusts the radio frequency power P, and the control module (32) adjusts the xenon working medium flow M of the xenon storage and supply unit (5) to adapt to different working conditions; Step 2: If the current working condition is the standard working condition, execute step 3a; If the current working condition is a high resistance working condition, execute step 3b; If the current working condition is a low resistance working condition, execute step 3c; If the current working condition is an extremely large resistance condition, execute step 3d; If the current working condition is a particularly rarefied atmosphere condition, execute step 3e; Define standard voltage U0, standard flow M0, standard power P0, maximum flow M max ; Step 3a, the DC module (31) adjusts the gate voltage U to U0±5%U0, the RF module (33) adjusts the RF power P to P0±5%P0, and the control module (32) adjusts the xenon working fluid flow M to M0±5%M0, and the working mode at this time is defined as the standard working mode; Step 3b, the DC module (31) adjusts the gate voltage U to 0.9U0±5%U0, the RF module (33) adjusts the RF power P to P0±5%P0, and the control module (32) adjusts the xenon working fluid flow M to M0-1.4M0, and the working mode at this time is defined as a high thrust working mode; Step 3c, the DC module (31) adjusts the gate voltage U to 1.2U0±5%U0, the RF module (33) adjusts the RF power P to P0±5%P0, and the control module (32) adjusts the xenon working fluid flow M to 0-1.2M0, and the working mode at this time is defined as a high specific impulse working mode; Step 3d, the DC module (31) adjusts the gate voltage U to 0.9U0±5%U0, the RF module (33) adjusts the RF power P to 1.2P0±5%P0, and the control module (32) adjusts the xenon working fluid flow M to 1.4M0~M max , define the working mode at this time as a high flow and high thrust working mode; Step 3e, the DC module (31) adjusts the gate voltage U to 1.2U0±5%U0, the RF module (33) adjusts the RF power P to P0±5%P0, and the control module (32) adjusts the xenon working fluid flow M to 1.2M0~M max , define the working mode at this time as high flow and high specific impulse working mode.

9. The multi-mode working method of the mixed working fluid powered air-breathing radio frequency ion electric propulsion system according to claim 8, characterized in that: Step 2 also includes: if the current working condition is other working conditions, executing step 3f; Step 3f, the DC module (31) adjusts the gate voltage U to U1, the RF module (33) adjusts the RF power P to P1, and the control module (32) adjusts the xenon working fluid flow M to M1, and the working mode at this time is defined as a custom working mode, wherein U1, P1 and M1 are all custom values.

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