Hall thruster with mixed structure

Abstract

The utility model provides a Hall thruster with a mixed structure, which is characterized by at least comprising a metal cavity, an anode, an outer ceramic ring, an inner ceramic ring and an air supply pipe, the metal cavity is an annular cavity with an opening in one end, the anode is an annular cavity with a U-shaped cross section, the anode is arranged in the metal cavity, and the outer edge of the opening end of the anode is fixedly connected with the opening end of the metal cavity; the outer side surface of the anode and the inner side surface of the metal cavity are arranged at an interval to form a primary buffer cavity, and the inner cavity of the anode is a metal discharge channel; the outer ceramic ring and the inner ceramic ring are concentrically arranged at the opening end of the anode to form a ceramic discharge channel communicated with the metal discharge channel; wherein the air supply pipe is communicated with the first-stage buffer cavity, and the first-stage buffer cavity is communicated with the metal discharge channel.

Description

TECHNICAL FIELD

[0001] The utility model relates to space propulsion technical field especially relates to a hall thruster of mixed structure. BACKGROUND

[0002] The hall thruster is widely applied in spacecraft position keeping, orbit transfer, attitude control and interstellar navigation and other tasks with the characteristics of simple structure, high efficiency and long service life. At present, the hall thrusters applied in electric propulsion systems mostly adopt krypton gas working medium, and if the thruster performance is to be improved, the gas ionization degree needs to be improved. However, due to the high ionization energy of krypton gas, the traditional thruster configuration cannot meet the ionization requirement. In addition, the ionization zone of krypton gas working medium is wider, and the ion focusing effect is poorer, and the channel wall surface is easily subjected to a large number of particle bombardment to cause heat deposition, which seriously reduces the performance of the thruster, and the traditional cylindrical discharge channel morphology has not adapted to the development requirement of krypton gas working medium thruster.

[0003] In order to comply with the development direction of high performance and high specific impulse of the hall thruster, and improve the performance index thereof under xenon and krypton working medium, it is necessary to newly design the thruster configuration. SUMMARY

[0004] To solve the above technical problems, the utility model provides a hall thruster of mixed structure, which can greatly improve the acceleration ability of the working medium (especially krypton working medium with high ionization energy), reduce the energy loss of particles in the discharge channel, and improve the specific impulse and performance of the thruster.

[0005] The utility model provides a hall thruster of mixed structure at least includes: metal chamber, anode, outer ceramic ring, inner ceramic ring and gas supply pipe, the metal chamber is the annular cavity of one end opening, the anode is the annular cavity of U type cross section, the anode is placed in the metal chamber, and the open end outer edge of the anode is fixedly connected with the open end of the metal chamber, the outer side of the anode and the inner side of the metal chamber are spaced apart to form a primary buffer chamber, and the inner chamber of the anode is a metal discharge channel, the outer ceramic ring and the inner ceramic ring are concentrically arranged at the open end of the anode and form a ceramic discharge channel in communication with the metal discharge channel, wherein the gas supply pipe is in communication with the primary buffer chamber, and the primary buffer chamber is in communication with the metal discharge channel.

[0006] In one embodiment, the ceramic discharge channel includes a front-stage channel and a rear-stage channel in turn in communication with the metal discharge channel, the diameter of the front-stage channel is less than the diameter of the metal discharge channel, and the diameter of the rear-stage channel is greater than the diameter of the front-stage channel.

[0007] In one embodiment, the inner wall of the outer ceramic ring and the outer wall of the inner ceramic ring are wedge-shaped expanded at the rear stage channel portion, so that the rear stage channel forms a tapered expansion structure.

[0008] In one embodiment, the anode is provided with two circles of gas outlet holes on the first side close to the opening thereof, and two circles of gas outlet holes on the second side away from the opening thereof; each circle of the gas outlet holes is uniformly distributed along the circumference of the anode; the primary buffer cavity is communicated with the metal discharge channel through the gas outlet holes.

[0009] In one embodiment, the diameter of the gas outlet holes on the second side is greater than that of the gas outlet holes on the first side.

[0010] In one embodiment, the metal chamber comprises an inner ring, an outer ring and a bottom ring connecting the inner ring and the outer ring, and the gas supply pipe is communicated with the primary buffer cavity through the bottom ring.

[0011] In one embodiment, the diameter of the front stage channel is 1-2 mm smaller than that of the metal discharge channel.

[0012] In one embodiment, the end face of the inner ceramic ring abutting against the opening end of the anode is provided with a first extension section abutting against the inner side face of the inner ring; and the end face of the outer ceramic ring abutting against the opening end of the anode is provided with a second extension section abutting against the outer side face of the outer ring.

[0013] In one embodiment, a radial gap is left between the first extension section and the inner ring; and a radial gap is left between the second extension section and the outer ring.

[0014] In one embodiment, the taper angle of the tapered expansion structure ranges from 40° to 50°.

[0015] The Hall thruster with the mixed structure has at least one of the following beneficial effects:

[0016] Firstly, the metal discharge cavity composed of the metal chamber and the anode can buffer the gas entering the channel, so as to reduce the flow rate of the incoming gas; the width of the metal discharge channel gradually increases along the outlet direction of the discharge channel, so as to further buffer the gas in the channel, further reduce the flow rate of the gas, prolong the residence time of the gas in the channel, improve the ionization rate of the working medium, and make the thruster have smaller discharge oscillation.

[0017] Secondly, the Hall thruster is provided with gas outlet holes near the outlet of the anode, so that a part of the gas working medium is injected near the outlet of the anode, the gas density near the ionization zone is increased, and the ionization rate of the working medium is further improved.

[0018] Third, the Hall thruster anode of the embodiment of the utility model is closer to the discharge channel outlet, which greatly shortens the ionization acceleration zone length. The magnetic field gradient is larger under the design configuration, the mirror effect is enhanced, the particle wall loss is reduced, and thus the thruster performance is significantly improved.

[0019] Fourth, the Hall thruster of the embodiment of the utility model is metal upstream of the discharge cavity and is ceramic downstream, the metal secondary electron emission coefficient is smaller than that of the traditional ceramic, the metal discharge channel wall sheath potential is lower than that of the traditional channel wall potential, the electron is more likely to return to the discharge cavity, the electron bombardment wall caused heat deposition is greatly reduced, the thruster is more suitable for working at high voltage, and thus the specific impulse of the thruster is improved.

[0020] Fifth, the contraction and expansion structure at the discharge channel outlet shortens the ionization zone expansion, improves the working medium pre-ionization rate, and thus the thruster has better acceleration effect. In addition, the expansion type appearance at the ceramic channel outlet can effectively reduce the recombination of the ionized working medium gas in the channel with the channel outlet wall during the acceleration process, reduce the ion and thrust loss, improve the wall over-temperature problem of the thruster, and improve the working stability.

[0021] After reading the specific embodiments and after viewing the drawings, those skilled in the art will realize additional features and advantages. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the utility model or the prior art, the drawings needed in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the utility model, and those skilled in the art can also obtain other drawings according to these drawings without creative labor.

[0023] Figure 1 is a structural schematic view of the Hall thruster of the embodiment of the utility model.

[0024] Figure 2 is a cross-sectional schematic view of the Hall thruster of the embodiment of the utility model.

[0025] Figure 3 is a structural schematic view of the ceramic and metal cooperation part of the embodiment of the utility model. DETAILED DESCRIPTION

[0026] The features and exemplary embodiments of each aspect of the present application will be described in detail below, in order to make the purpose, technical scheme and advantages of the present application more clear and understandable, the present application will be further described in detail below with reference to the drawings and specific embodiments. It should be understood that the specific embodiments described herein are only configured to explain the present application, for example, to illustrate the principles of the present application, and are not configured to limit the present application. In addition, the components in the drawings are not necessarily drawn to scale. For example, the size of some components in the drawings can be enlarged for other components or areas to help understand the embodiments of the present application.

[0027] The orientation words appearing in the following description are the directions shown in the drawings, and are not limited to the specific structure of the embodiments of the present application. In the description of the present application, it should be noted that, unless otherwise stated, the terms "mounting", "connection", "connection" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be directly connected, or indirectly connected through an intermediate medium. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0028] In addition, the terms "include", "contain", "have" or any other variant thereof are intended to cover non-exclusive inclusion, so that the inclusion of a series of element structures or components not only includes those elements, but also includes other elements not explicitly listed or inherent in the structure, component. Without more limitation, the elements defined by the sentence "include" do not exclude the presence of other identical elements in the article or device including the elements.

[0029] Spatial relationship terms such as "below", "under", "under", "low", "above", "on", "high" are used to make the description convenient to explain the position of one element relative to the second element, which is intended to cover different orientations of the device in addition to those shown in the drawings. In addition, for example, "one element is on / under another element" can mean that the two elements are in direct contact, or that there are other elements between the two elements. In addition, terms such as "first", "second" are also used to describe various elements, regions, parts, etc., and should not be considered as limiting. Similar terms are used throughout the description to represent similar elements.

[0030] For those skilled in the art, the present application can be implemented without some of these specific details. The following description of the embodiments is only to provide a better understanding of the present application by showing examples of the present application.

[0031] The anode of the traditional Hall thruster is far away from the discharge channel outlet, and the ion acceleration area is too long, which causes serious sputtering erosion and thermal deposition of ions on the wall, and reduces the thruster efficiency and specific impulse. Currently, the Hall thruster applied in the electric propulsion system uses krypton gas as the working gas. However, for the traditional thruster configuration, on the one hand, the voltage needs to be increased and the flow needs to be increased to improve the through-flow density, but the flow has a limited effect on the improvement of the through-flow density, and the electron temperature is higher at high voltage, the wall thermal deposition is serious, and the efficiency decreases sharply. On the other hand, the length of the discharge channel needs to be extended, but this will cause the acceleration area to move upstream of the anode, increase the sputtering loss of particles on the wall, and reduce the specific impulse and efficiency. Therefore, in order to solve the above technical problems, the thruster configuration needs to be newly designed.

[0032] Referring to Figure 1 and Figure 2 simultaneously, the utility model provides a kind of Hall thruster of mixed structure, at least including metal chamber 1, anode 2, outer ceramic ring 3, inner ceramic ring 4 and gas supply pipe 5.Metal chamber 1 is annular cavity with one end opening, and anode 2 is annular cavity with U-shaped cross section, and anode 2 is placed in metal chamber 1 and covers the opening of metal chamber 1, and the opening end outer edge of anode 2 is fixedly connected with the beginning end of metal chamber, to form primary buffer chamber A and metal discharge channel B (or called metal discharge cavity).Wherein, the outside of anode 2 and the inside of metal chamber 1 are spaced apart to form primary buffer chamber A, and the inner cavity of anode 2 is to the opening of anode 2 as metal discharge channel B.Outer ceramic ring 3 and inner ceramic ring 4 are concentrically arranged at the opening end of anode 2, and the inner ring surface of outer ceramic ring 3 and the outer ring surface of inner ceramic ring 4 form ceramic discharge channel C, and ceramic discharge channel C is communicated with metal discharge channel B through the opening of anode 2.Further, primary buffer chamber A is also communicated with metal discharge channel and gas supply pipe 5 respectively.

[0033] The Hall thruster of the embodiment provides gas working substance through gas supply pipe 5, and the gas working substance first enters primary buffer chamber A for buffering and flow equalization, then enters metal discharge channel B for secondary buffering and flow equalization, and then flows out through ceramic discharge channel C. Figure 2 The arrow marks the flow path of the gas working substance.

[0034] Referring to Figure 2 and Figure 3In order to improve the ionization efficiency of the gas working substance, the discharge channel (including the metal discharge channel and the ceramic discharge channel) can be arranged in an expansion-constriction-expansion structure. For example, the ceramic discharge channel C includes a front-stage channel 31 and a rear-stage channel 32 which are sequentially communicated with the metal discharge channel. The front-stage channel 31 is in a constricted structure, and the rear-stage channel 32 is in a tapered expansion structure. The diameter of the front-stage channel 31 is smaller than that of the metal discharge channel B, and the diameter of the rear-stage channel 32 is larger than that of the front-stage channel 31. Thus, the flow rate of the gas working substance flowing out of the metal discharge channel B is reduced, and the gas working substance flows out after being constricted and expanded in the ceramic discharge channel C. This flow mode improves the ionization degree of the gas, reduces the low-frequency oscillation of the thruster, and increases the gas density near the ionization region.

[0035] Compared with the traditional Hall thruster with a full-ceramic discharge channel, the Hall thruster in the embodiment has a metal (metal discharge channel) upstream of the discharge region and a ceramic (ceramic discharge channel) downstream of the discharge region. The ionization region and the main acceleration region are arranged in the ceramic discharge channel, the length of the ionization and acceleration region is shortened, the anode is close to the inlet of the ceramic discharge channel, the magnetic field gradient is increased, the magnetic mirror effect is increased, the ionization collision is more sufficient, and the specific impulse and efficiency of the thruster are improved. Such an arrangement is conducive to improving the radial gradient of the axial magnetic field, improving the discharge stability of the thruster, and making the thruster more suitable for working under high specific impulse conditions.

[0036] Further, the diameter of the front-stage channel of the Hall thruster in the embodiment is 1 to 2 mm smaller than the diameter of the metal discharge channel. In this way, the ceramic discharge channel inlet is constricted, the through-flow density is increased, the ionization region is widened and shortened, which is conducive to the focusing and acceleration of the thruster plume. The diameter of the rear-stage channel is larger than that of the front-stage channel, which aims to reduce the thrust loss and ceramic temperature caused by the recombination of the ionized and accelerated ions at the channel wall, and to improve the working stability of the thruster. On the other hand, such a design does not significantly affect the density of the working gas in the channel and the plasma potential distribution, ensuring the ionization efficiency of the working gas and the axial acceleration efficiency of the ions.

[0037] For example, the inner wall of the outer ceramic ring and the outer wall of the inner ceramic ring are wedge-shaped expanded in the rear-stage channel part, so that the rear-stage channel forms a tapered expansion structure. The inclination angle of the tapered expansion structure can be 40° to 50°. Specifically, the outlet of the outer wall of the inner ceramic ring and the inner wall of the outer ceramic ring can be provided with an outward expansion inclination angle, and the angle (the angle between the tangent plane and the axis of the rear-stage channel) of the outward expansion inclination angle ranges from 40° to 50°. In this structure, the magnetic field lines are approximately parallel to the ceramic surface, forming a magnetic shielding effect. At the same time, the anode 3 is closer to the outlet of the discharge channel, the ionization and acceleration region is narrower, the sputtering corrosion of the particles to the wall is reduced, which is more conducive to the ionization and acceleration of the thruster, improves the performance, and prolongs the service life of the thruster.

[0038] In the above embodiments, the metal chamber is an annular cavity with one open end, the outer ring of the metal chamber has the same diameter as the outer edge of the anode flange (the outer edge of the open end), and the inner ring of the metal chamber has the same diameter as the inner edge of the anode flange (the inner edge of the open end). After covering the open end of the anode with the metal chamber, the outer edge of the open end of the anode and the opening of the metal chamber are fixed by circumferential welding.

[0039] Referring to Figure 2 In one embodiment, the anode 2 is provided with two rows of gas outlet holes 21 on the first side close to the open end of the anode 2 and two rows of gas outlet holes 22 on the second side away from the open end of the anode 2. Each row of gas outlet holes is evenly distributed circumferentially along the anode 2, and the primary buffer cavity A is in communication with the metal discharge channel B through the gas outlet holes 21 and the gas outlet holes 22. Specifically, since the anode is an annular cavity with a U-shaped cross-section, the two rows of gas outlet holes provided on the first side close to the open end of the anode are arranged on the inner side wall and the outer side wall, respectively. Similarly, the two rows of gas outlet holes provided on the second side away from the open end of the anode are also arranged on the inner side wall and the outer side wall, respectively.

[0040] In the Hall thruster of the present embodiment, the gas outlet holes 22 on the second side are used as the main gas outlet holes, and most of the gas working substance in the primary buffer cavity enters the metal discharge channel through the gas outlet holes 22 on the second side, and a small part of the gas working substance enters the metal discharge channel through the gas outlet holes 21 on the first side, which can greatly improve the utilization rate of the gas working substance.

[0041] Further, as Figure 2 shown, the diameter of the gas outlet holes on the second side is greater than that of the gas outlet holes on the first side. For example, the diameter of the second row of gas outlet holes is 1.5 to 2 times the diameter of the first row of gas outlet holes. Alternatively, the distance from the center of the gas outlet holes on the second side to the outlet plane of the anode is 1.5 to 4 times the diameter of the gas outlet holes on the second side, and the diameter of the gas outlet holes on the second side is 1.5 to 3 times the diameter of the gas outlet holes on the first side.

[0042] Referring to Figure 2 In any of the above embodiments, the metal chamber 1 comprises an inner ring 11, an outer ring 12 concentrically arranged, and a bottom ring 13 connecting the inner ring 11 and the outer ring 12. The gas supply pipe 5 penetrates the bottom ring 13 and is in communication with the primary buffer cavity A, and the gas supply pipe 5 is inserted into the bottom ring 13 and fixed by circumferential welding. The gas supply pipe 5 is used to provide the Hall thruster of the present embodiment with a gas working substance. The inner ring 11, the outer ring 12 and the bottom ring 13 can be integrally formed.

[0043] In one embodiment, in order to facilitate positioning and installation of the inner ceramic ring, the outer ceramic ring and the anode, an extension section 41 can be arranged on the end face abutting the open end of the anode of the inner ceramic ring and the outer ceramic ring. Specifically, the end face abutting the open end of the anode of the inner ceramic ring is provided with a first extension section, and the first extension section abuts the inner side face of the inner ring. The end face abutting the open end of the anode of the outer ceramic ring is provided with a second extension section, and the second extension section abuts the outer side face of the outer ring.

[0044] Further, a radial gap is left between the first extension section and the inner ring, and a radial gap is left between the second extension section and the outer ring. In this way, the metal discharge cavity can be prevented from causing the inner ceramic ring and the outer ceramic ring to rupture due to radial expansion caused by heat.

[0045] The above embodiments can be combined with each other and have corresponding technical effects.

[0046] Compared with the conventional full-ceramic discharge channel structure, the metal discharge channel of the Hall thruster according to the present application helps to reduce the temperature of the anode, and a buffer cavity is formed between the metal cavity and the anode, thereby reducing plasma discharge oscillation and improving the stability of thruster discharge. In addition, the gas undergoes an expansion-constriction-expansion process in the discharge channel, thereby improving the gas ionization efficiency. The Hall thruster according to the present application reduces the distance between the anode and the channel outlet, increases the axial magnetic field gradient, enhances the magnetic mirror effect, and is more conducive to ion acceleration, thereby improving the specific impulse and comprehensive performance of the thruster.

[0047] The above merely describes the preferred embodiments of the present application and is not used to limit the present application, and any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A hybrid Hall thruster, characterized in that, At least comprising: a metal chamber, an anode, an outer ceramic ring, an inner ceramic ring and a gas supply pipe; the metal chamber is an annular cavity with one end open, the anode is an annular cavity with a U-shaped cross section, the anode is placed in the metal chamber, and the open end of the anode is fixedly connected with the open end of the metal chamber; the outer side of the anode and the inner side of the metal chamber are spaced apart to form a first buffer cavity, and the inner cavity of the anode is a metal discharge channel; The outer ceramic ring and the inner ceramic ring are concentrically arranged at the open end of the anode to form a ceramic discharge channel in communication with the metal discharge channel; Wherein, the gas supply pipe is in communication with the first buffer cavity, and the first buffer cavity is in communication with the metal discharge channel.

2. The Hall Thruster of claim 1, wherein, The ceramic discharge channel comprises a front-stage channel and a rear-stage channel in turn in communication with the metal discharge channel; the diameter of the front-stage channel is smaller than the diameter of the metal discharge channel, and the diameter of the rear-stage channel is larger than the diameter of the front-stage channel.

3. The Hall Thruster of claim 2, wherein, The inner wall of the outer ceramic ring and the outer wall of the inner ceramic ring are wedge-shaped expanded at the rear-stage channel part, so that the rear-stage channel forms a tapered expansion structure.

4. The Hall Thruster of claim 3, wherein, The anode oppositely sets two circles of gas outlet holes at a first side close to the opening thereof, and oppositely sets two circles of gas outlet holes at a second side away from the opening thereof; Each circle of the gas outlet holes is uniformly distributed along the circumference of the anode; the first buffer cavity is in communication with the metal discharge channel through the gas outlet holes.

5. The Hall Thruster of claim 4, wherein, The diameter of the gas outlet holes at the second side is larger than that at the first side.

6. The Hall Thruster of claim 1, wherein, The metal chamber comprises an inner ring, an outer ring and a bottom ring connecting the inner ring and the outer ring; the gas supply pipe penetrates through the bottom ring and is in communication with the first buffer cavity.

7. The Hall Thruster of claim 6, wherein, The end face of the inner ceramic ring abutting against the open end of the anode is provided with a first extension section, and the first extension section abuts against the inner side of the inner ring; the end face of the outer ceramic ring abutting against the open end of the anode is provided with a second extension section, and the second extension section abuts against the outer side of the outer ring.

8. The Hall Thruster of claim 7, wherein, A radial gap is left between the first extension section and the inner ring; a radial gap is left between the second extension section and the outer ring.

9. The Hall Thruster of claim 2, wherein, The channel diameter of the front-stage channel is 1 to 2 mm smaller than the diameter of the metal discharge channel.

10. The Hall Thruster of claim 3, wherein, The inclination angle of the tapered expansion structure ranges from 40° to 50°.

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