阅读说明：本技术 一种高可靠性电推进用空心阴极结构 (High-reliability hollow cathode structure for electric propulsion ) 是由 郝广辉 邵文生 张珂 于志强 于 2020-12-11 设计创作，主要内容包括：本发明实施例公开了一种高可靠性电推进用空心阴极结构,所述空心阴极结构包括：具有出射孔的触持极；沿触持极上出射孔的轴线依次设置的导气管、发射体以及顶孔板；所述导气管的外壁上包括有热子；所述阴极结构还包括有用以增强发射体表面的电场强度的内电极；所述内电极穿过所述导气管插设在所述发射体的内腔中。本发明所提供的空心阴极结构可有效降低发射体的点火时间,提高电推进设备启动时间的可控性,本发明还可以短时间内清除发射体表面变质的物质,使发射体性能迅速恢复,保障空心阴极点火时间的一致性以及电推进设备的可控性。(The embodiment of the invention discloses a high-reliability hollow cathode structure for electric propulsion, which comprises: a touch support pole having an exit aperture; the gas guide tube, the emitter and the top hole plate are sequentially arranged along the axis of the emergent hole on the touch holder; the outer wall of the air duct comprises a heater; the cathode structure also comprises an inner electrode used for enhancing the electric field intensity of the surface of the emitter; the inner electrode penetrates through the air duct and is inserted into the inner cavity of the emitter. The hollow cathode structure provided by the invention can effectively reduce the ignition time of the emitter and improve the controllability of the starting time of the electric propulsion equipment, and can also remove substances deteriorated on the surface of the emitter in a short time, so that the performance of the emitter is quickly recovered, and the consistency of the ignition time of the hollow cathode and the controllability of the electric propulsion equipment are ensured.)

1. A high reliability hollow cathode structure for electric propulsion, the structure comprising:

a touch support pole having an exit aperture;

the gas guide tube, the emitter and the top hole plate are sequentially arranged along the axis of the emergent hole on the touch holder;

the outer wall of the air duct comprises a heater;

the cathode structure also comprises an inner electrode used for enhancing the electric field intensity of the surface of the emitter;

the inner electrode penetrates through the air duct and is inserted into the inner cavity of the emitter.

2. The hollow cathode structure for electric propulsion according to claim 1, characterized in that the emitter is closely attached to the top orifice plate, and the emitter and the top orifice plate may be of an integral structure.

3. The hollow cathode structure for electric propulsion according to claim 1, characterized in that the top aperture plate comprises a coaxially arranged gas outlet hole corresponding to the exit hole;

the diameter of the air outlet hole is smaller than that of the emergent hole.

4. The hollow cathode structure for electric propulsion according to claim 1, characterized in that the outer diameter of the emitter is smaller than the inner diameter of the air duct, and the emitter is located on the right side inside the air duct.

5. An electrically propelled hollow cathode structure according to claim 4, wherein said thermionic structure is a helix, said thermionic structure being positioned to correspond to the position of said emitter.

6. The hollow cathode structure for electric propulsion according to claim 1, characterized in that the material of the inner electrode is a high melting point metal.

7. The hollow cathode structure for electric propulsion according to claim 1, characterized in that it comprises a heat shield cylinder between the thermions and the sustain electrode, said heat shield cylinder being configured to reduce the heat losses of the emitter.

Technical Field

The present invention relates to the field of plasma physics and thermophysics. And more particularly, to a hollow cathode structure for high reliability electric propulsion.

Background

Electric propulsion is used as an advanced space propulsion technology, has been widely applied to spacecrafts such as America and Russia due to the advantage of high specific impulse, can reduce the system quality, prolong the service life, increase the load and improve the control precision of the orbit and the attitude. The traditional hollow cathode structure mainly comprises an emitter, a top hole plate, a heater, a touch electrode and an air duct, wherein the touch electrode inner cavity, the air duct inner cavity, the emitter inner cavity and three inner cavities are communicated and coaxially communicated with an emergent hole on the touch electrode, and the emitter is responsible for ignition of the electric propulsion system, supplement of electrons in a discharge channel in the working process and neutralization of a plume region. The hollow cathode which works efficiently and reliably is the basis for stable discharge of the electric propulsion system. The existing electric propulsion system uses more emitter materials such as oxide cathode, barium-tungsten cathode and lanthanum hexaboride cathode, and the long-term exposure of the emitter to the atmosphere can cause the deterioration of active substances on the surface of the emitter, lead to the poisoning of the emitter, reduce the electron emission performance of the emitter, greatly prolong the ignition time of the hollow cathode and lead to the uncontrollable starting time of the electric propulsion device.

Disclosure of Invention

In order to solve the above problems, an object of the present invention is to provide a hollow cathode structure for electric propulsion with high reliability, so as to solve the problem of uncontrollable starting time of the electric propulsion device in the prior art.

In order to achieve the purpose, the invention adopts the following technical scheme:

a high reliability hollow cathode structure for electric propulsion, comprising:

a touch support pole having an exit aperture;

the gas guide tube, the emitter and the top hole plate are sequentially arranged along the axis of the emergent hole on the touch holder;

the outer wall of the air duct comprises a heater;

the cathode structure also comprises an inner electrode used for enhancing the electric field intensity of the surface of the emitter;

the inner electrode penetrates through the air duct and is inserted into the inner cavity of the emitter.

In addition, preferably, the emitter is closely attached to the top hole plate, and the emitter and the top hole plate may be of an integral structure.

In addition, preferably, the top hole plate comprises an air outlet hole which corresponds to the exit hole and is coaxially arranged;

the diameter of the air outlet hole is smaller than that of the emergent hole.

In addition, it is preferable that the outer diameter of the emitting body is smaller than the inner diameter of the airway tube, and the emitting body is located at the right side inside the airway tube.

In addition, it is preferable that the thermionic reactor has a spiral structure, and the thermionic reactor is located at a position corresponding to the position of the emitter.

In addition, it is preferable that the material of the internal electrode is a high melting point metal.

Furthermore, it is preferable that the structure includes a heat shield cylinder located between the thermionic electrons and the sustain electrode, the heat shield cylinder being configured to reduce heat loss from the emitter.

The beneficial effect of this application is as follows:

to the technical problem that exists among the prior art, the embodiment of this application provides a hollow cathode structure for high reliability electric propulsion to the problem of the surface active material that produces is rotten because of the emitter exposes for a long time in the atmosphere among the prior art, emitter poisoning and then influence emission performance is solved, and the hollow cathode ignition time extension that arouses from this, the uncontrollable problem of electric propulsion equipment start-up time. According to the invention, on the basis of the traditional hollow cathode component, the inner electrode is arranged in the air guide tube, so that the electric field intensity on the surface of the emitter can be effectively improved, the emission of electrons by the emitter is accelerated, the ignition time of the emitter is effectively reduced, the consistency of the ignition time is improved, and the controllability of the starting time of the electric propulsion equipment is improved.

In addition, the invention also adds the function of cleaning the surface of the hollow cathode by glow discharge plasma, can remove the deteriorated substances on the surface of the emitter in a short time, quickly recover the performance of the emitter, and ensure the consistency of the ignition time of the hollow cathode and the controllability of electric propulsion equipment.

Drawings

The following describes embodiments of the present invention in further detail with reference to the accompanying drawings.

Fig. 1 shows a schematic structural diagram of a hollow cathode structure provided by the present invention.

Detailed Description

In order to more clearly illustrate the invention, the invention is further described below with reference to preferred embodiments and the accompanying drawings. Similar parts in the figures are denoted by the same reference numerals. It is to be understood by persons skilled in the art that the following detailed description is illustrative and not restrictive, and is not to be taken as limiting the scope of the invention.

In the description of the present application, it should be noted that the terms "upper", "lower", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, which are only for convenience in describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed in a specific orientation, and operate, and thus, should not be construed as limiting the present application. Unless expressly stated or limited otherwise, the terms "mounted," "connected," and "connected" are intended to be inclusive and mean, for example, that they may be fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art as appropriate.

It is further noted that, in the description of the present application, relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.

Electric propulsion is used as an advanced space propulsion technology, has been widely applied to spacecrafts such as America and Russia due to the advantage of high specific impulse, can reduce the system quality, prolong the service life, increase the load and improve the control precision of the orbit and the attitude. The traditional hollow cathode structure mainly comprises an emitter, a top hole plate, a heater, a touch electrode and an air duct, wherein the touch electrode inner cavity, the air duct inner cavity, the emitter inner cavity and three inner cavities are communicated and coaxially communicated with an emergent hole on the touch electrode, and the emitter is responsible for ignition of the electric propulsion system, supplement of electrons in a discharge channel in the working process and neutralization of a plume region. The hollow cathode which works efficiently and reliably is the basis for stable discharge of the electric propulsion system. The existing electric propulsion system uses more emitter materials such as oxide cathode, barium-tungsten cathode and lanthanum hexaboride cathode, and the long-term exposure of the emitter to the atmosphere can cause the deterioration of active substances on the surface of the emitter, lead to the poisoning of the emitter, reduce the electron emission performance of the emitter, greatly prolong the ignition time of the hollow cathode and lead to the uncontrollable starting time of the electric propulsion device.

In order to overcome the defects in the prior art, an embodiment of the present invention provides a hollow cathode structure for high-reliability space electric propulsion, which is shown in fig. 1 and includes:

a touch pole 1 with an exit aperture 11;

the gas guide tube 2, the emitter 3 and the top orifice plate 4 are sequentially arranged along the axis of the emergent hole 11 on the touch pole 1;

the gas guide tube 2 is used for conveying working medium gas 10 to the inner cavity of the emitter 3, and in a specific example, the working medium gas 10 may be, but is not limited to, xenon or iodine vapor;

the outer wall of the air duct 2 comprises a heater 5;

the cathode structure further comprises an inner electrode 6 for enhancing the electric field intensity on the surface of the emitter 3;

the inner electrode 6 penetrates through the gas guide tube 2 and is inserted into the inner cavity of the emitter 3.

The emitter 3 and the top orifice plate 4 are closely attached, in a specific example, the emitter 3 and the top orifice plate 4 can be welded in a brazing or laser welding mode, and in order to avoid the influence of the sputtering corrosion of the plate surface ions of the top orifice plate 4 on the welding seam, the welding seam is placed on the side surface of the emitter during welding. In another embodiment, the emitter 3 and the top perforated plate 4 can also be machined as one piece. The top orifice plate 4 can be made of high-melting-point anti-sputtering metal such as tungsten, tantalum, molybdenum and the like.

In a specific example, the top orifice plate 4 is provided with an air outlet 41 which corresponds to and is coaxial with the exit hole 11, the diameter of the air outlet 41 is smaller than that of the exit hole 11, the working medium gas 10 is conveyed to the inner cavity of the emitter 3 through the air guide tube 2, and a pressure difference is formed between two ends of the air outlet 41 under the action of the air outlet 41, so that the working condition of the emitter 3 is met.

In a specific embodiment, the outer diameter of the emitter 3 is smaller than the inner diameter of the gas guide tube 2, the emitter 3 is arranged inside the gas guide tube 2 in a brazing or laser welding mode and is located at the right end of the gas guide tube 2, and the gas guide tube 2 is used for conveying working medium gas 10 to the inner cavity of the emitter 3 so as to provide conditions for the operation of the emitter 3.

In a specific example, the heater 5 is a spiral structure, is wound on the outer wall of the gas guide tube 2 at a position corresponding to the emitter 3, and is in a suspended and non-contact state with the gas guide tube 2, and the lead of the heater 5 is sleeved with an insulating tube, so that short circuit failure caused by contact between the heater 5 and other parts can be prevented. The heater 5 can be made of high-melting-point metal such as tungsten wires, and the heater 5 is used for heating the emitter 3 to reach the working temperature, so that a low-work-function surface is formed on the emitter 3, the required electron emission density is generated, and the hollow cathode can be reliably ignited at lower voltage.

In one embodiment, the material of the inner electrode 6 should be tungsten wire or other high melting point metal, and one end of the inner electrode 6 penetrates through the gas guide tube 2 and is inserted inside the emitter 3, so that the voltage on the inner electrode 6 can be directly applied to the surface of the emitter 3, the electric field strength on the surface of the emitter 3 can be enhanced, the emission of electrons by the emitter 3 can be accelerated, the ignition time of the emitter 3 can be effectively reduced, and the consistency of the ignition time and the controllability of the electric propulsion device can be improved; the other end of the inner electrode 6 is welded on an insulating base (not shown) and is insulated from other electrodes.

In a specific example, the hollow cathode structure further includes a heat shielding cylinder 7 located between the thermionic emitter 5 and the contact electrode 1, where the heat shielding cylinder 7 is mainly used to reduce heat lost in the form of heat radiation in the area of the emitter 3, so as to rapidly raise the temperature of the emitter 3, and to make the emitted thermionic current sufficiently large in a shorter time, so as to transition to glow discharge with low voltage and large current, thereby achieving rapid start and improving energy utilization rate, and the heat shielding cylinder 7 may be made of metals such as tantalum and molybdenum, and the number of layers is generally 3-4. It should be noted that the heat shield 7 is not an essential component of the hollow cathode structure, and the heat shield 7 is generally applied to a low-current hollow cathode structure, because the low-current hollow cathode structure is compact and has a higher requirement for heat for self-sustaining operation.

In a specific example, the function of the contact electrode 1 is to realize arc discharge ignition between the emitter 3 and the contact electrode 1 after applying ignition air pressure, and stable working current emission is performed under a proper working voltage, another important function of the contact electrode 1 is a protection function against sputtering corrosion of the top orifice plate 4, the gas outlet hole 41 and the thermions 5, and the contact electrode 1 is generally made of a metal material such as stainless steel or a material resistant to sputtering corrosion such as graphite.

In a specific example, when a certain amount of xenon is filled in the gas guide tube 2 as working medium gas 10 and the emitter 3 reaches normal working temperature under the heating action of the thermions 5, the voltage on the inner electrode 6 can be directly applied to the surface of the emitter 3 to accelerate the emitter 3 to emit electrons, and the electrons can ionize xenon atoms when colliding with the xenon atoms after acquiring enough energy. The xenon ions are accelerated to the surface of the emitter 3 under the action of the electric field, and finally collide with the surface of the emitter 3. As the ion concentration increases, the emitter 3 can transition from a non-self-sustaining discharge state to a self-sustaining discharge state, i.e., a glow discharge state. When a large amount of xenon ions collide with the surface of the emitter 3, the ion purification can be realized on the surface of the emitter 3, so that pollutants can be quickly separated and discharged through the air outlet 41 on the top orifice plate 4 along with the xenon, and the activity of the emitter 3 is promoted to be recovered within a few seconds. At this time, the voltage of the lead wire is closed, and when the voltage of the touch pole 1 is opened, the ignition can be completed instantly. Therefore, the hollow cathode with the structure can effectively guarantee the consistency of ignition time. In addition, the structure is also suitable for the emitter 3 which does not adsorb pollutants, can effectively reduce the ignition time of the emitter 3, and can effectively improve the consistency of the ignition time and the controllability of the electric propulsion equipment.

It should be understood that the above-mentioned embodiments of the present invention are only examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention, and it will be obvious to those skilled in the art that other variations or modifications may be made on the basis of the above description, and all embodiments may not be exhaustive, and all obvious variations or modifications may be included within the scope of the present invention.