An ion liquid electrospray thruster suitable for high-pressure storage and supply modules

Abstract

An ionic liquid electrospray thruster suitable for high-pressure propellant storage and supply modules includes: an emitter mounted on one end of the thruster housing to form a cavity structure; a solenoid valve flange fixedly connected to the thruster housing via an insulating column; a capillary tube for spraying propellant into the cavity structure to form a mist cone; propellant residue inside the capillary tube precipitates bubbles under vacuum conditions, using the bubbles to divide the propellant inside the capillary tube into multiple cavities, providing insulation; an extraction electrode is fixedly installed on the thruster housing, the extraction electrode is grounded and does not contact the emitter; an emitter electrode is fixedly connected to the emitter; and vent holes are machined on the thruster housing. The electrospray thruster of this invention can be connected to a high-pressure propellant storage and supply system to replenish propellant, extend the life of a single thruster, and achieve optimized utilization of propellant in the propulsion system. The propellant storage and supply system connected to this invention can reuse existing non-toxic single-component propellant tanks, solenoid valves, and other components.

Description

Technical Field

[0001] This invention belongs to the field of space propulsion technology, and in particular to an ion liquid electrospray thruster suitable for high-pressure storage and supply modules. Background Technology

[0002] An ion liquid electrospray thruster is a type of space-based miniature electric propulsion device. The propellant it uses is composed of cations and anions, and remains liquid during both storage and operation. Under the influence of an electric field, the propellant is easily extracted into charged droplets or ions, which are then emitted from the thruster, generating thrust on the order of 10–100 μN. It boasts advantages such as small size, high specific impulse, and high efficiency. It is suitable for micro / nano satellites to perform orbit adjustment and orbit maintenance missions.

[0003] With the development of microsatellite applications, higher demands are being placed on the total impulse of their propulsion systems to complete tasks such as orbit raising, phase adjustment, and formation flying. In recent years, electro-chemical dual-mode ionic liquid propulsion systems have been proposed both domestically and internationally. These systems utilize combustible ionic liquid propellants and a propellant tank to supply both the electrospray thruster and the monocomponent chemical thruster. This allows for long-term orbit maintenance through high-specific-impulse electrospray propulsion, and also enables rapid maneuvering response when necessary via the monocomponent chemical thruster. However, existing ionic liquid electrospray thrusters mainly suffer from the following problems:

[0004] (1) The propellant is encapsulated inside, with limited storage capacity, and it is not possible to optimize the distribution of the propellant or construct an electro-chemical ionic liquid dual-mode propulsion system.

[0005] (2) The propellant tank needs a certain pressure to discharge the propellant. In particular, for electro-chemical ionic liquid dual-mode propulsion, the single-component propulsion requires the tank to provide a pressure of about 1 MPa, which does not match the extremely low pressure required by the ionic liquid thruster.

[0006] (3) Since the thruster requires a high voltage of thousands of volts to operate and the propellant itself is conductive, direct connection will cause the entire propellant storage and supply system to become electrified, which will seriously affect reliability.

[0007] (4) If the propellant storage and supply system is directly connected to the thruster, the flow rate needs to be precisely controlled at the μg / L level, otherwise it will affect the electrospray working mode. Summary of the Invention

[0008] The technical problem solved by this invention is to overcome the shortcomings of the prior art and provide an ionic liquid electrospray thruster suitable for high-pressure storage and supply modules. It solves the technical problems of high-pressure tank adaptation, insulation between the electrospray thruster and the storage and supply system, and propellant supply control, so as to realize the supply of a single propellant tank to multiple ionic liquid electrospray thrusters or realize an electro-chemical ionic liquid dual-mode propulsion system.

[0009] The technical solution of this invention is:

[0010] An ionic liquid electrospray thruster suitable for high-voltage storage and supply modules includes: a solenoid valve docking flange, a capillary tube, an emitter, an emitter electrode, an extraction electrode, an insulating column, and a thruster housing;

[0011] One end of the thruster housing is open, and an emitter is installed inside to form a cavity structure; the other end of the thruster housing is fixedly connected to the solenoid valve docking flange through an insulating column, and the solenoid valve docking flange is connected to the solenoid valve.

[0012] One end of the capillary tube is connected to a through hole on the other end of the thruster housing, which is used to inject propellant into the cavity structure to form a mist cone; the other end of the capillary tube is connected to a solenoid valve to receive externally supplied propellant.

[0013] When the solenoid valve is closed, the propellant remaining inside the capillary precipitates bubbles under vacuum conditions. These bubbles divide the propellant inside the capillary into multiple cavities, thus providing insulation.

[0014] A extraction electrode is fixedly installed on one end face of the thruster housing. The extraction electrode is grounded and does not contact the emitter.

[0015] An emitter electrode is fixedly connected to the emitter; a vent hole is machined on the thruster housing; the vent hole connects the cavity structure and the external environment of the thruster housing.

[0016] Preferably, the inner diameter of the capillary is less than or equal to 0.2 mm, and the capillary is made of polyetheretherketone or polytetrafluoroethylene propylene.

[0017] Preferably, both the insulating column and the thruster housing are made of insulating material; the extraction electrode is a thin metal sheet.

[0018] Preferably, the diameter of the vent hole is in the range of 0.5mm to 2mm.

[0019] Preferably, the inner wall of the thruster housing facing one side is provided with a non-wetting coating, which is a hydrophobic and oleophobic nano-coating.

[0020] Preferably, the emitter has a groove structure machined on the side facing the capillary, and the cross-sectional size of the groove structure is larger than the outer envelope of the propellant mist cone; a cavity structure is formed between the emitter groove structure and the thruster shell.

[0021] Preferably, the material of the emitter is capable of transporting the propellant on the inner surface of the cavity structure to the extractor side through capillary action.

[0022] Preferably, the emitter is sintered from aluminum oxide particles, metal particles or silicate particles, or microchannels are formed on a dense material through micromachining, or a structure with microchannels is directly formed through additive manufacturing.

[0023] Preferably, the outer surface of the emitter facing the extraction electrode is machined with a raised structure, and the extraction electrode is hollowed out at the corresponding position of the raised structure on the emitter surface, so that the ionic liquid can be emitted to the outside.

[0024] Preferably, the protrusion structure is an array of teeth, a prismatic protrusion, or a columnar protrusion.

[0025] Preferably, the top of the protruding structure cross-section is machined into a sharp corner, and the included angle between the apex of the sharp corner and the two sides of the extracted hollow area is not less than 40°.

[0026] The advantages of this invention compared to the prior art are:

[0027] Compared with the prior art, the advantages of the present invention are mainly reflected in the following aspects:

[0028] (1) This invention can be connected to a high-pressure propellant storage and supply system to achieve optimized propellant distribution or to construct an electro-chemical ionic liquid dual-mode propulsion system.

[0029] (2) The present invention ensures the insulation between the electro-spray thruster and the storage and supply system through structural design.

[0030] (3) The propellant supply of the present invention is controlled by the opening time of the solenoid valve. The emitter structure of the thruster has a certain buffering effect, so there is no need to use a high-precision micro-flow controller. Attached Figure Description

[0031] Figure 1 It is a traditional ionic liquid electrospray thruster;

[0032] Figure 2 It is an electro-chemical dual-mode ionic liquid propulsion system;

[0033] Figure 3 This is a structural diagram of the ionic liquid electrospray thruster of the present invention;

[0034] Figure 4 This is a structural diagram of the emitter protrusion structure in one embodiment of the present invention;

[0035] Figure 5 This is a diagram of the extracted pole structure in one embodiment of the present invention;

[0036] Figure 6 This is a schematic diagram showing the relationship between the size of the extraction electrode hollowing and the size of the emitter protrusion structure in one embodiment of the present invention. Detailed Implementation

[0037] To better describe the present invention, the present invention will be described in detail below with reference to schematic diagrams and examples.

[0038] This invention relates to an ionic liquid electrospray thruster and a propellant supply method adapted to a high-pressure storage and supply module. The structure of a conventional ionic liquid electrospray thruster is as follows: Figure 1 As shown. It mainly consists of an insulating shell, porous ceramic, emitter electrodes, extractor electrodes, etc., with the propellant encapsulated inside the thruster. To make fuller use of the carried propellant, this invention provides, as shown... Figure 2 The propulsion system design shown consists of a single tank supplying propellant to multiple thrusters.

[0039] like Figure 3 As shown, the present invention is an ion liquid electrospray thruster suitable for high-voltage storage and supply modules, mainly comprising: a solenoid valve docking flange 1, a capillary tube 2, an emitter 4, an emitter electrode 6, an extraction electrode 7, an insulating column 8, and a thruster housing 9.

[0040] One end of the capillary tube 2 is fixedly connected to the solenoid valve flange 1, and the other end of the capillary tube 2 is inserted into the through hole of the thruster housing 9 and fixedly connected to the thruster housing 9. The inner diameter of the capillary tube 2 is less than or equal to 0.2 mm, and it can be made of materials such as polyetheretherketone (PEEK) or perfluoroethylene propylene, and the selected material must be non-wetting to the propellant. The solenoid valve flange 1 and the thruster housing 9 are connected by an insulating post 8. When the solenoid valve is closed, the propellant remaining inside the capillary tube 2 precipitates bubbles under vacuum conditions, ensuring the insulation of both ends of the capillary tube 2. When the solenoid valve is open, the capillary tube 2 acts as a throttling device, the pressure of the propellant decreases after passing through, and a mist cone is formed at the outlet of the capillary tube 2 (i.e., in the cavity between the emitter 4 and the thruster housing 9).

[0041] An emitter 4 is installed inside the thruster housing 9. The emitter 4 has a grooved structure machined on the side facing the capillary tube 2 to reduce propellant splashing. The cross-sectional dimension of the grooved structure is larger than the outer envelope of the propellant mist cone. The emitter 4 and the thruster housing 9 are connected and fixed together. A cavity structure is formed between the grooved structure of the emitter 4 and the thruster housing 9. Figure 3 As shown, the extraction electrode 7 is fixedly installed on the upper end face of the thruster housing 9, and the extraction electrode 7 is usually made of a thin metal sheet.

[0042] The emitter 4 can be made of sintered aluminum oxide particles, metal particles, silicate particles, etc., or microchannels can be formed on a dense material through micromachining, or a structure with microchannels can be directly formed through additive manufacturing. The material of the emitter 4 can transport the propellant on the inner surface of the cavity structure to the extractor 7 side through capillary action. The emitter 4 can be machined as a single piece or assembled from multiple materials.

[0043] The inner wall of the thruster housing 9, facing side 4, is provided with a non-wetting coating 3. This non-wetting coating 3 can be a hydrophobic and oleophobic nano-coating, which reduces propellant residue on the inner surface of the thruster housing 9 and further increases insulation. Vent holes 5 are provided on the side wall of the thruster housing 9 to balance the internal and external pressures of the thruster. The diameter of the vent holes 5 ranges from 0.5 mm to 2 mm.

[0044] The structure for ionic liquid emission is similar to conventional designs. The outer surface of the emitter 4 facing the extractor 7 has a raised structure. The extractor 7 has corresponding cutouts at the positions of the raised structures on the emitter 4 surface, allowing the ionic liquid to be emitted outwards. The raised structure can be an array of teeth, prismatic protrusions, or columnar protrusions, with a height of approximately 200–500 micrometers. One embodiment of the invention is as follows: Figure 4 As shown, the cross-section is triangular, with a base width of approximately 100 to 300 micrometers and a pointed apex. Figure 6 As shown, the included angle between the vertex of the protruding structure cross-section and the two sides of the hollowed-out area of ​​the extraction electrode 7 is not less than 40°. The hollowed-out area of ​​the extraction electrode 7 in one embodiment of the present invention is as follows: Figure 5 As shown.

[0045] An emitter electrode 6 is disposed on the outer wall of emitter 4, and the two are in close contact. A high voltage of approximately 1000–5000V passes through the emitter electrode 6 and emitter 4. The contact area between emitter electrode 6 and emitter 4 should be maximized to ensure conductivity. The ground wire is directly connected to the extraction electrode 7.

[0046] Before initial operation, this invention does not store propellant inside the thruster, thus avoiding oxidation of the surface propellant due to long-term storage and propellant leakage caused by vibration during launch. During initial operation, the solenoid valve opens with a short pulse, allowing propellant to enter the capillary tube 2 through the solenoid valve flange 1. At the end of the capillary tube 2, propellant is atomized to form a propellant mist cone, reaching the recessed area of ​​the emitter electrode 4. Subsequently, the emitter electrode 4 rapidly absorbs the propellant and transports it to the outer surface via capillary action, wetting the outer surface of the protruding structure of the emitter electrode 4. At this point, the device is energized, providing operating voltage to the emitter electrode 6 of the thruster, initiating operation and generating thrust through electrospray launch.

[0047] The high-voltage power supply is connected to the emitter electrode 6, and the ground wire is connected to the extraction electrode 7. The thruster's power supply provides high-voltage power to the thruster and can measure the current in the circuit (between the emitter electrode 6 and the extraction electrode 7). When the propellant inside the emitter 4 is low, the thruster's operating current decreases, and the solenoid valve is opened again in a pulse to replenish the thruster with propellant.

[0048] To meet insulation requirements, insulating pillars 8 and the thruster housing 9 are constructed using insulating materials, while capillary tubes 2 are made of insulating non-wetting materials. At this point, the ionic liquid propellant itself is the only conductive material between the electrode 6 and the solenoid valve. Because a vent 5 is provided on the thruster housing 9, the interior of the thruster is a vacuum environment. Under normal conditions, a certain amount of propellant will remain inside the capillary tube 2. In the vacuum environment, small amounts of dissolved N2, H2O, and other components in the propellant will precipitate and form bubbles, creating multiple cavities within the capillary tube 2, or even eliminating all the propellant to achieve an insulating effect. The length of the capillary tube 2 should be no less than 5 cm, and its outer diameter no greater than 2 mm. A non-wetting coating 3 or special materials are used to ensure the non-wetting characteristics of the cavity structure, reducing propellant residue in the cavities. These multiple measures ensure the insulation of the device.

[0049] Example

[0050] This invention discloses an ionic liquid electrospray thruster suitable for high-pressure storage and supply modules, comprising a docking structure and an electrospray launching device. The docking structure is directly connected to a solenoid valve of the propellant storage and supply system. When the solenoid valve is open, propellant flows through the docking device into the electrospray launching device, thus loading the thruster and meeting the operating conditions. When the electrodes are energized, the propellant is launched, generating thrust.

[0051] The docking structure includes: a solenoid valve docking flange 1, a capillary tube 2, and an insulating column 8. The electrospray emission device includes: an emitter 4, an emitter electrode 6, an extraction electrode 7, and a thruster housing 9. The emitter 4 can be made of porous ceramic material or material with micro-liquid channels, which can transport the ionic liquid propellant inside the thruster to its surface through capillary action. The surface of the emitter 4 usually has an array of protrusions, which emit the ionic liquid propellant under electric field conditions. The extraction electrode 7 is placed above the surface of the emitter 4, and the extraction electrode 7 has hollowed-out sections at the corresponding positions of the protrusions on the surface of the emitter 4, allowing the ionic liquid to be emitted to the outside.

[0052] The thruster uses a pulsed propellant supply, rather than a continuous supply. When the solenoid valve is open, the propellant, under pressure, enters the electrospray launcher through capillary tube 2, forming a mist cone at the outlet of capillary tube 2. This mist cone reaches the inner surface of the emitter 4 and is then slowly transported to its outer surface via capillary action. When the solenoid valve is closed, air bubbles precipitate from the propellant inside capillary tube 2, causing the liquid circuit to disconnect and ensuring insulation between the thruster and flange 1. The timing of the solenoid valve opening is determined by feedback from the power supply.

[0053] The inner side of the emitter 4 of the electrospray launcher has a groove to reduce propellant splashing onto the thruster housing 9. Simultaneously, the inner surface of the thruster housing 9 has a non-wetting coating 3 to reduce propellant adhesion and increase insulation. The thruster housing 9 has vents 5 to balance internal and external pressure.

[0054] While the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the invention. Any person skilled in the art can make possible variations and modifications to the technical solutions of the present invention using the disclosed methods and techniques without departing from the spirit and scope of the invention. Therefore, any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention, without departing from the content of the technical solutions of the present invention, shall fall within the protection scope of the present invention. Where there is no conflict, the embodiments of this application and the technical features thereof can be combined with each other.

[0055] The contents not described in detail in this specification are common knowledge to those skilled in the art.

Claims

1. An ion liquid electrospray thruster suitable for high-pressure storage and supply modules, characterized in that, include: The solenoid valve includes a connecting flange (1), a capillary tube (2), an emitter (4), an emitter electrode (6), an extraction electrode (7), an insulating column (8), and a thruster housing (9). One end of the thruster housing (9) is open, and an emitter (4) is installed inside to form a cavity structure; the other end of the thruster housing (9) is fixedly connected to the solenoid valve docking flange (1) through an insulating column (8), and the solenoid valve docking flange (1) is connected to the solenoid valve. One end of the capillary tube (2) is connected to the through hole on the other end of the thruster housing (9) for injecting propellant into the cavity structure to form a mist cone; the other end of the capillary tube (2) is connected to the solenoid valve to receive externally supplied propellant. When the solenoid valve is closed, the propellant remaining inside the capillary tube (2) precipitates bubbles under vacuum conditions. The bubbles are used to divide the propellant inside the capillary tube (2) into multiple cavities, which serve as insulation. A extraction electrode (7) is fixedly installed on one end face of the thruster housing (9). The extraction electrode (7) is grounded and does not contact the emitter electrode (4). An emitter electrode (6) is fixedly connected to the emitter (4); a vent hole (5) is machined on the thruster housing (9); the vent hole (5) connects the cavity structure and the external environment of the thruster housing (9); The inner diameter of the capillary tube (2) is less than or equal to 0.2 mm, and the capillary tube (2) is made of polyetheretherketone or polytetrafluoroethylene. The emitter (4) has a groove structure on the side facing the capillary (2), and the cross-sectional size of the groove structure is larger than the outer envelope of the propellant mist cone; a cavity structure is formed between the groove structure of the emitter (4) and the thruster shell (9); The material of the emitter (4) can transport the propellant on the inner surface of the cavity structure to the extractor (7) side through capillary action; The emitter (4) is sintered from aluminum oxide particles, metal particles or silicate particles, or formed into microchannels on a dense material through micromachining, or formed directly into a structure with microchannels through additive manufacturing.

2. The ion liquid electrospray thruster suitable for high-pressure storage and supply modules according to claim 1, characterized in that, The insulating column (8) and the thruster housing (9) are both made of insulating material; the extraction electrode (7) is a thin metal sheet.

3. An ion liquid electrospray thruster suitable for high-pressure storage and supply modules according to claim 1, characterized in that, The diameter of the vent (5) ranges from 0.5 mm to 2 mm.

4. An ion liquid electrospray thruster suitable for high-pressure storage and supply modules according to claim 1, characterized in that, The inner wall of the thruster housing (9) facing the emitter (4) is provided with a non-wetting coating (3), which is a hydrophobic and oleophobic nano-coating.

5. An ion liquid electrospray thruster suitable for high-pressure storage and supply modules according to any one of claims 1-4, characterized in that, The outer surface of the emitter (4) facing the extraction electrode (7) has a raised structure. The extraction electrode (7) is hollowed out at the corresponding position of the raised structure on the surface of the emitter (4) so ​​that the ionic liquid can be emitted to the outside. The protruding structure is an array of teeth, prismatic protrusions, or columnar protrusions.

6. An ion liquid electrospray thruster suitable for high-pressure storage and supply modules according to claim 5, characterized in that, The top of the protruding structure section is processed into a sharp corner, and the angle between the tip of the sharp corner and the two sides of the hollow area of ​​the extraction pole (7) is not less than 40°.

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